59 lines
2.1 KiB
Python
59 lines
2.1 KiB
Python
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import hashlib
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import mimetypes
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from collections.abc import Generator
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from datetime import datetime, timezone
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from pathlib import Path
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from fastapi import Request
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from fastapi.responses import Response, StreamingResponse
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mimetypes.init()
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def get_range_response(file: Path, request: Request, chunk_size: int) -> Response:
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"""Get a Response for the given file, supporting range-requests, E-Tag and Last-Modified."""
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file_size = file.stat().st_size
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last_modified_time = datetime.fromtimestamp(file.stat().st_mtime, timezone.utc)
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start = 0
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end = file_size - 1
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status_code = 200
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e_tag = hashlib.md5((str(last_modified_time) + str(file_size)).encode()).hexdigest()
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if_match_header = request.headers.get('If-None-Match')
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if if_match_header and if_match_header == e_tag:
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return Response(status_code=304) # Not Modified
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headers = {
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'E-Tag': e_tag,
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'Last-Modified': last_modified_time.strftime(r'%a, %d %b %Y %H:%M:%S GMT'),
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}
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range_header = request.headers.get('range')
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media_type = mimetypes.guess_type(str(file))[0] or 'application/octet-stream'
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if range_header is not None:
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byte1, byte2 = range_header.split('=')[1].split('-')
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start = int(byte1)
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if byte2:
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end = int(byte2)
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status_code = 206 # Partial Content
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content_length = end - start + 1
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headers.update({
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'Content-Length': str(content_length),
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'Content-Range': f'bytes {start}-{end}/{file_size}',
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'Accept-Ranges': 'bytes',
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})
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def content_reader(file: Path, start: int, end: int) -> Generator[bytes, None, None]:
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with open(file, 'rb') as data:
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data.seek(start)
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remaining_bytes = end - start + 1
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while remaining_bytes > 0:
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chunk = data.read(min(chunk_size, remaining_bytes))
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if not chunk:
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break
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yield chunk
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remaining_bytes -= len(chunk)
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return StreamingResponse(
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content_reader(file, start, end),
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media_type=media_type,
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headers=headers,
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status_code=status_code,
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)
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