REST Easy With Symfony

Introduction

Recently, I had to figure out how to validate a person's details in the DMZ using some standard reference; the main concern was that the machine in the DMZ could not “send” any sensitive (useful) information. This is “typically” what is done, that is to say “hide” information. There was a dilemma of how to communicate this information from external (DMZ) to internal (secure data). RESTful web services seemed like the best way to go.

One of the most downloaded Symfony bundles is FOSRestBundle, and this is understandable, since REST is becoming more prevalent nowadays. So I decided to use FOSRestBundle for my application. This blog describes how to install the bundle and get it working.

Installation

If you haven’t installed Symfony before, you’ll need to install that and all its requirements first. My post Apache & Symfony on RHEL describes details on installing Apache (httpd), PHP 7.0, MariaDB, Composer, and the Symfony binary. So I would suggest you look at that blog first and then proceed with these steps.

I’ll presume you’ve created a Symfony project called “restTest”, and then you’ll need to issue the following commands to install FOSRestBundle:

composer require friendsofsymfony/rest-bundle

If for some reason, on your machine, you can’t write to the html folder (example /var/www/html), and you need to use sudo to create the permissions, then you’ll need to run composer differently. Use the command “whereis composer” to find out the path to composer, then issue the following command:

sudo /usr/local/bin/composer require friendsofsymfony/rest-bundle

Then, enable the bundle by editing “restTest/app/AppKernel.php”:

// app/AppKernel.php

class AppKernel extends Kernel
{
   public function registerBundles()
   {
      $bundles = [
         ...
         new FOS\RestBundle\FOSRestBundle(),
         ...
      ];

After that, you’ll need to enable a JSON serializer and the configuration for the FOSRestBundle. To do this, edit the file “restTest/app/config/config.yml” as follows:

# app/config/config.yml
...
framework:
   ...
   serializer: { enable_annotations: true }
   ...
...
fos_rest:
   body_listener: true
   format_listener:
      rules:
         - { path: '^/', priorities: ['json'], 
         fallback_format: json, prefer_extension: false }
   param_fetcher_listener: true
   view:
      view_response_listener: 'force'
      formats:
         json: true
...

That’s it for installation!

Create a Default Controller

Next let’s edit the default controller and create a simple controller that returns a very simple JSON response. In the controller example below, I’ll use @Rest annotations that simplify routing. Open the PHP file “restTest/src/AppBundle/Controller/DefaultController.php” and make the following changes:

<?php
namespace AppBundle\Controller;
use FOS\RestBundle\Controller\Annotations as Rest;
use FOS\RestBundle\Controller\FOSRestController;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpFoundation\Response;

class DefaultController extends FOSRestController {
    /**
     * @Rest\Get("/api/{testID}")
     */
    public function apiAction(Request $request)
    {
       $data = [
          'test1' => 'someData1',
          'test2' => false,
       ];
 
       $view = $this->view($data, Response::HTTP_OK);
 
       return $view;
   }

That’s it! Now open a browser and enter the URL:

http://192.168.1.15/api/1234

In the above example, the value “192.168.1.15” is the IP address of the host running the Apache/Symfony server. You could also setup the “ServerName” directive and configure your hosts file (as described in my Apache httpd VirtualHost Config post), and then use a hostname in the URL. If everything is working and setup correctly, this will return the following JSON response:

{ "test1":"someData","test2":false }

This demonstrates a simple REST controller, you can modify the controller to return the desired data that you need.

Returning Useful Information

The above default controller works great, except it only returns static data and nothing really useful. What if we wanted the passed in parameter “testID” to represent an ID of a user table in a database? Then, we can pass in the parameter and then return via the controller information about the user.

Most Symfony users use the default (local) database which is MySQL. However, you can use other databases such as PostgreSQL, MSSQL, Oracle, etc., and the database can also be external to the Symfony host. In my example, I’ll use an external Oracle database connection using a Doctrine Database Abstraction Layer connection. Here is an example code getting user information:

/**
 * @Rest\Get("/api/{testID}")
 */
public function apiAction(Request $request)
{
   // Get an Oracle database connection.
   $orc = $this->get('doctrine.dbal.oracle_connection');
 
   // Query for user ID, and get first & last names.
   $query = "SELECT U.FIRST_NAME,U.LAST_NAME FROM USERS U
             WHERE U.ID = '".$request->get('testID')."'";
   $result = $orc->fetchAll( $query );
 
   if ($result == null){
      $data = [];
   }
   else{
      $data = [
         'fname' => $result[0]['FIRST_NAME'],
         'lname' => $result[0]['LAST_NAME'],
      ];
   }
 
   $view = $this->view($data, Response::HTTP_OK);
 
   return $view;
}

In the above code, we retrieve the “testID” from the Request and then run a query on the database for the passed in “testID” and return the First & Last names for the particular user in the JSON response.

Using the above controller, presuming the database contained the user with a “testID” of “3333” has a USERS tables values of “Tony Baloney” for First & Last names; then using the REST API URL of “http://192.168.1.15/api/333” would return:

{"fname":"Tony","lname":"Baloney"}

This is much more useful, since passing in the ID returns the users name as a response.