This file is indexed.

/usr/share/doc/feed2exec-doc/html/plugins.html is in feed2exec-doc 0.11.0.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

   1
   2
   3
   4
   5
   6
   7
   8
   9
  10
  11
  12
  13
  14
  15
  16
  17
  18
  19
  20
  21
  22
  23
  24
  25
  26
  27
  28
  29
  30
  31
  32
  33
  34
  35
  36
  37
  38
  39
  40
  41
  42
  43
  44
  45
  46
  47
  48
  49
  50
  51
  52
  53
  54
  55
  56
  57
  58
  59
  60
  61
  62
  63
  64
  65
  66
  67
  68
  69
  70
  71
  72
  73
  74
  75
  76
  77
  78
  79
  80
  81
  82
  83
  84
  85
  86
  87
  88
  89
  90
  91
  92
  93
  94
  95
  96
  97
  98
  99
 100
 101
 102
 103
 104
 105
 106
 107
 108
 109
 110
 111
 112
 113
 114
 115
 116
 117
 118
 119
 120
 121
 122
 123
 124
 125
 126
 127
 128
 129
 130
 131
 132
 133
 134
 135
 136
 137
 138
 139
 140
 141
 142
 143
 144
 145
 146
 147
 148
 149
 150
 151
 152
 153
 154
 155
 156
 157
 158
 159
 160
 161
 162
 163
 164
 165
 166
 167
 168
 169
 170
 171
 172
 173
 174
 175
 176
 177
 178
 179
 180
 181
 182
 183
 184
 185
 186
 187
 188
 189
 190
 191
 192
 193
 194
 195
 196
 197
 198
 199
 200
 201
 202
 203
 204
 205
 206
 207
 208
 209
 210
 211
 212
 213
 214
 215
 216
 217
 218
 219
 220
 221
 222
 223
 224
 225
 226
 227
 228
 229
 230
 231
 232
 233
 234
 235
 236
 237
 238
 239
 240
 241
 242
 243
 244
 245
 246
 247
 248
 249
 250
 251
 252
 253
 254
 255
 256
 257
 258
 259
 260
 261
 262
 263
 264
 265
 266
 267
 268
 269
 270
 271
 272
 273
 274
 275
 276
 277
 278
 279
 280
 281
 282
 283
 284
 285
 286
 287
 288
 289
 290
 291
 292
 293
 294
 295
 296
 297
 298
 299
 300
 301
 302
 303
 304
 305
 306
 307
 308
 309
 310
 311
 312
 313
 314
 315
 316
 317
 318
 319
 320
 321
 322
 323
 324
 325
 326
 327
 328
 329
 330
 331
 332
 333
 334
 335
 336
 337
 338
 339
 340
 341
 342
 343
 344
 345
 346
 347
 348
 349
 350
 351
 352
 353
 354
 355
 356
 357
 358
 359
 360
 361
 362
 363
 364
 365
 366
 367
 368
 369
 370
 371
 372
 373
 374
 375
 376
 377
 378
 379
 380
 381
 382
 383
 384
 385
 386
 387
 388
 389
 390
 391
 392
 393
 394
 395
 396
 397
 398
 399
 400
 401
 402
 403
 404
 405
 406
 407
 408
 409
 410
 411
 412
 413
 414
 415
 416
 417
 418
 419
 420
 421
 422
 423
 424
 425
 426
 427
 428
 429
 430
 431
 432
 433
 434
 435
 436
 437
 438
 439
 440
 441
 442
 443
 444
 445
 446
 447
 448
 449
 450
 451
 452
 453
 454
 455
 456
 457
 458
 459
 460
 461
 462
 463
 464
 465
 466
 467
 468
 469
 470
 471
 472
 473
 474
 475
 476
 477
 478
 479
 480
 481
 482
 483
 484
 485
 486
 487
 488
 489
 490
 491
 492
 493
 494
 495
 496
 497
 498
 499
 500
 501
 502
 503
 504
 505
 506
 507
 508
 509
 510
 511
 512
 513
 514
 515
 516
 517
 518
 519
 520
 521
 522
 523
 524
 525
 526
 527
 528
 529
 530
 531
 532
 533
 534
 535
 536
 537
 538
 539
 540
 541
 542
 543
 544
 545
 546
 547
 548
 549
 550
 551
 552
 553
 554
 555
 556
 557
 558
 559
 560
 561
 562
 563
 564
 565
 566
 567
 568
 569
 570
 571
 572
 573
 574
 575
 576
 577
 578
 579
 580
 581
 582
 583
 584
 585
 586
 587
 588
 589
 590
 591
 592
 593
 594
 595
 596
 597
 598
 599
 600
 601
 602
 603
 604
 605
 606
 607
 608
 609
 610
 611
 612
 613
 614
 615
 616
 617
 618
 619
 620
 621
 622
 623
 624
 625
 626
 627
 628
 629
 630
 631
 632
 633
 634
 635
 636
 637
 638
 639
 640
 641
 642
 643
 644
 645
 646
 647
 648
 649
 650
 651
 652
 653
 654
 655
 656
 657
 658
 659
 660
 661
 662
 663
 664
 665
 666
 667
 668
 669
 670
 671
 672
 673
 674
 675
 676
 677
 678
 679
 680
 681
 682
 683
 684
 685
 686
 687
 688
 689
 690
 691
 692
 693
 694
 695
 696
 697
 698
 699
 700
 701
 702
 703
 704
 705
 706
 707
 708
 709
 710
 711
 712
 713
 714
 715
 716
 717
 718
 719
 720
 721
 722
 723
 724
 725
 726
 727
 728
 729
 730
 731
 732
 733
 734
 735
 736
 737
 738
 739
 740
 741
 742
 743
 744
 745
 746
 747
 748
 749
 750
 751
 752
 753
 754
 755
 756
 757
 758
 759
 760
 761
 762
 763
 764
 765
 766
 767
 768
 769
 770
 771
 772
 773
 774
 775
 776
 777
 778
 779
 780
 781
 782
 783
 784
 785
 786
 787
 788
 789
 790
 791
 792
 793
 794
 795
 796
 797
 798
 799
 800
 801
 802
 803
 804
 805
 806
 807
 808
 809
 810
 811
 812
 813
 814
 815
 816
 817
 818
 819
 820
 821
 822
 823
 824
 825
 826
 827
 828
 829
 830
 831
 832
 833
 834
 835
 836
 837
 838
 839
 840
 841
 842
 843
 844
 845
 846
 847
 848
 849
 850
 851
 852
 853
 854
 855
 856
 857
 858
 859
 860
 861
 862
 863
 864
 865
 866
 867
 868
 869
 870
 871
 872
 873
 874
 875
 876
 877
 878
 879
 880
 881
 882
 883
 884
 885
 886
 887
 888
 889
 890
 891
 892
 893
 894
 895
 896
 897
 898
 899
 900
 901
 902
 903
 904
 905
 906
 907
 908
 909
 910
 911
 912
 913
 914
 915
 916
 917
 918
 919
 920
 921
 922
 923
 924
 925
 926
 927
 928
 929
 930
 931
 932
 933
 934
 935
 936
 937
 938
 939
 940
 941
 942
 943
 944
 945
 946
 947
 948
 949
 950
 951
 952
 953
 954
 955
 956
 957
 958
 959
 960
 961
 962
 963
 964
 965
 966
 967
 968
 969
 970
 971
 972
 973
 974
 975
 976
 977
 978
 979
 980
 981
 982
 983
 984
 985
 986
 987
 988
 989
 990
 991
 992
 993
 994
 995
 996
 997
 998
 999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
<!DOCTYPE html>
<!--[if IE 8]><html class="no-js lt-ie9" lang="en" > <![endif]-->
<!--[if gt IE 8]><!--> <html class="no-js" lang="en" > <!--<![endif]-->
<head>
  <meta charset="utf-8">
  
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  
  <title>Plugins &mdash; feed2exec 0.11.0 documentation</title>
  

  
  
  
  

  

  
  
    

  

  
  
    <link rel="stylesheet" href="_static/css/theme.css" type="text/css" />
  

  

  
        <link rel="index" title="Index"
              href="genindex.html"/>
        <link rel="search" title="Search" href="search.html"/>
    <link rel="top" title="feed2exec 0.11.0 documentation" href="index.html"/>
        <link rel="next" title="Support" href="support.html"/>
        <link rel="prev" title="API documentation" href="api.html"/> 

  
  <script src="_static/js/modernizr.min.js"></script>

</head>

<body class="wy-body-for-nav" role="document">

   
  <div class="wy-grid-for-nav">

    
    <nav data-toggle="wy-nav-shift" class="wy-nav-side">
      <div class="wy-side-scroll">
        <div class="wy-side-nav-search">
          

          
            <a href="index.html" class="icon icon-home"> feed2exec
          

          
          </a>

          
            
            
              <div class="version">
                0.11.0
              </div>
            
          

          
<div role="search">
  <form id="rtd-search-form" class="wy-form" action="search.html" method="get">
    <input type="text" name="q" placeholder="Search docs" />
    <input type="hidden" name="check_keywords" value="yes" />
    <input type="hidden" name="area" value="default" />
  </form>
</div>

          
        </div>

        <div class="wy-menu wy-menu-vertical" data-spy="affix" role="navigation" aria-label="main navigation">
          
            
            
              
            
            
              <ul class="current">
<li class="toctree-l1"><a class="reference internal" href="usage.html">Usage</a></li>
<li class="toctree-l1"><a class="reference internal" href="design.html">Design</a></li>
<li class="toctree-l1"><a class="reference internal" href="api.html">API documentation</a></li>
<li class="toctree-l1 current"><a class="current reference internal" href="#">Plugins</a><ul>
<li class="toctree-l2"><a class="reference internal" href="#output-plugins">Output plugins</a><ul>
<li class="toctree-l3"><a class="reference internal" href="#module-feed2exec.plugins.archive">Archive</a></li>
<li class="toctree-l3"><a class="reference internal" href="#module-feed2exec.plugins.echo">Echo</a></li>
<li class="toctree-l3"><a class="reference internal" href="#module-feed2exec.plugins.error">Error</a></li>
<li class="toctree-l3"><a class="reference internal" href="#module-feed2exec.plugins.exec">Exec</a></li>
<li class="toctree-l3"><a class="reference internal" href="#module-feed2exec.plugins.maildir">Maildir</a></li>
<li class="toctree-l3"><a class="reference internal" href="#module-feed2exec.plugins.mbox">Mbox</a></li>
<li class="toctree-l3"><a class="reference internal" href="#module-feed2exec.plugins.null">Null</a></li>
<li class="toctree-l3"><a class="reference internal" href="#module-feed2exec.plugins.transmission">Transmission</a></li>
<li class="toctree-l3"><a class="reference internal" href="#module-feed2exec.plugins.wayback">Wayback</a></li>
</ul>
</li>
<li class="toctree-l2"><a class="reference internal" href="#filter-plugins">Filter plugins</a><ul>
<li class="toctree-l3"><a class="reference internal" href="#module-feed2exec.plugins.droptitle">Droptitle</a></li>
<li class="toctree-l3"><a class="reference internal" href="#module-feed2exec.plugins.emptysummary">Emptysummary</a></li>
<li class="toctree-l3"><a class="reference internal" href="#module-feed2exec.plugins.html2text">Html2text</a></li>
<li class="toctree-l3"><a class="reference internal" href="#module-feed2exec.plugins.ikiwiki_recentchanges">Ikiwiki Recentchanges</a></li>
</ul>
</li>
<li class="toctree-l2"><a class="reference internal" href="#writing-new-plugins">Writing new plugins</a><ul>
<li class="toctree-l3"><a class="reference internal" href="#basic-plugin-principles">Basic plugin principles</a></li>
<li class="toctree-l3"><a class="reference internal" href="#filters">Filters</a></li>
<li class="toctree-l3"><a class="reference internal" href="#id2">Output plugins</a><ul>
<li class="toctree-l4"><a class="reference internal" href="#basic-arguments">Basic arguments</a></li>
<li class="toctree-l4"><a class="reference internal" href="#sanitizing-contents">Sanitizing contents</a></li>
<li class="toctree-l4"><a class="reference internal" href="#user-configuration">User configuration</a></li>
<li class="toctree-l4"><a class="reference internal" href="#making-http-requests">Making HTTP requests</a></li>
<li class="toctree-l4"><a class="reference internal" href="#plugin-return-values">Plugin return values</a></li>
<li class="toctree-l4"><a class="reference internal" href="#catchup">Catchup</a></li>
</ul>
</li>
<li class="toctree-l3"><a class="reference internal" href="#writing-tests">Writing tests</a></li>
</ul>
</li>
<li class="toctree-l2"><a class="reference internal" href="#see-also">See also</a></li>
</ul>
</li>
<li class="toctree-l1"><a class="reference internal" href="support.html">Support</a></li>
<li class="toctree-l1"><a class="reference internal" href="contribute.html">Contribute</a></li>
<li class="toctree-l1"><a class="reference internal" href="code.html">Code of Conduct</a></li>
<li class="toctree-l1"><a class="reference internal" href="changelog.html">Changelog</a></li>
<li class="toctree-l1"><a class="reference internal" href="license.html">License</a></li>
<li class="toctree-l1"><a class="reference internal" href="contact.html">Contact</a></li>
</ul>

            
          
        </div>
      </div>
    </nav>

    <section data-toggle="wy-nav-shift" class="wy-nav-content-wrap">

      
      <nav class="wy-nav-top" role="navigation" aria-label="top navigation">
        
          <i data-toggle="wy-nav-top" class="fa fa-bars"></i>
          <a href="index.html">feed2exec</a>
        
      </nav>


      
      <div class="wy-nav-content">
        <div class="rst-content">
          















<div role="navigation" aria-label="breadcrumbs navigation">

  <ul class="wy-breadcrumbs">
    
      <li><a href="index.html">Docs</a> &raquo;</li>
        
      <li>Plugins</li>
    
    
      <li class="wy-breadcrumbs-aside">
        
            
            <a href="https://gitlab.com/anarcat/feed2exec/blob/HEAD/doc/plugins.rst">View page source</a>
          
        
      </li>
    
  </ul>

  
  <hr/>
</div>
          <div role="main" class="document" itemscope="itemscope" itemtype="http://schema.org/Article">
           <div itemprop="articleBody">
            
  <div class="section" id="plugins">
<h1>Plugins<a class="headerlink" href="#plugins" title="Permalink to this headline"></a></h1>
<p>This is a quick overview of the available plugins.</p>
<div class="section" id="output-plugins">
<h2>Output plugins<a class="headerlink" href="#output-plugins" title="Permalink to this headline"></a></h2>
<div class="section" id="module-feed2exec.plugins.archive">
<span id="archive"></span><h3>Archive<a class="headerlink" href="#module-feed2exec.plugins.archive" title="Permalink to this headline"></a></h3>
<dl class="data">
<dt id="feed2exec.plugins.archive.DEFAULT_ARCHIVE_DIR">
<code class="descclassname">feed2exec.plugins.archive.</code><code class="descname">DEFAULT_ARCHIVE_DIR</code><em class="property"> = '/run/user/1000/'</em><a class="headerlink" href="#feed2exec.plugins.archive.DEFAULT_ARCHIVE_DIR" title="Permalink to this definition"></a></dt>
<dd><p>default archive directory</p>
</dd></dl>

<dl class="function">
<dt id="feed2exec.plugins.archive.output">
<code class="descclassname">feed2exec.plugins.archive.</code><code class="descname">output</code><span class="sig-paren">(</span><em>*args</em>, <em>feed=None</em>, <em>item=None</em>, <em>**kwargs</em><span class="sig-paren">)</span><a class="reference internal" href="_modules/feed2exec/plugins/archive.html#output"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#feed2exec.plugins.archive.output" title="Permalink to this definition"></a></dt>
<dd><p>The archive plugin saves the feed’s item.link URLs into a
directory, specified by DEFAULT_ARCHIVE_DIR or through the output
<cite>args</cite> value.</p>
<p>Example:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="p">[</span><span class="n">NASA</span> <span class="n">breaking</span> <span class="n">news</span><span class="p">]</span>
<span class="n">url</span> <span class="o">=</span> <span class="n">https</span><span class="p">:</span><span class="o">//</span><span class="n">www</span><span class="o">.</span><span class="n">nasa</span><span class="o">.</span><span class="n">gov</span><span class="o">/</span><span class="n">rss</span><span class="o">/</span><span class="n">dyn</span><span class="o">/</span><span class="n">breaking_news</span><span class="o">.</span><span class="n">rss</span>
<span class="n">output</span> <span class="o">=</span> <span class="n">archive</span>
<span class="n">args</span> <span class="o">=</span> <span class="o">/</span><span class="n">srv</span><span class="o">/</span><span class="n">archive</span><span class="o">/</span><span class="n">nasa</span><span class="o">/</span>
</pre></div>
</div>
<p>The above will save the “NASA breaking news” into the
<code class="docutils literal"><span class="pre">/srv/archive/nasa</span></code> directory. Do <em>not</em> use interpolation here
as the feed’s variable could be used to mount a directory
transversal attack.</p>
</dd></dl>

</div>
<div class="section" id="module-feed2exec.plugins.echo">
<span id="echo"></span><h3>Echo<a class="headerlink" href="#module-feed2exec.plugins.echo" title="Permalink to this headline"></a></h3>
<dl class="class">
<dt id="feed2exec.plugins.echo.output">
<em class="property">class </em><code class="descclassname">feed2exec.plugins.echo.</code><code class="descname">output</code><span class="sig-paren">(</span><em>*args</em>, <em>feed=None</em>, <em>**kwargs</em><span class="sig-paren">)</span><a class="reference internal" href="_modules/feed2exec/plugins/echo.html#output"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#feed2exec.plugins.echo.output" title="Permalink to this definition"></a></dt>
<dd><p>This plugin outputs, to standard output, the arguments it receives. It
can be useful to test your configuration. It also creates a side
effect for the test suite to determine if the plugin was called.</p>
<p>This plugin does a similar thing when acting as a filter.</p>
</dd></dl>

<dl class="attribute">
<dt id="feed2exec.plugins.echo.filter">
<code class="descclassname">feed2exec.plugins.echo.</code><code class="descname">filter</code><a class="headerlink" href="#feed2exec.plugins.echo.filter" title="Permalink to this definition"></a></dt>
<dd><p>This filter just keeps the feed unmodified. It is just there for testing
purposes.</p>
<p>alias of <a class="reference internal" href="#feed2exec.plugins.echo.output" title="feed2exec.plugins.echo.output"><code class="xref py py-class docutils literal"><span class="pre">output</span></code></a></p>
</dd></dl>

</div>
<div class="section" id="module-feed2exec.plugins.error">
<span id="error"></span><h3>Error<a class="headerlink" href="#module-feed2exec.plugins.error" title="Permalink to this headline"></a></h3>
<dl class="function">
<dt id="feed2exec.plugins.error.output">
<code class="descclassname">feed2exec.plugins.error.</code><code class="descname">output</code><span class="sig-paren">(</span><em>*args</em>, <em>**kwargs</em><span class="sig-paren">)</span><a class="reference internal" href="_modules/feed2exec/plugins/error.html#output"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#feed2exec.plugins.error.output" title="Permalink to this definition"></a></dt>
<dd><p>The error plugin is a simple plugin which raises an exception when
called. It is designed for use in the test suite and should generally
not be used elsewhere.</p>
</dd></dl>

</div>
<div class="section" id="module-feed2exec.plugins.exec">
<span id="exec"></span><h3>Exec<a class="headerlink" href="#module-feed2exec.plugins.exec" title="Permalink to this headline"></a></h3>
<dl class="function">
<dt id="feed2exec.plugins.exec.output">
<code class="descclassname">feed2exec.plugins.exec.</code><code class="descname">output</code><span class="sig-paren">(</span><em>command</em>, <em>*args</em>, <em>feed=None</em>, <em>**kwargs</em><span class="sig-paren">)</span><a class="reference internal" href="_modules/feed2exec/plugins/exec.html#output"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#feed2exec.plugins.exec.output" title="Permalink to this definition"></a></dt>
<dd><p>The exec plugin is the ultimate security disaster. It simply
executes whatever you feed it without any sort of sanitization. It
does avoid to call to the shell and executes the command directly,
however. Feed contents are also somewhat sanitized by the
feedparser module, see the <a class="reference external" href="https://pythonhosted.org/feedparser/html-sanitization.html">Sanitization</a>
documentation for more information in that regard. That is limited
to stripping out hostile HTML tags, however.</p>
<p>You should be careful when sending arbitrary parameters to other
programs. Even if we do not use the shell to execute the program,
an hostile feed could still inject commandline flags to change the
program behavior without injecting shell commands themselves.</p>
<p>For example, if a program can write files with the <code class="docutils literal"><span class="pre">-o</span></code> option,
a feed could set their title to <code class="docutils literal"><span class="pre">-oevil</span></code> to overwrite the
<code class="docutils literal"><span class="pre">evil</span></code> file. The only way to workaround that issue is to
carefully craft the commandline so that this cannot happen.</p>
<p>Alternatively, writing a Python plugin is much safer as you can
sanitize the arguments yourself.</p>
<p>Example:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span>[NASA Whats up?]
url = https://www.nasa.gov/rss/dyn/whats_up.rss
output = feed2exec.plugins.exec
args = wget -P /srv/archives/nasa/ {item.link}
</pre></div>
</div>
<p>The above is the equivalent of the archive plugin: it will save
feed item links to the given directory.</p>
</dd></dl>

</div>
<div class="section" id="module-feed2exec.plugins.maildir">
<span id="maildir"></span><h3>Maildir<a class="headerlink" href="#module-feed2exec.plugins.maildir" title="Permalink to this headline"></a></h3>
<dl class="class">
<dt id="feed2exec.plugins.maildir.output">
<em class="property">class </em><code class="descclassname">feed2exec.plugins.maildir.</code><code class="descname">output</code><span class="sig-paren">(</span><em>to_addr=None</em>, <em>feed=None</em>, <em>item=None</em>, <em>lock=None</em>, <em>*args</em>, <em>**kwargs</em><span class="sig-paren">)</span><a class="reference internal" href="_modules/feed2exec/plugins/maildir.html#output"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#feed2exec.plugins.maildir.output" title="Permalink to this definition"></a></dt>
<dd><p>The maildir plugin will save a feed item into a Maildir folder.</p>
<p>The configuration is a little clunky, but it should be safe
against hostile feeds.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><strong>to_addr</strong> (<a class="reference external" href="https://docs.python.org/3/library/stdtypes.html#str" title="(in Python v3.6)"><em>str</em></a>) – the email to use as “to” (defaults to
<a class="reference external" href="mailto:USER&#37;&#52;&#48;localdomain">USER<span>&#64;</span>localdomain</a>)</td>
</tr>
</tbody>
</table>
<p>Example:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="p">[</span><span class="n">NASA</span> <span class="n">breaking</span> <span class="n">news</span><span class="p">]</span>
<span class="n">url</span> <span class="o">=</span> <span class="n">https</span><span class="p">:</span><span class="o">//</span><span class="n">www</span><span class="o">.</span><span class="n">nasa</span><span class="o">.</span><span class="n">gov</span><span class="o">/</span><span class="n">rss</span><span class="o">/</span><span class="n">dyn</span><span class="o">/</span><span class="n">breaking_news</span><span class="o">.</span><span class="n">rss</span>
<span class="n">mailbox</span> <span class="o">=</span> <span class="o">~/</span><span class="n">Maildir</span><span class="o">/</span>
<span class="n">folder</span> <span class="o">=</span> <span class="n">nasa</span>
<span class="n">args</span> <span class="o">=</span> <span class="n">me</span><span class="nd">@example</span><span class="o">.</span><span class="n">com</span>
</pre></div>
</div>
<p>The above will save new feed items from the NASA feed into the
~/Maildir/nasa/ maildir folder, and will set the <cite>To</cite> field of the
email to <cite>me&#64;example.com</cite>.</p>
</dd></dl>

</div>
<div class="section" id="module-feed2exec.plugins.mbox">
<span id="mbox"></span><h3>Mbox<a class="headerlink" href="#module-feed2exec.plugins.mbox" title="Permalink to this headline"></a></h3>
<dl class="class">
<dt id="feed2exec.plugins.mbox.output">
<em class="property">class </em><code class="descclassname">feed2exec.plugins.mbox.</code><code class="descname">output</code><span class="sig-paren">(</span><em>to_addr=None</em>, <em>feed=None</em>, <em>item=None</em>, <em>lock=None</em>, <em>*args</em>, <em>**kwargs</em><span class="sig-paren">)</span><a class="reference internal" href="_modules/feed2exec/plugins/mbox.html#output"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#feed2exec.plugins.mbox.output" title="Permalink to this definition"></a></dt>
<dd><p>The mbox plugin will save a feed item in a Mbox mailbox.</p>
<p>This is mostly for testing purposes, but can of course be used in
the unlikely event where you prefer mbox folders over the
<a class="reference internal" href="#module-feed2exec.plugins.maildir" title="feed2exec.plugins.maildir"><code class="xref py py-mod docutils literal"><span class="pre">feed2exec.plugins.maildir</span></code></a> plugin.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><strong>to_addr</strong> (<a class="reference external" href="https://docs.python.org/3/library/stdtypes.html#str" title="(in Python v3.6)"><em>str</em></a>) – the email to use as “to” (defaults to
<a class="reference external" href="mailto:USER&#37;&#52;&#48;localdomain">USER<span>&#64;</span>localdomain</a>)</td>
</tr>
<tr class="field-even field"><th class="field-name">Todo:</th><td class="field-body">There is some overlap between the code here and the maildir
implementation. Refactoring may be in order, particularly
if we add another mailbox format, though that is unlikely.</td>
</tr>
</tbody>
</table>
</dd></dl>

</div>
<div class="section" id="module-feed2exec.plugins.null">
<span id="null"></span><h3>Null<a class="headerlink" href="#module-feed2exec.plugins.null" title="Permalink to this headline"></a></h3>
<dl class="function">
<dt id="feed2exec.plugins.null.output">
<code class="descclassname">feed2exec.plugins.null.</code><code class="descname">output</code><span class="sig-paren">(</span><em>*args</em>, <em>**kwargs</em><span class="sig-paren">)</span><a class="reference internal" href="_modules/feed2exec/plugins/null.html#output"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#feed2exec.plugins.null.output" title="Permalink to this definition"></a></dt>
<dd><p>This plugin does nothing. It can be useful in cases where you want
to catchup with imported feeds.</p>
</dd></dl>

<dl class="function">
<dt id="feed2exec.plugins.null.filter">
<code class="descclassname">feed2exec.plugins.null.</code><code class="descname">filter</code><span class="sig-paren">(</span><em>item=None</em>, <em>*args</em>, <em>**kwargs</em><span class="sig-paren">)</span><a class="reference internal" href="_modules/feed2exec/plugins/null.html#filter"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#feed2exec.plugins.null.filter" title="Permalink to this definition"></a></dt>
<dd><p>The null filter removes all elements from a feed item</p>
</dd></dl>

</div>
<div class="section" id="module-feed2exec.plugins.transmission">
<span id="transmission"></span><h3>Transmission<a class="headerlink" href="#module-feed2exec.plugins.transmission" title="Permalink to this headline"></a></h3>
<dl class="function">
<dt id="feed2exec.plugins.transmission.sanitize">
<code class="descclassname">feed2exec.plugins.transmission.</code><code class="descname">sanitize</code><span class="sig-paren">(</span><em>text</em>, <em>repl='-'</em><span class="sig-paren">)</span><a class="reference internal" href="_modules/feed2exec/plugins/transmission.html#sanitize"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#feed2exec.plugins.transmission.sanitize" title="Permalink to this definition"></a></dt>
<dd><p>like utils.slug, but without lowercase and allow custom replacement</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="n">sanitize</span><span class="p">(</span><span class="s1">&#39;test&#39;</span><span class="p">)</span>
<span class="go">&#39;test&#39;</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">sanitize</span><span class="p">(</span><span class="s1">&#39;../../../etc/password&#39;</span><span class="p">)</span>
<span class="go">&#39;etc-password&#39;</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">sanitize</span><span class="p">(</span><span class="s1">&#39;Foo./.bar&#39;</span><span class="p">,</span> <span class="n">repl</span><span class="o">=</span><span class="s1">&#39;.&#39;</span><span class="p">)</span>
<span class="go">&#39;Foo.bar&#39;</span>
</pre></div>
</div>
</dd></dl>

<dl class="function">
<dt id="feed2exec.plugins.transmission.output">
<code class="descclassname">feed2exec.plugins.transmission.</code><code class="descname">output</code><span class="sig-paren">(</span><em>hostname='localhost'</em>, <em>*args</em>, <em>feed=None</em>, <em>item=None</em>, <em>**kwargs</em><span class="sig-paren">)</span><a class="reference internal" href="_modules/feed2exec/plugins/transmission.html#output"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#feed2exec.plugins.transmission.output" title="Permalink to this definition"></a></dt>
<dd><p>the transmission plugin will send feed items to a <a class="reference external" href="http://www.transmissionbt.com/">transmission</a> instance</p>
<p>it assumes the <code class="docutils literal"><span class="pre">transmission-remote</span></code> command is already
installed and configured to talk with transmission.</p>
<p>the hostname is passed in the <code class="docutils literal"><span class="pre">args</span></code> configuration and defaults
to localhost. the <code class="docutils literal"><span class="pre">folder</span></code> parameter is also used to determine
where to save the actual torrents files.</p>
<p>note that this will also append a sanitized version of the item
title, if a folder is provided. this is to allow saving series in
the same folder.</p>
<p>if the title is unique for each torrent, you may use a filter to
set the title to the right location.</p>
</dd></dl>

</div>
<div class="section" id="module-feed2exec.plugins.wayback">
<span id="wayback"></span><h3>Wayback<a class="headerlink" href="#module-feed2exec.plugins.wayback" title="Permalink to this headline"></a></h3>
<dl class="function">
<dt id="feed2exec.plugins.wayback.output">
<code class="descclassname">feed2exec.plugins.wayback.</code><code class="descname">output</code><span class="sig-paren">(</span><em>*args</em>, <em>feed=None</em>, <em>item=None</em>, <em>**kwargs</em><span class="sig-paren">)</span><a class="reference internal" href="_modules/feed2exec/plugins/wayback.html#output"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#feed2exec.plugins.wayback.output" title="Permalink to this definition"></a></dt>
<dd><p>This plugin saves the feed items <cite>link</cite> element to the wayback
machine. It will retry URLs that fail, so it may be necessary to
manually catchup feeds if they have broken <cite>link</cite> fields.</p>
<p>Example:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="p">[</span><span class="n">NASA</span> <span class="n">IOTD</span> <span class="n">wayback</span><span class="p">]</span>
<span class="n">url</span> <span class="o">=</span> <span class="n">https</span><span class="p">:</span><span class="o">//</span><span class="n">www</span><span class="o">.</span><span class="n">nasa</span><span class="o">.</span><span class="n">gov</span><span class="o">/</span><span class="n">rss</span><span class="o">/</span><span class="n">dyn</span><span class="o">/</span><span class="n">lg_image_of_the_day</span><span class="o">.</span><span class="n">rss</span>
<span class="n">output</span> <span class="o">=</span> <span class="n">feed2exec</span><span class="o">.</span><span class="n">plugins</span><span class="o">.</span><span class="n">wayback</span>
</pre></div>
</div>
<p>The above will save the Image of the day updates to the wayback
machine.</p>
</dd></dl>

</div>
</div>
<div class="section" id="filter-plugins">
<h2>Filter plugins<a class="headerlink" href="#filter-plugins" title="Permalink to this headline"></a></h2>
<div class="section" id="module-feed2exec.plugins.droptitle">
<span id="droptitle"></span><h3>Droptitle<a class="headerlink" href="#module-feed2exec.plugins.droptitle" title="Permalink to this headline"></a></h3>
<dl class="function">
<dt id="feed2exec.plugins.droptitle.filter">
<code class="descclassname">feed2exec.plugins.droptitle.</code><code class="descname">filter</code><span class="sig-paren">(</span><em>*args</em>, <em>feed=None</em>, <em>item=None</em>, <em>**kwargs</em><span class="sig-paren">)</span><a class="reference internal" href="_modules/feed2exec/plugins/droptitle.html#filter"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#feed2exec.plugins.droptitle.filter" title="Permalink to this definition"></a></dt>
<dd><p>the droptitle filter will drop any feed item with a title matching
the given args.</p>
<p>Example:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="p">[</span><span class="n">NASA</span> <span class="n">breaking</span> <span class="n">news</span><span class="p">]</span>
<span class="n">url</span> <span class="o">=</span> <span class="n">https</span><span class="p">:</span><span class="o">//</span><span class="n">www</span><span class="o">.</span><span class="n">nasa</span><span class="o">.</span><span class="n">gov</span><span class="o">/</span><span class="n">rss</span><span class="o">/</span><span class="n">dyn</span><span class="o">/</span><span class="n">breaking_news</span><span class="o">.</span><span class="n">rss</span>
<span class="nb">filter</span> <span class="o">=</span> <span class="n">feed2exec</span><span class="o">.</span><span class="n">plugins</span><span class="o">.</span><span class="n">droptitle</span>
<span class="n">filter_args</span> <span class="o">=</span> <span class="n">Trump</span>
</pre></div>
</div>
<p>The above will process the feed items according to the global
configuration, but will skip any item that has the word “Trump”
anywhere in the title field.</p>
</dd></dl>

</div>
<div class="section" id="module-feed2exec.plugins.emptysummary">
<span id="emptysummary"></span><h3>Emptysummary<a class="headerlink" href="#module-feed2exec.plugins.emptysummary" title="Permalink to this headline"></a></h3>
<dl class="function">
<dt id="feed2exec.plugins.emptysummary.filter">
<code class="descclassname">feed2exec.plugins.emptysummary.</code><code class="descname">filter</code><span class="sig-paren">(</span><em>*args</em>, <em>feed=None</em>, <em>item=None</em>, <em>**kwargs</em><span class="sig-paren">)</span><a class="reference internal" href="_modules/feed2exec/plugins/emptysummary.html#filter"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#feed2exec.plugins.emptysummary.filter" title="Permalink to this definition"></a></dt>
<dd><p>example of fixes for a broken feed, in this case, the GitHub
release feed which (sometimes) sends empty contents, in which case
the item link field is used as a summary instead.</p>
</dd></dl>

</div>
<div class="section" id="module-feed2exec.plugins.html2text">
<span id="html2text"></span><h3>Html2text<a class="headerlink" href="#module-feed2exec.plugins.html2text" title="Permalink to this headline"></a></h3>
<dl class="class">
<dt id="feed2exec.plugins.html2text.filter">
<em class="property">class </em><code class="descclassname">feed2exec.plugins.html2text.</code><code class="descname">filter</code><span class="sig-paren">(</span><em>*args</em>, <em>feed=None</em>, <em>item=None</em>, <em>**kwargs</em><span class="sig-paren">)</span><a class="reference internal" href="_modules/feed2exec/plugins/html2text.html#filter"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#feed2exec.plugins.html2text.filter" title="Permalink to this definition"></a></dt>
<dd><p>This filter plugin takes a given feed item and adds a
<code class="docutils literal"><span class="pre">content_plain</span></code> field with the HTML parsed as text.</p>
<div class="admonition important">
<p class="first admonition-title">Important</p>
<p class="last">the html2text plugin is called automatically from
the email output plugins and should normally not be
called directly.</p>
</div>
<dl class="staticmethod">
<dt id="feed2exec.plugins.html2text.filter.parse">
<em class="property">static </em><code class="descname">parse</code><span class="sig-paren">(</span><em>html=None</em><span class="sig-paren">)</span><a class="reference internal" href="_modules/feed2exec/plugins/html2text.html#filter.parse"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#feed2exec.plugins.html2text.filter.parse" title="Permalink to this definition"></a></dt>
<dd><p>parse html to text according to our preferences. this is where
subclasses can override the HTML2Text settings or use a
completely different parser</p>
</dd></dl>

</dd></dl>

</div>
<div class="section" id="module-feed2exec.plugins.ikiwiki_recentchanges">
<span id="ikiwiki-recentchanges"></span><h3>Ikiwiki Recentchanges<a class="headerlink" href="#module-feed2exec.plugins.ikiwiki_recentchanges" title="Permalink to this headline"></a></h3>
<dl class="function">
<dt id="feed2exec.plugins.ikiwiki_recentchanges.filter">
<code class="descclassname">feed2exec.plugins.ikiwiki_recentchanges.</code><code class="descname">filter</code><span class="sig-paren">(</span><em>*args</em>, <em>item=None</em>, <em>**kwargs</em><span class="sig-paren">)</span><a class="reference internal" href="_modules/feed2exec/plugins/ikiwiki_recentchanges.html#filter"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#feed2exec.plugins.ikiwiki_recentchanges.filter" title="Permalink to this definition"></a></dt>
<dd><p>the ikiwiki_recentchanges plugin fixes links in ikiwiki feeds</p>
<p>Ikiwiki recent changes show all the recent edits to pages, but the
<code class="docutils literal"><span class="pre">&lt;link&gt;</span></code> element doesn’t point to the edit page: it points to
the recent changes page itself, which make them useless for link
checking or archival purposes.</p>
<p>This parses the recent changes entries and extracts the relevant
links from it.</p>
<p>An alternative to this is to use the following entry to generate a
special feed in Ikiwiki:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span>[[!inline pages=&quot;*&quot; feeds=yes feedonly=yes feedfile=archive show=10]]
</pre></div>
</div>
<p>This generates a feed with proper <code class="docutils literal"><span class="pre">&lt;link&gt;</span></code> elements but requires
write access to the wiki.</p>
</dd></dl>

</div>
</div>
<div class="section" id="writing-new-plugins">
<span id="writing-plugins"></span><h2>Writing new plugins<a class="headerlink" href="#writing-new-plugins" title="Permalink to this headline"></a></h2>
<p>Most of the actual work in the program is performed by plugins. A
plugin is a simple Python module that has a <code class="docutils literal"><span class="pre">output</span></code> or <code class="docutils literal"><span class="pre">filter</span></code>
“callable” (function or class) with a predefined interface.</p>
<div class="section" id="basic-plugin-principles">
<h3>Basic plugin principles<a class="headerlink" href="#basic-plugin-principles" title="Permalink to this headline"></a></h3>
<p>To write a new plugin, you should start by creating a simple Python
module, in your <a class="reference external" href="https://docs.python.org/3/using/cmdline.html#envvar-PYTHONPATH">PYTHONPATH</a>. You
can find which directories are in the path by calling:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span>$ python3 -c &quot;import sys; print(sys.path)&quot;
[&#39;&#39;, &#39;/usr/lib/python35.zip&#39;, &#39;/usr/lib/python3.5&#39;, &#39;/usr/lib/python3.5/plat-x86_64-linux-gnu&#39;, &#39;/usr/lib/python3.5/lib-dynload&#39;, &#39;/usr/local/lib/python3.5/dist-packages&#39;, &#39;/usr/lib/python3/dist-packages&#39;]
</pre></div>
</div>
<p>In the above example, a good location would be
<code class="docutils literal"><span class="pre">/usr/local/lib/python3.5/dist-packages</span></code>. The naming convention is
loose: as long as the plugin matches the expected API, it should just
work. For the purpose of this demonstration, we’ll call our plugin
<a class="reference external" href="https://en.wiktionary.org/wiki/trumpery">trumpery</a>, so we will
create the plugin code like this:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="n">touch</span> <span class="o">/</span><span class="n">usr</span><span class="o">/</span><span class="n">local</span><span class="o">/</span><span class="n">lib</span><span class="o">/</span><span class="n">python3</span><span class="o">.</span><span class="mi">5</span><span class="o">/</span><span class="n">dist</span><span class="o">-</span><span class="n">packages</span><span class="o">/</span><span class="n">trumpery</span><span class="o">.</span><span class="n">py</span>
</pre></div>
</div>
<p>Naturally, if you are going to write multiple plugins, you may want to
regroup your multiple plugins in a package, see the <a class="reference external" href="https://docs.python.org/3/tutorial/modules.html">module
documentation</a> for
more information about this concept in Python.</p>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">There is a rudimentary plugin resolution process that looks
for plugins first in the <cite>feed2exec.plugins</cite> namespace but
then globally. This is done in
<a class="reference internal" href="api.html#feed2exec.plugins.resolve" title="feed2exec.plugins.resolve"><code class="xref py py-func docutils literal"><span class="pre">feed2exec.plugins.resolve()</span></code></a>, called from the <code class="docutils literal"><span class="pre">add</span></code>
and <code class="docutils literal"><span class="pre">parse</span></code> commands. This means that the absolute path is
expected to be used in the configuration file and
internally.</p>
</div>
<p>You are welcome to distribute plugins separately or send them as merge
requests, see <a class="reference internal" href="contribute.html"><span class="doc">Contribution guide</span></a> for more information on how to
participate in this project. We of course welcome contributions to
this documentation as well!</p>
</div>
<div class="section" id="filters">
<h3>Filters<a class="headerlink" href="#filters" title="Permalink to this headline"></a></h3>
<p>Now, you need your plugin to do something. In our case, let’s say we’d
like to skip any feed entry that has the word <a class="reference external" href="https://en.wikipedia.org/wiki/Trump">Trump</a> in it. For that purpose, we’ll
create a plugin similar to the already existing
<a class="reference internal" href="#module-feed2exec.plugins.droptitle" title="feed2exec.plugins.droptitle"><code class="xref py py-mod docutils literal"><span class="pre">feed2exec.plugins.droptitle</span></code></a> plugin, but that operates on the
<em>body</em> of the feed, but that also hardcodes the word, because this is
just a demonstration and we want to keep it simple. Let’s look at the
title plugin to see how it works:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="k">def</span> <span class="nf">filter</span><span class="p">(</span><span class="o">*</span><span class="n">args</span><span class="p">,</span> <span class="n">feed</span><span class="o">=</span><span class="kc">None</span><span class="p">,</span> <span class="n">item</span><span class="o">=</span><span class="kc">None</span><span class="p">,</span> <span class="o">**</span><span class="n">kwargs</span><span class="p">):</span>
    <span class="sd">&#39;&#39;&#39;the droptitle filter will drop any feed item with a title matching</span>
<span class="sd">    the given args.</span>

<span class="sd">    Example::</span>

<span class="sd">      [NASA breaking news]</span>
<span class="sd">      url = https://www.nasa.gov/rss/dyn/breaking_news.rss</span>
<span class="sd">      filter = feed2exec.plugins.droptitle</span>
<span class="sd">      filter_args = Trump</span>

<span class="sd">    The above will process the feed items according to the global</span>
<span class="sd">    configuration, but will skip any item that has the word &quot;Trump&quot;</span>
<span class="sd">    anywhere in the title field.</span>
<span class="sd">    &#39;&#39;&#39;</span>
    <span class="n">item</span><span class="p">[</span><span class="s1">&#39;skip&#39;</span><span class="p">]</span> <span class="o">=</span> <span class="s1">&#39; &#39;</span><span class="o">.</span><span class="n">join</span><span class="p">(</span><span class="n">args</span><span class="p">)</span> <span class="ow">in</span> <span class="n">item</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="s1">&#39;title&#39;</span><span class="p">,</span> <span class="s1">&#39;&#39;</span><span class="p">)</span>
</pre></div>
</div>
<p>That may look like complete gibberish to you if you are not familiar
with programming or with Python programming in particular. But let’s
take this from the top and copy that in our own plugin. The first line
declares a <a class="reference external" href="https://en.wikibooks.org/wiki/Python_Programming/Functions">function</a> that
takes at least a <code class="docutils literal"><span class="pre">feed</span></code> and a <code class="docutils literal"><span class="pre">item</span></code> argument, but can also accept
any other arbitrary argument. This is important because we want to
have the plugin keep on working if the plugin API changes in the
future. This is called “forward-compatibility”. So let’s copy that in
our plugin and add a <code class="docutils literal"><span class="pre">pass</span></code> statement to make sure the plugin works
(even if it does nothing for now):</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="k">def</span> <span class="nf">filter</span><span class="p">(</span><span class="o">*</span><span class="n">args</span><span class="p">,</span> <span class="n">feed</span><span class="o">=</span><span class="kc">None</span><span class="p">,</span> <span class="n">item</span><span class="o">=</span><span class="kc">None</span><span class="p">,</span> <span class="o">**</span><span class="n">kwargs</span><span class="p">):</span>
    <span class="k">pass</span>
</pre></div>
</div>
<p>We can already test our plugin by adding it to our configuration, in
<code class="docutils literal"><span class="pre">~/.config/feed2exec/feed2exec.ini</span></code>:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="p">[</span><span class="n">NASA</span><span class="p">]</span>
<span class="n">url</span> <span class="o">=</span> <span class="n">https</span><span class="p">:</span><span class="o">//</span><span class="n">www</span><span class="o">.</span><span class="n">nasa</span><span class="o">.</span><span class="n">gov</span><span class="o">/</span><span class="n">rss</span><span class="o">/</span><span class="n">dyn</span><span class="o">/</span><span class="n">breaking_news</span><span class="o">.</span><span class="n">rss</span>
<span class="n">output</span> <span class="o">=</span> <span class="n">feed2exec</span><span class="o">.</span><span class="n">plugins</span><span class="o">.</span><span class="n">echo</span>
<span class="n">args</span> <span class="o">=</span> <span class="p">{</span><span class="n">item</span><span class="o">.</span><span class="n">title</span><span class="p">}</span>
<span class="nb">filter</span> <span class="o">=</span> <span class="n">trumpery</span>
</pre></div>
</div>
<p>Notice how we use the <code class="docutils literal"><span class="pre">output</span></code> plugin to show the title of feed
items selected, as a debugging tool. Let’s fetch this feed in
debugging mode to see what happens:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span>$ python3 -m feed2exec --verbose fetch --force
opening local file /home/anarcat/src/feed2exec/feed2exec/tests/files/breaking_news.xml
parsing feed file:///home/anarcat/src/feed2exec/feed2exec/tests/files/breaking_news.xml (10355 bytes)
connecting to database at ./doc/feed2exec.db
arguments received: (&#39;President Trump Welcomes Home Record-breaking NASA Astronaut Peggy Whitson&#39;,)
arguments received: (&#39;Three International Space Station Crewmates Safely Return to Earth&#39;,)
arguments received: (&#39;NASA Statement on Nomination for Agency Administrator&#39;,)
arguments received: (&#39;NASA Television to Air Return of Three International Space Station Crew Members&#39;,)
arguments received: (&#39;NASA and Iconic Museum Honor Voyager Spacecraft 40th Anniversary&#39;,)
arguments received: (&#39;NASA’s Johnson Space Center Closes Through Labor Day for Tropical Storm Harvey&#39;,)
arguments received: (&#39;NASA Cancels Planned Media Availabilities with Astronauts&#39;,)
arguments received: (&#39;NASA Awards $400,000 to Top Teams at Second Phase of 3D-Printing Competition&#39;,)
arguments received: (&#39;NASA Awards Contract for Center Protective Services for Glenn Research Center&#39;,)
arguments received: (&#39;NASA Announces Cassini End-of-Mission Media Activities&#39;,)
1 feeds processed
</pre></div>
</div>
<p>Good! The feed is fetched and items are displayed. It means our filter
didn’t interfere, but now it’s time to make it <em>do</em> something. To skip
items, we need to set the <code class="docutils literal"><span class="pre">skip</span></code> attribute for the feed item to
<cite>True</cite> if we want to skip it and <cite>False</cite> otherwise. So we’ll use a
simple recipe, a bit like <cite>droptitle</cite> does, but simpler, to look at
the feed content to look for our evil word. The <code class="xref py py-mod docutils literal"><span class="pre">feedparser</span></code>
documentation tells us feed items have a <a class="reference external" href="https://pythonhosted.org/feedparser/reference-entry-summary.html">summary</a>
field which we can inspect. There’s also a <a class="reference external" href="https://pythonhosted.org/feedparser/reference-entry-content.html#reference-entry-content">content</a>
list, but that’s a little more complicated so we’ll skip that for
now. So, let’s set the <code class="docutils literal"><span class="pre">skip</span></code> parameter to match if there is the
evil word in our feed item, like this:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="k">def</span> <span class="nf">filter</span><span class="p">(</span><span class="o">*</span><span class="n">args</span><span class="p">,</span> <span class="n">feed</span><span class="o">=</span><span class="kc">None</span><span class="p">,</span> <span class="n">item</span><span class="o">=</span><span class="kc">None</span><span class="p">,</span> <span class="o">**</span><span class="n">kwargs</span><span class="p">):</span>
    <span class="n">item</span><span class="p">[</span><span class="s1">&#39;skip&#39;</span><span class="p">]</span> <span class="o">=</span> <span class="s1">&#39;Trump&#39;</span> <span class="ow">in</span> <span class="n">item</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="s1">&#39;summary&#39;</span><span class="p">,</span> <span class="s1">&#39;&#39;</span><span class="p">)</span>
</pre></div>
</div>
<p>And let’s see the result (note that we use the <code class="docutils literal"><span class="pre">--force</span></code> argument
here otherwise we would just skip all items because of the cache):</p>
<div class="highlight-default"><div class="highlight"><pre><span></span>$ python3 -m feed2exec --verbose fetch --force
opening local file /home/anarcat/src/feed2exec/feed2exec/tests/files/breaking_news.xml
parsing feed file:///home/anarcat/src/feed2exec/feed2exec/tests/files/breaking_news.xml (10355 bytes)
connecting to database at ./doc/feed2exec.db
item President Trump Welcomes Home Record-breaking NASA Astronaut Peggy Whitson of feed NASA filtered out
arguments received: (&#39;Three International Space Station Crewmates Safely Return to Earth&#39;,)
item NASA Statement on Nomination for Agency Administrator of feed NASA filtered out
arguments received: (&#39;NASA Television to Air Return of Three International Space Station Crew Members&#39;,)
arguments received: (&#39;NASA and Iconic Museum Honor Voyager Spacecraft 40th Anniversary&#39;,)
arguments received: (&#39;NASA’s Johnson Space Center Closes Through Labor Day for Tropical Storm Harvey&#39;,)
arguments received: (&#39;NASA Cancels Planned Media Availabilities with Astronauts&#39;,)
arguments received: (&#39;NASA Awards $400,000 to Top Teams at Second Phase of 3D-Printing Competition&#39;,)
arguments received: (&#39;NASA Awards Contract for Center Protective Services for Glenn Research Center&#39;,)
arguments received: (&#39;NASA Announces Cassini End-of-Mission Media Activities&#39;,)
1 feeds processed
</pre></div>
</div>
<p>Successs! We have skipped the two items that contain the fraud we
wanted to remove from the world. Notice how we were able to <em>modify</em>
the feed item: we can also use that to <em>change</em> the feed
content. Normally, we would use this to fix malformed feeds, but let’s
have some fun instead and <a class="reference external" href="https://en.wikipedia.org/wiki/Donald_Trump_(Last_Week_Tonight)">rename Trump to Drumpf</a>:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="k">def</span> <span class="nf">filter</span><span class="p">(</span><span class="o">*</span><span class="n">args</span><span class="p">,</span> <span class="n">feed</span><span class="o">=</span><span class="kc">None</span><span class="p">,</span> <span class="n">item</span><span class="o">=</span><span class="kc">None</span><span class="p">,</span> <span class="o">**</span><span class="n">kwargs</span><span class="p">):</span>
    <span class="n">item</span><span class="p">[</span><span class="s1">&#39;title&#39;</span><span class="p">]</span> <span class="o">=</span> <span class="n">item</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="s1">&#39;title&#39;</span><span class="p">,</span> <span class="s1">&#39;&#39;</span><span class="p">)</span><span class="o">.</span><span class="n">replace</span><span class="p">(</span><span class="s1">&#39;Trump&#39;</span><span class="p">,</span> <span class="s1">&#39;Drumpf&#39;</span><span class="p">)</span>
</pre></div>
</div>
<p>And the result:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span>$ python3 -m feed2exec --verbose fetch --force
opening local file /home/anarcat/src/feed2exec/feed2exec/tests/files/breaking_news.xml
parsing feed file:///home/anarcat/src/feed2exec/feed2exec/tests/files/breaking_news.xml (10355 bytes)
connecting to database at ./doc/feed2exec.db
arguments received: (&#39;President Drumpf Welcomes Home Record-breaking NASA Astronaut Peggy Whitson&#39;,)
arguments received: (&#39;Three International Space Station Crewmates Safely Return to Earth&#39;,)
arguments received: (&#39;NASA Statement on Nomination for Agency Administrator&#39;,)
arguments received: (&#39;NASA Television to Air Return of Three International Space Station Crew Members&#39;,)
arguments received: (&#39;NASA and Iconic Museum Honor Voyager Spacecraft 40th Anniversary&#39;,)
arguments received: (&#39;NASA’s Johnson Space Center Closes Through Labor Day for Tropical Storm Harvey&#39;,)
arguments received: (&#39;NASA Cancels Planned Media Availabilities with Astronauts&#39;,)
arguments received: (&#39;NASA Awards $400,000 to Top Teams at Second Phase of 3D-Printing Competition&#39;,)
arguments received: (&#39;NASA Awards Contract for Center Protective Services for Glenn Research Center&#39;,)
arguments received: (&#39;NASA Announces Cassini End-of-Mission Media Activities&#39;,)
1 feeds processed
</pre></div>
</div>
<p>I know, absolutely hilarious, right? More seriously, this is also how
the <a class="reference internal" href="#module-feed2exec.plugins.html2text" title="feed2exec.plugins.html2text"><code class="xref py py-class docutils literal"><span class="pre">feed2exec.plugins.html2text</span></code></a> filter works, which is
enabled by default and helps the email output plugin do its job by
turning HTML into text. At this point, the only limit is your
knowledge of Python programming and your imagination!</p>
</div>
<div class="section" id="id2">
<h3>Output plugins<a class="headerlink" href="#id2" title="Permalink to this headline"></a></h3>
<p>Output plugins are another beast entirely. While they operate with the
same principle than filter plugins (search path and function signature
are similar), they are designed to actually output something for each
new feed item found. This can be anything: a file, email, HTTP
request, whatever. If there is a commandline tool that does what you
need, it is probably simpler to just call the <code class="docutils literal"><span class="pre">exec</span></code> plugin and
there are numerous examples of this in the sample configuration
file. For more complex things, however, it may be easier to actually
write this as a Python.</p>
<div class="section" id="basic-arguments">
<h4>Basic arguments<a class="headerlink" href="#basic-arguments" title="Permalink to this headline"></a></h4>
<p>For our example, we’ll write an archival plugin which writes each new
entry to a file hierarchy. First, we start with the same simple
function signature as filters, except we name it output:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="k">def</span> <span class="nf">output</span><span class="p">(</span><span class="o">*</span><span class="n">args</span><span class="p">,</span> <span class="n">feed</span><span class="o">=</span><span class="kc">None</span><span class="p">,</span> <span class="n">item</span><span class="o">=</span><span class="kc">None</span><span class="p">,</span> <span class="o">**</span><span class="n">kwargs</span><span class="p">):</span>
    <span class="k">pass</span>
</pre></div>
</div>
<p>This is the equivalent of the <code class="docutils literal"><span class="pre">null</span></code> plugin and basically outputs
nothing at all. To archive the feed items, we’ll need to look at the
<a class="reference external" href="https://pythonhosted.org/feedparser/reference-entry-link.html">link</a>
element feedparser gives us. Let’s see what that looks like for the
NASA feed:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="k">def</span> <span class="nf">output</span><span class="p">(</span><span class="o">*</span><span class="n">args</span><span class="p">,</span> <span class="n">feed</span><span class="o">=</span><span class="kc">None</span><span class="p">,</span> <span class="n">item</span><span class="o">=</span><span class="kc">None</span><span class="p">,</span> <span class="o">**</span><span class="n">kwargs</span><span class="p">):</span>
    <span class="c1"># only operate on items that actually have a link</span>
    <span class="k">if</span> <span class="n">item</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="s1">&#39;link&#39;</span><span class="p">):</span>
        <span class="nb">print</span><span class="p">(</span><span class="n">item</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="s1">&#39;link&#39;</span><span class="p">,</span> <span class="s1">&#39;&#39;</span><span class="p">))</span>
    <span class="k">else</span><span class="p">:</span>
        <span class="n">logging</span><span class="o">.</span><span class="n">info</span><span class="p">(</span><span class="s1">&#39;no link for feed item </span><span class="si">%s</span><span class="s1">, not archiving&#39;</span><span class="p">,</span> <span class="n">item</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="s1">&#39;title&#39;</span><span class="p">))</span>
</pre></div>
</div>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">Note that we try to make plugins silent in general. You can
use <a class="reference external" href="https://docs.python.org/3/library/logging.html#logging.info" title="(in Python v3.6)"><code class="xref py py-func docutils literal"><span class="pre">logging.info()</span></code></a> to have things show up in
<code class="docutils literal"><span class="pre">--verbose</span></code> and <a class="reference external" href="https://docs.python.org/3/library/logging.html#logging.debug" title="(in Python v3.6)"><code class="xref py py-func docutils literal"><span class="pre">logging.debug()</span></code></a> for <code class="docutils literal"><span class="pre">--debug</span></code> but
by default, your plugin should be silent unless there’s an
error that requires the user’s intervention, in which case
you should use <a class="reference external" href="https://docs.python.org/3/library/logging.html#logging.warning" title="(in Python v3.6)"><code class="xref py py-func docutils literal"><span class="pre">logging.warning()</span></code></a> for transient errors
that may be automatically recovered and
<a class="reference external" href="https://docs.python.org/3/library/logging.html#logging.error" title="(in Python v3.6)"><code class="xref py py-func docutils literal"><span class="pre">logging.error()</span></code></a> for errors that require user
intervention. This is to allow users to ignore warnings
safely.</p>
</div>
<p>Note that here we first check to see if the feed item actually <em>has</em> a
link - not all feeds do! After adding the above to our <code class="docutils literal"><span class="pre">trumpery</span></code>
plugin and adding it as an output plugin:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="p">[</span><span class="n">NASA</span><span class="p">]</span>
<span class="n">url</span> <span class="o">=</span> <span class="n">https</span><span class="p">:</span><span class="o">//</span><span class="n">www</span><span class="o">.</span><span class="n">nasa</span><span class="o">.</span><span class="n">gov</span><span class="o">/</span><span class="n">rss</span><span class="o">/</span><span class="n">dyn</span><span class="o">/</span><span class="n">breaking_news</span><span class="o">.</span><span class="n">rss</span>
<span class="n">output</span> <span class="o">=</span> <span class="n">trumpery</span>
<span class="nb">filter</span> <span class="o">=</span> <span class="n">trumpery</span>
</pre></div>
</div>
<p>We can try to see what happens when we call it:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span>$ python3 -m feed2exec --verbose fetch --force
opening local file /home/anarcat/src/feed2exec/feed2exec/tests/files/breaking_news.xml
parsing feed file:///home/anarcat/src/feed2exec/feed2exec/tests/files/breaking_news.xml (10355 bytes)
connecting to database at ./doc/feed2exec.db
http://www.nasa.gov/press-release/president-trump-welcomes-home-record-breaking-nasa-astronaut-peggy-whitson
http://www.nasa.gov/press-release/three-international-space-station-crewmates-safely-return-to-earth
http://www.nasa.gov/press-release/nasa-statement-on-nomination-for-agency-administrator
http://www.nasa.gov/press-release/nasa-television-to-air-return-of-three-international-space-station-crew-members
http://www.nasa.gov/press-release/nasa-and-iconic-museum-honor-voyager-spacecraft-40th-anniversary
http://www.nasa.gov/press-release/nasa-s-johnson-space-center-closes-through-labor-day-for-tropical-storm-harvey
http://www.nasa.gov/press-release/nasa-cancels-planned-media-availabilities-with-astronauts
http://www.nasa.gov/press-release/nasa-awards-400000-to-top-teams-at-second-phase-of-3d-printing-competition
http://www.nasa.gov/press-release/nasa-awards-contract-for-center-protective-services-for-glenn-research-center
http://www.nasa.gov/press-release/nasa-announces-cassini-end-of-mission-media-activities
1 feeds processed
</pre></div>
</div>
</div>
<div class="section" id="sanitizing-contents">
<h4>Sanitizing contents<a class="headerlink" href="#sanitizing-contents" title="Permalink to this headline"></a></h4>
<p>Good. Those are the URLs we want to save to disk. Let’s start by just
writing those to a file. We will also use a simple <cite>slug</cite> function to
make a filesystem-safe name from the feed title and save those files
in a pre-determined location:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">logging</span>
<span class="kn">import</span> <span class="nn">os.path</span>
<span class="kn">from</span> <span class="nn">feed2exec.utils</span> <span class="k">import</span> <span class="n">slug</span>

<span class="n">ARCHIVE_DIR</span><span class="o">=</span><span class="s1">&#39;/run/user/1000/feed-archives/&#39;</span>

<span class="k">def</span> <span class="nf">output</span><span class="p">(</span><span class="o">*</span><span class="n">args</span><span class="p">,</span> <span class="n">feed</span><span class="o">=</span><span class="kc">None</span><span class="p">,</span> <span class="n">item</span><span class="o">=</span><span class="kc">None</span><span class="p">,</span> <span class="o">**</span><span class="n">kwargs</span><span class="p">):</span>
    <span class="c1"># make a safe path from the item name</span>
    <span class="n">path</span> <span class="o">=</span> <span class="n">slug</span><span class="p">(</span><span class="n">item</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="s1">&#39;title&#39;</span><span class="p">,</span> <span class="s1">&#39;no-name&#39;</span><span class="p">))</span>
    <span class="c1"># put the file in the archive directory</span>
    <span class="n">path</span> <span class="o">=</span> <span class="n">os</span><span class="o">.</span><span class="n">path</span><span class="o">.</span><span class="n">join</span><span class="p">(</span><span class="n">ARCHIVE_DIR</span><span class="p">,</span> <span class="n">path</span><span class="p">)</span>
    <span class="c1"># only operate on items that actually have a link</span>
    <span class="k">if</span> <span class="n">item</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="s1">&#39;link&#39;</span><span class="p">):</span>
        <span class="c1"># tell the user what&#39;s going on, if verbose</span>
        <span class="c1"># otherwise, we try to stay silent if all goes well</span>
        <span class="n">logging</span><span class="o">.</span><span class="n">info</span><span class="p">(</span><span class="s1">&#39;saving feed item </span><span class="si">%s</span><span class="s1"> to </span><span class="si">%s</span><span class="s1"> from </span><span class="si">%s</span><span class="s1">&#39;</span><span class="p">,</span>
                     <span class="n">item</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="s1">&#39;title&#39;</span><span class="p">),</span> <span class="n">path</span><span class="p">,</span> <span class="n">item</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="s1">&#39;link&#39;</span><span class="p">))</span>
        <span class="c1"># open the file</span>
        <span class="k">with</span> <span class="nb">open</span><span class="p">(</span><span class="n">path</span><span class="p">,</span> <span class="s1">&#39;w&#39;</span><span class="p">)</span> <span class="k">as</span> <span class="n">archive</span><span class="p">:</span>
            <span class="c1"># write the response</span>
            <span class="n">archive</span><span class="o">.</span><span class="n">write</span><span class="p">(</span><span class="n">item</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="s1">&#39;link&#39;</span><span class="p">))</span>
    <span class="k">else</span><span class="p">:</span>
        <span class="n">logging</span><span class="o">.</span><span class="n">info</span><span class="p">(</span><span class="s1">&#39;no link for feed item </span><span class="si">%s</span><span class="s1">, not archiving&#39;</span><span class="p">,</span> <span class="n">item</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="s1">&#39;title&#39;</span><span class="p">))</span>
</pre></div>
</div>
<p>Now I know this may look like a <a class="reference external" href="http://knowyourmeme.com/memes/how-to-draw-an-owl">huge step from the previous one</a> but I’m sorry, I
couldn’t find a simpler second step. :) The output now looks like
this:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span>$ python3 -m feed2exec --config ./doc/ --verbose fetch --force
opening local file /home/anarcat/src/feed2exec/feed2exec/tests/files/breaking_news.xml
parsing feed file:///home/anarcat/src/feed2exec/feed2exec/tests/files/breaking_news.xml (10355 bytes)
connecting to database at ./doc/feed2exec.db
saving feed item President Drumpf Welcomes Home Record-breaking NASA Astronaut Peggy Whitson to /run/user/1000/president-drumpf-welcomes-home-record-breaking-nasa-astronaut-peggy-whitson from http://www.nasa.gov/press-release/president-trump-welcomes-home-record-breaking-nasa-astronaut-peggy-whitson
saving feed item Three International Space Station Crewmates Safely Return to Earth to /run/user/1000/three-international-space-station-crewmates-safely-return-to-earth from http://www.nasa.gov/press-release/three-international-space-station-crewmates-safely-return-to-earth
saving feed item NASA Statement on Nomination for Agency Administrator to /run/user/1000/nasa-statement-on-nomination-for-agency-administrator from http://www.nasa.gov/press-release/nasa-statement-on-nomination-for-agency-administrator
saving feed item NASA Television to Air Return of Three International Space Station Crew Members to /run/user/1000/nasa-television-to-air-return-of-three-international-space-station-crew-members from http://www.nasa.gov/press-release/nasa-television-to-air-return-of-three-international-space-station-crew-members
saving feed item NASA and Iconic Museum Honor Voyager Spacecraft 40th Anniversary to /run/user/1000/nasa-and-iconic-museum-honor-voyager-spacecraft-40th-anniversary from http://www.nasa.gov/press-release/nasa-and-iconic-museum-honor-voyager-spacecraft-40th-anniversary
saving feed item NASA’s Johnson Space Center Closes Through Labor Day for Tropical Storm Harvey to /run/user/1000/nasa-s-johnson-space-center-closes-through-labor-day-for-tropical-storm-harvey from http://www.nasa.gov/press-release/nasa-s-johnson-space-center-closes-through-labor-day-for-tropical-storm-harvey
saving feed item NASA Cancels Planned Media Availabilities with Astronauts to /run/user/1000/nasa-cancels-planned-media-availabilities-with-astronauts from http://www.nasa.gov/press-release/nasa-cancels-planned-media-availabilities-with-astronauts
saving feed item NASA Awards $400,000 to Top Teams at Second Phase of 3D-Printing Competition to /run/user/1000/nasa-awards-400-000-to-top-teams-at-second-phase-of-3d-printing-competition from http://www.nasa.gov/press-release/nasa-awards-400000-to-top-teams-at-second-phase-of-3d-printing-competition
saving feed item NASA Awards Contract for Center Protective Services for Glenn Research Center to /run/user/1000/nasa-awards-contract-for-center-protective-services-for-glenn-research-center from http://www.nasa.gov/press-release/nasa-awards-contract-for-center-protective-services-for-glenn-research-center
saving feed item NASA Announces Cassini End-of-Mission Media Activities to /run/user/1000/nasa-announces-cassini-end-of-mission-media-activities from http://www.nasa.gov/press-release/nasa-announces-cassini-end-of-mission-media-activities
</pre></div>
</div>
<p>Sweet! Now it’s not really nice to save this in <code class="docutils literal"><span class="pre">/run/user/1000</span></code>. I
just chose this directory because it was a safe place to write but
it’s not a persistent directory. Best make that configurable, which is
where plugin arguments come in.</p>
</div>
<div class="section" id="user-configuration">
<h4>User configuration<a class="headerlink" href="#user-configuration" title="Permalink to this headline"></a></h4>
<p>You see that <code class="docutils literal"><span class="pre">*args</span></code> parameter? That comes straight from the
configuration file. So you could set the path in the configuration
file, like this:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="p">[</span><span class="n">NASA</span><span class="p">]</span>
<span class="n">url</span> <span class="o">=</span> <span class="n">https</span><span class="p">:</span><span class="o">//</span><span class="n">www</span><span class="o">.</span><span class="n">nasa</span><span class="o">.</span><span class="n">gov</span><span class="o">/</span><span class="n">rss</span><span class="o">/</span><span class="n">dyn</span><span class="o">/</span><span class="n">breaking_news</span><span class="o">.</span><span class="n">rss</span>
<span class="n">output</span> <span class="o">=</span> <span class="n">trumpery</span>
<span class="n">args</span> <span class="o">=</span> <span class="o">/</span><span class="n">srv</span><span class="o">/</span><span class="n">archives</span><span class="o">/</span><span class="n">nasa</span><span class="o">/</span>
<span class="nb">filter</span> <span class="o">=</span> <span class="n">trumpery</span>
</pre></div>
</div>
<p>We also need to modify the plugin to fetch that configuration, like
this:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="k">def</span> <span class="nf">output</span><span class="p">(</span><span class="o">*</span><span class="n">args</span><span class="p">,</span> <span class="n">feed</span><span class="o">=</span><span class="kc">None</span><span class="p">,</span> <span class="n">item</span><span class="o">=</span><span class="kc">None</span><span class="p">,</span> <span class="o">**</span><span class="n">kwargs</span><span class="p">):</span>
    <span class="c1"># make a safe path from the item name</span>
    <span class="n">path</span> <span class="o">=</span> <span class="n">slug</span><span class="p">(</span><span class="n">item</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="s1">&#39;title&#39;</span><span class="p">,</span> <span class="s1">&#39;no-name&#39;</span><span class="p">))</span>
    <span class="c1"># take the archive dir from the user or use the default</span>
    <span class="n">archive_dir</span> <span class="o">=</span> <span class="s1">&#39; &#39;</span><span class="o">.</span><span class="n">join</span><span class="p">(</span><span class="n">args</span><span class="p">)</span> <span class="k">if</span> <span class="n">args</span> <span class="k">else</span> <span class="n">DEFAULT_ARCHIVE_DIR</span>
    <span class="c1"># put the file in the archive directory</span>
    <span class="n">path</span> <span class="o">=</span> <span class="n">os</span><span class="o">.</span><span class="n">path</span><span class="o">.</span><span class="n">join</span><span class="p">(</span><span class="n">archive_dir</span><span class="p">,</span> <span class="n">path</span><span class="p">)</span>
    <span class="c1"># [...]</span>
    <span class="c1"># rest of the function unchanged</span>
</pre></div>
</div>
</div>
<div class="section" id="making-http-requests">
<h4>Making HTTP requests<a class="headerlink" href="#making-http-requests" title="Permalink to this headline"></a></h4>
<p>And now obviously, we only saved the link itself, not the link
<em>content</em>. For that we need some help from the <code class="xref py py-mod docutils literal"><span class="pre">requests</span></code>
module, and do something like this:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="c1"># fetch the URL in memory</span>
<span class="n">result</span> <span class="o">=</span> <span class="n">requests</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="n">item</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="s1">&#39;link&#39;</span><span class="p">))</span>
<span class="k">if</span> <span class="n">result</span><span class="o">.</span><span class="n">status_code</span> <span class="o">!=</span> <span class="n">requests</span><span class="o">.</span><span class="n">codes</span><span class="o">.</span><span class="n">ok</span><span class="p">:</span>
    <span class="n">logging</span><span class="o">.</span><span class="n">warning</span><span class="p">(</span><span class="s1">&#39;failed to fetch link </span><span class="si">%s</span><span class="s1">: </span><span class="si">%s</span><span class="s1">&#39;</span><span class="p">,</span>
                    <span class="n">item</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="s1">&#39;link&#39;</span><span class="p">),</span> <span class="n">result</span><span class="o">.</span><span class="n">status_code</span><span class="p">)</span>
    <span class="c1"># make sure we retry next time</span>
    <span class="k">return</span> <span class="kc">False</span>
<span class="c1"># open the file</span>
<span class="k">with</span> <span class="nb">open</span><span class="p">(</span><span class="n">path</span><span class="p">,</span> <span class="s1">&#39;w&#39;</span><span class="p">)</span> <span class="k">as</span> <span class="n">archive</span><span class="p">:</span>
    <span class="c1"># write the response</span>
    <span class="n">archive</span><span class="o">.</span><span class="n">write</span><span class="p">(</span><span class="n">result</span><span class="o">.</span><span class="n">text</span><span class="p">)</span>
</pre></div>
</div>
<p>This will save the actual link content (<code class="docutils literal"><span class="pre">result.text</span></code>) to the
file. The important statement here is:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="c1"># fetch the URL in memory</span>
<span class="n">result</span> <span class="o">=</span> <span class="n">requests</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="n">item</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="s1">&#39;link&#39;</span><span class="p">))</span>
</pre></div>
</div>
<p>which fetches the URL in memory and checks for errors. The other
change in the final plugin is simply:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="n">archive</span><span class="o">.</span><span class="n">write</span><span class="p">(</span><span class="n">result</span><span class="o">.</span><span class="n">text</span><span class="p">)</span>
</pre></div>
</div>
<p>which writes the article content instead of the link.</p>
</div>
<div class="section" id="plugin-return-values">
<h4>Plugin return values<a class="headerlink" href="#plugin-return-values" title="Permalink to this headline"></a></h4>
<p>Notice how we <code class="docutils literal"><span class="pre">return</span> <span class="pre">False</span></code> here: this makes the plugin system
avoid adding the item to the cache, so it is retried on the next
run. If the plugin returns <code class="docutils literal"><span class="pre">True</span></code> or nothing (<code class="docutils literal"><span class="pre">None</span></code>), the plugin
is considered to have succeeded and the entry is added to the
cache. That logic is defined in <code class="xref py py-func docutils literal"><span class="pre">feed2exec.feeds.parse()</span></code>.</p>
</div>
<div class="section" id="catchup">
<h4>Catchup<a class="headerlink" href="#catchup" title="Permalink to this headline"></a></h4>
<p>A final thing that is missing that is critical in all plugins is
to respect the <code class="docutils literal"><span class="pre">catchup</span></code> setting. It is propagated up from the
commandline or configuration all the way down to plugins, through the
<code class="docutils literal"><span class="pre">feed</span></code> parameters. How you handle it varies from plugin to plugin,
but the basic idea is to give feedback (when verbose) of activity when
the plugin is run <em>but</em> to not actually <em>do</em> anything. In our case, we
simply return success, right before we fetch the URL:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="k">if</span> <span class="n">feed</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="s1">&#39;catchup&#39;</span><span class="p">):</span>
    <span class="k">return</span> <span class="kc">True</span>
<span class="c1"># fetch the URL in memory</span>
<span class="n">result</span> <span class="o">=</span> <span class="n">requests</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="n">item</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="s1">&#39;link&#39;</span><span class="p">))</span>
</pre></div>
</div>
<p>Notice how we still fetch the actual feed content but stop before
doing any permanent operation. That is the spirit of the “catchup”
operation: we not only skip “write” operation, but also any operation
which could slow down the “catchup”: fetching stuff over the network
takes time and while it can be considered a “readonly” operation as
far as the local machine is concerned, we are effectively <em>writing</em> to
the network so that operation shouldn’t occur.</p>
<p>Hopefully that should get you going with most of the plugins you are
thinking of writing!</p>
</div>
</div>
<div class="section" id="writing-tests">
<span id="id3"></span><h3>Writing tests<a class="headerlink" href="#writing-tests" title="Permalink to this headline"></a></h3>
<p>Writing tests is essential in ensuring that the code will stay
maintainable in the future. It allows for easy refactoring and can
find bugs that manual testing may not, especially when you get
complete coverage (although that is no garantee either).</p>
<p>We’ll take our <cite>archive</cite> plugin as an example. The first step is to
edit the <code class="docutils literal"><span class="pre">tests/test/test_plugins.py</span></code> file, where other plugins are
tests as well. We start by creating a function named <code class="docutils literal"><span class="pre">test_archive</span></code>
so that <a class="reference external" href="https://pytest.org/">Pytest</a>, our test bed, will find
it:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="k">def</span> <span class="nf">test_archive</span><span class="p">(</span><span class="n">tmpdir</span><span class="p">,</span> <span class="n">betamax</span><span class="p">):</span>  <span class="c1"># noqa</span>
    <span class="k">pass</span>
</pre></div>
</div>
<p>Notice the two arguments named <code class="docutils literal"><span class="pre">tmpdir</span></code> and <code class="docutils literal"><span class="pre">betamax</span></code>. Both
of those are <a class="reference external" href="https://docs.pytest.org/en/latest/fixture.html">fixtures</a>, a pytest concept
that allows to simulate an environment. In particular, the <code class="docutils literal"><span class="pre">tmpdir</span></code>
fixture, shipped with pytest, allows you to easily manage (and
automatically remove) temporary directories. The <code class="docutils literal"><span class="pre">betamax</span></code> fixtures
is a uses the <a class="reference external" href="https://betamax.readthedocs.io/">betamax</a> module to
record then replay HTTP requests.</p>
<p>Then we need to do something. We need to create a feed and a feed item
that we can then send into the plugin. We could also directly parse an
existing feed and indeed some plugins do exactly that. But our plugin
is simple and we can afford to skip full feed parsing and just
synthesize what we need:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="n">feed</span> <span class="o">=</span> <span class="n">Feed</span><span class="p">(</span><span class="s1">&#39;test archive&#39;</span><span class="p">,</span> <span class="n">test_sample</span><span class="p">)</span>
<span class="n">item</span> <span class="o">=</span> <span class="n">feedparser</span><span class="o">.</span><span class="n">FeedParserDict</span><span class="p">({</span><span class="s1">&#39;link&#39;</span><span class="p">:</span> <span class="s1">&#39;http://example.com/&#39;</span><span class="p">,</span>
                                 <span class="s1">&#39;title&#39;</span><span class="p">:</span> <span class="s1">&#39;example site&#39;</span><span class="p">})</span>
</pre></div>
</div>
<p>This creates a new feed based on the <code class="docutils literal"><span class="pre">test_sample</span></code> feed. This is
necessary so that the <code class="docutils literal"><span class="pre">session</span></code> is properly re-initialized in the
feed item (otherwise the <code class="docutils literal"><span class="pre">betamax</span></code> fixture will not work). Then it
creates a fake feed entry simply with one link and a title. Then we
can call our plugin, and verify that it saves the file as we
expected. The test for the most common case looks like this:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="k">def</span> <span class="nf">test_archive</span><span class="p">(</span><span class="n">tmpdir</span><span class="p">,</span> <span class="n">betamax</span><span class="p">):</span>  <span class="c1"># noqa</span>
    <span class="n">dest</span> <span class="o">=</span> <span class="n">tmpdir</span><span class="o">.</span><span class="n">join</span><span class="p">(</span><span class="s1">&#39;archive&#39;</span><span class="p">)</span>
    <span class="n">feed</span> <span class="o">=</span> <span class="n">Feed</span><span class="p">(</span><span class="s1">&#39;test archive&#39;</span><span class="p">,</span> <span class="n">test_sample</span><span class="p">)</span>
    <span class="n">item</span> <span class="o">=</span> <span class="n">feedparser</span><span class="o">.</span><span class="n">FeedParserDict</span><span class="p">({</span><span class="s1">&#39;link&#39;</span><span class="p">:</span> <span class="s1">&#39;http://example.com/&#39;</span><span class="p">,</span>
                                      <span class="s1">&#39;title&#39;</span><span class="p">:</span> <span class="s1">&#39;example site&#39;</span><span class="p">})</span>
    <span class="k">assert</span> <span class="n">archive_plugin</span><span class="o">.</span><span class="n">output</span><span class="p">(</span><span class="nb">str</span><span class="p">(</span><span class="n">dest</span><span class="p">),</span> <span class="n">feed</span><span class="o">=</span><span class="n">feed</span><span class="p">,</span> <span class="n">item</span><span class="o">=</span><span class="n">item</span><span class="p">)</span>
    <span class="k">assert</span> <span class="n">dest</span><span class="o">.</span><span class="n">join</span><span class="p">(</span><span class="s1">&#39;example-site&#39;</span><span class="p">)</span><span class="o">.</span><span class="n">check</span><span class="p">()</span>
</pre></div>
</div>
<p>Then we can try to run this with <code class="docutils literal"><span class="pre">pytest-3</span></code>:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span>[1084]anarcat@curie:feed2exec$ pytest-3
=============================== test session starts ===============================
platform linux -- Python 3.5.3, pytest-3.0.6, py-1.4.32, pluggy-0.4.0
rootdir: /home/anarcat/src/feed2exec, inifile: setup.cfg
plugins: profiling-1.2.11, cov-2.4.0, betamax-0.8.0
collected 26 items

feed2exec/utils.py ..
feed2exec/plugins/transmission.py .
feed2exec/tests/test_feeds.py ........
feed2exec/tests/test_main.py .....
feed2exec/tests/test_opml.py .
feed2exec/tests/test_plugins.py .........

----------- coverage: platform linux, python 3.5.3-final-0 -----------
Name                                         Stmts   Miss  Cover
----------------------------------------------------------------
feed2exec/__init__.py                           12      0   100%
feed2exec/__main__.py                           87      1    99%
feed2exec/_version.py                            1      0   100%
feed2exec/email.py                              81      7    91%
feed2exec/feeds.py                             243      8    97%
feed2exec/logging.py                            31     11    65%
feed2exec/plugins/__init__.py                   47      6    87%
feed2exec/plugins/archive.py                    23      5    78%
feed2exec/plugins/droptitle.py                   2      0   100%
feed2exec/plugins/echo.py                        8      0   100%
feed2exec/plugins/emptysummary.py                5      0   100%
feed2exec/plugins/error.py                       2      0   100%
feed2exec/plugins/exec.py                        7      0   100%
feed2exec/plugins/html2text.py                  20      4    80%
feed2exec/plugins/ikiwiki_recentchanges.py       9      5    44%
feed2exec/plugins/maildir.py                    28      0   100%
feed2exec/plugins/mbox.py                       29      1    97%
feed2exec/plugins/null.py                        5      1    80%
feed2exec/plugins/transmission.py               20      0   100%
feed2exec/plugins/wayback.py                    20      0   100%
feed2exec/tests/__init__.py                      0      0   100%
feed2exec/tests/conftest.py                      3      0   100%
feed2exec/tests/fixtures.py                     19      0   100%
feed2exec/tests/test_feeds.py                  124      0   100%
feed2exec/tests/test_main.py                    90      0   100%
feed2exec/tests/test_opml.py                    17      0   100%
feed2exec/tests/test_plugins.py                162      0   100%
feed2exec/utils.py                              41     12    71%
----------------------------------------------------------------
TOTAL                                         1136     61    95%


=========================== 26 passed in 10.83 seconds ============================
</pre></div>
</div>
<p>Notice the test coverage: we only have 78% test coverage for our
plugin. This means that some branches of the code were not executed at
all! Let’s see if we can improve that. Looking at the code, I see
there are some conditionals for error handling. So let’s simulate an
error, and make sure that we don’t create a file on error:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="n">dest</span><span class="o">.</span><span class="n">remove</span><span class="p">()</span>
<span class="n">item</span> <span class="o">=</span> <span class="n">feedparser</span><span class="o">.</span><span class="n">FeedParserDict</span><span class="p">({</span><span class="s1">&#39;link&#39;</span><span class="p">:</span> <span class="s1">&#39;http://example.com/404&#39;</span><span class="p">,</span>
                                <span class="s1">&#39;title&#39;</span><span class="p">:</span> <span class="s1">&#39;example site&#39;</span><span class="p">})</span>
<span class="k">assert</span> <span class="ow">not</span> <span class="n">archive_plugin</span><span class="o">.</span><span class="n">output</span><span class="p">(</span><span class="nb">str</span><span class="p">(</span><span class="n">dest</span><span class="p">),</span> <span class="n">feed</span><span class="o">=</span><span class="n">feed</span><span class="p">,</span> <span class="n">item</span><span class="o">=</span><span class="n">item</span><span class="p">)</span>
<span class="k">assert</span> <span class="ow">not</span> <span class="n">dest</span><span class="o">.</span><span class="n">join</span><span class="p">(</span><span class="s1">&#39;example-site&#39;</span><span class="p">)</span><span class="o">.</span><span class="n">check</span><span class="p">()</span>
</pre></div>
</div>
<p>There. Let’s see the effect on the test coverage:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span>[1085]anarcat@curie:feed2exec2$ pytest-3 feed2exec/tests/test_plugins.py::test_archive
=============================== test session starts ===============================
platform linux -- Python 3.5.3, pytest-3.0.6, py-1.4.32, pluggy-0.4.0
rootdir: /home/anarcat/src/feed2exec, inifile: setup.cfg
plugins: profiling-1.2.11, cov-2.4.0, betamax-0.8.0
collected 10 items

feed2exec/tests/test_plugins.py .

----------- coverage: platform linux, python 3.5.3-final-0 -----------
Name                                         Stmts   Miss  Cover
----------------------------------------------------------------
feed2exec/__init__.py                           12      0   100%
feed2exec/__main__.py                           87     87     0%
feed2exec/_version.py                            1      0   100%
feed2exec/email.py                              81     64    21%
feed2exec/feeds.py                             243    172    29%
feed2exec/logging.py                            31     31     0%
feed2exec/plugins/__init__.py                   47     38    19%
feed2exec/plugins/archive.py                    23      3    87%
feed2exec/plugins/droptitle.py                   2      2     0%
feed2exec/plugins/echo.py                        8      3    62%
feed2exec/plugins/emptysummary.py                5      5     0%
feed2exec/plugins/error.py                       2      2     0%
feed2exec/plugins/exec.py                        7      7     0%
feed2exec/plugins/html2text.py                  20     13    35%
feed2exec/plugins/ikiwiki_recentchanges.py       9      9     0%
feed2exec/plugins/maildir.py                    28     19    32%
feed2exec/plugins/mbox.py                       29     29     0%
feed2exec/plugins/null.py                        5      5     0%
feed2exec/plugins/transmission.py               20     12    40%
feed2exec/plugins/wayback.py                    20     20     0%
feed2exec/tests/__init__.py                      0      0   100%
feed2exec/tests/conftest.py                      3      0   100%
feed2exec/tests/fixtures.py                     19      6    68%
feed2exec/tests/test_feeds.py                  124    101    19%
feed2exec/tests/test_main.py                    90     90     0%
feed2exec/tests/test_opml.py                    17     17     0%
feed2exec/tests/test_plugins.py                166    123    26%
feed2exec/utils.py                              41     16    61%
----------------------------------------------------------------
TOTAL                                         1140    874    23%


============================ 1 passed in 2.46 seconds =============================
</pre></div>
</div>
<p>Much better! Only 3 lines left to cover!</p>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">Notice how I explicitly provided a path to my test. This is
entirely optional. You can just run <code class="docutils literal"><span class="pre">pytest-3</span></code> and it will
run the whole test suite: this method is just faster. Notice
also how the coverage ratio is very low: this is normal; we
are testing, after all, only <em>one</em> plugin here.</p>
</div>
<p>The only branches left to test in the code is the other possible error
(“no link in the feed”) and to test the “catchup” mode. You can see
this in the actual <code class="docutils literal"><span class="pre">test_plugins.py</span></code> file distributed with this
documentation.</p>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">If you discover a bug associated with a single feed, you can
use the betamax session and the
<a class="reference internal" href="api.html#feed2exec.feeds.Feed.parse" title="feed2exec.feeds.Feed.parse"><code class="xref py py-func docutils literal"><span class="pre">feed2exec.feeds.Feed.parse()</span></code></a> function to manually
parse a feed and fire your plugin. This is how email
functionality is tested: see the
<code class="xref py py-func docutils literal"><span class="pre">feed2exec.tests.test_plugins.test_email()</span></code> function for
an example.</p>
</div>
</div>
</div>
<div class="section" id="see-also">
<h2>See also<a class="headerlink" href="#see-also" title="Permalink to this headline"></a></h2>
<p><em class="manpage">feed2exec(1)</em></p>
</div>
</div>


           </div>
           <div class="articleComments">
            
           </div>
          </div>
          <footer>
  
    <div class="rst-footer-buttons" role="navigation" aria-label="footer navigation">
      
        <a href="support.html" class="btn btn-neutral float-right" title="Support" accesskey="n" rel="next">Next <span class="fa fa-arrow-circle-right"></span></a>
      
      
        <a href="api.html" class="btn btn-neutral" title="API documentation" accesskey="p" rel="prev"><span class="fa fa-arrow-circle-left"></span> Previous</a>
      
    </div>
  

  <hr/>

  <div role="contentinfo">
    <p>
        &copy; Copyright Copyright (C) 2016  Antoine Beaupré.

    </p>
  </div>
  Built with <a href="http://sphinx-doc.org/">Sphinx</a> using a <a href="https://github.com/snide/sphinx_rtd_theme">theme</a> provided by <a href="https://readthedocs.org">Read the Docs</a>. 

</footer>

        </div>
      </div>

    </section>

  </div>
  


  

    <script type="text/javascript">
        var DOCUMENTATION_OPTIONS = {
            URL_ROOT:'./',
            VERSION:'0.11.0',
            COLLAPSE_INDEX:false,
            FILE_SUFFIX:'.html',
            HAS_SOURCE:  true,
            SOURCELINK_SUFFIX: '.txt'
        };
    </script>
      <script type="text/javascript" src="_static/jquery.js"></script>
      <script type="text/javascript" src="_static/underscore.js"></script>
      <script type="text/javascript" src="_static/doctools.js"></script>

  

  
  
    <script type="text/javascript" src="_static/js/theme.js"></script>
  

  
  
  <script type="text/javascript">
      jQuery(function () {
          SphinxRtdTheme.StickyNav.enable();
      });
  </script>
   

</body>
</html>