bilibili/flv.js · error · RuntimeException

FetchStreamLoader: Http code invalid, ' + res.status + ' ' +

Error message

FetchStreamLoader: Http code invalid, ' + res.status + ' ' + res.statusText

What it means

FetchStreamLoader.open() checks the fetch() Response; if response.ok is false (non-2xx HTTP status) the loader enters kError state. Normally it reports the failure via the onError callback with LoaderErrors.HTTP_STATUS_CODE_INVALID, but when no onError handler is registered it throws RuntimeException 'FetchStreamLoader: Http code invalid, <status> <statusText>'. It is the library surfacing an HTTP-level rejection from the streaming fetch.

Source

Thrown at src/io/fetch-stream-loader.js:157

                }

                let lengthHeader = res.headers.get('Content-Length');
                if (lengthHeader != null) {
                    this._contentLength = parseInt(lengthHeader);
                    if (this._contentLength !== 0) {
                        if (this._onContentLengthKnown) {
                            this._onContentLengthKnown(this._contentLength);
                        }
                    }
                }

                return this._pump.call(this, res.body.getReader());
            } else {
                this._status = LoaderStatus.kError;
                if (this._onError) {
                    this._onError(LoaderErrors.HTTP_STATUS_CODE_INVALID, {code: res.status, msg: res.statusText});
                } else {
                    throw new RuntimeException('FetchStreamLoader: Http code invalid, ' + res.status + ' ' + res.statusText);
                }
            }
        }).catch((e) => {
            if (this._abortController && this._abortController.signal.aborted) {
                return;
            }

            this._status = LoaderStatus.kError;
            if (this._onError) {
                this._onError(LoaderErrors.EXCEPTION, {code: -1, msg: e.message});
            } else {
                throw e;
            }
        });
    }

    abort() {
        this._requestAbort = true;

View on GitHub (pinned to 42343088f2)

Solutions

Fix the server-side cause so the URL returns 200 (valid token, correct path, available stream)
Register an onError handler on the loader to receive LoaderErrors.HTTP_STATUS_CODE_INVALID gracefully instead of a thrown exception
Check the URL and credentials in devtools/network tab and retry with a corrected or refreshed URL

Example fix

// before
const loader = new FetchStreamLoader();
loader.open(...); // throws on 404 because no onError set
// after
const loader = new FetchStreamLoader();
loader.onError = (type, data) => console.error('HTTP', data.code, data.msg);
loader.open(...);

Defensive patterns

Strategy: try-catch

Validate before calling

const res = await fetch(url, {method: 'HEAD'});
if (!res.ok) {
  throw new Error(`Stream URL unavailable: ${res.status} ${res.statusText}`);
}

Type guard

function isOkayResponse(res) {
  return typeof res !== 'undefined' && res !== null && typeof res.ok === 'boolean' && res.ok === true;
}

Try / catch

loader.onError = (type, data) => {
  if (type === LoaderErrors.HTTP_STATUS_CODE_INVALID) {
    console.error(`Stream fetch failed: ${data.code} ${data.msg}`);
    scheduleRetryWithBackoff();
  }
};
try {
  loader.open(url);
} catch (e) {
  if (e instanceof RuntimeException && e.message.includes('Http code invalid')) {
    console.error('Fetch failed without onError handler registered');
  } else { throw e; }
}

Prevention

Always register onError on loaders so HTTP failures are reported, not thrown
Check the URL, auth token, and CORS headers return 200 (verify with curl/HEAD)
Refresh signed/expired CDN URLs before reopening the stream
Add retry with backoff for transient 5xx responses

When it happens

Trigger: Fetching an FLV stream URL that returns 404 (file missing), 403 (expired signed URL / wrong token), 5xx (server error), or any non-2xx status, while this._onError is undefined so the else branch throws instead.

Common situations: Expired CDN signatures or auth cookies; CORS misconfiguration surfacing as unexpected status; mis-typed stream URL; forgetting to register loader onError in a custom io pipeline so failures throw instead of being reported.

Related errors

AI-assisted analysis of bilibili/flv.js@42343088f2 (2026-09-01). Data as JSON: /api/errors/9c0f31bba5a2f7ea. Report an issue: GitHub.