[Support]: missing content-length on API-requests

[der--flo]

Checklist

• I have updated to the latest available Frigate version.
• I have cleared the cache of my browser.
• I have tried a different browser to see if it is related to my browser.
• I have tried reproducing the issue in incognito mode to rule out problems with any third party extensions or plugins I have installed.

Describe the problem you are having

Responses to requests to the frigate API do not longer provide the header "content-length". Probably related to the switch to FastAPI. That was kind of useful to judge if a clip should get stored or not.

Steps to reproduce

Simply request a clip via API:

$ curl -I http://<frigate-ip>:5000/api/events/1739302339.54446-7yknza/clip.mp4
HTTP/1.1 200 OK
Server: nginx/1.25.3
Date: Tue, 11 Feb 2025 20:10:57 GMT
Content-Type: video/mp4
Connection: keep-alive
Cache-Control: no-store
X-Cache-Status: MISS

Version

15

In which browser(s) are you experiencing the issue with?

Frigate config file

not relevant

docker-compose file or Docker CLI command

not relevant

Relevant Frigate log output

not relevant

Relevant go2rtc log output

not relevant

Operating system

Other Linux

Install method

Docker Compose

Network connection

Wired

Camera make and model

Screenshots of the Frigate UI's System metrics pages

Any other information that may be helpful

No response

[NickM-27]

This is not a bug. The response is streamed and there is no way to know the exact content length of the concatenated MP4 file beforehand

[der--flo]

i'm not sure about that. I'm talking about a event clip that is not concatenated. The header is actually in the function but does not make it to client.

@router.get("/events/{event_id}/clip.mp4")
def event_clip(request: Request, event_id: str):
    try:
        event: Event = Event.get(Event.id == event_id)
    except DoesNotExist:
        return JSONResponse(
            content={"success": False, "message": "Event not found"}, status_code=404
        )

    if not event.has_clip:
        return JSONResponse(
            content={"success": False, "message": "Clip not available"}, status_code=404
        )

    file_name = f"{event.camera}-{event.id}.mp4"
    clip_path = os.path.join(CLIPS_DIR, file_name)

    if not os.path.isfile(clip_path):
        end_ts = (
            datetime.now().timestamp() if event.end_time is None else event.end_time
        )
        return recording_clip(request, event.camera, event.start_time, end_ts)

    headers = {
        "Content-Description": "File Transfer",
        "Cache-Control": "no-cache",
        "Content-Type": "video/mp4",
        "Content-Length": str(os.path.getsize(clip_path)),    <=====================================
        # nginx: https://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_ignore_headers
        "X-Accel-Redirect": f"/clips/{file_name}",
    }

    return FileResponse(
        clip_path,
        media_type="video/mp4",
        filename=file_name,
        headers=headers,
    )

[NickM-27]

I'm talking about a event clip that is not concatenated

that has not existed for many years at this point, and the code you are showing there is only there to handle the case where these very old clips existed which is very unlikely because they stopped being created that way long before favoriting clips was a feature.

so it is following this code path:

    if not os.path.isfile(clip_path):
        end_ts = (
            datetime.now().timestamp() if event.end_time is None else event.end_time
        )
        return recording_clip(request, event.camera, event.start_time, end_ts)

[der--flo]

Thats curious, as my script (which relied on the content-length) started to fail with the update because of the missing header. But never mind, its not that important.

[NickM-27]

Right, because the header was removed in this commit, as I said #14346