[plt-scheme] Cookies in the PLT Web Server

From: Jay McCarthy (jay.mccarthy at gmail.com)
Date: Tue Feb 3 17:42:59 EST 2009

>From http://jay-mccarthy.blogspot.com/2009/02/cookies-in-plt-web-server.html:

It has always been possible to use cookies in PLT Web Server
applications, but a lot of the work was not done for you.

Now it is!

The PLT Web Server now provides two modules as part of web-server/http
for cookies: web-server/http/cookie [1] for installing cookies and
web-server/http/cookie-parse [2] for extracting them.

Here's a simple example:

#lang web-server/insta
(require net/url)

(define (start req)
  (define cookies (request-cookies req))
  (define id-cookie
    (findf (lambda (c)
             (string=? "id" (client-cookie-name c)))
  (define who
    (if id-cookie
        (client-cookie-value id-cookie)
  (define new-req
     (lambda (k-url)
       `(html (head (title "Hello!"))
              (body (h1 "Hello " ,(if who who ""))
                    (form ([action ,k-url])
                          (input ([name "who"]))))))))
  (define binds
    (request-bindings/raw new-req))
  (match (bindings-assq #"who" binds)
    [(? binding:form? b)
     (define new-who
       (bytes->string/utf-8 (binding:form-value b)))
     (redirect-to (url->string (request-uri req))
       (cookie->header (make-cookie "id" new-who))))]
      (url->string (request-uri req))

This addition is based on code written for the PLaneT server by Jacob
Matthews and the existing net/cookie client-side cookie library.

1. http://faculty.cs.byu.edu/~jay/plt-doc/web-server/cookie.html
2. http://faculty.cs.byu.edu/~jay/plt-doc/web-server/cookie-parse.html

Jay McCarthy <jay at cs.byu.edu>
Assistant Professor / Brigham Young University

"The glory of God is Intelligence" - D&C 93

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