Viewing file:  web_fileresponse.py (10.53 KB) -rw-r--r--
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import asyncio
import mimetypes
import os
import pathlib
import sys
from typing import ( # noqa
IO,
TYPE_CHECKING,
Any,
Awaitable,
Callable,
Iterator,
List,
Optional,
Tuple,
Union,
cast,
)
from . import hdrs
from .abc import AbstractStreamWriter
from .helpers import ETAG_ANY, ETag
from .typedefs import Final, LooseHeaders
from .web_exceptions import (
HTTPNotModified,
HTTPPartialContent,
HTTPPreconditionFailed,
HTTPRequestRangeNotSatisfiable,
)
from .web_response import StreamResponse
__all__ = ("FileResponse",)
if TYPE_CHECKING: # pragma: no cover
from .web_request import BaseRequest
_T_OnChunkSent = Optional[Callable[[bytes], Awaitable[None]]]
NOSENDFILE: Final[bool] = bool(os.environ.get("AIOHTTP_NOSENDFILE"))
class FileResponse(StreamResponse):
"""A response object can be used to send files."""
def __init__(
self,
path: Union[str, pathlib.Path],
chunk_size: int = 256 * 1024,
status: int = 200,
reason: Optional[str] = None,
headers: Optional[LooseHeaders] = None,
) -> None:
super().__init__(status=status, reason=reason, headers=headers)
if isinstance(path, str):
path = pathlib.Path(path)
self._path = path
self._chunk_size = chunk_size
async def _sendfile_fallback(
self, writer: AbstractStreamWriter, fobj: IO[Any], offset: int, count: int
) -> AbstractStreamWriter:
# To keep memory usage low,fobj is transferred in chunks
# controlled by the constructor's chunk_size argument.
chunk_size = self._chunk_size
loop = asyncio.get_event_loop()
await loop.run_in_executor(None, fobj.seek, offset)
chunk = await loop.run_in_executor(None, fobj.read, chunk_size)
while chunk:
await writer.write(chunk)
count = count - chunk_size
if count <= 0:
break
chunk = await loop.run_in_executor(None, fobj.read, min(chunk_size, count))
await writer.drain()
return writer
async def _sendfile(
self, request: "BaseRequest", fobj: IO[Any], offset: int, count: int
) -> AbstractStreamWriter:
writer = await super().prepare(request)
assert writer is not None
if NOSENDFILE or sys.version_info < (3, 7) or self.compression:
return await self._sendfile_fallback(writer, fobj, offset, count)
loop = request._loop
transport = request.transport
assert transport is not None
try:
await loop.sendfile(transport, fobj, offset, count)
except NotImplementedError:
return await self._sendfile_fallback(writer, fobj, offset, count)
await super().write_eof()
return writer
@staticmethod
def _strong_etag_match(etag_value: str, etags: Tuple[ETag, ...]) -> bool:
if len(etags) == 1 and etags[0].value == ETAG_ANY:
return True
return any(etag.value == etag_value for etag in etags if not etag.is_weak)
async def _not_modified(
self, request: "BaseRequest", etag_value: str, last_modified: float
) -> Optional[AbstractStreamWriter]:
self.set_status(HTTPNotModified.status_code)
self._length_check = False
self.etag = etag_value # type: ignore[assignment]
self.last_modified = last_modified # type: ignore[assignment]
# Delete any Content-Length headers provided by user. HTTP 304
# should always have empty response body
return await super().prepare(request)
async def _precondition_failed(
self, request: "BaseRequest"
) -> Optional[AbstractStreamWriter]:
self.set_status(HTTPPreconditionFailed.status_code)
self.content_length = 0
return await super().prepare(request)
async def prepare(self, request: "BaseRequest") -> Optional[AbstractStreamWriter]:
filepath = self._path
gzip = False
if "gzip" in request.headers.get(hdrs.ACCEPT_ENCODING, ""):
gzip_path = filepath.with_name(filepath.name + ".gz")
if gzip_path.is_file():
filepath = gzip_path
gzip = True
loop = asyncio.get_event_loop()
st: os.stat_result = await loop.run_in_executor(None, filepath.stat)
etag_value = f"{st.st_mtime_ns:x}-{st.st_size:x}"
last_modified = st.st_mtime
# https://tools.ietf.org/html/rfc7232#section-6
ifmatch = request.if_match
if ifmatch is not None and not self._strong_etag_match(etag_value, ifmatch):
return await self._precondition_failed(request)
unmodsince = request.if_unmodified_since
if (
unmodsince is not None
and ifmatch is None
and st.st_mtime > unmodsince.timestamp()
):
return await self._precondition_failed(request)
ifnonematch = request.if_none_match
if ifnonematch is not None and self._strong_etag_match(etag_value, ifnonematch):
return await self._not_modified(request, etag_value, last_modified)
modsince = request.if_modified_since
if (
modsince is not None
and ifnonematch is None
and st.st_mtime <= modsince.timestamp()
):
return await self._not_modified(request, etag_value, last_modified)
if hdrs.CONTENT_TYPE not in self.headers:
ct, encoding = mimetypes.guess_type(str(filepath))
if not ct:
ct = "application/octet-stream"
should_set_ct = True
else:
encoding = "gzip" if gzip else None
should_set_ct = False
status = self._status
file_size = st.st_size
count = file_size
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] = f"bytes */{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] = f"bytes */{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:
self.content_type = ct # type: ignore[assignment]
if encoding:
self.headers[hdrs.CONTENT_ENCODING] = encoding
if gzip:
self.headers[hdrs.VARY] = hdrs.ACCEPT_ENCODING
self.etag = etag_value # type: ignore[assignment]
self.last_modified = st.st_mtime # type: ignore[assignment]
self.content_length = count
self.headers[hdrs.ACCEPT_RANGES] = "bytes"
real_start = cast(int, start)
if status == HTTPPartialContent.status_code:
self.headers[hdrs.CONTENT_RANGE] = "bytes {}-{}/{}".format(
real_start, real_start + count - 1, file_size
)
# If we are sending 0 bytes calling sendfile() will throw a ValueError
if count == 0 or request.method == hdrs.METH_HEAD or self.status in [204, 304]:
return await super().prepare(request)
fobj = await loop.run_in_executor(None, filepath.open, "rb")
if start: # be aware that start could be None or int=0 here.
offset = start
else:
offset = 0
try:
return await self._sendfile(request, fobj, offset, count)
finally:
await loop.run_in_executor(None, fobj.close)
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