Tutorial: Creating a Simple REST API

In this tutorial, we will explain how to create a simple application that provides a RESTful API using the different HTTP methods:

  • GET to retrieve and search data
  • POST to add data
  • PUT to update data
  • DELETE to delete data

Defining the API

The API consists of the following methods:

MethodURLAction
GET/api/robotsRetrieves all robots
GET/api/robots/search/AstroSearches for robots with ‘Astro’ in their name
GET/api/robots/2Retrieves robots based on primary key
POST/api/robotsAdds a new robot
PUT/api/robots/2Updates robots based on primary key
DELETE/api/robots/2Deletes robots based on primary key

Creating the Application

As the application is so simple, we will not implement any full MVC environment to develop it. In this case, we will use a micro application to meet our goal.

The following file structure is more than enough:

  1. my-rest-api/
  2.     models/
  3.         Robots.php
  4.     index.php
  5.     .htaccess

First, we need a .htaccess file that contains all the rules to rewrite the request URIs to the index.php file (application entry-point):

  1. <IfModule mod_rewrite.c>
  2.     RewriteEngine On
  3.     RewriteCond %{REQUEST_FILENAME} !-f
  4.     RewriteRule ^((?s).*)$ index.php?_url=/$1 [QSA,L]
  5. </IfModule>

The bulk of our code will be placed in index.php. The file is created as follows:

  1. <?php
  3. use Phalcon\Mvc\Micro;
  5. $app = new Micro();
  7. // Define the routes here
  9. $app->handle();

Now we will create the routes as we defined above:

  1. <?php
  3. use Phalcon\Mvc\Micro;
  5. $app = new Micro();
  7. // Retrieves all robots
  8. $app->get(
  9.     '/api/robots',
  10.     function () {
  11.         // Operation to fetch all the robots
  12.     }
  13. );
  15. // Searches for robots with $name in their name
  16. $app->get(
  17.     '/api/robots/search/{name}',
  18.     function ($name) {
  19.         // Operation to fetch robot with name $name
  20.     }
  21. );
  23. // Retrieves robots based on primary key
  24. $app->get(
  25.     '/api/robots/{id:[0-9]+}',
  26.     function ($id) {
  27.         // Operation to fetch robot with id $id
  28.     }
  29. );
  31. // Adds a new robot
  32. $app->post(
  33.     '/api/robots',
  34.     function () {
  35.         // Operation to create a fresh robot
  36.     }
  37. );
  39. // Updates robots based on primary key
  40. $app->put(
  41.     '/api/robots/{id:[0-9]+}',
  42.     function ($id) {
  43.         // Operation to update a robot with id $id
  44.     }
  45. );
  47. // Deletes robots based on primary key
  48. $app->delete(
  49.     '/api/robots/{id:[0-9]+}',
  50.     function ($id) {
  51.         // Operation to delete the robot with id $id
  52.     }
  53. );
  55. $app->handle();

Each route is defined with a method with the same name as the HTTP method, as first parameter we pass a route pattern, followed by a handler. In this case, the handler is an anonymous function. The following route: /api/robots/{id:[0-9]+}, by example, explicitly sets that the id parameter must have a numeric format.

When a defined route matches the requested URI then the application executes the corresponding handler.

Creating a Model

Our API provides information about robots, these data are stored in a database. The following model allows us to access that table in an object-oriented way. We have implemented some business rules using built-in validators and simple validations. Doing this will give us the peace of mind that saved data meet the requirements of our application. This model file should be placed in your Models folder.

  1. <?php
  3. namespace Store\Toys;
  5. use Phalcon\Mvc\Model;
  6. use Phalcon\Mvc\Model\Message;
  7. use Phalcon\Validation;
  8. use Phalcon\Validation\Validator\Uniqueness
  9. use Phalcon\Validation\Validator\InclusionIn;
  12. class Robots extends Model
  13. {
  14.     public function validation()
  15.     {
  16.         $validator = new Validation();
  18.         // Type must be: droid, mechanical or virtual
  19.         $validator->add(
  20.             "type",
  21.             new InclusionIn(
  22.                 [
  23.                     'message' => 'Type must be "droid", "mechanical", or "virtual"',
  24.                     'domain' => [
  25.                         'droid',
  26.                         'mechanical',
  27.                         'virtual',
  28.                     ],
  29.                 ]
  30.             )
  31.         );
  33.         // Robot name must be unique
  34.         $validator->add(
  35.             'name',
  36.             new Uniqueness(
  37.                 [
  38.                     'field'   => 'name',
  39.                     'message' => 'The robot name must be unique',
  40.                 ]
  41.             )
  42.         );
  44.         // Year cannot be less than zero
  45.         if ($this->year < 0) {
  46.             $this->appendMessage(
  47.                 new Message('The year cannot be less than zero')
  48.             );
  49.         }
  51.         // Check if any messages have been produced
  52.         if ($this->validationHasFailed() === true) {
  53.             return false;
  54.         }
  55.     }
  56. }

Now, we must set up a connection to be used by this model and load it within our app [File: index.php]:

  1. <?php
  3. use Phalcon\Loader;
  4. use Phalcon\Mvc\Micro;
  5. use Phalcon\Di\FactoryDefault;
  6. use Phalcon\Db\Adapter\Pdo\Mysql as PdoMysql;
  8. // Use Loader() to autoload our model
  9. $loader = new Loader();
  11. $loader->registerNamespaces(
  12.     [
  13.         'Store\Toys' => __DIR__ . '/models/',
  14.     ]
  15. );
  17. $loader->register();
  19. $di = new FactoryDefault();
  21. // Set up the database service
  22. $di->set(
  23.     'db',
  24.     function () {
  25.         return new PdoMysql(
  26.             [
  27.                 'host'     => 'localhost',
  28.                 'username' => 'asimov',
  29.                 'password' => 'zeroth',
  30.                 'dbname'   => 'robotics',
  31.             ]
  32.         );
  33.     }
  34. );
  36. // Create and bind the DI to the application
  37. $app = new Micro($di);

Retrieving Data

The first handler that we will implement is which by method GET returns all available robots. Let’s use PHQL to perform this simple query returning the results as JSON. [File: index.php]

  1. <?php
  3. // Retrieves all robots
  4. $app->get(
  5.     '/api/robots',
  6.     function () use ($app) {
  7.         $phql = 'SELECT * FROM Store\Toys\Robots ORDER BY name';
  9.         $robots = $app->modelsManager->executeQuery($phql);
  11.         $data = [];
  13.         foreach ($robots as $robot) {
  14.             $data[] = [
  15.                 'id'   => $robot->id,
  16.                 'name' => $robot->name,
  17.             ];
  18.         }
  20.         echo json_encode($data);
  21.     }
  22. );

PHQL, allow us to write queries using a high-level, object-oriented SQL dialect that internally translates to the right SQL statements depending on the database system we are using. The clause use in the anonymous function allows us to pass some variables from the global to local scope easily.

The searching by name handler would look like [File: index.php]:

  1. <?php
  3. // Searches for robots with $name in their name
  4. $app->get(
  5.     '/api/robots/search/{name}',
  6.     function ($name) use ($app) {
  7.         $phql = 'SELECT * FROM Store\Toys\Robots WHERE name LIKE :name: ORDER BY name';
  9.         $robots = $app->modelsManager->executeQuery(
  10.             $phql,
  11.             [
  12.                 'name' => '%' . $name . '%'
  13.             ]
  14.         );
  16.         $data = [];
  18.         foreach ($robots as $robot) {
  19.             $data[] = [
  20.                 'id'   => $robot->id,
  21.                 'name' => $robot->name,
  22.             ];
  23.         }
  25.         echo json_encode($data);
  26.     }
  27. );

Searching by the field id it’s quite similar, in this case, we’re also notifying if the robot was found or not [File: index.php]:

  1. <?php
  3. use Phalcon\Http\Response;
  5. // Retrieves robots based on primary key
  6. $app->get(
  7.     '/api/robots/{id:[0-9]+}',
  8.     function ($id) use ($app) {
  9.         $phql = 'SELECT * FROM Store\Toys\Robots WHERE id = :id:';
  11.         $robot = $app->modelsManager->executeQuery(
  12.             $phql,
  13.             [
  14.                 'id' => $id,
  15.             ]
  16.         )->getFirst();
  20.         // Create a response
  21.         $response = new Response();
  23.         if ($robot === false) {
  24.             $response->setJsonContent(
  25.                 [
  26.                     'status' => 'NOT-FOUND'
  27.                 ]
  28.             );
  29.         } else {
  30.             $response->setJsonContent(
  31.                 [
  32.                     'status' => 'FOUND',
  33.                     'data'   => [
  34.                         'id'   => $robot->id,
  35.                         'name' => $robot->name
  36.                     ]
  37.                 ]
  38.             );
  39.         }
  41.         return $response;
  42.     }
  43. );

Inserting Data

Taking the data as a JSON string inserted in the body of the request, we also use PHQL for insertion [File: index.php]:

  1. <?php
  3. use Phalcon\Http\Response;
  5. // Adds a new robot
  6. $app->post(
  7.     '/api/robots',
  8.     function () use ($app) {
  9.         $robot = $app->request->getJsonRawBody();
  11.         $phql = 'INSERT INTO Store\Toys\Robots (name, type, year) VALUES (:name:, :type:, :year:)';
  13.         $status = $app->modelsManager->executeQuery(
  14.             $phql,
  15.             [
  16.                 'name' => $robot->name,
  17.                 'type' => $robot->type,
  18.                 'year' => $robot->year,
  19.             ]
  20.         );
  22.         // Create a response
  23.         $response = new Response();
  25.         // Check if the insertion was successful
  26.         if ($status->success() === true) {
  27.             // Change the HTTP status
  28.             $response->setStatusCode(201, 'Created');
  30.             $robot->id = $status->getModel()->id;
  32.             $response->setJsonContent(
  33.                 [
  34.                     'status' => 'OK',
  35.                     'data'   => $robot,
  36.                 ]
  37.             );
  38.         } else {
  39.             // Change the HTTP status
  40.             $response->setStatusCode(409, 'Conflict');
  42.             // Send errors to the client
  43.             $errors = [];
  45.             foreach ($status->getMessages() as $message) {
  46.                 $errors[] = $message->getMessage();
  47.             }
  49.             $response->setJsonContent(
  50.                 [
  51.                     'status'   => 'ERROR',
  52.                     'messages' => $errors,
  53.                 ]
  54.             );
  55.         }
  57.         return $response;
  58.     }
  59. );

Updating Data

The data update is similar to insertion. The id passed as parameter indicates what robot must be updated [File: index.php]:

  1. <?php
  3. use Phalcon\Http\Response;
  5. // Updates robots based on primary key
  6. $app->put(
  7.     '/api/robots/{id:[0-9]+}',
  8.     function ($id) use ($app) {
  9.         $robot = $app->request->getJsonRawBody();
  11.         $phql = 'UPDATE Store\Toys\Robots SET name = :name:, type = :type:, year = :year: WHERE id = :id:';
  13.         $status = $app->modelsManager->executeQuery(
  14.             $phql,
  15.             [
  16.                 'id'   => $id,
  17.                 'name' => $robot->name,
  18.                 'type' => $robot->type,
  19.                 'year' => $robot->year,
  20.             ]
  21.         );
  23.         // Create a response
  24.         $response = new Response();
  26.         // Check if the insertion was successful
  27.         if ($status->success() === true) {
  28.             $response->setJsonContent(
  29.                 [
  30.                     'status' => 'OK'
  31.                 ]
  32.             );
  33.         } else {
  34.             // Change the HTTP status
  35.             $response->setStatusCode(409, 'Conflict');
  37.             $errors = [];
  39.             foreach ($status->getMessages() as $message) {
  40.                 $errors[] = $message->getMessage();
  41.             }
  43.             $response->setJsonContent(
  44.                 [
  45.                     'status'   => 'ERROR',
  46.                     'messages' => $errors,
  47.                 ]
  48.             );
  49.         }
  51.         return $response;
  52.     }
  53. );

Deleting Data

The data delete is similar to update. The id passed as parameter indicates what robot must be deleted [File: index.php]:

  1. <?php
  3. use Phalcon\Http\Response;
  5. // Deletes robots based on primary key
  6. $app->delete(
  7.     '/api/robots/{id:[0-9]+}',
  8.     function ($id) use ($app) {
  9.         $phql = 'DELETE FROM Store\Toys\Robots WHERE id = :id:';
  11.         $status = $app->modelsManager->executeQuery(
  12.             $phql,
  13.             [
  14.                 'id' => $id,
  15.             ]
  16.         );
  18.         // Create a response
  19.         $response = new Response();
  21.         if ($status->success() === true) {
  22.             $response->setJsonContent(
  23.                 [
  24.                     'status' => 'OK'
  25.                 ]
  26.             );
  27.         } else {
  28.             // Change the HTTP status
  29.             $response->setStatusCode(409, 'Conflict');
  31.             $errors = [];
  33.             foreach ($status->getMessages() as $message) {
  34.                 $errors[] = $message->getMessage();
  35.             }
  37.             $response->setJsonContent(
  38.                 [
  39.                     'status'   => 'ERROR',
  40.                     'messages' => $errors,
  41.                 ]
  42.             );
  43.         }
  45.         return $response;
  46.     }
  47. );

Creating database

Now we will create database for our application.Run SQL queries as follows:

  1. CREATE DATABASE `robotics`;
  2. CREATE TABLE `robotics`.`robots` (
  3.  `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  4.  `name` varchar(200) COLLATE utf8_bin NOT NULL,
  5.  `type` varchar(200) COLLATE utf8_bin NOT NULL,
  6.  `year` smallint(2) unsigned NOT NULL,
  7.  PRIMARY KEY (`id`)
  8. )

Testing our Application

Using curl we’ll test every route in our application verifying its proper operation.

Obtain all the robots:

  1. curl -i -X GET http://localhost/my-rest-api/api/robots
  3. HTTP/1.1 200 OK
  4. Date: Tue, 21 Jul 2015 07:05:13 GMT
  5. Server: Apache/2.2.22 (Unix) DAV/2
  6. Content-Length: 117
  7. Content-Type: text/html; charset=UTF-8
  9. [{"id":"1","name":"Robotina"},{"id":"2","name":"Astro Boy"},{"id":"3","name":"Terminator"}]

Search a robot by its name:

  1. curl -i -X GET http://localhost/my-rest-api/api/robots/search/Astro
  3. HTTP/1.1 200 OK
  4. Date: Tue, 21 Jul 2015 07:09:23 GMT
  5. Server: Apache/2.2.22 (Unix) DAV/2
  6. Content-Length: 31
  7. Content-Type: text/html; charset=UTF-8
  9. [{"id":"2","name":"Astro Boy"}]

Obtain a robot by its id:

  1. curl -i -X GET http://localhost/my-rest-api/api/robots/3
  3. HTTP/1.1 200 OK
  4. Date: Tue, 21 Jul 2015 07:12:18 GMT
  5. Server: Apache/2.2.22 (Unix) DAV/2
  6. Content-Length: 56
  7. Content-Type: text/html; charset=UTF-8
  9. {"status":"FOUND","data":{"id":"3","name":"Terminator"}}

Insert a new robot:

  1. curl -i -X POST -d '{"name":"C-3PO","type":"droid","year":1977}'
  2.     http://localhost/my-rest-api/api/robots
  4. HTTP/1.1 201 Created
  5. Date: Tue, 21 Jul 2015 07:15:09 GMT
  6. Server: Apache/2.2.22 (Unix) DAV/2
  7. Content-Length: 75
  8. Content-Type: text/html; charset=UTF-8
  10. {"status":"OK","data":{"name":"C-3PO","type":"droid","year":1977,"id":"4"}}

Try to insert a new robot with the name of an existing robot:

  1. curl -i -X POST -d '{"name":"C-3PO","type":"droid","year":1977}'
  2.     http://localhost/my-rest-api/api/robots
  4. HTTP/1.1 409 Conflict
  5. Date: Tue, 21 Jul 2015 07:18:28 GMT
  6. Server: Apache/2.2.22 (Unix) DAV/2
  7. Content-Length: 63
  8. Content-Type: text/html; charset=UTF-8
  10. {"status":"ERROR","messages":["The robot name must be unique"]}

Or update a robot with an unknown type:

  1. curl -i -X PUT -d '{"name":"ASIMO","type":"humanoid","year":2000}'
  2.     http://localhost/my-rest-api/api/robots/4
  4. HTTP/1.1 409 Conflict
  5. Date: Tue, 21 Jul 2015 08:48:01 GMT
  6. Server: Apache/2.2.22 (Unix) DAV/2
  7. Content-Length: 104
  8. Content-Type: text/html; charset=UTF-8
  10. {"status":"ERROR","messages":["Value of field 'type' must be part of
  11.     list: droid, mechanical, virtual"]}

Finally, delete a robot:

  1. curl -i -X DELETE http://localhost/my-rest-api/api/robots/4
  3. HTTP/1.1 200 OK
  4. Date: Tue, 21 Jul 2015 08:49:29 GMT
  5. Server: Apache/2.2.22 (Unix) DAV/2
  6. Content-Length: 15
  7. Content-Type: text/html; charset=UTF-8
  9. {"status":"OK"}

Conclusion

As we saw, developing a RESTful API with Phalcon is easy using micro applications and PHQL.