26
from bisect import bisect
27
26
from cStringIO import StringIO
30
from bzrlib import errors
31
from bzrlib.trace import mutter
34
class ResponseRange(object):
35
"""A range in a RangeFile-object."""
37
__slots__ = ['_ent_start', '_ent_end', '_data_start']
39
def __init__(self, ent_start, ent_end, data_start):
40
self._ent_start = ent_start
41
self._ent_end = ent_end
42
self._data_start = data_start
44
def __cmp__(self, other):
45
"""Compare this to other.
47
We need this both for sorting, and so that we can
48
bisect the list of ranges.
50
if isinstance(other, int):
51
# Later on we bisect for a starting point
52
# so we allow comparing against a single integer
53
return cmp(self._ent_start, other)
55
return cmp((self._ent_start, self._ent_end, self._data_start),
56
(other._ent_start, other._ent_end, other._data_start))
59
return "%s(%s-%s,%s)" % (self.__class__.__name__,
60
self._ent_start, self._ent_end,
35
# A RangeFile expects the following grammar (simplified to outline the
36
# assumptions we rely upon).
42
# whole_file: [content_length_header] data
44
# single_range: content_range_header data
46
# multiple_range: boundary_header boundary (content_range_header data boundary)+
64
48
class RangeFile(object):
65
49
"""File-like object that allow access to partial available data.
67
Specified by a set of ranges.
51
All accesses should happen sequentially since the acquisition occurs during
52
an http response reception (as sockets can't be seeked, we simulate the
53
seek by just reading and discarding the data).
55
The access pattern is defined by a set of ranges discovered as reading
56
progress. Only one range is available at a given time, so all accesses
57
should happen with monotonically increasing offsets.
70
def __init__(self, path, input_file):
60
# in _checked_read() below, we may have to discard several MB in the worst
61
# case. To avoid buffering that much, we read and discard by chunks
62
# instead. The underlying file is either a socket or a StringIO, so reading
63
# 8k chunks should be fine.
64
_discarded_buf_size = 8192
66
# maximum size of read requests -- used to avoid MemoryError issues in recv
67
_max_read_size = 512 * 1024
69
def __init__(self, path, infile):
72
:param path: File url, for error reports.
73
:param infile: File-like socket set at body start.
75
self._data = input_file.read()
77
def _add_range(self, ent_start, ent_end, data_start):
78
"""Add an entity range.
80
:param ent_start: Start offset of entity
81
:param ent_end: End offset of entity (inclusive)
82
:param data_start: Start offset of data in data stream.
84
self._ranges.append(ResponseRange(ent_start, ent_end, data_start))
85
self._len = max(self._len, ent_end)
87
def _finish_ranges(self):
78
# When using multi parts response, this will be set with the headers
79
# associated with the range currently read.
81
# Default to the whole file of unspecified size
84
def set_range(self, start, size):
85
"""Change the range mapping"""
88
# Set the new _pos since that's what we want to expose
89
self._pos = self._start
91
def set_boundary(self, boundary):
92
"""Define the boundary used in a multi parts message.
94
The file should be at the beginning of the body, the first range
95
definition is read and taken into account.
97
self._boundary = boundary
98
# Decode the headers and setup the first range
100
self.read_range_definition()
102
def read_boundary(self):
103
"""Read the boundary headers defining a new range"""
104
boundary_line = '\r\n'
105
while boundary_line == '\r\n':
106
# RFC2616 19.2 Additional CRLFs may precede the first boundary
108
# To be on the safe side we allow it before any boundary line
109
boundary_line = self._file.readline()
111
if boundary_line == '':
112
# A timeout in the proxy server caused the response to end early.
113
# See launchpad bug 198646.
114
raise errors.HttpBoundaryMissing(
118
if boundary_line != '--' + self._boundary + '\r\n':
119
# rfc822.unquote() incorrectly unquotes strings enclosed in <>
120
# IIS 6 and 7 incorrectly wrap boundary strings in <>
121
# together they make a beautiful bug, which we will be gracious
123
if (self._unquote_boundary(boundary_line) !=
124
'--' + self._boundary + '\r\n'):
125
raise errors.InvalidHttpResponse(
127
"Expected a boundary (%s) line, got '%s'"
128
% (self._boundary, boundary_line))
130
def _unquote_boundary(self, b):
131
return b[:2] + rfc822.unquote(b[2:-2]) + b[-2:]
133
def read_range_definition(self):
134
"""Read a new range definition in a multi parts message.
136
Parse the headers including the empty line following them so that we
137
are ready to read the data itself.
139
self._headers = httplib.HTTPMessage(self._file, seekable=0)
140
# Extract the range definition
141
content_range = self._headers.getheader('content-range', None)
142
if content_range is None:
143
raise errors.InvalidHttpResponse(
145
'Content-Range header missing in a multi-part response')
146
self.set_range_from_header(content_range)
148
def set_range_from_header(self, content_range):
149
"""Helper to set the new range from its description in the headers"""
151
rtype, values = content_range.split()
153
raise errors.InvalidHttpRange(self._path, content_range,
156
raise errors.InvalidHttpRange(self._path, content_range,
157
"Unsupported range type '%s'" % rtype)
159
# We don't need total, but note that it may be either the file size
160
# or '*' if the server can't or doesn't want to return the file
162
start_end, total = values.split('/')
163
start, end = start_end.split('-')
167
raise errors.InvalidHttpRange(self._path, content_range,
168
'Invalid range values')
169
size = end - start + 1
171
raise errors.InvalidHttpRange(self._path, content_range,
172
'Invalid range, size <= 0')
173
self.set_range(start, size)
175
def _checked_read(self, size):
176
"""Read the file checking for short reads.
178
The data read is discarded along the way.
183
data = self._file.read(min(remaining, self._discarded_buf_size))
184
remaining -= len(data)
186
raise errors.ShortReadvError(self._path, pos, size,
190
def _seek_to_next_range(self):
191
# We will cross range boundaries
192
if self._boundary is None:
193
# If we don't have a boundary, we can't find another range
194
raise errors.InvalidRange(self._path, self._pos,
195
"Range (%s, %s) exhausted"
196
% (self._start, self._size))
198
self.read_range_definition()
200
def read(self, size=-1):
91
201
"""Read size bytes from the current position in the file.
93
Reading across ranges is not supported.
203
Reading across ranges is not supported. We rely on the underlying http
204
client to clean the socket if we leave bytes unread. This may occur for
205
the final boundary line of a multipart response or for any range
206
request not entirely consumed by the client (due to offset coalescing)
208
:param size: The number of bytes to read. Leave unspecified or pass
95
# find the last range which has a start <= pos
96
i = bisect(self._ranges, self._pos) - 1
98
if i < 0 or self._pos > self._ranges[i]._ent_end:
99
raise errors.InvalidRange(self._path, self._pos)
103
# mutter('found range %s %s for pos %s', i, self._ranges[i], self._pos)
105
if (self._pos + size - 1) > r._ent_end:
106
raise errors.InvalidRange(self._path, self._pos)
108
start = r._data_start + (self._pos - r._ent_start)
110
# mutter("range read %d bytes at %d == %d-%d", size, self._pos,
112
self._pos += (end-start)
113
return self._data[start:end]
212
and self._pos == self._start + self._size):
216
self._seek_to_next_range()
217
elif self._pos < self._start:
218
raise errors.InvalidRange(
219
self._path, self._pos,
220
"Can't read %s bytes before range (%s, %s)"
221
% (size, self._start, self._size))
223
if size > 0 and self._pos + size > self._start + self._size:
224
raise errors.InvalidRange(
225
self._path, self._pos,
226
"Can't read %s bytes across range (%s, %s)"
227
% (size, self._start, self._size))
229
# read data from file
233
# Don't read past the range definition
234
limited = self._start + self._size - self._pos
236
limited = min(limited, size)
237
osutils.pumpfile(self._file, buffer, limited, self._max_read_size)
238
data = buffer.getvalue()
240
# Update _pos respecting the data effectively read
241
self._pos += len(data)
115
244
def seek(self, offset, whence=0):
245
start_pos = self._pos
118
248
elif whence == 1:
249
final_pos = start_pos + offset
120
250
elif whence == 2:
121
self._pos = self._len + offset
252
final_pos = self._start + self._size + offset # offset < 0
254
raise errors.InvalidRange(
255
self._path, self._pos,
256
"RangeFile: can't seek from end while size is unknown")
123
258
raise ValueError("Invalid value %s for whence." % whence)
260
if final_pos < self._pos:
261
# Can't seek backwards
262
raise errors.InvalidRange(
263
self._path, self._pos,
264
'RangeFile: trying to seek backwards to %s' % final_pos)
267
cur_limit = self._start + self._size
268
while final_pos > cur_limit:
269
# We will cross range boundaries
270
remain = cur_limit - self._pos
272
# Finish reading the current range
273
self._checked_read(remain)
274
self._seek_to_next_range()
275
cur_limit = self._start + self._size
277
size = final_pos - self._pos
278
if size > 0: # size can be < 0 if we crossed a range boundary
279
# We don't need the data, just read it and throw it away
280
self._checked_read(size)
132
class HttpRangeResponse(RangeFile):
133
"""A single-range HTTP response."""
135
# TODO: jam 20060706 Consider compiling these regexes on demand
136
_CONTENT_RANGE_RE = re.compile(
137
'\s*([^\s]+)\s+([0-9]+)-([0-9]+)/([0-9]+)\s*$')
139
def __init__(self, path, content_range, input_file):
140
# mutter("parsing 206 non-multipart response for %s", path)
141
RangeFile.__init__(self, path, input_file)
142
start, end = self._parse_range(content_range, path)
143
self._add_range(start, end, 0)
144
self._finish_ranges()
147
def _parse_range(range, path='<unknown>'):
148
"""Parse an http Content-range header and return start + end
150
:param range: The value for Content-range
151
:param path: Provide to give better error messages.
152
:return: (start, end) A tuple of integers
154
match = HttpRangeResponse._CONTENT_RANGE_RE.match(range)
156
raise errors.InvalidHttpRange(path, range,
157
"Invalid Content-range")
159
rtype, start, end, total = match.groups()
162
raise errors.InvalidHttpRange(path, range,
163
"Unsupported range type '%s'" % (rtype,))
168
except ValueError, e:
169
raise errors.InvalidHttpRange(path, range, str(e))
174
class HttpMultipartRangeResponse(RangeFile):
175
"""A multi-range HTTP response."""
177
_CONTENT_TYPE_RE = re.compile(
178
'^\s*multipart/byteranges\s*;\s*boundary\s*=\s*(.*?)\s*$')
180
# Start with --<boundary>\r\n
181
# and ignore all headers ending in \r\n
182
# except for content-range:
183
# and find the two trailing \r\n separators
184
# indicating the start of the text
185
# TODO: jam 20060706 This requires exact conformance
186
# to the spec, we probably could relax the requirement
187
# of \r\n, and use something more like (\r?\n)
189
"^--%s(?:\r\n(?:(?:content-range:([^\r]+))|[^\r]+))+\r\n\r\n")
191
def __init__(self, path, content_type, input_file):
192
# mutter("parsing 206 multipart response for %s", path)
193
# TODO: jam 20060706 Is it valid to initialize a
194
# grandparent without initializing parent?
195
RangeFile.__init__(self, path, input_file)
197
self.boundary_regex = self._parse_boundary(content_type, path)
199
for match in self.boundary_regex.finditer(self._data):
200
ent_start, ent_end = HttpRangeResponse._parse_range(match.group(1),
202
self._add_range(ent_start, ent_end, match.end())
204
self._finish_ranges()
207
def _parse_boundary(ctype, path='<unknown>'):
208
"""Parse the Content-type field.
210
This expects a multipart Content-type, and returns a
211
regex which is capable of finding the boundaries
212
in the multipart data.
214
match = HttpMultipartRangeResponse._CONTENT_TYPE_RE.match(ctype)
216
raise errors.InvalidHttpContentType(path, ctype,
217
"Expected multipart/byteranges with boundary")
219
boundary = match.group(1)
220
# mutter('multipart boundary is %s', boundary)
221
pattern = HttpMultipartRangeResponse._BOUNDARY_PATT
222
return re.compile(pattern % re.escape(boundary),
223
re.IGNORECASE | re.MULTILINE)
226
def _is_multipart(content_type):
227
return content_type.startswith('multipart/byteranges;')
230
def handle_response(url, code, headers, data):
231
"""Interpret the code & headers and return a HTTP response.
233
This is a factory method which returns an appropriate HTTP response
234
based on the code & headers it's given.
286
def handle_response(url, code, msg, data):
287
"""Interpret the code & headers and wrap the provided data in a RangeFile.
289
This is a factory method which returns an appropriate RangeFile based on
290
the code & headers it's given.
236
292
:param url: The url being processed. Mostly for error reporting
237
293
:param code: The integer HTTP response code
238
:param headers: A dict-like object that contains the HTTP response headers
294
:param msg: An HTTPMessage containing the headers for the response
239
295
:param data: A file-like object that can be read() to get the
241
:return: A file-like object that can seek()+read() the
297
:return: A file-like object that can seek()+read() the
242
298
ranges indicated by the headers.
247
content_type = headers['Content-Type']
249
raise errors.InvalidHttpContentType(url, '',
250
msg='Missing Content-Type')
252
if _is_multipart(content_type):
300
rfile = RangeFile(url, data)
303
size = msg.getheader('content-length', None)
308
rfile.set_range(0, size)
310
content_type = msg.getheader('content-type', None)
311
if content_type is None:
312
# When there is no content-type header we treat the response as
313
# being of type 'application/octet-stream' as per RFC2616 section
315
# Therefore it is obviously not multipart
316
content_type = 'application/octet-stream'
319
is_multipart = (msg.getmaintype() == 'multipart'
320
and msg.getsubtype() == 'byteranges')
253
323
# Full fledged multipart response
254
return HttpMultipartRangeResponse(url, content_type, data)
324
rfile.set_boundary(msg.getparam('boundary'))
256
326
# A response to a range request, but not multipart
258
content_range = headers['Content-Range']
327
content_range = msg.getheader('content-range', None)
328
if content_range is None:
260
329
raise errors.InvalidHttpResponse(url,
261
330
'Missing the Content-Range header in a 206 range response')
262
return HttpRangeResponse(url, content_range, data)
264
# A regular non-range response, unfortunately the result from
265
# urllib doesn't support seek, so we wrap it in a StringIO
266
tell = getattr(data, 'tell', None)
268
return StringIO(data.read())
271
raise errors.NoSuchFile(url)
273
# TODO: jam 20060713 Properly handle redirects (302 Found, etc)
274
# The '_get' code says to follow redirects, we probably
275
# should actually handle the return values
331
rfile.set_range_from_header(content_range)
277
raise errors.InvalidHttpResponse(url, "Unknown response code %s"
333
raise errors.InvalidHttpResponse(url,
334
'Unknown response code %s' % code)
added
removed
bzrlib/transport/http/response.py
