paraproxio.py 文件源码

def download(self) -> str:
        if self._state != NOT_STARTED:
            return self._state

        # Prepare an empty buffer file.
        await self._loop.run_in_executor(None, self._create_buffer_file)

        try:
            # Create client session for downloading a file part from a host.
            async with aiohttp.ClientSession(loop=self._loop, headers=self._headers) as session:
                # Request a host for a file part.
                async with session.request('GET', self._url) as res:  # type: aiohttp.ClientResponse
                    if res.status != 206:
                        raise WrongResponseError('Expected status code 206, but {!s} ({!s}) received.',
                                                 res.status,
                                                 res.reason)

                    hrh = res.headers  # type: CIMultiDictProxy
                    # TODO: check headers.

                    # Read content by chunks and write to the buffer file.
                    if self._state == NOT_STARTED:
                        self._state = DOWNLOADING
                    while self._state is DOWNLOADING:
                        with aiohttp.Timeout(self._chunk_download_timeout, loop=self._loop):
                            chunk = await res.content.read(self._chunk_size)
                            self._bytes_downloaded += len(chunk)

                            self._debug("Read ({!s} bytes). Downloaded: {!s} of {!s} bytes. [{:.2%}]".format(
                                len(chunk), self._bytes_downloaded, self._length,
                                self._bytes_downloaded / self._length))

                            if not chunk:
                                self._state = DOWNLOADED
                                break
                            await self._write_chunk(chunk)
                    await self._flush_and_release()
                    if self._state != DOWNLOADED:
                        res.close()  # Close the response if not downloaded.
        except aiohttp.ServerDisconnectedError as exc:
            self._debug('Server disconnected error: {!r}.'.format(exc))
            self.cancel()
        except WrongResponseError as exc:
            self._debug('Wrong response error: {!r}.'.format(exc))
            self.cancel()
        except asyncio.TimeoutError:
            self._debug('Timeout.')
            self.cancel()
        except Exception as exc:
            self._debug('Unexpected exception: {!r}.'.format(exc))
            self.cancel()
        finally:
            return self._state