Using Cloud Datastore with PHP

This part of the PHP Bookshelf app tutorial shows how to create, read, update, and delete structured data in Cloud Datastore.

This page is part of a multipage tutorial. To start from the beginning and read the setup instructions, go to PHP Bookshelf app.

Configuring settings

  1. Go to the getting-started-php/2-structured-data directory, and copy the settings.yml.dist file:

    cp config/settings.yml.dist config/settings.yml
    
  2. Open config/settings.yml for editing.

  3. Replace [YOUR_PROJECT_ID] with your GCP project ID.

  4. Set the value of bookshelf_backend to datastore.

  5. Save and close settings.yml.

Cloud Datastore is a fully managed service that is automatically initialized and connected to your App Engine app. No further configuration is required.

Installing dependencies

In the 2-structured-data directory, enter this command:

composer install

Running the app on your local machine

  1. Start a local web server:

    php -S localhost:8000 -t web
    
  2. In your browser, enter this address:

    http://localhost:8000

Now you can browse the app's web pages and add, edit, and delete books.

Deploying the app to the App Engine flexible environment

  1. In your terminal window, deploy the sample app:

    gcloud app deploy
    
  2. In your browser, enter this address. Replace [YOUR_PROJECT_ID] with your Google Cloud Platform (GCP) project ID:

    https://[YOUR_PROJECT_ID].appspot.com
    

If you update your app, you can deploy the updated version by entering the same command you used when you first deployed the app. The new deployment creates a version of your app and promotes it to the default version.

The older versions of your app remain, as do their associated virtual machine (VM) instances. Be aware that all of these app versions and VM instances are billable resources.

You can reduce costs by deleting the non-default versions of your app.

When you finish this tutorial, you can avoid continued billing by deleting the resources you created. See Cleaning up for more detail.

App structure

The following diagram shows the app's components and how they fit together.

Bookshelf app deployment process and structure

Understanding the code

Previously, you edited settings.yml and set the value of bookshelf_backend to datastore. This setting tells the app to load the Datastore class, which is defined in src/DataModel/Datastore.php. The Datastore class wraps the Cloud Datastore API and stores books in your Cloud Datastore database.

The following code in controllers.php defines and registers a handler for the GET '/books/' route. The $model variable is an instance of the Datastore class. The $model->listBooks method returns an array that contains an array of books and a cursor. Then the Twig template engine renders the list of books according to the list.html.twig template:

$app->get('/books/', function (Request $request) use ($app) {
    /** @var DataModelInterface $model */
    $model = $app['bookshelf.model'];
    /** @var Twig_Environment $twig */
    $twig = $app['twig'];
    $token = $request->query->get('page_token');
    $bookList = $model->listBooks($app['bookshelf.page_size'], $token);

    return $twig->render('list.html.twig', array(
        'books' => $bookList['books'],
        'next_page_token' => $bookList['cursor'],
    ));
});

Here is the Twig template for listing books that are retrieved from Cloud Datastore. The template receives an array variable named books. For each book in the array, it displays the title and author. The template also receives a next_page_token variable that determines whether the More button is displayed:

{% for book in books %}
<div class="media">
  <a href="/books/{{book.id}}">
    <div class="media-left">
      <img src="http://placekitten.com/g/128/192">
    </div>
    <div class="media-body">
      <h4>{{book.title}}</h4>
      <p>{{book.author}}</p>
    </div>
  </a>
</div>
{% else %}
<p>No books found</p>
{% endfor %}

The following code defines and registers a handler for the GET '/books/{id}' route, where {id} is the ID of an individual book. The handler calls the $model->read method to get the specified book from Cloud Datastore. The Twig template engine renders the book according to the view.html.twig template:

$app->get('/books/{id}', function ($id) use ($app) {
    /** @var DataModelInterface $model */
    $model = $app['bookshelf.model'];
    $book = $model->read($id);
    if (!$book) {
        return new Response('', Response::HTTP_NOT_FOUND);
    }
    /** @var Twig_Environment $twig */
    $twig = $app['twig'];

    return $twig->render('view.html.twig', array('book' => $book));
});

The view.html.twig template receives a variable named book, and displays the book's title, publication date, author, and description:

<div class="media">
  <div class="media-body">
    <h4 class="book-title">
      {{book.title}}
      <small>{{book.published_date}}</small>
    </h4>
    <h5 class="book-author">By {{book.author|default('Unknown', True)}}</h5>
    <p class="book-description">{{book.description}}</p>
  </div>
</div>

When the user clicks Add book, the handler for GET /books/add displays a form for entering the title, author, and other information about a book. When the user clicks Save, the handler for POST /books/add gets the new book from the request and calls $model->create to store the book in Cloud Datastore:

$app->get('/books/add', function () use ($app) {
    /** @var Twig_Environment $twig */
    $twig = $app['twig'];

    return $twig->render('form.html.twig', array(
        'action' => 'Add',
        'book' => array(),
    ));
});

$app->post('/books/add', function (Request $request) use ($app) {
    /** @var DataModelInterface $model */
    $model = $app['bookshelf.model'];
    $book = $request->request->all();
    $id = $model->create($book);

    return $app->redirect("/books/$id");
});

Here's the template for the book entry form:

{% extends "base.html.twig" %}

{% block content %}
<h3>{{action}} book</h3>

<form method="POST" enctype="multipart/form-data">

  <div class="form-group">
    <label for="title">Title</label>
    <input type="text" name="title" id="title" value="{{book.title}}" class="form-control"/>
  </div>

  <div class="form-group">
    <label for="author">Author</label>
    <input type="text" name="author" id="author" value="{{book.author}}" class="form-control"/>
  </div>

  <div class="form-group">
    <label for="published_date">Date Published</label>
    <input type="text" name="published_date" id="published_date" value="{{book.published_date}}" class="form-control"/>
  </div>

  <div class="form-group">
    <label for="description">Description</label>
    <textarea name="description" id="description" class="form-control">{{book.description}}</textarea>
  </div>

  <button id="submit" type="submit" class="btn btn-success">Save</button>
</form>

{% endblock %}

The sample code includes extra handlers for editing and deleting individual books:

$app->get('/books/{id}/edit', function ($id) use ($app) {
    /** @var DataModelInterface $model */
    $model = $app['bookshelf.model'];
    $book = $model->read($id);
    if (!$book) {
        return new Response('', Response::HTTP_NOT_FOUND);
    }
    /** @var Twig_Environment $twig */
    $twig = $app['twig'];

    return $twig->render('form.html.twig', array(
        'action' => 'Edit',
        'book' => $book,
    ));
});

$app->post('/books/{id}/edit', function (Request $request, $id) use ($app) {
    $book = $request->request->all();
    $book['id'] = $id;
    /** @var DataModelInterface $model */
    $model = $app['bookshelf.model'];
    if (!$model->read($id)) {
        return new Response('', Response::HTTP_NOT_FOUND);
    }
    if ($model->update($book)) {
        return $app->redirect("/books/$id");
    }

    return new Response('Could not update book');
});
$app->post('/books/{id}/delete', function ($id) use ($app) {
    /** @var DataModelInterface $model */
    $model = $app['bookshelf.model'];
    $book = $model->read($id);
    if ($book) {
        $model->delete($id);

        return $app->redirect('/books/', Response::HTTP_SEE_OTHER);
    }

    return new Response('', Response::HTTP_NOT_FOUND);
});

See the Datastore client library for PHP documentation to learn more about calling the Datastore API from PHP.

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