Events

Using Events

Event Handler Structure

All DocPad events receive two arguments (both optional):

1. opts, a simple object containing any options that the event provides

2. next, a completion callback

DocPad's events are fired in a synchronous (or serial) fashion. In other words, when the first event runs until finished, then the next event fires and runs until finished, and so on.

Asynchronous code, however, has no implicit guarantees about the order of execution. It will fire the first event, and may then immediately fire the second event while the first is still running.

That's why asynchronous code requires callbacks. When the first event is done, it will run the callback function it was invoked with. It's the callback's job to signal when it's okay to proceed to the next event.

Node.js itself is built for asynchronous execution, so it's pretty common for Node.js programs to run asynchronously.

Since DocPad's events are run synchronously, omitting the next callback is perfectly valid (even encouraged) if you're using DocPad in your own synchronous code. (Of course, you're free to write in whatever style works best for you! If you enjoy coding in the asynchronous style, the next callback is available for you.)

Inside your Configuration File

You can bind to events in your DocPad configuration file by adding them to the events property.

Example: Let's use a docpad.coffee configuration file. Binding to the serverExtend event would look like so:

docpadConfig =

    # =================================
    # DocPad Events

    # Here we can define handlers for events that DocPad fires
    # You can find a full listing of events on the DocPad Wiki
    events:

        # Server Extend
        # Used to add our own custom routes to the server before the docpad routes are added
        serverExtend: (opts) ->
            # Extract the server from the options
            {server} = opts
            docpad = @docpad

            # Perform our server extensions
            # ...

# Export our DocPad Configuration
module.exports = docpadConfig

The context (what this/@ points to) of event handlers is a shared object between the event handlers that contains only the docpad instance variable.

Inside your Plugins

You can bind to events inside your DocPad plugin by just adding the event handler directly to your plugin's definition. As such, binding to the render event to render from one extension to the other would look like so:

# Export Plugin
module.exports = (BasePlugin) ->
    # Define Plugin
    class RenderPlugin extends BasePlugin
        # ...

        # Render some content synchronously
        render: (opts) ->
            # Prepare
            {inExtension,outExtension,content} = opts
            docpad = @docpad

            # Perform our rendering
            # ...

The context (what this/@ points to) of event handlers in your plugin will be your plugin's instance.

Available Events

Sorted by their flow of execution within DocPad

extendCollections

Called each time the configuration for DocPad reloads. Called after most of the configuration has loaded and when it is time to extend our collections.

Use to create additional collections.

Examples:

• Partials Plugin

extendTemplateData

Called each time the configuration for DocPad reloads. Called after most of the configuration has loaded and when it is time to extend our template data.

Options:

• templateData the object to inject your additions to

Use to inject new template data variables and helpers into the template data.

Examples:

• Services Plugin

• Feedr Plugin

docpadLoaded

Called each time the configuration for DocPad reloads. Called before docpadReady as we have to load the configuration in order to be ready.

docpadReady

Called once DocPad when DocPad is now ready to perform actions which is once it has finished initializing and loading its configuration. Partnered with the docpadDestroy event.

consoleSetup

Called once the command line interface for DocPad has loaded.

Options:

• consoleInterface the console interface instance we are using

• commander the instance of commander we are using

Use to extend the console interface with additional commands.

Examples:

• GitHub Pages Plugin

populateCollectionsBefore

Called just before we start to insert dynamic files into the database. Called before each generation, just before the generateBefore event. Partnered with the populateCollections event.

populateCollections

Called just after we've inserted dynamic files into the collections. Called before each generation, just before the generateBefore event. Partnered with the populateCollectionsBefore event.

Use this for inserting your dynamic files into the database.

Examples:

• Tumblr Importer Plugin

generateBefore

Called just before we start generating your project. Partnered with the generateAfter event.

Options:

• reset whether or not this is a partial- (false) or full-regeneration (true)

• server Deprecated; use getServer() API method instead

parseBefore

Deprecated/removed since DocPad v6.58.0. See issue #736 for information.

parseAfter

Deprecated/removed since DocPad v6.58.0. See issue #736 for information.

conextualizeBefore

Called just before we start to contextualize all the files. Partnered with the contextualizeAfter event. Contextualizing is the process of adding layouts and awareness of other documents to our document.

Options:

• collection the collection we are working with

• templateData Deprecated; use extendTemplateData event instead

contextualizeAfter

Called just after we've finished contextualize all the files. Partnered with the conextualizeBefore event. Contextualizing is the process of adding layouts and awareness of other documents to our document.

Options:

• collection the collection we are working with

• templateData Deprecated; use extendTemplateData event instead

renderBefore

Called just before we start rendering all the files. Partnered with the renderAfter event.

Options:

• collection a query-engine collection containing the models we are about to render

• templateData the template data that will be provided to the documents

renderCollectionBefore

Triggered before a render collection is about to be rendered. Added by Bruno Heridet with Pull Request #608.

Options:

• collection a query-engine collection containing the models we are about to render

• renderPass which render pass is this render collection for?

renderCollectionAfter

Triggered before a render collection is about to be rendered. Added by Bruno Heridet with Pull Request #608.

Options:

• collection a query-engine collection containing the models we are about to render

• renderPass which render pass is this render collection for?

render

Called per document, for each extension conversion.

Use to render one extension to another.

Options:

• inExtension the extension we are rendering from

• outExtension the extension we are rendering to

• templateData the template data that we will use for this document's rendering

• file the model instance for the document we are rendering

• content the current content that this document contains, you shall overwrite this option with any updates you do

Notes: The file blah.html.md.eco will call trigger this event twice. The first time for the eco to md conversion. The second time for the md to htmlconversion.

Example: You would check the inExtension and outExtension options to make sure we only apply our rendering for the desired extension conversions. To apply the rendering, we would write our result back to opts.content. For example here is a render event handler that will convert the content of files to upper case when named like file.txt.captialize|uppercase|upper:

render: (opts) ->
    # Prepare
    {inExtension,outExtension,templateData,file,content} = opts
    docpad = @docpad

    # Render if applicable
    if inExtension in ['capitalize','uppercase','upper'] and outExtension in ['txt']
        opts.content = content.toUpperCase() # your conversion to be saved

renderDocument

Called per document, after all the extensions have been rendered.

Use to perform transformations to the entire document.

Options:

• extension the resulted extension for our document

• templateData the template data that we will use for this document's rendering

• file the model instance for the document we are rendering

• content the current content that this document contains, you shall overwrite this option with any updates you do

Notes: It is also called for each of the layout rendering for the document, as well as for each render pass, as such care should be taken with ensuring your transformation does not re-transform an already transformed part.

Example: The Pygments Plugin more or less uses this event to search for all <code> HTML elements that have the CSS class highlight (e.g., <code class="highlight">) and replaces the element with one that has been syntax highlighted by the popular pygments syntax highlighting engine.

renderAfter

Called just just after we've rendered all the files. Partnered with the renderBefore event.

Options:

• collection a query-engine collection containing the models we've rendered

writeBefore

Called just before we start writing all the files. Partnered with the writeAfter event.

Options:

• collection a query-engine collection containing the models we are about to write

• templateData the template data that was provided to the documents

writeAfter

Called just just after we've wrote all the files. Partnered with the writeBefore event.

Options:

• collection a query-engine collection containing the models we are about to render

generateAfter

Called just after we've finished generating your project. Partnered with the generateBefore event.

generated

Called just after the initial generation has completed.

serverBefore

Called just before we start setting up the server. Partnered with the serverAfter event.

serverExtend

Called just while we are setting up the server, and just before the DocPad routes are applied.

Use to extend the server with routes that will be triggered before the DocPad routes.

Options:

• server and serverExpress are the Express.js server instance we are using

• serverHttp is the raw Node.js HTTP server we are using

• express is the Express module we are using

serverAfter

Called just after we finished setting up the server.

Use to extend the server with routes that will be triggered after the DocPad routes.

Options:

• server and serverExpress are the Express.js server instance we are using

• serverHttp is the raw Node.js HTTP server we are using

• express is the Express module we are using

docpadDestroy

Called when it is time for DocPad to shutdown. Partnered with the docpadReady event.

Use this to shutdown anything inside your plugins, close all connections, file system handlers, files, etc.