NAME

WWW::Mechanize::Plugin::JavaScript - JavaScript plugin for WWW::Mechanize

VERSION

Version 0.003

WARNING: This is an alpha release. The API is subject to change without notice.

This set of modules is at a very early stage. Only a few features have been implemented so far. Whether it will work for a particular case is hard to say. Try it and see. (And patches are always welcome.)

SYNOPSIS

  use WWW::Mechanize;
  $m = new WWW::Mechanize;
  
  $m->use_plugin('JavaScript');
  $m->get('http://www.cpan.org/');
  $m->get('javascript:alert("Hello!")'); # prints Hello!
  
  $m->use_plugin(JavaScript =>
          engine  => 'SpiderMonkey',
          alert   => \&alert, # custom alert function
          confirm => \&confirm,
          prompt  => \&prompt,
          init    => \&init, # initialisation function
  );                         # for the JS environment
  

DESCRIPTION

This module is a plugin for WWW::Mechanize that provides JavaScript capabilities (who would have guessed?).

To load the plugin, just use WWW::Mechanize's use_plugin method (note that the current stable release of that module doesn't support this; see "PREREQUISITES", below):

  $m = new WWW::Mechanize;
  $m->use_plugin('JavaScript');

You can pass options to the plugin via the use_plugin method. It takes hash-style arguments and they are as follows:

engine

Which JavaScript back end to use. Currently, this module only supports JE, a pure-Perl JavaScript interpreter. Later it will support SpiderMonkey via either JavaScript::SpiderMonkey or JavaScript.pm. If this option is not specified, either SpiderMonkey or JE will be used, whichever is available. It is possible to write one's own bindings for a particular JavaScript engine. See below, under "BACK ENDS".

alert

Use this to provide a custom alert function. The default one will print its arguments followed by a new line.

confirm

Like alert, but for the confirm function instead. There is no default.

prompt

Likewise.

init

Pass to this option a reference to a subroutine and it will be run every time a new JavaScript environment is initialised. This happens after the functions above have been created. The first argument will be the plugin object (more on that below). You can use this, for instance, to make your own functions available to JavaScript.

METHODS

WWW::Mechanize's use_plugin method will return a plugin object. The same object can be retrieved via $m->plugin('JavaScript') after the plugin is loaded. The following methods can be called on that object:

eval

This evaluates the JavaScript code passed to it. You can optionally pass two more arguments: the file name or URL, and the first line number.

new_function

This creates a new global JavaScript function out of a coderef. Pass the name as the first argument and the code ref as the second.

set

Sets the named variable to the value given. If you want to assign to a property of a property ... of a global property, pass each property name as a separate argument:

  $m->plugin('JavaScript')->set(
          'document', 'location', 'href' => 'http://www.perl.org/'
  );

bind_classes

With this you can bind Perl classes to JavaScript, so that JavaScript can handle objects of those classes. These class bindings will persist from one page to the next.

You should pass a hash ref that has the structure described in HTML::DOM::Interface, except that this method also accepts a _constructor hash element, which should be set to the name of the method to be called when the constructor function is called within JavaScript; e.g., _constructor => 'new'.

check_timeouts

This will evaluate the code associated with each timeout registered with the JS setTimeout function, if the appropriate interval has elapsed.

JAVASCRIPT FEATURES

The members of the HTML DOM that are available depend on the versions of HTML::DOM and CSS::DOM installed. See HTML::DOM::Interface and CSS::DOM::Interface.

The objects and properties specific to browsers that are supported so far are:

  location
      .hash
      .host
      .hostname
      .href
      .pathname
      .port
      .protocol
      .search
      .reload()
      .replace()
  document
      .location (alias to the global var)
  alert()
  navigator
      .userAgent (same as $mech->agent)
      .appName (WWW::Mechanize)
  setTimeout()
  clearTimeout()
  screen (just an empty object)
  open()

open is a temporary placeholder. Right now it ignores all its args except the first, and goes to the given URL, such that open(foo) is equivalent to location = foo.

BACK ENDS

A back end has to be in the WWW::Mechanize::Plugin::JavaScript:: name space. It will be required by this plugin implicitly when its name is passed to the engine option.

The following methods must be implemented:

Class methods

new

This method simply has to create a JavaScript environment, with window and self properties that refer to the global object, and return an object.

Object Methods

eval

new_function

set

bind_classes

These correspond to those listed above for the plugin object. Those methods are simply delegated to the back end, except that bind_classes also does some caching if the back end hasn't been initialised yet.

new_function must also accept a third argument, indicating the return type. This (when specified) will be the name of a JavaScript function that does the type conversion. Only 'Number' is used right now.

event2sub ($code, $elem, $url, $first_line)

This method needs to turn the event handler code in $code into a coderef, or an object that can be used as such, and then return it. That coderef will be called with an HTML::DOM::Event object as its sole argument. It's return value, if defined, will be used to determine whether the event's preventDefault method should be called.

define_setter

This will be called with a list of property names representing the 'path' to the property. The last argument will be a coderef that must be called with the value assigned to the property.

PREREQUISITES

perl 5.8.3 or later (actually, this module doesn't use any features that perl 5.6 doesn't provide, but its prerequisites require 5.8.3)

HTML::DOM 0.010 or later

JE 0.022 or later (when there is a SpiderMonkey binding available it will become optional)

The experimental version of WWW::Mechanize available at http://www-mechanize.googlecode.com/svn/branches/plugins/

CSS::DOM

BUGS

(See also "Bugs" in WWW::Mechanize::Plugin::DOM.)

To report bugs, please e-mail the author.

AUTHOR & COPYRIGHT

Copyright (C) 2007 Father Chrysostomos <join '@', sprout => join '.', reverse org => 'cpan'>

This program is free software; you may redistribute it and/or modify it under the same terms as perl.

SEE ALSO

-

WWW::Mechanize

-

WWW::Mechanize::Plugin::DOM

-

HTML::DOM

-

JE

-

JavaScript::SpiderMonkey

cpanm WWW::Mechanize::Plugin::JavaScript

perl -MCPAN -e shell
install WWW::Mechanize::Plugin::JavaScript