Simple support for range headers #1090
Conversation
Without this FileResponse cannot be used to satisfy range headers.
|
In case maintainers reject this, for anyone else who needs to support range header queries in FastAPI or Starlette, you can still achieve the same functionality by extending class MediaResponse(FileResponse):
def __init__(self, *args, **kwargs):
self.offset = kwargs.pop('offset')
super(MediaResponse, self).__init__(*args, **kwargs)
async def __call__(self, scope: Scope, receive: Receive, send: Send) -> None:
if self.stat_result is None:
try:
stat_result = await aiofiles.os.stat(self.path)
self.set_stat_headers(stat_result)
except FileNotFoundError:
raise RuntimeError(f"File at path {self.path} does not exist.")
else:
mode = stat_result.st_mode
if not stat.S_ISREG(mode):
raise RuntimeError(f"File at path {self.path} is not a file.")
await send(
{
"type": "http.response.start",
"status": self.status_code,
"headers": self.raw_headers,
}
)
if self.send_header_only:
await send({"type": "http.response.body", "body": b"", "more_body": False})
else:
async with aiofiles.threadpool.open(self.path, mode='rb') as file:
await file.seek(self.offset)
more_body = True
while more_body:
chunk = await file.read(self.chunk_size)
more_body = len(chunk) == self.chunk_size
await send(
{
"type": "http.response.body",
"body": chunk,
"more_body": more_body,
}
)
if self.background is not None:
await self.background()and using like this: @app.get("/media/{path}")
async def media(path: str, range_header: Optional[str] = Header('bytes=0-', alias="Range")):
if '..' in path:
raise Exception(path + ' is not allowed')
full_path = os.path.join('media', path)
start, end = range_header.strip('bytes=').split('-')
start = int(start)
size = os.stat(full_path)[6]
end = min(size-1, start+10)
return MediaResponse(path=full_path, status_code=206, offset=start, headers={
'Accept-Ranges': 'bytes',
'Content-Range': 'bytes %s-%s/%s' % (start, end, size),
'Content-Length': str(size-start)
}) |
|
This has been in the PR queue for quite a while: #1013 |
|
@kevinastone I wasn't able to use #1013 via monkey-patching or extension, but I agree it is a better solution to enable this out-of-box through staticfiles. I almost didn't make a PR after seeing how long yours had been waiting. However, I wanted to share my work-around since it could be a while before range header support makes it to FastAPI. This solution could also enable other functionality that is currently lacking. Chunked file transfer or anything that uses 206 to resume is currently impossible (or incredibly slow using StreamResponse) without some trickery. |
|
@Kojiro20 Here's a copy of the monkey-patch I'm currently running to support range requests: https://gist.github.com/kevinastone/a6a62db57577b3f24e8a6865ed311463 |
|
@kevinastone thank you! Will use that if I do another server project in python. But, TBH, will probably stick with node or java for a few more years after this experience. It's too hard to get real http2 support out of python and I'm very confused about all the busted/incompatible versions for asgi tooling. Even Conda not solved dependency tree for fastAPI + h2 etc 😖 ... Will never touch wsgi again, but solid asgi support feels nascent at best. Watching for python to natively support promises 🤔 – that was about the time node seemed mature. Seems like Guido letting go of the helm was a mixed blessing. Now everyone is fearless to break APIs 🥳 but slow to adopt upstream changes 🥉 |
|
For posterity - starlette has a memory leak with I think the fix would involve adding a watchdog of some sort inside the Honestly curious if anyone runs a python service that doesn't need to be rebooted periodically to stay afloat. I have added something like this to my Dockerfile to mitigate. |
have you done a PR? I think they should update this block of code |
Not sure if this is still the preferred solution for ranged support for static files, but I think there's an off-by-one error in OpenRange. This is easily verified with curl.
|
With this change
FileResponsecan be used to serve media that use the range header such as HTML5audioandvideotags.For example, using FastAPI app container you can support range like this:
with HTML: