Webjure: simple web app programming for clojure

[Tatu Tarvainen]

I have been working on a simple web "framework" for programming web
apps using clojure.

I'm planning to put it to sourceforge under the CPL license very soon.

Features:

Basic dispatching to clojure functions:
Functions can be registered to the servlet's dispatch table with
(webjure/publish <fn> <url-pattern>)

Where <fn> is a 3 argument handler function (method, request and
response) and
<url-pattern> is an url pattern (like "/foo" or "/bar*"). The shortest
matching handler
will be called for a request.

HTML generation expressions:
HTML output can be generated from clojure forms with html-format.

(webjure/html-format
(webjure/response-writer resp)
`(:html
(:body
(:a {:href "http://clojure.sf.net" :style "font-weight: bold;"}
"Clojure site"))))

SQL queries:
Simple SQL query (with query parameters) support using JDBC.
(sql/query *db* "SELECT * FROM cities WHERE country_iso_code = ?"
"FI")
Returns a sequence of rows where each row is a sequence of values.
The returned result sequence has a meta attached to it that provides
information on the result set columns and size.

Trying it out:
You can try the current version by downloading
http://homepage.mac.com/tatu.tarvainen/webjure.war
into a servlet container's webapps directory (tested with Jetty 6.1.7
on Mac OS X and Linux).

When the servlet container is started, point your browser to
http://localhost:8080/webjure/index
Demos included:
- simple html generation (the index page)
- request header dump
- SQL listings as tables (requires the "toursdb" directory from derby)
- AJAX REPL (very buggy and basic functionality)

Extract the war to look at the source files.

Also: this is running with a slightly patched version of clojure
20080106, but the classloader
issues should be resolved in the SVN version, so I should be able to
get that working soon.

[Stuart Sierra]

On Jan 15, 2008 12:21 PM, Tatu Tarvainen <tatu.ta...@mac.com> wrote:
> I have been working on a simple web "framework" for programming web
> apps using clojure.

Very cool. I've been hoping for something like this.

It ran without a hitch on Jetty 6.1.6. The AJAX repl didn't print the
results of expressions in Firefox, and it wouldn't load at all in IE7,
but that's probably a JavaScript issue.

Thanks for putting this together!
-Stuart

[Rich Hickey]

On Jan 15, 12:21 pm, Tatu Tarvainen <tatu.tarvai...@mac.com> wrote:
> I have been working on a simple web "framework" for programming web
> apps using clojure.
>

Very neat! Thanks. Same results for me Jetty 6.1.6 on OS X.

This will be a fun application of Clojure.

Rich

[Tatu Tarvainen]

On 16 tammi, 05:26, Rich Hickey <richhic...@gmail.com> wrote:
>
> Very neat! Thanks. Same results for me Jetty 6.1.6 on OS X.

I've put the code up to google project hosting. I decided to go with
the new BSD license.
It's available at: http://code.google.com/p/webjure/

It runs against the latest SVN version of clojure. I'm using Maven2 so
I had to make
one minor tweak to clojure pom file (because maven has one artifact
per project, the boot.clj has to
be included in the created jar).

I added:
<resources>
<resource>
<directory>src/</directory>
</resource>
</resources>

to the <build> section.

>
> Rich

- Tatu

[Robin]

Works on OSX 10.5, Jetty 6.1.7, and Clojure 20080106.

What is the best way to setup automatic reloading of modified .clj on
each request?

Thanks,

Robin

[Robin]

I force reloading demos.clj before each dispatch WebjureServlet.java:
190:

loadFromResource("demos.clj");
dispatch.invoke(method, request, response);

The auto-reloading is nice for development and experimenting.

Robin

[Tatu Tarvainen]

On 24 tammi, 00:26, Robin <robi...@gmail.com> wrote:
> I force reloading demos.clj before each dispatch WebjureServlet.java:
> 190:
>
>   loadFromResource("demos.clj");
>   dispatch.invoke(method, request, response);
>
> The auto-reloading is nice for development and experimenting.

Another way to experiment is to use the socket shell (which is
configured in the servlet).
The Shell opens up a socket listener which can be telnet'ed to and
behaves like the normal
Clojure REPL.

It can be used from emacs as an inferior lisp, by setting:
(setq inferior-lisp-program "telnet localhost 27272")

The functionality is working in the current SVN version.


>
> Robin

- Tatu

[Robin]

Nice, the shell works for me.

rcb@rcb:~$ telnet localhost 27272
Trying ::1...
telnet: connect to address ::1: Connection refused
Trying ::1...
telnet: connect to address ::1: Connection refused
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
Welcome to webjure shell. Happy hacking!
webjure=> (+ 1 1)
2webjure=> (rest [1 2 3 4 5])
clojure.lang.APersistentVector$Seq@e46688dewebjure=>

In order to print vectors that are returned I use this:

(import (quote (java.io BufferedWriter OutputStreamWriter
ByteArrayOutputStream)))
(defn pp [form]
(let [bytearray (new ByteArrayOutputStream )]
(with-open wtr (new BufferedWriter (new OutputStreamWriter
bytearray "US-ASCII"))
(. clojure.lang.RT (print form wtr)))
((memfn toString) bytearray)))

webjure=> (pp (rest [1 2 3 4 5]))
(2 3 4 5)

Robin

[Tatu Tarvainen]

> webjure=> (+ 1 1)
> 2webjure=> (rest [1 2 3 4 5])
> clojure.lang.APersistentVector$Seq@e46688dewebjure=>
>

The printing stuff has been fixed in the SVN version along with other
improvements to the shell.

> Robin


- Tatu