26
from bisect import bisect
26
27
from cStringIO import StringIO
36
# A RangeFile expects the following grammar (simplified to outline the
37
# assumptions we rely upon).
43
# whole_file: [content_length_header] data
45
# single_range: content_range_header data
47
# multiple_range: boundary_header boundary (content_range_header data boundary)+
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,
49
64
class RangeFile(object):
50
65
"""File-like object that allow access to partial available data.
52
All accesses should happen sequentially since the acquisition occurs during
53
an http response reception (as sockets can't be seeked, we simulate the
54
seek by just reading and discarding the data).
56
The access pattern is defined by a set of ranges discovered as reading
57
progress. Only one range is available at a given time, so all accesses
58
should happen with monotonically increasing offsets.
67
Specified by a set of ranges.
61
# in _checked_read() below, we may have to discard several MB in the worst
62
# case. To avoid buffering that much, we read and discard by chunks
63
# instead. The underlying file is either a socket or a StringIO, so reading
64
# 8k chunks should be fine.
65
_discarded_buf_size = 8192
67
# maximum size of read requests -- used to avoid MemoryError issues in recv
68
_max_read_size = 512 * 1024
70
def __init__(self, path, infile):
73
:param path: File url, for error reports.
74
:param infile: File-like socket set at body start.
70
def __init__(self, path, input_file):
79
# When using multi parts response, this will be set with the headers
80
# associated with the range currently read.
82
# Default to the whole file of unspecified size
85
def set_range(self, start, size):
86
"""Change the range mapping"""
89
# Set the new _pos since that's what we want to expose
90
self._pos = self._start
92
def set_boundary(self, boundary):
93
"""Define the boundary used in a multi parts message.
95
The file should be at the beginning of the body, the first range
96
definition is read and taken into account.
98
self._boundary = boundary
99
# Decode the headers and setup the first range
101
self.read_range_definition()
103
def read_boundary(self):
104
"""Read the boundary headers defining a new range"""
105
boundary_line = '\r\n'
106
while boundary_line == '\r\n':
107
# RFC2616 19.2 Additional CRLFs may precede the first boundary
109
# To be on the safe side we allow it before any boundary line
110
boundary_line = self._file.readline()
112
if boundary_line != '--' + self._boundary + '\r\n':
113
# rfc822.unquote() incorrectly unquotes strings enclosed in <>
114
# IIS 6 and 7 incorrectly wrap boundary strings in <>
115
# together they make a beautiful bug, which we will be gracious
117
if (self._unquote_boundary(boundary_line) !=
118
'--' + self._boundary + '\r\n'):
119
raise errors.InvalidHttpResponse(
121
"Expected a boundary (%s) line, got '%s'"
122
% (self._boundary, boundary_line))
124
def _unquote_boundary(self, b):
125
return b[:2] + rfc822.unquote(b[2:-2]) + b[-2:]
127
def read_range_definition(self):
128
"""Read a new range definition in a multi parts message.
130
Parse the headers including the empty line following them so that we
131
are ready to read the data itself.
133
self._headers = httplib.HTTPMessage(self._file, seekable=0)
134
# Extract the range definition
135
content_range = self._headers.getheader('content-range', None)
136
if content_range is None:
137
raise errors.InvalidHttpResponse(
139
'Content-Range header missing in a multi-part response')
140
self.set_range_from_header(content_range)
142
def set_range_from_header(self, content_range):
143
"""Helper to set the new range from its description in the headers"""
145
rtype, values = content_range.split()
147
raise errors.InvalidHttpRange(self._path, content_range,
150
raise errors.InvalidHttpRange(self._path, content_range,
151
"Unsupported range type '%s'" % rtype)
153
# We don't need total, but note that it may be either the file size
154
# or '*' if the server can't or doesn't want to return the file
156
start_end, total = values.split('/')
157
start, end = start_end.split('-')
161
raise errors.InvalidHttpRange(self._path, content_range,
162
'Invalid range values')
163
size = end - start + 1
165
raise errors.InvalidHttpRange(self._path, content_range,
166
'Invalid range, size <= 0')
167
self.set_range(start, size)
169
def _checked_read(self, size):
170
"""Read the file checking for short reads.
172
The data read is discarded along the way.
177
data = self._file.read(min(remaining, self._discarded_buf_size))
178
remaining -= len(data)
180
raise errors.ShortReadvError(self._path, pos, size,
184
def _seek_to_next_range(self):
185
# We will cross range boundaries
186
if self._boundary is None:
187
# If we don't have a boundary, we can't find another range
188
raise errors.InvalidRange(self._path, self._pos,
189
"Range (%s, %s) exhausted"
190
% (self._start, self._size))
192
self.read_range_definition()
194
def read(self, size=-1):
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):
195
91
"""Read size bytes from the current position in the file.
197
Reading across ranges is not supported. We rely on the underlying http
198
client to clean the socket if we leave bytes unread. This may occur for
199
the final boundary line of a multipart response or for any range
200
request not entirely consumed by the client (due to offset coalescing)
202
:param size: The number of bytes to read. Leave unspecified or pass
93
Reading across ranges is not supported.
206
and self._pos == self._start + self._size):
210
self._seek_to_next_range()
211
elif self._pos < self._start:
212
raise errors.InvalidRange(
213
self._path, self._pos,
214
"Can't read %s bytes before range (%s, %s)"
215
% (size, self._start, self._size))
217
if size > 0 and self._pos + size > self._start + self._size:
218
raise errors.InvalidRange(
219
self._path, self._pos,
220
"Can't read %s bytes across range (%s, %s)"
221
% (size, self._start, self._size))
223
# read data from file
227
# Don't read past the range definition
228
limited = self._start + self._size - self._pos
230
limited = min(limited, size)
231
osutils.pumpfile(self._file, buffer, limited, self._max_read_size)
232
data = buffer.getvalue()
234
# Update _pos respecting the data effectively read
235
self._pos += len(data)
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]
238
115
def seek(self, offset, whence=0):
239
start_pos = self._pos
242
118
elif whence == 1:
243
final_pos = start_pos + offset
244
120
elif whence == 2:
246
final_pos = self._start + self._size + offset # offset < 0
248
raise errors.InvalidRange(
249
self._path, self._pos,
250
"RangeFile: can't seek from end while size is unknown")
121
self._pos = self._len + offset
252
123
raise ValueError("Invalid value %s for whence." % whence)
254
if final_pos < self._pos:
255
# Can't seek backwards
256
raise errors.InvalidRange(
257
self._path, self._pos,
258
'RangeFile: trying to seek backwards to %s' % final_pos)
261
cur_limit = self._start + self._size
262
while final_pos > cur_limit:
263
# We will cross range boundaries
264
remain = cur_limit - self._pos
266
# Finish reading the current range
267
self._checked_read(remain)
268
self._seek_to_next_range()
269
cur_limit = self._start + self._size
271
size = final_pos - self._pos
272
if size > 0: # size can be < 0 if we crossed a range boundary
273
# We don't need the data, just read it and throw it away
274
self._checked_read(size)
280
def handle_response(url, code, msg, data):
281
"""Interpret the code & headers and wrap the provided data in a RangeFile.
283
This is a factory method which returns an appropriate RangeFile based on
284
the code & headers it's given.
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
236
:param url: The url being processed. Mostly for error reporting
287
237
:param code: The integer HTTP response code
288
:param msg: An HTTPMessage containing the headers for the response
238
:param headers: A dict-like object that contains the HTTP response headers
289
239
:param data: A file-like object that can be read() to get the
291
:return: A file-like object that can seek()+read() the
241
:return: A file-like object that can seek()+read() the
292
242
ranges indicated by the headers.
294
rfile = RangeFile(url, data)
297
size = msg.getheader('content-length', None)
302
rfile.set_range(0, size)
304
content_type = msg.getheader('content-type', None)
305
if content_type is None:
306
# When there is no content-type header we treat the response as
307
# being of type 'application/octet-stream' as per RFC2616 section
309
# Therefore it is obviously not multipart
310
content_type = 'application/octet-stream'
313
is_multipart = (msg.getmaintype() == 'multipart'
314
and msg.getsubtype() == 'byteranges')
247
content_type = headers['Content-Type']
249
raise errors.InvalidHttpContentType(url, '',
250
msg='Missing Content-Type')
252
if _is_multipart(content_type):
317
253
# Full fledged multipart response
318
rfile.set_boundary(msg.getparam('boundary'))
254
return HttpMultipartRangeResponse(url, content_type, data)
320
256
# A response to a range request, but not multipart
321
content_range = msg.getheader('content-range', None)
322
if content_range is None:
258
content_range = headers['Content-Range']
323
260
raise errors.InvalidHttpResponse(url,
324
261
'Missing the Content-Range header in a 206 range response')
325
rfile.set_range_from_header(content_range)
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
327
raise errors.InvalidHttpResponse(url,
328
'Unknown response code %s' % code)
277
raise errors.InvalidHttpResponse(url, "Unknown response code %s"
added
removed
bzrlib/transport/http/response.py
