2.3 Common Contracts

(require web-server/servlet/servlet-structs)

"servlet/servlet-structs.ss" provides a number of contracts for use in servlets.

k-url? : contract?

Equivalent to string?.

Example: "http://localhost:8080/servlets;1*1*20131636/examples/add.ss"

response-generator/c : contract?

Equivalent to (-> k-url? response?).

Example:

(lambda (k-url)

`(html

(body

(a ([href ,k-url])

"Click Me to Invoke the Continuation!"))))

expiration-handler/c : contract?

Equivalent to (or/c false/c (-> request? response?)).

Example:

(lambda (req)

`(html (head (title "Expired"))

(body (h1 "Expired")

(p "This URL has expired. "

"Please return to the home page."))))

embed/url/c : contract?

Equivalent to (opt-> ((-> request? any/c)) (expiration-handler/c) string?).

This is what send/suspend/dispatch gives to its function argument.