View rendering plugins

In this chapter, we will take a closer look at the view rendering plugin you already used.

As you already know, there is a default behaviour to render static files or html strings. This behaviour is override by the plugin you load. How does it work ?

On the load of the framework, you provide a plugin array with the class which represent your plugin. Every single plugin must have an identifier. For the view rendering plugins, this identifier is ViewEngine.

Because the plugins are store in a classic object, if you register multiple plugins with the same identifier, the last one will be used (an object is a simple key/value).

Because this is a core plugin, it is used by the framework, so it means the plugin should follow a specific interface. Here is what it looks like :

class MyNewViewRenderingPlugin {
  constructor (configuration = {}) {
    /*
      The constructor of your plugin
      It takes a configuration as parameter which allows you to provide additionnal datas to customize the behavior of your plugin
      For example, the Handlebars plugin we talked in a previous chapter check if a key "viewEngine" is in the configuration and use it as parameter when it reads the html file
      The configuration is the exact same you inject in Cherry during the initialization
    */
  }

  /**
   * The method that EVERY plugins needs to have. It defines what kind of plugin it is
   */
  static getIdentifier () {
    return 'ViewEngine'
  }

  async loadTemplate (filePath) {
    // The method which will read the template file
  }

  useHtml (source) {
    // The method that compile the raw html string you can sent
  }

  bindTemplate (variables = {}) {
    // Bind variables in your html template
  }

  getRenderedHtml () {
    // The method which returns the final html
  }
}

By following this API, you can create a view rendering plugin for every templating engine you want. Or even code your own template language in the plugin.

This plugin is only used with the built-in method "html" attached to the response object of a request