aldenks Comments - Answer Overflow

aldenks

•Created by aldenks on 5/5/2025 in #workers-help

How to stream responses and return a known content length?

An example of the relevant code. I am seeing the X-Content-Length header so I know it's hitting that branch but the Content-Length header is removed (following spec). I do want to follow http spec. I'm wondering if there's a way for workers to send the data along without be buffering in memory and with a content length header? HTTP2+ not having transfer encoding chunked at all seems to suggest there might be a way?

const s3Response = await getS3Object(catalogItem.s3Region, fullS3Url, rangeHeader);

const headers = new Headers({
    'Content-Type': 'application/octet-stream',
});

setCacheHeaders(headers, path);

if (s3Response.ContentLength != null) {
    headers.set('Content-Length', s3Response.ContentLength.toString());
    headers.set('X-Content-Length', s3Response.ContentLength.toString());
}

const response = new Response(s3Response.Body as ReadableStream, {
    headers,
    status: 200,
});

const s3Response = await getS3Object(catalogItem.s3Region, fullS3Url, rangeHeader);

const headers = new Headers({
    'Content-Type': 'application/octet-stream',
});

setCacheHeaders(headers, path);

if (s3Response.ContentLength != null) {
    headers.set('Content-Length', s3Response.ContentLength.toString());
    headers.set('X-Content-Length', s3Response.ContentLength.toString());
}

const response = new Response(s3Response.Body as ReadableStream, {
    headers,
    status: 200,
});

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