Scieneer Common Lisp 1.3.9 online documentation

http:server-service-headers-function object[Generic Function]

The optional HTTP server request headers service function. This service function is called after reading the request headers but before reading the request body. The function may modify the request parameters affecting the reading of the body: the maximum body size, and the stream timeout and expiration time.

If the function returns a http:response object then this response is sent to the client immediately without firstly reading the response. This can be useful when the client has sent an expect: 100-continue' header, or to close the stream to defend against denial-of-service attacks and broken clients.

If the function returns nil then the server continues to read the request body, firsly sending a continue response if the client sent an expect: 100-continue' header. The request will be passed to the server service function when read.

(setf (http:server-service-headers-function object) new-value)[Generic Function]