/usr/lib/python2.7/dist-packages/hpack/table.py is in python-hpack 2.3.0-1.
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 | # -*- coding: utf-8 -*-
# flake8: noqa
from collections import deque
import logging
from .exceptions import InvalidTableIndex
log = logging.getLogger(__name__)
def table_entry_size(name, value):
"""
Calculates the size of a single entry
This size is mostly irrelevant to us and defined
specifically to accommodate memory management for
lower level implementations. The 32 extra bytes are
considered the "maximum" overhead that would be
required to represent each entry in the table.
See RFC7541 Section 4.1
"""
return 32 + len(name) + len(value)
class HeaderTable(object):
"""
Implements the combined static and dynamic header table
The name and value arguments for all the functions
should ONLY be byte strings (b'') however this is not
strictly enforced in the interface.
See RFC7541 Section 2.3
"""
#: Default maximum size of the dynamic table. See
#: RFC7540 Section 6.5.2.
DEFAULT_SIZE = 4096
#: Constant list of static headers. See RFC7541 Section
#: 2.3.1 and Appendix A
STATIC_TABLE = (
(b':authority' , b'' ), # noqa
(b':method' , b'GET' ), # noqa
(b':method' , b'POST' ), # noqa
(b':path' , b'/' ), # noqa
(b':path' , b'/index.html' ), # noqa
(b':scheme' , b'http' ), # noqa
(b':scheme' , b'https' ), # noqa
(b':status' , b'200' ), # noqa
(b':status' , b'204' ), # noqa
(b':status' , b'206' ), # noqa
(b':status' , b'304' ), # noqa
(b':status' , b'400' ), # noqa
(b':status' , b'404' ), # noqa
(b':status' , b'500' ), # noqa
(b'accept-charset' , b'' ), # noqa
(b'accept-encoding' , b'gzip, deflate'), # noqa
(b'accept-language' , b'' ), # noqa
(b'accept-ranges' , b'' ), # noqa
(b'accept' , b'' ), # noqa
(b'access-control-allow-origin' , b'' ), # noqa
(b'age' , b'' ), # noqa
(b'allow' , b'' ), # noqa
(b'authorization' , b'' ), # noqa
(b'cache-control' , b'' ), # noqa
(b'content-disposition' , b'' ), # noqa
(b'content-encoding' , b'' ), # noqa
(b'content-language' , b'' ), # noqa
(b'content-length' , b'' ), # noqa
(b'content-location' , b'' ), # noqa
(b'content-range' , b'' ), # noqa
(b'content-type' , b'' ), # noqa
(b'cookie' , b'' ), # noqa
(b'date' , b'' ), # noqa
(b'etag' , b'' ), # noqa
(b'expect' , b'' ), # noqa
(b'expires' , b'' ), # noqa
(b'from' , b'' ), # noqa
(b'host' , b'' ), # noqa
(b'if-match' , b'' ), # noqa
(b'if-modified-since' , b'' ), # noqa
(b'if-none-match' , b'' ), # noqa
(b'if-range' , b'' ), # noqa
(b'if-unmodified-since' , b'' ), # noqa
(b'last-modified' , b'' ), # noqa
(b'link' , b'' ), # noqa
(b'location' , b'' ), # noqa
(b'max-forwards' , b'' ), # noqa
(b'proxy-authenticate' , b'' ), # noqa
(b'proxy-authorization' , b'' ), # noqa
(b'range' , b'' ), # noqa
(b'referer' , b'' ), # noqa
(b'refresh' , b'' ), # noqa
(b'retry-after' , b'' ), # noqa
(b'server' , b'' ), # noqa
(b'set-cookie' , b'' ), # noqa
(b'strict-transport-security' , b'' ), # noqa
(b'transfer-encoding' , b'' ), # noqa
(b'user-agent' , b'' ), # noqa
(b'vary' , b'' ), # noqa
(b'via' , b'' ), # noqa
(b'www-authenticate' , b'' ), # noqa
) # noqa
def __init__(self):
self._maxsize = HeaderTable.DEFAULT_SIZE
self._current_size = 0
self.resized = False
self.dynamic_entries = deque()
def get_by_index(self, index):
"""
Returns the entry specified by index
Note that the table is 1-based ie an index of 0 is
invalid. This is due to the fact that a zero value
index signals that a completely unindexed header
follows.
The entry will either be from the static table or
the dynamic table depending on the value of index.
"""
index -= 1
if 0 <= index < len(HeaderTable.STATIC_TABLE):
return HeaderTable.STATIC_TABLE[index]
index -= len(HeaderTable.STATIC_TABLE)
if 0 <= index < len(self.dynamic_entries):
return self.dynamic_entries[index]
raise InvalidTableIndex("Invalid table index %d" % index)
def __repr__(self):
return "HeaderTable(%d, %s, %r)" % (
self._maxsize,
self.resized,
self.dynamic_entries
)
def add(self, name, value):
"""
Adds a new entry to the table
We reduce the table size if the entry will make the
table size greater than maxsize.
"""
# We just clear the table if the entry is too big
size = table_entry_size(name, value)
if size > self._maxsize:
self.dynamic_entries.clear()
self._current_size = 0
# Add new entry if the table actually has a size
elif self._maxsize > 0:
self.dynamic_entries.appendleft((name, value))
self._current_size += size
self._shrink()
def search(self, name, value):
"""
Searches the table for the entry specified by name
and value
Returns one of the following:
- ``None``, no match at all
- ``(index, name, None)`` for partial matches on name only.
- ``(index, name, value)`` for perfect matches.
"""
offset = len(HeaderTable.STATIC_TABLE)
partial = None
for (i, (n, v)) in enumerate(HeaderTable.STATIC_TABLE):
if n == name:
if v == value:
return i + 1, n, v
elif partial is None:
partial = (i + 1, n, None)
for (i, (n, v)) in enumerate(self.dynamic_entries):
if n == name:
if v == value:
return i + offset + 1, n, v
elif partial is None:
partial = (i + offset + 1, n, None)
return partial
@property
def maxsize(self):
return self._maxsize
@maxsize.setter
def maxsize(self, newmax):
newmax = int(newmax)
log.debug("Resizing header table to %d from %d", newmax, self._maxsize)
oldmax = self._maxsize
self._maxsize = newmax
self.resized = (newmax != oldmax)
if newmax <= 0:
self.dynamic_entries.clear()
self._current_size = 0
elif oldmax > newmax:
self._shrink()
def _shrink(self):
"""
Shrinks the dynamic table to be at or below maxsize
"""
cursize = self._current_size
while cursize > self._maxsize:
name, value = self.dynamic_entries.pop()
cursize -= table_entry_size(name, value)
log.debug("Evicting %s: %s from the header table", name, value)
self._current_size = cursize
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