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Orion/Documentation/Developer Guide/Simple plugin example

< Orion‎ | Documentation‎ | Developer Guide
Revision as of 10:13, 6 May 2011 by Mamacdon.ca.ibm.com (Talk | contribs) (Testing the plugin)

This page explains how to write a plugin for Orion. It's intended for developers who want to extend Orion's functionality.

What's a plugin?

A plugin is basically just an HTML file that knows how to connect to the Orion client. A plugin can be hosted on any web server. Plugins are written in HTML and JavaScript.

In order to be useful, a plugin should provide one or more services. When Orion needs a service contributed by a plugin, it loads the plugin inside an IFrame.

Orion currently supports a small set of extension points — service types that plugins can contribute to, in order to customize the client and add more functionality. These include:

  • Adding more commands to the editor toolbar
  • Adding more commands to the navigator view
  • Adding content assist for new file types
  • Adding syntax highlighting rules for new file types

What you need

Every plugin must include the following JavaScript libraries:

The easiest way to satisfy these is to get orion-plugin.js, which is a minified file that includes both of them. You can then copy-paste its contents into a <script> tag in your plugin, or load it externally like so:

<script src="orion-plugin.js" />

Writing the plugin

Let's make a plugin that adds a button to the toolbar of the Orion editor. When clicked, it will reverse the selected text in the editor. This is not a very useful feature, but it'll be a good introduction to the concepts involved.

Creating the plugin HTML file

  • Create a new HTML file called reversePlugin.html with the following content:
<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8" />
    <title>Reverse Plugin</title>
</head>
<body></body>
</html>
  • What we have now isn't a plugin yet. It's just a bare-bones HTML file. The next step is to include the API we'll need to talk to Orion.
  • Grab the orion-plugin.js file (see What you need) and put it in the same folder as reversePlugin.html. Then add this inside the <head> tags of the HTML file:
<script src="orion-plugin.js" />
  • Next, we'll add some code that exposes a service to Orion. Add the following, again inside the <head> tags:
<script>
    window.onload = function() {
        var provider = new eclipse.PluginProvider();
        var serviceImpl = { /* TODO */ };
        var serviceProperties = { /* TODO */ };
        provider.registerServiceProvider("editorAction", serviceImpl, serviceProperties);
        provider.connect();
    }
</script>
  • At this point, we've got an honest-to-goodness Orion plugin, albeit one that doesn't do anything. Let's go over the various parts in detail:
    • var provider = new eclipse.PluginProvider()TODO
      Optionally, an object giving metadata about the plugin can be provided as an argument to the constructor.
    • var serviceImpl — This object gives the implementation of our service, the part that will do the actual work.
      When someone requests our service — for example, by calling getService() on a ServiceReference object — our plugin will be loaded into an IFrame, and our service becomes available for use. The function-typed properties of the serviceImpl object define the methods of our service that people can call.
    • var serviceProperties — Every service provider can supply properties, which is an object that holds metadata about the service provider. Orion stores these properties when a plugin is installed (?), and they can later be queried without causing the plugin to be loaded.
      Properties are often used to filter out service providers that are irrelevant to a particular task. For example, if you're writing a service provider for content assist, you'd specify what file types your provider applies to in its properties. The content assist loader then only loads plugins that provide content assist for the particular file type being edited. This is important because plugin load can be an expensive operation, so we want to avoid doing it if possible.
    • provider.registerServiceProvider("editorAction", serviceImpl, serviceProperties);TODO
    • provider.connect();TODO
  • Now we'll fill in the serviceImpl and serviceProperties objects with the actual details of the service that our plugin will provide.

TODO

  • Before continuing, make sure that reversePlugin.html looks like this:
<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8" />
    <title>Reverse Plugin</title>
    <script>
    window.onload = function() {
        var provider = new eclipse.PluginProvider();
        var serviceImpl = {
                run: function(text) {
                    return text.split("").reverse().join("");
                }
            };
        var serviceProperties = { name: "Reverse Text", key: ["e", true] };
        provider.registerServiceProvider("editorAction", serviceImpl, serviceProperties);
        provider.connect();
    }
</script>
</head>
<body></body>
</html>

Testing the plugin

First we need to host our plugin somewhere.

Once you've got a URL for reversePlugin, you can install it:

Now let's try it out.

  • In Orion, go to the navigator and create a new file called test.txt.
  • Click on test.txt to open the editor.
  • You'll see a new button on the editor toolbar:
    Image
  • Select some text, click the button, and it should be reversed.

Examples

Here are some existing plugins we've written. View their source code to see how they work:

http://bokowski.github.com/format-js.html
Contributes a "Beautify JS" button to the editor toolbar by using the editorAction service type.
http://mamacdon.github.com/m6/uglify/uglify-plugin.html
Contributes an "Uglify JS" button to the editor toolbar byusing the editorAction service type.
http://orionhub.org/plugins/sampleCommandsPlugin.html
Contributes several sample actions to the Orion navigator by using the fileCommands service type.
http://orionhub.org/plugins/htmlSyntaxHighlightPlugin.html
Contributes syntax highlighting support for HTML files by using the ISyntaxHighlight service type.

See also

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