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Editing: web_fileresponse.py
import asyncio import mimetypes import os import pathlib from typing import ( # noqa IO, TYPE_CHECKING, Any, Awaitable, Callable, Final, Iterator, List, Optional, Tuple, Union, cast, ) from . import hdrs from .abc import AbstractStreamWriter from .helpers import ETAG_ANY, ETag, must_be_empty_body from .typedefs import LooseHeaders, PathLike from .web_exceptions import ( HTTPNotModified, HTTPPartialContent, HTTPPreconditionFailed, HTTPRequestRangeNotSatisfiable, ) from .web_response import StreamResponse __all__ = ("FileResponse",) if TYPE_CHECKING: 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: PathLike, 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) self._path = pathlib.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 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) def _get_file_path_stat_and_gzip( self, check_for_gzipped_file: bool ) -> Tuple[pathlib.Path, os.stat_result, bool]: """Return the file path, stat result, and gzip status. This method should be called from a thread executor since it calls os.stat which may block. """ filepath = self._path if check_for_gzipped_file: gzip_path = filepath.with_name(filepath.name + ".gz") try: return gzip_path, gzip_path.stat(), True except OSError: # Fall through and try the non-gzipped file pass return filepath, filepath.stat(), False async def prepare(self, request: "BaseRequest") -> Optional[AbstractStreamWriter]: loop = asyncio.get_event_loop() check_for_gzipped_file = "gzip" in request.headers.get(hdrs.ACCEPT_ENCODING, "") filepath, st, gzip = await loop.run_in_executor( None, self._get_file_path_stat_and_gzip, check_for_gzipped_file ) 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 # Disable compression if we are already sending # a compressed file since we don't want to double # compress. self._compression = False 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 must_be_empty_body(request.method, self.status): 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 asyncio.shield(loop.run_in_executor(None, fobj.close))
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