/usr/share/pyshared/coherence/backend.py is in python-coherence 0.6.6.2-8.
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# Licensed under the MIT license
# http://opensource.org/licenses/mit-license.php
# Copyright 2007,, Frank Scholz <coherence@beebits.net>
import time
from coherence.extern.simple_plugin import Plugin
from coherence import log
import coherence.extern.louie as louie
from coherence.upnp.core.utils import getPage
from coherence.extern.et import parse_xml
from coherence.upnp.core import DIDLLite
class Backend(log.Loggable,Plugin):
""" the base class for all backends
if there are any UPnP service actions, that can't
be handled by the service classes itself, or need some
special adjustments for the backend, they need to be
defined here.
Like maybe upnp_Browse for the CDS Browse action.
"""
implements = [] # list the device classes here
# like [BinaryLight'] or ['MediaServer','MediaRenderer']
logCategory = 'backend'
def __init__(self,server,**kwargs):
""" the init method for a backend,
should probably most of the time be overwritten
when the init is done, send a signal to its device
the device will then setup and announce itself,
after that it calls the backends upnp_init method
"""
self.config = kwargs
self.server = server # the UPnP device that's hosting that backend
""" do whatever is necessary with the stuff we can
extract from the config dict,
connect maybe to an external data-source and
start up the backend
after that's done, tell Coherence about it
"""
log.Loggable.__init__(self)
Plugin.__init__(self)
""" this has to be done in the actual backend, maybe it has
to wait for an answer from an external data-source first
"""
#self.init_completed()
def init_completed(self, *args, **kwargs):
""" inform Coherence that this backend is ready for
announcement
this method just accepts any form of arguments
as we don't under which circumstances it is called
"""
louie.send('Coherence.UPnP.Backend.init_completed',
None, backend=self)
def upnp_init(self):
""" this method gets called after the device is fired,
here all initializations of service related state variables
should happen, as the services aren't available before that point
"""
pass
class BackendStore(Backend):
""" the base class for all MediaServer backend stores
"""
logCategory = 'backend_store'
def __init__(self,server,*args,**kwargs):
""" the init method for a MediaServer backend,
should probably most of the time be overwritten
when the init is done, send a signal to its device
the device will then setup and announce itself,
after that it calls the backends upnp_init method
"""
Backend.__init__(self, server, *args)
self.config = kwargs
self.server = server # the UPnP device that's hosting that backend
self.update_id = 0
""" do whatever is necessary with the stuff we can
extract from the config dict
"""
""" in case we want so serve something via
the MediaServer web backend
the BackendItem should pass an URI assembled
of urlbase + '/' + id to the DIDLLite.Resource
"""
self.urlbase = kwargs.get('urlbase','')
if not self.urlbase.endswith('/'):
self.urlbase += '/'
self.wmc_mapping = {'4':'4', '5':'5', '6':'6','7':'7','14':'14','F':'F',
'11':'11','16':'16','B':'B','C':'C','D':'D',
'13':'13', '17':'17',
'8':'8', '9':'9', '10':'10', '15':'15', 'A':'A', 'E':'E'}
self.wmc_mapping.update({'4':lambda: self._get_all_items(0),
'8':lambda: self._get_all_items(0),
'B':lambda: self._get_all_items(0),
})
""" and send out the signal when ready
"""
#louie.send('Coherence.UPnP.Backend.init_completed', None, backend=self)
def release(self):
""" if anything needs to be cleaned up upon
shutdown of this backend, this is the place
for it
"""
pass
def _get_all_items(self,id):
""" a helper method to get all items as a response
to some XBox 360 UPnP Search action
probably never be used as the backend will overwrite
the wmc_mapping with more appropriate methods
"""
items = []
item = self.get_by_id(id)
if item is not None:
containers = [item]
while len(containers)>0:
container = containers.pop()
if container.mimetype not in ['root', 'directory']:
continue
for child in container.get_children(0,0):
if child.mimetype in ['root', 'directory']:
containers.append(child)
else:
items.append(child)
return items
def get_by_id(self,id):
""" called by the CDS or the MediaServer web
id is the id property of our DIDLLite item
if this MediaServer implements containers, that can
share their content, like 'all tracks', 'album' and
'album_of_artist' - they all have the same track item as content -
then the id may be passed by the CDS like this:
'id@container' or 'id@container@container@container...'
therefore a
if isinstance(id, basestring):
id = id.split('@',1)
id = id[0]
may be appropriate as the first thing to do
when entering this method
should return
- None when no matching item for that id is found,
- a BackendItem,
- or a Deferred
"""
return None
class BackendItem(log.Loggable):
""" the base class for all MediaServer backend items
"""
logCategory = 'backend_item'
def __init__(self, *args, **kwargs):
""" most of the time we collect the necessary data for
an UPnP ContentDirectoryService Container or Object
and instantiate it here
self.item = DIDLLite.Container(id,parent_id,name,...)
or
self.item = DIDLLite.MusicTrack(id,parent_id,name,...)
To make that a valid UPnP CDS Object it needs one or
more DIDLLite.Resource(uri,protocolInfo)
self.item.res = []
res = DIDLLite.Resource(url, 'http-get:*:%s:*' % mimetype)
url : the urlbase of our backend + '/' + our id
res.size = size
self.item.res.append(res)
"""
self.name = u'my_name' # the basename of a file, the album title,
# the artists name,...
# is expected to be unicode
self.item = None
self.update_id = 0 # the update id of that item,
# when an UPnP ContentDirectoryService Container
# this should be incremented on every modification
self.location = None # the filepath of our media file, or alternatively
# a FilePath or a ReverseProxyResource object
self.cover = None # if we have some album art image, let's put
# the filepath or link into here
def get_children(self,start=0,end=0):
""" called by the CDS and the MediaServer web
should return
- a list of its childs[start:end]
- or a Deferred
if end == 0, the request is for all childs
after start - childs[start:]
"""
pass
def get_child_count(self):
""" called by the CDS
should return
- the number of its childs - len(childs)
- or a Deferred
"""
def get_item(self):
""" called by the CDS and the MediaServer web
should return
- an UPnP ContentDirectoryServer DIDLLite object
- or a Deferred
"""
return self.item
def get_name(self):
""" called by the MediaServer web
should return
- the name of the item,
it is always expected to be in unicode
"""
return self.name
def get_path(self):
""" called by the MediaServer web
should return
- the filepath where to find the media file
that this item does refer to
"""
return self.location
def get_cover(self):
""" called by the MediaServer web
should return
- the filepath where to find the album art file
only needed when we have created for that item
an albumArtURI property that does point back to us
"""
return self.cover
class BackendRssMixin:
def update_data(self,rss_url,container=None,encoding="utf-8"):
""" creates a deferred chain to retrieve the rdf file,
parse and extract the metadata and reschedule itself
"""
def fail(f):
self.info("fail %r", f)
self.debug(f.getTraceback())
return f
dfr = getPage(rss_url)
dfr.addCallback(parse_xml, encoding=encoding)
dfr.addErrback(fail)
dfr.addCallback(self.parse_data,container)
dfr.addErrback(fail)
dfr.addBoth(self.queue_update,rss_url,container)
return dfr
def parse_data(self,xml_data,container):
""" extract media info and create BackendItems
"""
pass
def queue_update(self, error_or_failure,rss_url,container):
from twisted.internet import reactor
reactor.callLater(self.refresh, self.update_data,rss_url,container)
class Container(BackendItem):
def __init__(self, parent, title):
BackendItem.__init__(self)
self.parent = parent
if self.parent is not None:
self.parent_id = self.parent.get_id()
else:
self.parent_id = -1
self.store = None
self.storage_id = None
self.name = title
self.mimetype = 'directory'
self.children = []
self.children_ids = {}
self.children_by_external_id = {}
self.update_id = 0
self.item = None
self.sorted = False
def register_child(self, child, external_id = None):
id = self.store.append_item(child)
child.url = self.store.urlbase + str(id)
child.parent = self
if external_id is not None:
child.external_id = external_id
self.children_by_external_id[external_id] = child
def add_child(self, child, external_id = None, update=True):
id = self.register_child(child, external_id)
if self.children is None:
self.children = []
self.children.append(child)
self.sorted = False
if update == True:
self.update_id += 1
def remove_child(self, child, external_id = None, update=True):
self.children.remove(child)
self.store.remove_item(child)
if update == True:
self.update_id += 1
if external_id is not None:
child.external_id = None
del self.children_by_external_id[external_id]
def get_children(self, start=0, end=0):
if self.sorted == False:
def childs_sort(x,y):
r = cmp(x.name,y.name)
return r
self.children.sort(cmp=childs_sort)
self.sorted = True
if end != 0:
return self.children[start:end]
return self.children[start:]
def get_child_count(self):
if self.children is None:
return 0
return len(self.children)
def get_path(self):
return self.store.urlbase + str(self.storage_id)
def get_item(self):
if self.item is None:
self.item = DIDLLite.Container(self.storage_id, self.parent_id, self.name)
self.item.childCount = len(self.children)
return self.item
def get_name(self):
return self.name
def get_id(self):
return self.storage_id
def get_update_id(self):
return self.update_id
class LazyContainer(Container, log.Loggable):
logCategory = 'lazyContainer'
def __init__(self, parent, title, external_id=None, refresh=0, childrenRetriever=None, **kwargs):
Container.__init__(self, parent, title)
self.childrenRetrievingNeeded = False
self.childrenRetrievingDeferred = None
self.childrenRetriever = childrenRetriever
self.children_retrieval_campaign_in_progress = False
self.childrenRetriever_params = kwargs
self.childrenRetriever_params['parent']=self
self.has_pages = (self.childrenRetriever_params.has_key('per_page'))
self.external_id = None
self.external_id = external_id
self.retrieved_children = {}
self.last_updated = 0
self.refresh = refresh
def replace_by(self, item):
if self.external_id is not None and item.external_id is not None:
return (self.external_id == item.external_id)
return True
def add_child(self, child, external_id = None, update=True):
if self.children_retrieval_campaign_in_progress is True:
self.retrieved_children[external_id] = child
else:
Container.add_child(self, child, external_id=external_id, update=update)
def update_children(self, new_children, old_children):
children_to_be_removed = {}
children_to_be_replaced = {}
children_to_be_added = {}
# Phase 1
# let's classify the item between items to be removed,
# to be updated or to be added
self.debug("Refresh pass 1:%d %d" % (len(new_children), len(old_children)))
for id,item in old_children.items():
children_to_be_removed[id] = item
for id,item in new_children.items():
if old_children.has_key(id):
#print(id, "already there")
children_to_be_replaced[id] = old_children[id]
del children_to_be_removed[id]
else:
children_to_be_added[id] = new_children[id]
# Phase 2
# Now, we remove, update or add the relevant items
# to the list of items
self.debug("Refresh pass 2: %d %d %d" % (len(children_to_be_removed), len(children_to_be_replaced), len(children_to_be_added)))
# Remove relevant items from Container children
for id,item in children_to_be_removed.items():
self.remove_child(item, external_id=id, update=False)
# Update relevant items from Container children
for id,item in children_to_be_replaced.items():
old_item = item
new_item = new_children[id]
replaced = False
if self.replace_by:
#print "Replacement method available: Try"
replaced = old_item.replace_by(new_item)
if replaced is False:
#print "No replacement possible: we remove and add the item again"
self.remove_child(old_item, external_id=id, update=False)
self.add_child(new_item, external_id=id, update=False)
# Add relevant items to COntainer children
for id,item in children_to_be_added.items():
self.add_child(item, external_id=id, update=False)
self.update_id += 1
def start_children_retrieval_campaign(self):
#print "start_update_campaign"
self.last_updated = time.time()
self.retrieved_children = {}
self.children_retrieval_campaign_in_progress = True
def end_children_retrieval_campaign(self, success=True):
#print "end_update_campaign"
self.children_retrieval_campaign_in_progress = False
if success is True:
self.update_children(self.retrieved_children, self.children_by_external_id)
self.update_id += 1
self.last_updated = time.time()
self.retrieved_children = {}
def retrieve_children(self, start=0):
def items_retrieved(result, source_deferred):
childrenRetrievingOffset = len(self.retrieved_children)
if self.childrenRetrievingNeeded is True:
return self.retrieve_children(childrenRetrievingOffset)
return self.retrieved_children
self.childrenRetrievingNeeded = False
if self.has_pages is True:
self.childrenRetriever_params['offset'] = start
d = self.childrenRetriever(**self.childrenRetriever_params)
d.addCallback(items_retrieved, d)
return d
def retrieve_all_children(self, start=0, request_count=0):
def all_items_retrieved (result):
#print "All items retrieved!"
self.end_children_retrieval_campaign(True)
return Container.get_children(self, start, request_count)
def error_while_retrieving_items (error):
#print "All items retrieved!"
self.end_children_retrieval_campaign(False)
return Container.get_children(self, start, request_count)
# if first retrieval and refresh required
# we start a looping call to periodically update the children
#if ((self.last_updated == 0) and (self.refresh > 0)):
# task.LoopingCall(self.retrieve_children,0,0).start(self.refresh, now=False)
self.start_children_retrieval_campaign()
if self.childrenRetriever is not None:
d = self.retrieve_children(start)
if start == 0:
d.addCallbacks(all_items_retrieved, error_while_retrieving_items)
return d
else:
self.end_children_retrieval_campaign()
return self.children
def get_children(self,start=0,request_count=0):
# Check if an update is needed since last update
current_time = time.time()
delay_since_last_updated = current_time - self.last_updated
period = self.refresh
if (period > 0) and (delay_since_last_updated > period):
self.info("Last update is older than %d s -> update data" % period)
self.childrenRetrievingNeeded = True
if self.childrenRetrievingNeeded is True:
#print "children Retrieving IS Needed (offset is %d)" % start
return self.retrieve_all_children()
else:
return Container.get_children(self, start, request_count)
ROOT_CONTAINER_ID = 0
SEED_ITEM_ID = 1000
class AbstractBackendStore (BackendStore):
def __init__(self, server, **kwargs):
BackendStore.__init__(self, server, **kwargs)
self.next_id = SEED_ITEM_ID
self.store = {}
def len(self):
return len(self.store)
def set_root_item(self, item):
return self.append_item(item, storage_id = ROOT_CONTAINER_ID)
def get_root_id(self):
return ROOT_CONTAINER_ID
def get_root_item(self):
return self.get_by_id(ROOT_CONTAINER_ID)
def append_item(self, item, storage_id=None):
if storage_id is None:
storage_id = self.getnextID()
self.store[storage_id] = item
item.storage_id = storage_id
item.store = self
return storage_id
def remove_item(self, item):
item.storage_id = -1
item.store = None
del self.store[child.storage_id]
def get_by_id(self,id):
if isinstance(id, basestring):
id = id.split('@',1)
id = id[0].split('.')[0]
try:
return self.store[int(id)]
except (ValueError,KeyError):
pass
return None
def getnextID(self):
ret = self.next_id
self.next_id += 1
return ret
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