Getting Started

This page shows how to implement a REST API using Taffy. For an index of documentation, see the Home page, and for a high level explanation of Taffy, see the project homepage.

By and large, Taffy uses convention over configuration, but there are a few configuration details that can't be pragmatically solved with conventions. In those cases, configuration is needed, but minimal.

Step 0: Installing Taffy

Simply unzip the taffy folder into your webroot. An application-specific mapping to a non-web-accessible folder is not sufficient; however a global mapping in your ColdFusion Administrator will work -- in which case you should map /taffy to the location of your unzipped taffy folder.

Step 1: Application.cfc

Much like a FW/1 application, Taffy implements a majority of its logic in Application.cfc, as a base class that the Application.cfc of your application will extend. At a minimum, your APIs Application.cfc needs the following:

component extends="taffy.core.api" {

	this.name = hash(getCurrentTemplatePath());

	void function applicationHook(){
		registerMimeType("json", "text/json");
	}

	void function registerURIs(){
		//let taffy know about the cfcs in your api so that it can map URIs to them
		addURI("taffy.example.api.artistCollection");
		addURI("taffy.example.api.artistMember");
		//...
	}

}

• Application.cfc extends taffy.core.api

• Application name is unique

• DO NOT implement the onApplicationStart, onRequestStart, or onRequest methods; these are used by the framework. ApplicationHook is called during onApplicationStart, and requestHook is called during onRequestStart, if you need to add code to these event listeners.

• applicationHook method is used to set any application-specific variables, as well as register Mime Types that your API supports (more on this later), and set values for some special url parameters (see: setDebugKey, setReloadKey, setReloadPassword)

• registerURIs is a special method called during framework initialization that inspects the metadata from each of your CFCs and caches some information to enable requests to be properly routed. Inside this function, use the addURI method to notify the framework about each CFC in your API. Pass the dot-notation path of the CFC to the addURI method.

Of course, there are a few more things you can do. The Index of API Methods lists all methods, what they do, and where you can use them.

Step 2: Implement API Resources as CFCs

Each resource in your API (eg. Artists, Art) should be defined as its own CFC. In a Taffy API, you implement Collections and Members as separate CFCs (eg. artistCollection.cfc and artistMember.cfc). They won't be exposed by name via the framework, so you can name them whatever you like. In addition, if you like, your API CFCs may be outside the web-root, as long as they are accessible via CF mappings. Application-specific mappings are acceptable in this case.

Here is an example resource implementation:

artCollection.cfc:

component extends="taffy.core.restapi" taffy_uri="/artists/{artistId}/art" {

	public function get(string city = ""){
		//query the database for matches, making use of optional parameter "city"
		return representationOf(queryObject).withStatus(200);
	}

}

• Each CFC extends taffy.core.restapi.

• Each CFC should implement up to 4 methods: get, post, put, and delete. As you may have guessed, these map directly to the HTTP verb used by the api consumer.
  

  • If the consumer uses the PUT verb, it runs the PUT method in the corresponding CFC.
    
    
  • Since the POST, PUT, and DELETE methods are not implemented in the example above, the POST, PUT, and DELETE verbs will be refused (with HTTP status code 405 Not Allowed) for the corresponding resource.

• Tokens from the component attribute taffy_uri, defined as {token_name} (including the curly braces, see example above) will be extracted from the URI and passed by name to the requested method. In addition, all query string parameters (except those defined for debugging and reloading) will also be included in the argument collection sent to the method.
  
  For example: GET /artist/44/art?city=Philadelphia will result in the GET method being called on the art collection, with the arguments: { artistId: 44, city: "Philadelphia" }.
  
  The artistId parameter is defined by the taffy_uri attribute of the component (not the function), and the city parameter is defined as an optional argument to the function, and was provided in the query string.

• The representationOf method is a special method provided by the restapi base class that creates a new object instance capable of serializing your data into the appropriate format. A generic class capable of serializing as JSON is included with the framework and used by default. To use a custom object, pass the dot-notation CFC path to your custom representation object as the 2nd argument to the representationOf method. (It is also planned to implement a global default representation object override, but that is not yet available.) See Using a Custom Representation Class for more details.
  
  ** For the PUT and DELETE verbs, you may choose not to return any data -- in these cases, a status code is usually enough. For those cases, the noData method is available.
  
  ** With either representationOf or noData, you may optionally use the withStatus method to set the http status code. If you do not include it, a default status of 200 will be returned.

Step 3: Accessing Your API

Now that you've got a working API, you and your consumers need to know how to access it. This is extremely simple.

The folder containing your API should contain, at a minimum, the Application.cfc from Step 1, and an empty index.cfm. (index.cfm's contents will be ignored, but it must exist.) To compose a complete URL, append the URI to the location of index.cfm. Assuming your API is located at http://example.com/api/index.cfm, and you've implemented the resource with URI /artists and the GET method, then you could open up the URL: http://example.com/api/index.cfm/artists in your browser and the data would be returned, serialized using the default mime type (JSON unless otherwise defined).

Some people would prefer to remove the /index.cfm portion of the URL. To do so, you must use URL-rewriting. The good news is that you should only need one simple rule. With Apache you can use mod_rewrite, or with IIS 6 you can use IIRF (free) or ISAPI Rewrite (paid). IIS 7 has url rewriting built-in. For specific rewriting rule examples for each engine, see URL Rewrite Rule Examples. There are also Java Servlet Filters to accomplish this, should that be more to your liking.