fileresponse content-range header (#2847)

CHANGES/2844.feature

@@ -0,0 +1 @@
+Provide Content-Range header for Range requests

CONTRIBUTORS.txt

@@ -208,6 +208,7 @@ Weiwei Wang
 Yang Zhou
 Yannick Koechlin
 Yannick Péroux
+Ye Cao
 Yegor Roganov
 Young-Ho Cha
 Yuriy Shatrov

aiohttp/web_fileresponse.py

@@ -7,6 +7,7 @@
 from .http_writer import StreamWriter
 from .log import server_logger
 from .web_exceptions import (HTTPNotModified, HTTPOk, HTTPPartialContent,
+ HTTPPreconditionFailed,
  HTTPRequestRangeNotSatisfiable)
 from .web_response import StreamResponse
 
@@ -167,6 +168,13 @@ async def prepare(self, request):
  if modsince is not None and st.st_mtime <= modsince.timestamp():
  self.set_status(HTTPNotModified.status_code)
  self._length_check = False
+ # Delete any Content-Length headers provided by user. HTTP 304
+ # should always have empty response body
+ return await super().prepare(request)
+
+ unmodsince = request.if_unmodified_since
+ if unmodsince is not None and st.st_mtime > unmodsince.timestamp():
+ self.set_status(HTTPPreconditionFailed.status_code)
  return await super().prepare(request)
 
  if hdrs.CONTENT_TYPE not in self.headers:
@@ -182,38 +190,75 @@ async def prepare(self, request):
  file_size = st.st_size
  count = file_size
 
- try:
- rng = request.http_range
- start = rng.start
- end = rng.stop
- except ValueError:
- self.set_status(HTTPRequestRangeNotSatisfiable.status_code)
- return await super().prepare(request)
-
- # If a range request has been made, convert start, end slice notation
- # into file pointer offset and count
- if start is not None or end is not None:
- if start < 0 and end is None: # return tail of file
- start = file_size + start
- count = file_size - start
- else:
- count = (end or file_size) - start
-
- if start + count > file_size:
- # rfc7233:If the last-byte-pos value is
- # absent, or if the value is greater than or equal to
- # the current length of the representation data,
- # the byte range is interpreted as the remainder
- # of the representation (i.e., the server replaces the
- # value of last-byte-pos with a value that is one less than
- # the current length of the selected representation).
- count = file_size - start
-
- if start >= file_size:
- count = 0
-
- if count != file_size:
- status = HTTPPartialContent.status_code
+ start = None
+
+ ifrange = request.if_range
+ if ifrange is None or st.st_mtime <= ifrange.timestamp():
+ # If-Range header check:
+ # condition = cached date >= last modification date
+ # return 206 if True else 200.
+ # if False:
+ # Range header would not be processed, return 200
+ # if True but Range header missing
+ # return 200
+ try:
+ rng = request.http_range
+ start = rng.start
+ end = rng.stop
+ except ValueError:
+ # https://tools.ietf.org/html/rfc7233:
+ # A server generating a 416 (Range Not Satisfiable) response to
+ # a byte-range request SHOULD send a Content-Range header field
+ # with an unsatisfied-range value.
+ # The complete-length in a 416 response indicates the current
+ # length of the selected representation.
+ #
+ # Will do the same below. Many servers ignore this and do not
+ # send a Content-Range header with HTTP 416
+ self.headers[hdrs.CONTENT_RANGE] = 'bytes */{0}'.format(
+ file_size)
+ self.set_status(HTTPRequestRangeNotSatisfiable.status_code)
+ return await super().prepare(request)
+
+ # If a range request has been made, convert start, end slice
+ # notation into file pointer offset and count
+ if start is not None or end is not None:
+ if start < 0 and end is None: # return tail of file
+ start += file_size
+ if start < 0:
+ # if Range:bytes=-1000 in request header but file size
+ # is only 200, there would be trouble without this
+ start = 0
+ count = file_size - start
+ else:
+ # rfc7233:If the last-byte-pos value is
+ # absent, or if the value is greater than or equal to
+ # the current length of the representation data,
+ # the byte range is interpreted as the remainder
+ # of the representation (i.e., the server replaces the
+ # value of last-byte-pos with a value that is one less than
+ # the current length of the selected representation).
+ count = min(end if end is not None else file_size,
+ file_size) - start
+
+ if start >= file_size:
+ # HTTP 416 should be returned in this case.
+ #
+ # According to https://tools.ietf.org/html/rfc7233:
+ # If a valid byte-range-set includes at least one
+ # byte-range-spec with a first-byte-pos that is less than
+ # the current length of the representation, or at least one
+ # suffix-byte-range-spec with a non-zero suffix-length,
+ # then the byte-range-set is satisfiable. Otherwise, the
+ # byte-range-set is unsatisfiable.
+ self.headers[hdrs.CONTENT_RANGE] = 'bytes */{0}'.format(
+ file_size)
+ self.set_status(HTTPRequestRangeNotSatisfiable.status_code)
+ return await super().prepare(request)
+
+ status = HTTPPartialContent.status_code
+ # Even though you are sending the whole file, you should still
+ # return a HTTP 206 for a Range request.
 
  self.set_status(status)
  if should_set_ct:
@@ -225,11 +270,14 @@ async def prepare(self, request):
  self.last_modified = st.st_mtime
  self.content_length = count
 
- if count:
- with filepath.open('rb') as fobj:
- if start:
- fobj.seek(start)
+ self.headers[hdrs.ACCEPT_RANGES] = 'bytes'
+
+ if status == HTTPPartialContent.status_code:
+ self.headers[hdrs.CONTENT_RANGE] = 'bytes {0}-{1}/{2}'.format(
+ start, start + count - 1, file_size)
 
- return await self._sendfile(request, fobj, count)
+ with filepath.open('rb') as fobj:
+ if start: # be aware that start could be None or int=0 here.
+ fobj.seek(start)
 
- return await super().prepare(request)
+  return await self._sendfile(request, fobj, count)

aiohttp/web_request.py

@@ -388,19 +388,41 @@ def raw_headers(self):
  """A sequence of pars for all headers."""
  return self._message.raw_headers
 
+ @staticmethod
+ def _http_date(_date_str):
+ """Process a date string, return a datetime object
+ """
+ if _date_str is not None:
+ timetuple = parsedate(_date_str)
+ if timetuple is not None:
+ return datetime.datetime(*timetuple[:6],
+ tzinfo=datetime.timezone.utc)
+ return None
+
  @reify
  def if_modified_since(self, _IF_MODIFIED_SINCE=hdrs.IF_MODIFIED_SINCE):
  """The value of If-Modified-Since HTTP header, or None.
 
  This header is represented as a `datetime` object.
  """
- httpdate = self.headers.get(_IF_MODIFIED_SINCE)
- if httpdate is not None:
- timetuple = parsedate(httpdate)
- if timetuple is not None:
- return datetime.datetime(*timetuple[:6],
- tzinfo=datetime.timezone.utc)
- return None
+ return self._http_date(self.headers.get(_IF_MODIFIED_SINCE))
+
+ @reify
+ def if_unmodified_since(self,
+ _IF_UNMODIFIED_SINCE=hdrs.IF_UNMODIFIED_SINCE):
+ """The value of If-Unmodified-Since HTTP header, or None.
+
+ This header is represented as a `datetime` object.
+ """
+ return self._http_date(self.headers.get(_IF_UNMODIFIED_SINCE))
+
+ @reify
+ def if_range(self, _IF_RANGE=hdrs.IF_RANGE):
+ """The value of If-Range HTTP header, or None.
+
+ This header is represented as a `datetime` object.
+ """
+ return self._http_date(self.headers.get(_IF_RANGE))
 
  @property
  def keep_alive(self):

docs/web_reference.rst

@@ -329,6 +329,28 @@ and :ref:`aiohttp-web-signals` handlers.
  *If-Modified-Since* header is absent or is not a valid
  HTTP date.
 
+ .. attribute:: if_unmodified_since
+
+ Read-only property that returns the date specified in the
+ *If-Unmodified-Since* header.
+
+ Returns :class:`datetime.datetime` or ``None`` if
+ *If-Unmodified-Since* header is absent or is not a valid
+ HTTP date.
+
+ .. versionadded:: 3.1
+
+ .. attribute:: if_range
+
+ Read-only property that returns the date specified in the
+ *If-Range* header.
+
+ Returns :class:`datetime.datetime` or ``None`` if
+ *If-Range* header is absent or is not a valid
+ HTTP date.
+
+ .. versionadded:: 3.1
+
  .. method:: clone(*, method=..., rel_url=..., headers=...)
 
  Clone itself with replacement some attributes.