Tutorial

This tutorial will outline how to create a very simple notes app. The finished app is available on GitHub.

Setup

First the development environment needs to be set up. This can be done by either downloading the zip from the website or cloning it directly from GitHub:

git clone git@github.com:nextcloud/server.git --branch $BRANCH
cd server
git submodule update --init

Note

$BRANCH is the desired Nextcloud branch (e.g. stable9 for Nextcloud 9, stable10 for Nextcloud 10, ..., master for the upcoming release)

First you want to enable debug mode to get proper error messages. To do that set debug to true in the nextcloud/config/config.php file:

<?php
$CONFIG = array (
    'debug' => true,
    ... configuration goes here ...
);

Note

PHP errors are logged to nextcloud/data/nextcloud.log

Now open another terminal window and start the development server:

cd nextcloud
php -S localhost:8080

Afterwards a skeleton app can be created in the app store.

Download the compressed file that contains the generated app and extract it into your apps/ directory. Afterwards the application can be enabled on the apps page.

The first basic app is now available at http://localhost:8080/index.php/apps/yourappid/

Routes & controllers

A typical web application consists of server side and client side code. The glue between those two parts are the URLs. In case of the notes app the following URLs will be used:

• GET /: Returns the interface in HTML
• GET /notes: Returns a list of all notes in JSON
• GET /notes/1: Returns a note with the id 1 in JSON
• DELETE /notes/1: Deletes a note with the id 1
• POST /notes: Creates a new note by passing in JSON
• PUT /notes/1: Updates a note with the id 1 by passing in JSON

On the client side we can call these URLs with the following jQuery code:

// example for calling the PUT /notes/1 URL
var baseUrl = OC.generateUrl('/apps/ownnotes');
var note = {
    title: 'New note',
    content: 'This is the note text'
};
var id = 1;
$.ajax({
    url: baseUrl + '/notes/' + id,
    type: 'PUT',
    contentType: 'application/json',
    data: JSON.stringify(note)
}).done(function (response) {
    // handle success
}).fail(function (response, code) {
    // handle failure
});

On the server side we need to register a callback that is executed once the request comes in. The callback itself will be a method on a controller and the controller will be connected to the URL with a route. The controller and route for the page are already set up in ownnotes/appinfo/routes.php:

<?php
return ['routes' => [
    ['name' => 'page#index', 'url' => '/', 'verb' => 'GET']
]];

This route calls the controller OCA\OwnNotes\PageController->index() method which is defined in ownnotes/lib/Controller/PageController.php. The controller returns a template, in this case ownnotes/templates/main.php:

Note

@NoAdminRequired and @NoCSRFRequired in the comments above the method turn off security checks, see Controllers

<?php
 namespace OCA\OwnNotes\Controller;

 use OCP\IRequest;
 use OCP\AppFramework\Http\TemplateResponse;
 use OCP\AppFramework\Controller;

 class PageController extends Controller {

     public function __construct(string $AppName, IRequest $request){
         parent::__construct($AppName, $request);
     }

     /**
      * @NoAdminRequired
      * @NoCSRFRequired
      */
     public function index() {
         return new TemplateResponse('ownnotes', 'main');
     }

 }

Since the route which returns the initial HTML has been taken care of, the controller which handles the AJAX requests for the notes needs to be set up. Create the following file: ownnotes/lib/Controller/NoteController.php with the following content:

<?php
 namespace OCA\OwnNotes\Controller;

 use OCP\IRequest;
 use OCP\AppFramework\Controller;

 class NoteController extends Controller {

     public function __construct(string $AppName, IRequest $request){
         parent::__construct($AppName, $request);
     }

     /**
      * @NoAdminRequired
      */
     public function index() {
         // empty for now
     }

     /**
      * @NoAdminRequired
      *
      * @param int $id
      */
     public function show(int $id) {
         // empty for now
     }

     /**
      * @NoAdminRequired
      *
      * @param string $title
      * @param string $content
      */
     public function create(string $title, string $content) {
         // empty for now
     }

     /**
      * @NoAdminRequired
      *
      * @param int $id
      * @param string $title
      * @param string $content
      */
     public function update(int $id, string $title, string $content) {
         // empty for now
     }

     /**
      * @NoAdminRequired
      *
      * @param int $id
      */
     public function destroy(int $id) {
         // empty for now
     }

 }

Note

The parameters are extracted from the request body and the URL using the controller method’s variable names. Since PHP does not support type hints for primitive types such as ints and booleans, we need to add them as annotations in the comments. In order to type cast a parameter to an int, add @param int $parameterName

Now the controller methods need to be connected to the corresponding URLs in the ownnotes/appinfo/routes.php file:

<?php
return [
    'routes' => [
        ['name' => 'page#index', 'url' => '/', 'verb' => 'GET'],
        ['name' => 'note#index', 'url' => '/notes', 'verb' => 'GET'],
        ['name' => 'note#show', 'url' => '/notes/{id}', 'verb' => 'GET'],
        ['name' => 'note#create', 'url' => '/notes', 'verb' => 'POST'],
        ['name' => 'note#update', 'url' => '/notes/{id}', 'verb' => 'PUT'],
        ['name' => 'note#destroy', 'url' => '/notes/{id}', 'verb' => 'DELETE']
    ]
];

Since those 5 routes are so common, they can be abbreviated by adding a resource instead:

<?php
return [
    'resources' => [
        'note' => ['url' => '/notes']
    ],
    'routes' => [
        ['name' => 'page#index', 'url' => '/', 'verb' => 'GET']
    ]
];

Database

Now that the routes are set up and connected the notes should be saved in the database. To do that first create a database migration by creating a file ownnotes/lib/Migration/VersionXXYYZZDateYYYYMMDDHHSSAA.php, so for example ownnotes/lib/Migration/Version000000Date20181224140601.php“”

<?php

  namespace OCA\Notes\Migration;

  use Closure;
  use OCP\DB\ISchemaWrapper;
  use OCP\Migration\SimpleMigrationStep;
  use OCP\Migration\IOutput;

  class Version000000Date20181224140601 extends SimpleMigrationStep {

      /**
        * @param IOutput $output
        * @param Closure $schemaClosure The `\Closure` returns a `ISchemaWrapper`
        * @param array $options
        * @return null|ISchemaWrapper
       */
       public function changeSchema(IOutput $output, Closure $schemaClosure, array $options) {
          /** @var ISchemaWrapper $schema */
          $schema = $schemaClosure();

          if (!$schema->hasTable('notes_meta')) {
              $table = $schema->createTable('notes_meta');
              $table->addColumn('id', 'integer', [
                  'autoincrement' => true,
                  'notnull' => true,
              ]);
              $table->addColumn('file_id', 'integer', [
                  'notnull' => true,
              ]);
              $table->addColumn('user_id', 'string', [
                  'notnull' => true,
                  'length' => 64,
              ]);
              $table->addColumn('last_update', 'integer', [
                  'notnull' => true,
              ]);
              $table->addColumn('etag', 'string', [
                  'notnull' => true,
                  'length' => 32,
              ]);

              $table->setPrimaryKey(['id']);
              $table->addIndex(['file_id'], 'notes_meta_file_id_index');
              $table->addIndex(['user_id'], 'notes_meta_user_id_index');
              $table->addUniqueIndex(['file_id', 'user_id'], 'notes_meta_file_user_index');
          }

          return $schema;
      }
  }

To create the tables in the database, the version tag in ownnotes/appinfo/info.xml needs to be increased:

<?xml version="1.0"?>
<info>
    <id>ownnotes</id>
    <name>Own Notes</name>
    <description>My first Nextcloud app</description>
    <licence>AGPL</licence>
    <author>Your Name</author>
    <version>0.0.2</version>
    <namespace>OwnNotes</namespace>
    <category>tool</category>
    <dependencies>
        <owncloud min-version="8" />
    </dependencies>
</info>

Reload the page to trigger the database migration.

Now that the tables are created we want to map the database result to a PHP object to be able to control data. First create an entity in ownnotes/lib/Db/Note.php:

<?php
namespace OCA\OwnNotes\Db;

use JsonSerializable;

use OCP\AppFramework\Db\Entity;

class Note extends Entity implements JsonSerializable {

    protected $title;
    protected $content;
    protected $userId;

    public function __construct() {
        $this->addType('id','integer');
    }

    public function jsonSerialize() {
        return [
            'id' => $this->id,
            'title' => $this->title,
            'content' => $this->content
        ];
    }
}

Note

A field id is automatically set in the Entity base class

We also define a jsonSerializable method and implement the interface to be able to transform the entity to JSON easily.

Entities are returned from so called Mappers. Let’s create one in ownnotes/lib/Db/NoteMapper.php and add a find and findAll method:

<?php
namespace OCA\OwnNotes\Db;

use OCP\IDbConnection;
use OCP\AppFramework\Db\QBMapper;

class NoteMapper extends QBMapper {

    public function __construct(IDbConnection $db) {
        parent::__construct($db, 'ownnotes_notes', Note::class);
    }

    public function find(int $id, string $userId) {
        $qb = $this->db->getQueryBuilder();

                    $qb->select('*')
                             ->from($this->getTableName())
                             ->where(
                                     $qb->expr()->eq('id', $qb->createNamedParameter($id))
                             )->andWhere(
             $qb->expr()->eq('user_id', $qb->createNamedParameter($userId))
           );

        return $this->findEntity($qb);
    }

    public function findAll(string $userId) {
        $qb = $this->db->getQueryBuilder();

        $qb->select('*')
           ->from($this->getTableName())
           ->where(
            $qb->expr()->eq('user_id', $qb->createNamedParameter($userId))
           );

        return $this->findEntities($qb);
    }

}

Note

The first parent constructor parameter is the database layer, the second one is the database table and the third is the entity on which the result should be mapped onto. Insert, delete and update methods are already implemented.

Connect database & controllers

The mapper which provides the database access is finished and can be passed into the controller.

You can pass in the mapper by adding it as a type hinted parameter. Nextcloud will figure out how to assemble them by itself. Additionally we want to know the userId of the currently logged in user. Simply add a $UserId parameter to the constructor (case sensitive!). To do that open ownnotes/lib/Controller/NoteController.php and change it to the following:

<?php
 namespace OCA\OwnNotes\Controller;

 use Exception;

 use OCP\IRequest;
 use OCP\AppFramework\Http;
 use OCP\AppFramework\Http\DataResponse;
 use OCP\AppFramework\Controller;

 use OCA\OwnNotes\Db\Note;
 use OCA\OwnNotes\Db\NoteMapper;

 class NoteController extends Controller {

     private $mapper;
     private $userId;

     public function __construct(string $AppName, IRequest $request, NoteMapper $mapper, $UserId){
         parent::__construct($AppName, $request);
         $this->mapper = $mapper;
         $this->userId = $UserId;
     }

     /**
      * @NoAdminRequired
      */
     public function index() {
         return new DataResponse($this->mapper->findAll($this->userId));
     }

     /**
      * @NoAdminRequired
      *
      * @param int $id
      */
     public function show(int $id) {
         try {
             return new DataResponse($this->mapper->find($id, $this->userId));
         } catch(Exception $e) {
             return new DataResponse([], Http::STATUS_NOT_FOUND);
         }
     }

     /**
      * @NoAdminRequired
      *
      * @param string $title
      * @param string $content
      */
     public function create(string $title, string $content) {
         $note = new Note();
         $note->setTitle($title);
         $note->setContent($content);
         $note->setUserId($this->userId);
         return new DataResponse($this->mapper->insert($note));
     }

     /**
      * @NoAdminRequired
      *
      * @param int $id
      * @param string $title
      * @param string $content
      */
     public function update(int $id, string $title, string $content) {
         try {
             $note = $this->mapper->find($id, $this->userId);
         } catch(Exception $e) {
             return new DataResponse([], Http::STATUS_NOT_FOUND);
         }
         $note->setTitle($title);
         $note->setContent($content);
         return new DataResponse($this->mapper->update($note));
     }

     /**
      * @NoAdminRequired
      *
      * @param int $id
      */
     public function destroy(int $id) {
         try {
             $note = $this->mapper->find($id, $this->userId);
         } catch(Exception $e) {
             return new DataResponse([], Http::STATUS_NOT_FOUND);
         }
         $this->mapper->delete($note);
         return new DataResponse($note);
     }

 }

Note

The actual exceptions are OCP\AppFramework\Db\DoesNotExistException and OCP\AppFramework\Db\MultipleObjectsReturnedException but in this example we will treat them as the same. DataResponse is a more generic response than JSONResponse and also works with JSON.

This is all that is needed on the server side. Now let’s progress to the client side.

Making things reusable and decoupling controllers from the database

Let’s say our app is now on the app store and and we get a request that we should save the files in the filesystem which requires access to the filesystem.

The filesystem API is quite different from the database API and throws different exceptions, which means we need to rewrite everything in the NoteController class to use it. This is bad because a controller’s only responsibility should be to deal with incoming Http requests and return Http responses. If we need to change the controller because the data storage was changed the code is probably too tightly coupled and we need to add another layer in between. This layer is called Service.

Let’s take the logic that was inside the controller and put it into a separate class inside ownnotes/lib/Service/NoteService.php:

<?php
namespace OCA\OwnNotes\Service;

use Exception;

use OCP\AppFramework\Db\DoesNotExistException;
use OCP\AppFramework\Db\MultipleObjectsReturnedException;

use OCA\OwnNotes\Db\Note;
use OCA\OwnNotes\Db\NoteMapper;


class NoteService {

    private $mapper;

    public function __construct(NoteMapper $mapper){
        $this->mapper = $mapper;
    }

    public function findAll(string $userId) {
        return $this->mapper->findAll($userId);
    }

    private function handleException ($e) {
        if ($e instanceof DoesNotExistException ||
            $e instanceof MultipleObjectsReturnedException) {
            throw new NotFoundException($e->getMessage());
        } else {
            throw $e;
        }
    }

    public function find(int $id, string $userId) {
        try {
            return $this->mapper->find($id, $userId);

        // in order to be able to plug in different storage backends like files
        // for instance it is a good idea to turn storage related exceptions
        // into service related exceptions so controllers and service users
        // have to deal with only one type of exception
        } catch(Exception $e) {
            $this->handleException($e);
        }
    }

    public function create(string $title, string $content, string $userId) {
        $note = new Note();
        $note->setTitle($title);
        $note->setContent($content);
        $note->setUserId($userId);
        return $this->mapper->insert($note);
    }

    public function update(int $id, string $title, string $content, string $userId) {
        try {
            $note = $this->mapper->find($id, $userId);
            $note->setTitle($title);
            $note->setContent($content);
            return $this->mapper->update($note);
        } catch(Exception $e) {
            $this->handleException($e);
        }
    }

    public function delete(int $id, string $userId) {
        try {
            $note = $this->mapper->find($id, $userId);
            $this->mapper->delete($note);
            return $note;
        } catch(Exception $e) {
            $this->handleException($e);
        }
    }

}

Following up create the exceptions in ownnotes/lib/Service/ServiceException.php:

<?php
namespace OCA\OwnNotes\Service;

use Exception;

class ServiceException extends Exception {}

and ownnotes/lib/Service/NotFoundException.php:

<?php
namespace OCA\OwnNotes\Service;

class NotFoundException extends ServiceException {}

Remember how we had all those ugly try catches that where checking for DoesNotExistException and simply returned a 404 response? Let’s also put this into a reusable class. In our case we chose a trait so we can inherit methods without having to add it to our inheritance hierarchy. This will be important later on when you’ve got controllers that inherit from the ApiController class instead.

The trait is created in ownnotes/lib/Controller/Errors.php:

<?php

namespace OCA\OwnNotes\Controller;

use Closure;

use OCP\AppFramework\Http;
use OCP\AppFramework\Http\DataResponse;

use OCA\OwnNotes\Service\NotFoundException;


trait Errors {

    protected function handleNotFound (Closure $callback) {
        try {
            return new DataResponse($callback());
        } catch(NotFoundException $e) {
            $message = ['message' => $e->getMessage()];
            return new DataResponse($message, Http::STATUS_NOT_FOUND);
        }
    }

}

Now we can wire up the trait and the service inside the NoteController:

<?php
namespace OCA\OwnNotes\Controller;

use OCP\IRequest;
use OCP\AppFramework\Http\DataResponse;
use OCP\AppFramework\Controller;

use OCA\OwnNotes\Service\NoteService;

class NoteController extends Controller {

    private $service;
    private $userId;

    use Errors;

    public function __construct(string $AppName, IRequest $request,
                                NoteService $service, $UserId){
        parent::__construct($AppName, $request);
        $this->service = $service;
        $this->userId = $UserId;
    }

    /**
     * @NoAdminRequired
     */
    public function index() {
        return new DataResponse($this->service->findAll($this->userId));
    }

    /**
     * @NoAdminRequired
     *
     * @param int $id
     */
    public function show(int $id) {
        return $this->handleNotFound(function () use ($id) {
            return $this->service->find($id, $this->userId);
        });
    }

    /**
     * @NoAdminRequired
     *
     * @param string $title
     * @param string $content
     */
    public function create(string $title, string $content) {
        return $this->service->create($title, $content, $this->userId);
    }

    /**
     * @NoAdminRequired
     *
     * @param int $id
     * @param string $title
     * @param string $content
     */
    public function update(int $id, string $title, string $content) {
        return $this->handleNotFound(function () use ($id, $title, $content) {
            return $this->service->update($id, $title, $content, $this->userId);
        });
    }

    /**
     * @NoAdminRequired
     *
     * @param int $id
     */
    public function destroy(int $id) {
        return $this->handleNotFound(function () use ($id) {
            return $this->service->delete($id, $this->userId);
        });
    }

}

Great! Now the only reason that the controller needs to be changed is when request/response related things change.

Writing a test for the controller (recommended)

Tests are essential for having happy users and a carefree life. No one wants their users to rant about your app breaking their Nextcloud or being buggy. To do that you need to test your app. Since this amounts to a ton of repetitive tasks, we need to automate the tests.

Unit tests

A unit test is a test that tests a class in isolation. It is very fast and catches most of the bugs, so we want many unit tests.

Because Nextcloud uses Dependency Injection to assemble your app, it is very easy to write unit tests by passing mocks into the constructor. A simple test for the update method can be added by adding this to ownnotes/tests/Unit/Controller/NoteControllerTest.php:

<?php
namespace OCA\OwnNotes\Tests\Unit\Controller;

use PHPUnit_Framework_TestCase;

use OCP\AppFramework\Http;
use OCP\AppFramework\Http\DataResponse;

use OCA\OwnNotes\Service\NotFoundException;


class NoteControllerTest extends PHPUnit_Framework_TestCase {

    protected $controller;
    protected $service;
    protected $userId = 'john';
    protected $request;

    public function setUp() {
        $this->request = $this->getMockBuilder('OCP\IRequest')->getMock();
        $this->service = $this->getMockBuilder('OCA\OwnNotes\Service\NoteService')
            ->disableOriginalConstructor()
            ->getMock();
        $this->controller = new NoteController(
            'ownnotes', $this->request, $this->service, $this->userId
        );
    }

    public function testUpdate() {
        $note = 'just check if this value is returned correctly';
        $this->service->expects($this->once())
            ->method('update')
            ->with($this->equalTo(3),
                    $this->equalTo('title'),
                    $this->equalTo('content'),
                   $this->equalTo($this->userId))
            ->will($this->returnValue($note));

        $result = $this->controller->update(3, 'title', 'content');

        $this->assertEquals($note, $result->getData());
    }


    public function testUpdateNotFound() {
        // test the correct status code if no note is found
        $this->service->expects($this->once())
            ->method('update')
            ->will($this->throwException(new NotFoundException()));

        $result = $this->controller->update(3, 'title', 'content');

        $this->assertEquals(Http::STATUS_NOT_FOUND, $result->getStatus());
    }

}

We can and should also create a test for the NoteService class:

<?php
namespace OCA\OwnNotes\Tests\Unit\Service;

use PHPUnit_Framework_TestCase;

use OCP\AppFramework\Db\DoesNotExistException;

use OCA\OwnNotes\Db\Note;

class NoteServiceTest extends PHPUnit_Framework_TestCase {

    private $service;
    private $mapper;
    private $userId = 'john';

    public function setUp() {
        $this->mapper = $this->getMockBuilder('OCA\OwnNotes\Db\NoteMapper')
            ->disableOriginalConstructor()
            ->getMock();
        $this->service = new NoteService($this->mapper);
    }

    public function testUpdate() {
        // the existing note
        $note = Note::fromRow([
            'id' => 3,
            'title' => 'yo',
            'content' => 'nope'
        ]);
        $this->mapper->expects($this->once())
            ->method('find')
            ->with($this->equalTo(3))
            ->will($this->returnValue($note));

        // the note when updated
        $updatedNote = Note::fromRow(['id' => 3]);
        $updatedNote->setTitle('title');
        $updatedNote->setContent('content');
        $this->mapper->expects($this->once())
            ->method('update')
            ->with($this->equalTo($updatedNote))
            ->will($this->returnValue($updatedNote));

        $result = $this->service->update(3, 'title', 'content', $this->userId);

        $this->assertEquals($updatedNote, $result);
    }


    /**
     * @expectedException OCA\OwnNotes\Service\NotFoundException
     */
    public function testUpdateNotFound() {
        // test the correct status code if no note is found
        $this->mapper->expects($this->once())
            ->method('find')
            ->with($this->equalTo(3))
            ->will($this->throwException(new DoesNotExistException('')));

        $this->service->update(3, 'title', 'content', $this->userId);
    }

}

If PHPUnit is installed we can run the tests inside ownnotes/ with the following command:

phpunit

Note

You need to adjust the ownnotes/tests/Unit/Controller/PageControllerTest file to get the tests passing: remove the testEcho method since that method is no longer present in your PageController and do not test the user id parameters since they are not passed anymore

Integration tests

Integration tests are slow and need a fully working instance but make sure that our classes work well together. Instead of mocking out all classes and parameters we can decide whether to use full instances or replace certain classes. Because they are slow we don’t want as many integration tests as unit tests.

In our case we want to create an integration test for the udpate method without mocking out the NoteMapper class so we actually write to the existing database.

To do that create a new file called ownnotes/tests/Integration/NoteIntegrationTest.php with the following content:

<?php
namespace OCA\OwnNotes\Tests\Integration\Controller;

use OCP\AppFramework\Http\DataResponse;
use OCP\AppFramework\App;
use Test\TestCase;

use OCA\OwnNotes\Db\Note;

/**
 * @group DB
 */
class NoteIntegrationTest extends TestCase {

    private $controller;
    private $mapper;
    private $userId = 'john';

    public function setUp() {
        parent::setUp();
        $app = new App('ownnotes');
        $container = $app->getContainer();

        // only replace the user id
        $container->registerService('UserId', function($c) {
            return $this->userId;
        });

        $this->controller = $container->query(
            'OCA\OwnNotes\Controller\NoteController'
        );

        $this->mapper = $container->query(
            'OCA\OwnNotes\Db\NoteMapper'
        );
    }

    public function testUpdate() {
        // create a new note that should be updated
        $note = new Note();
        $note->setTitle('old_title');
        $note->setContent('old_content');
        $note->setUserId($this->userId);

        $id = $this->mapper->insert($note)->getId();

        // fromRow does not set the fields as updated
        $updatedNote = Note::fromRow([
            'id' => $id,
            'user_id' => $this->userId
        ]);
        $updatedNote->setContent('content');
        $updatedNote->setTitle('title');

        $result = $this->controller->update($id, 'title', 'content');

        $this->assertEquals($updatedNote, $result->getData());

        // clean up
        $this->mapper->delete($result->getData());
    }

}

To run the integration tests change into the ownnotes directory and run:

phpunit -c phpunit.integration.xml

Adding a RESTful API (optional)

A RESTful API allows other apps such as Android or iPhone apps to access and change your notes. Since syncing is a big core component of Nextcloud it is a good idea to add (and document!) your own RESTful API.

Because we put our logic into the NoteService class it is very easy to reuse it. The only pieces that need to be changed are the annotations which disable the CSRF check (not needed for a REST call usually) and add support for CORS so your API can be accessed from other webapps.

With that in mind create a new controller in ownnotes/lib/Controller/NoteApiController.php:

<?php
namespace OCA\OwnNotes\Controller;

use OCP\IRequest;
use OCP\AppFramework\Http\DataResponse;
use OCP\AppFramework\ApiController;

use OCA\OwnNotes\Service\NoteService;

class NoteApiController extends ApiController {

    private $service;
    private $userId;

    use Errors;

    public function __construct($AppName, IRequest $request,
                                NoteService $service, $UserId){
        parent::__construct($AppName, $request);
        $this->service = $service;
        $this->userId = $UserId;
    }

    /**
     * @CORS
     * @NoCSRFRequired
     * @NoAdminRequired
     */
    public function index() {
        return new DataResponse($this->service->findAll($this->userId));
    }

    /**
     * @CORS
     * @NoCSRFRequired
     * @NoAdminRequired
     *
     * @param int $id
     */
    public function show($id) {
        return $this->handleNotFound(function () use ($id) {
            return $this->service->find($id, $this->userId);
        });
    }

    /**
     * @CORS
     * @NoCSRFRequired
     * @NoAdminRequired
     *
     * @param string $title
     * @param string $content
     */
    public function create($title, $content) {
        return $this->service->create($title, $content, $this->userId);
    }

    /**
     * @CORS
     * @NoCSRFRequired
     * @NoAdminRequired
     *
     * @param int $id
     * @param string $title
     * @param string $content
     */
    public function update($id, $title, $content) {
        return $this->handleNotFound(function () use ($id, $title, $content) {
            return $this->service->update($id, $title, $content, $this->userId);
        });
    }

    /**
     * @CORS
     * @NoCSRFRequired
     * @NoAdminRequired
     *
     * @param int $id
     */
    public function destroy($id) {
        return $this->handleNotFound(function () use ($id) {
            return $this->service->delete($id, $this->userId);
        });
    }

}

All that is left is to connect the controller to a route and enable the built in preflighted CORS method which is defined in the ApiController base class:

<?php
return [
    'resources' => [
        'note' => ['url' => '/notes'],
        'note_api' => ['url' => '/api/0.1/notes']
    ],
    'routes' => [
        ['name' => 'page#index', 'url' => '/', 'verb' => 'GET'],
        ['name' => 'note_api#preflighted_cors', 'url' => '/api/0.1/{path}',
         'verb' => 'OPTIONS', 'requirements' => ['path' => '.+']]
    ]
];

Note

It is a good idea to version your API in your URL

You can test the API by running a GET request with curl:

curl -u user:password http://localhost:8080/index.php/apps/ownnotes/api/0.1/notes

Since the NoteApiController is basically identical to the NoteController, the unit test for it simply inherits its tests from the NoteControllerTest. Create the file ownnotes/tests/Unit/Controller/NoteApiControllerTest.php:

<?php
namespace OCA\OwnNotes\Tests\Unit\Controller;

require_once __DIR__ . '/NoteControllerTest.php';

class NoteApiControllerTest extends NoteControllerTest {

    public function setUp() {
        parent::setUp();
        $this->controller = new NoteApiController(
            'ownnotes', $this->request, $this->service, $this->userId
        );
    }

}

Adding JavaScript and CSS

To create a modern webapp you need to write JavaScript. You can use any JavaScript framework but for this tutorial we want to keep it as simple as possible and therefore only include the templating library handlebarsjs. Download the file into ownnotes/js/handlebars.js and include it at the very top of ownnotes/templates/main.php before the other scripts and styles:

<?php
script('ownnotes', 'handlebars');

Note

jQuery is included by default on every page.

Creating a navigation

The template file ownnotes/templates/part.navigation.php contains the navigation. Nextcloud defines many handy CSS styles which we are going to reuse to style the navigation. Adjust the file to contain only the following code:

Note

$l->t() is used to make your strings translatable and p() is used to print escaped HTML

<!-- translation strings -->
<div style="display:none" id="new-note-string"><?php p($l->t('New note')); ?></div>

<script id="navigation-tpl" type="text/x-handlebars-template">
    <li id="new-note"><a href="#"><?php p($l->t('Add note')); ?></a></li>
    {{#each notes}}
        <li class="note with-menu {{#if active}}active{{/if}}" data-id="{{ id }}">
            <a href="#">{{ title }}</a>
            <div class="app-navigation-entry-utils">
                <ul>
                    <li class="app-navigation-entry-utils-menu-button svg"><button></button></li>
                </ul>
            </div>

            <div class="app-navigation-entry-menu">
                <ul>
                    <li><button class="delete icon-delete svg" title="delete"></button></li>
                </ul>
            </div>
        </li>
    {{/each}}
</script>

<ul></ul>

Creating the content

The template file ownnotes/templates/part.content.php contains the content. It will just be a textarea and a button, so replace the content with the following:

<script id="content-tpl" type="text/x-handlebars-template">
    {{#if note}}
        <div class="input"><textarea>{{ note.content }}</textarea></div>
        <div class="save"><button><?php p($l->t('Save')); ?></button></div>
    {{else}}
        <div class="input"><textarea disabled></textarea></div>
        <div class="save"><button disabled><?php p($l->t('Save')); ?></button></div>
    {{/if}}
</script>
<div id="editor"></div>

Wiring it up

When the page is loaded we want all the existing notes to load. Furthermore we want to display the current note when you click on it in the navigation, a note should be deleted when we click the deleted button and clicking on New note should create a new note. To do that open ownnotes/js/script.js and replace the example code with the following:

(function (OC, window, $, undefined) {
'use strict';

$(document).ready(function () {

var translations = {
    newNote: $('#new-note-string').text()
};

// this notes object holds all our notes
var Notes = function (baseUrl) {
    this._baseUrl = baseUrl;
    this._notes = [];
    this._activeNote = undefined;
};

Notes.prototype = {
    load: function (id) {
        var self = this;
        this._notes.forEach(function (note) {
            if (note.id === id) {
                note.active = true;
                self._activeNote = note;
            } else {
                note.active = false;
            }
        });
    },
    getActive: function () {
        return this._activeNote;
    },
    removeActive: function () {
        var index;
        var deferred = $.Deferred();
        var id = this._activeNote.id;
        this._notes.forEach(function (note, counter) {
            if (note.id === id) {
                index = counter;
            }
        });

        if (index !== undefined) {
            // delete cached active note if necessary
            if (this._activeNote === this._notes[index]) {
                delete this._activeNote;
            }

            this._notes.splice(index, 1);

            $.ajax({
                url: this._baseUrl + '/' + id,
                method: 'DELETE'
            }).done(function () {
                deferred.resolve();
            }).fail(function () {
                deferred.reject();
            });
        } else {
            deferred.reject();
        }
        return deferred.promise();
    },
    create: function (note) {
        var deferred = $.Deferred();
        var self = this;
        $.ajax({
            url: this._baseUrl,
            method: 'POST',
            contentType: 'application/json',
            data: JSON.stringify(note)
        }).done(function (note) {
            self._notes.push(note);
            self._activeNote = note;
            self.load(note.id);
            deferred.resolve();
        }).fail(function () {
            deferred.reject();
        });
        return deferred.promise();
    },
    getAll: function () {
        return this._notes;
    },
    loadAll: function () {
        var deferred = $.Deferred();
        var self = this;
        $.get(this._baseUrl).done(function (notes) {
            self._activeNote = undefined;
            self._notes = notes;
            deferred.resolve();
        }).fail(function () {
            deferred.reject();
        });
        return deferred.promise();
    },
    updateActive: function (title, content) {
        var note = this.getActive();
        note.title = title;
        note.content = content;

        return $.ajax({
            url: this._baseUrl + '/' + note.id,
            method: 'PUT',
            contentType: 'application/json',
            data: JSON.stringify(note)
        });
    }
};

// this will be the view that is used to update the html
var View = function (notes) {
    this._notes = notes;
};

View.prototype = {
    renderContent: function () {
        var source = $('#content-tpl').html();
        var template = Handlebars.compile(source);
        var html = template({note: this._notes.getActive()});

        $('#editor').html(html);

        // handle saves
        var textarea = $('#app-content textarea');
        var self = this;
        $('#app-content button').click(function () {
            var content = textarea.val();
            var title = content.split('\n')[0]; // first line is the title

            self._notes.updateActive(title, content).done(function () {
                self.render();
            }).fail(function () {
                alert('Could not update note, not found');
            });
        });
    },
    renderNavigation: function () {
        var source = $('#navigation-tpl').html();
        var template = Handlebars.compile(source);
        var html = template({notes: this._notes.getAll()});

        $('#app-navigation ul').html(html);

        // create a new note
        var self = this;
        $('#new-note').click(function () {
            var note = {
                title: translations.newNote,
                content: ''
            };

            self._notes.create(note).done(function() {
                self.render();
                $('#editor textarea').focus();
            }).fail(function () {
                alert('Could not create note');
            });
        });

        // show app menu
        $('#app-navigation .app-navigation-entry-utils-menu-button').click(function () {
            var entry = $(this).closest('.note');
            entry.find('.app-navigation-entry-menu').toggleClass('open');
        });

        // delete a note
        $('#app-navigation .note .delete').click(function () {
            var entry = $(this).closest('.note');
            entry.find('.app-navigation-entry-menu').removeClass('open');

            self._notes.removeActive().done(function () {
                self.render();
            }).fail(function () {
                alert('Could not delete note, not found');
            });
        });

        // load a note
        $('#app-navigation .note > a').click(function () {
            var id = parseInt($(this).parent().data('id'), 10);
            self._notes.load(id);
            self.render();
            $('#editor textarea').focus();
        });
    },
    render: function () {
        this.renderNavigation();
        this.renderContent();
    }
};

var notes = new Notes(OC.generateUrl('/apps/ownnotes/notes'));
var view = new View(notes);
notes.loadAll().done(function () {
    view.render();
}).fail(function () {
    alert('Could not load notes');
});


});

})(OC, window, jQuery);

Apply finishing touches

Now the only thing left is to style the textarea in a nicer fashion. To do that open ownnotes/css/style.css and replace the content with the following CSS code:

#app-content-wrapper {
    height: 100%;
}

#editor {
    height: 100%;
    width: 100%;
}

#editor .input {
    height: calc(100% - 51px);
    width: 100%;
}

#editor .save {
    height: 50px;
    width: 100%;
    text-align: center;
    border-top: 1px solid #ccc;
    background-color: #fafafa;
}

#editor textarea {
    height: 100%;
    width: 100%;
    border: 0;
    margin: 0;
    border-radius: 0;
    overflow-y: auto;
}

#editor button {
    height: 44px;
}

Congratulations! You’ve written your first Nextcloud app. You can now either try to further improve the tutorial notes app or start writing your own app.