arangodb/Documentation/UserManual/Foxx.md

Foxx

Foxx: Build APIs and simple web applications in ArangoDB

Foxx is an easy way to create APIs and simple web applications from within ArangoDB. It is inspired by Sinatra, the classy Ruby web framework. If FoxxApplication is Sinatra, ArangoDB Actions are the corresponding Rack. They provide all the HTTP goodness.

So let's get started, shall we?

An application build with Foxx is written in JavaScript and deployed to ArangoDB directly. ArangoDB serves this application, you do not need a separate application server.

So given you want to build an application that sends a plain-text response "Worked!" for all requests to /my/wiese. How would you achieve that with Foxx?

First, create a directory my_app and save a file called app.js in this directory. Write the following content to this file:

FoxxApplication = require("org/arangodb/foxx").FoxxApplication;

app = new FoxxApplication();

app.get("/wiese", function(req, res) {
  res.set("Content-Type", "text/plain");
  res.body = "Worked!"
});

app.start(applicationContext);

This is your application. Now we need to mount it to the path /my. In order to achieve that, we create a file called manifest.json in our my_app directory with the following content:

{
  "apps": {
    "/my": "app.js"
  }
}

Now your application is done. Start ArangoDB as follows:

arangod --javascript.dev-app-path my_app /tmp/fancy_db

Now point your browser to /my/wiese and you should see "Worked!". After this short overview, let's get into the details.

Details on FoxxApplication

new FoxxApplication

@copydetails JSF_foxx_application_initializer

FoxxApplication#start

@copydetails JSF_foxx_application_start

requiresLibs and requiresModels

Using the base paths defined in the manifest file, you can require libraries (and the special models described later) that you need in this FoxxApplication. So for example:

app.requiresLibs = {
  "schafspelz": "wolf"
};

This will require the file wolf.js in the libs folder you have defined and make the module available via the variable schafspelz in your FoxxApplication definitions:

app.get("/bark", function (req, res) {
  schafspelz.bark();
});

Please note that you cannot use the normal require syntax in a FoxxApplication, because it's a special DSL and not a normal JavaScript file.

Handling Requests

If you do not redefine it, all requests that go to the root of your application will be redirected to index.html.

FoxxApplication#head

@copydetails JSF_foxx_application_head

FoxxApplication#get

@copydetails JSF_foxx_application_get

FoxxApplication#post

@copydetails JSF_foxx_application_post

FoxxApplication#put

@copydetails JSF_foxx_application_put

FoxxApplication#patch

@copydetails JSF_foxx_application_patch

FoxxApplication#delete

@copydetails JSF_foxx_application_delete

Documenting and Constraining the Routes

If you define a route like described above, you have the option to match parts of the URL to variables. If you for example define a route /animals/:animal and the URL animals/foxx is requested it is matched by this rule. You can then get the value of this variable (in this case "foxx") by calling request.params("animal").

Furthermore you can describe your API by chaining the following methods onto your path definition. With the provided information, Foxx will generate a nice documentation for you. Some of the methods additionally will check certain properties of the request.

Describing a pathParam

/// @fn JSF_foxx_RequestContext_pathParam

Describing a queryParam

/// @fn JSF_foxx_RequestContext_queryParam

Before and After Hooks

You can use the following two functions to do something before or respectively after the normal routing process is happening. You could use that for logging or to manipulate the request or response (translate it to a certain format for example).

FoxxApplication#before

@copydetails JSF_foxx_application_before

FoxxApplication#after

@copydetails JSF_foxx_application_after

More functionality

FoxxApplication#helper

@copydetails JSF_foxx_application_helper

FoxxApplication#accepts

@copydetails JSF_foxx_application_accepts

Models

If you do not require a module with requiresLibs, but instead use requiresModels, you will have three additional functions available in the module (otherwise it will behave the same):

• var a = requireModel("module"): Requires the model "module" (which again will have these functions available) and makes it available via the variable a.
• appCollection("test"): Returns the collection "test" prefixed with the application prefix
• appCollectionName("test"): Returns the name of the collection "test" prefixed with the application prefix

If you need access to a normal module from this model, just require it as usual.

The Request and Response Objects

When you have created your FoxxApplication you can now define routes on it. You provide each with a function that will handle the request. It gets two arguments (four, to be honest. But the other two are not relevant for now):

• The request object
• The response object

These objects are provided by the underlying ArangoDB actions and enhanced by the BaseMiddleware provided by Foxx.

The request object

Every request object has the following attributes from the underlying Actions, amongst others:

request.path

This is the complete path as supplied by the user as a String.

request.body

@copydetails JSF_foxx_BaseMiddleware_request_body

request.params

@copydetails JSF_foxx_BaseMiddleware_request_params

The response object

Every response object has the following attributes from the underlying Actions:

request.body

You provide your response body as a String here.

request.status

@copydetails JSF_foxx_BaseMiddleware_response_status

request.set

@copydetails JSF_foxx_BaseMiddleware_response_set

request.json

@copydetails JSF_foxx_BaseMiddleware_response_json

request.render

@copydetails JSF_foxx_BaseMiddleware_response_render

The Manifest File

In the manifest.json you define the components of your application: The content is a JSON object with the following keys:

• name: Name of the application (Meta information)
• version: Current version of the application (Meta information)
• description: A short description of the application (Meta information)
• thumbnail: Path to a thumbnail that represents the application (Meta information)
• apps: Map routes to FoxxApplications
• lib: Base path for the models you want to require
• models: Base path for the models you want to require
• files: Deliver files
• assets: Deliver pre-processed files
• setup: Path to a setup script
• teardown: Path to a teardown script

A more complete example for a Manifest file:

{
  "name": "my_website",
  "version": "1.2.1",
  "description": "My Website with a blog and a shop",
  "thumnail": "images/website-logo.png",

  "apps": {
    "/blog": "apps/blog.js",
    "/shop": "apps/shop.js"
  },

  "lib": "lib",
  "models": "models",

  "files": {
    "/images": "images"
  },

  "assets": {
    "application.js": [
      "vendor/jquery.js",
      "assets/javascripts/*"
    ]
  },

  "setup": "scripts/setup.js",
  "teardown": "scripts/teardown.js"
}

setup and teardown

You can provide a path to a JavaScript file that prepares ArangoDB for your application (or respectively removes it entirely). These scripts have access to appCollection and appCollectionName just like models. Use the setup script to create all collections your application needs and fill them with initial data if you want to. Use the teardown script to remove all collections you have created.

apps is an object that matches routes to files:

• The key is the route you want to mount at
• The value is the path to the JavaScript file containing the FoxxApplication you want to mount

You can add multiple applications in one manifest this way.

The files

Deliver all files in a certain folder without modifying them. You can deliver text files as well as binaries:

"files": {
  "/images": "images"
}

The assets

The value for the asset key is an object consisting of paths that are matched to the files they are composed of. Let's take the following example:

"assets": { "application.js": [ "vendor/jquery.js", "assets/javascripts/*" ] }

If a request is made to /application.js (in development mode), the array provided will be processed one element at a time. The elements are paths to files (with the option to use wildcards). The files will be concatenated and delivered as a single file.

Development Mode

If you start ArangoDB with the option --javascript.dev-app-path followed by the path to a directory containing a manifest file, you are starting ArangoDB in development mode with the application loaded. This means that on every request:

1. All routes are dropped
2. All module caches are flushed
3. Your manifest file is read
4. All files in your lib folder are loaded
5. All apps are executed. Each app.start() will put the routes in a temporary route object, prefixed with the path given in the manifest
6. All routes in the temporary route object are stored to the routes
7. The request will be processed

This means that you do not have to restart ArangoDB if you change anything in your app. It is of course not meant for production, because the reloading makes the app relatively slow.

Deploying on Production

The Production mode is in development right now. We will offer the option to process all assets at once and write the files to disk for production with the option to run Uglify2.js and similar tools in order to compress them.

Optional Functionality: FormatMiddleware

Unlike the BaseMiddleware this Middleware is only loaded if you want it. This Middleware gives you Rails-like format handling via the extension of the URL or the accept header. Say you request an URL like /people.json:

The FormatMiddleware will set the format of the request to JSON and then delete the .json from the request. You can therefore write handlers that do not take an extension into consideration and instead handle the format via a simple String. To determine the format of the request it checks the URL and then the accept header. If one of them gives a format or both give the same, the format is set. If the formats are not the same, an error is raised.

Use it by calling:

FormatMiddleware = require('foxx').FormatMiddleware;
app.before("/*", FormatMiddleware.new(['json']));

or the shortcut:

app.accepts(['json']);

In both forms you can give a default format as a second parameter, if no format could be determined. If you give no defaultFormat this case will be handled as an error.