S3 Presign Responses

For client uploads, return a presigned object URL and any headers that were part of the signature.

type PresignedUrlResponse = {
    key: string
    uploadUrl: string
    uploadHeaders?: Record<string, string>
    publicUrl?: string
    downloadUrl?: string
    expiresIn: number
}

Do not return browser-forbidden headers such as Content-Length in uploadHeaders: the browser sets them itself and ignores a script-set value. Signing Content-Length is fine as long as it equals the file size, which is how @useupup/server limits an upload to the size it approved. If the content type is signed, return it in uploadHeaders so upup can send the exact same value. Upload Files to S3 from React with Presigned URLs builds a complete endpoint.

return Response.json({
    key,
    uploadUrl,
    uploadHeaders: {
        'Content-Type': body.type || 'application/octet-stream',
    },
    downloadUrl,
    expiresIn: 3600,
})

Use @useupup/server when you want the server package to host these routes.