2.1 General
| (require web-server/dispatchers/dispatch) | |
| package: web-server-lib | |
This module provides a few functions for dispatchers in general.
value
procedure
any : any/c
struct
(struct exn:dispatcher () #:extra-constructor-name make-exn:dispatcher)
An exception thrown to indicate that a dispatcher does not apply to a particular
request.
procedure
(next-dispatcher) → void
Raises a exn:dispatcher
As the dispatcher/c contract suggests, a dispatcher is a function that takes a connection
and request object and does something to them. Mostly likely it will generate
some response and output it on the connection, but it may do something
different. For example, it may apply some test to the request object, perhaps
checking for a valid source IP address, and error if the test is not passed, and call next-dispatcher
otherwise.
Consider the following example dispatcher, that captures the essence of URL rewriting:
; (url? -> url?) dispatcher/c -> dispatcher/c (lambda (rule inner) (lambda (conn req) ; Call the inner dispatcher... (inner conn ; with a new request object... (struct-copy request req ; with a new URL! [request-uri (rule (request-uri req))]))))