Common Lisp/External libraries/Hunchentoot

      Hunchentoot is a web application server written in Common Lisp.

      Quick start

      Installing with ASDF

      Installing Hunchentoot on ASDF-enabled systems. The next command installs Hunchentoot and all dependencies.

      (require 'asdf-install)
(asdf-install:install 'hunchentoot)

      Generating a simple Web page

      (asdf:oos 'asdf:load-op :hunchentoot)
 
(defpackage :testserv
  (:use :cl :hunchentoot)
  (:export :start-server))
 
(in-package :testserv)
 
;; Add a simple prefix dispatcher to the *dispatch-table*
(setq *dispatch-table*
      `(,(create-prefix-dispatcher "/hello-world" 'hello-page)))
 
;; Handler functions either return generated Web pages as strings,
;; or write to the output stream returned by write-headers
(defun hello-page ()
  "<html><body>Hello World!</body></html>")
 
(defun start-server (&key (port 4242))
  (start (make-instance 'easy-acceptor :port port)))

      Start the server:

      (testserv:start-server :port 4242)

      The generated image is available on http://localhost:4242/hello-world.

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      Serving dynamic graphics

      This example shows how to generate PNG images with Vecto[1] and serve them with Hunchentoot.

      First step: load external dependencies

      (asdf:oos 'asdf:load-op :hunchentoot)
(asdf:oos 'asdf:load-op :vecto)

      Second step: declare a package

      (defpackage :testserv
  (:use :cl :vecto :hunchentoot)
  (:export :start-server))
 
(in-package :testserv)

      Add a simple prefix dispatcher to the *dispatch-table*:

      (setq *dispatch-table*
      `(,(create-prefix-dispatcher "/img" 'img-page)))

      The img-page function expects HTTP parameter height containing an integer value and generates a PNG image height pixels height. If the parameter is not specified a default value of 150 is used.

      (defun img-page ()
  (setf (content-type*) "image/png")
  (let ((out (send-headers))   ; send-headers returns the output flexi-stream
        (bar-height (or (and (parameter "height") (parse-integer (parameter "height")))
                        150)))
    (with-canvas (:width 10 :height bar-height)
      (rectangle 0 0 10 bar-height)
      (set-gradient-fill 0 0
                         0 1 1 1
                         0 bar-height
                         1 0 0 1)
      (fill-and-stroke)
      (save-png-stream out)))) ; write the image data to the output stream obtained from send-headers

      Start the server:

      (testserv:start-server :port 4242)

      The generated image is available on http://localhost:4242/img. Try to change the height: http://localhost:4242/img?height=350

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      References

      1. ↑ http://xach.com/lisp/vecto/
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      See also

      ↑Jump back a section
      Last modified on 5 February 2013, at 08:56