How to Connect a Web App to Hunchentoot

Question

I am writing a web app that would require the hunchentoot web server. I have almost no working knowledge of hunchentoot, or any web server for that matter, and I am wondering how my app written in Common Lisp would serve pages to a web client. I have seen some excellent examples (e.g. Hunchentoot Primer, Lisp for the Web) esp. the one listed on the Hunchentoot page. Do you know where I can find more of such examples? Thanks.

Untrimmed

What is it that you find lacking in the examples? If you don't say, chances are you'll get more links to examples that lack the same thing. – Elveraelves

Well, I'd like to see more clearly how to connect the rest of the application's code to hunchentoot; just how the app should talk to hunchentoot. – Untrimmed

The link is dead, long live the new link: newartisans.com/2007/11/a-quick-hunchentoot-primer – Ellingson

Answer 1

I am wondering how my app written in Common Lisp would serve pages to a web client.

Hunchentoot serves all things that are in its *dispatch-table*, which is just a list of dispatch handlers.

The simplest thing to do is to serve a static file. One typical example would be a CSS file:

(push (create-static-file-dispatcher-and-handler "/example.css"
                                                 "example.css")
      *dispatch-table*)

For a web application, you would most likely want to dynamically create a web page. You do this by defining a function that returns the page as a string (e.g. with CL-WHO), then creating a handler for this function:

(defun foo ()
  (with-html-output-to-string ; ...
  ))

(push (create-prefix-dispatcher "/foo.html" 'foo)
      *dispatch-table*)

You can eliminate a lot of boilerplate through macros, by the way:

(defmacro standard-page ((title) &body body)
  `(with-html-output-to-string (*standard-output* nil :prologue t :indent t)
     (:html :xmlns "http://www.w3.org/1999/xhtml"
          :xml\:lang "de"
          :lang "de"
          (:head 
           (:meta :http-equiv "Content-Type" 
                      :content "text/html;charset=utf-8")
           (:title ,title)
               (:link :type "text/css" 
              :rel "stylesheet"
              :href "/example.css"))
              (:body
               ,@body))))

(defmacro defpage (name (title) &body body)
  `(progn
     (defmethod ,name ()
       (standard-page (,title)
         ,@body))
     (push (create-prefix-dispatcher ,(format nil "/~(~a~).html" name) ',name)
           *dispatch-table*)))

The examples you have found should be sufficient to get you started, and if you run into problems, read the manual, then ask concrete questions.

Martijn

I cannot serve a static html linked to a css file by using create-static-file-dispatcher-and-handler for html file. What should i do? – Calia

@FSC: It seems that you have a new question. Post it as such, and provide the necessary context, please. – Martijn

Answer 2

define-easy-handler registers the handler you are defining automatically in a global variable which gets checked when a HTTP request arrives (the variable is called *easy-handler-alist*). So it's being taken care of automatically. Do you want to use a handler of a different form than the one defined in the tutorial?

I think there is an example using Hunchentoot in the Elephant distribution (Elephant being a Persistent Object Database for Common Lisp.)

Complementary