blossom/buds/06.md

BUD-06

Upload requirements

draft optional

Defines how clients can verify if the upload can be completed before sending the blob to the server. This mechanism helps prevent unnecessary traffic to other endpoints by rejecting files based on their hash, size, MIME type or other server-specific requirements.

HEAD /upload - Upload requirements

The HEAD /upload endpoint MUST use the X-SHA-256, X-Content-Type and X-Content-Length headers sent by client to get the sha256 hash, MIME type and size of the blob that will be uploaded, returning a HTTP status code and a custom header X-Reason to indicate some human readable message about the upload requirements.

Headers

• X-SHA-256: A lowercase hex-encoded sha256 string that represents the blob's hash.
• X-Content-Length: An integer that represents the blob size in bytes.
• X-Content-Type: A string that specifies the blob's MIME type, like application/pdf or image/png.

Upload Authorization

Servers MAY require authorization for this endpoint as defined by BUD-11.

Examples

Example request from the client:

X-Content-Type: application/pdf
X-Content-Length: 184292
X-SHA-256: 88a74d0b866c8ba79251a11fe5ac807839226870e77355f02eaf68b156522576

Example response from the server if the upload can be done:

HTTP/1.1 200 OK

If the upload cannot proceed, the server MUST return an appropriate 4xx HTTP status code and a custom header X-Reason with a human readable error message.

Some examples of error messages:

HTTP/1.1 400 Bad Request
X-Reason: Invalid X-SHA-256 header format. Expected a string.

HTTP/1.1 401 Unauthorized
X-Reason: Authorization required for uploading video files.

HTTP/1.1 403 Forbidden
X-Reason: SHA-256 hash banned.

HTTP/1.1 411 Length Required
X-Reason: Missing X-Content-Length header.

HTTP/1.1 413 Content Too Large
X-Reason: File too large. Max allowed size is 100MB.

HTTP/1.1 415 Unsupported Media Type
X-Reason: Unsupported file type.