What is the maximum chunk size in HTTP response with Transfer-Encoding chunked?

Question

The w3.org (RFC2616) seems not to define a maximum size for chunks. But without a maximum chunk-size there is no space for the chunk-extension. There must be a maximum chunk-size, else I can't ignore the chunk-extension as I'm advised to do if it can't be understood (Quote: "MUST ignore chunk-extension extensions they do not understand" ).

Answer 1

Each chunk extension must begin with a semi-colon and the list of chunk extensions must end with a CRLF. When parsing the chunk-size, stop at either a semi-colon or a CRLF. If you stopped at a semi-colon, ignore everything up to the next CRLF. There is no need for a maximum chunk-size.

chunk          = chunk-size [ chunk-extension ] CRLF
                 chunk-data CRLF

chunk-size     = 1*HEX

chunk-extension= *( ";" chunk-ext-name [ "=" chunk-ext-val ] )

Answer 2

The HTTP specification is pretty clear about the syntax of the HTTP messages.

The chunk size is always given as a hexadecimal number. If that number is not directly followed by a CRLF, but a ; instead, you know that there is an extension. This extension is identified by its name ( chunk-ext-name ). If you never heard of that particular name, you MUST ignore it.

So what exactly is your problem?

• Read a hexadecimal number
• Ignore everything up to the next CRLF
• Be happy