eventsourcingdb

The official PHP client SDK for EventSourcingDB – a purpose-built database for event sourcing.

EventSourcingDB enables you to build and operate event-driven applications with native support for writing, reading, and observing events. This client SDK provides convenient access to its capabilities in PHP.

For more information on EventSourcingDB, see its official documentation.

This client SDK includes support for Testcontainers to spin up EventSourcingDB instances in integration tests. For details, see Using Testcontainers.

Getting Started

Install the client SDK:

composer require thenativeweb/eventsourcingdb

Import the Client class and create an instance by providing the URL of your EventSourcingDB instance and the API token to use:

require __DIR__ . '/vendor/autoload.php';

use Thenativeweb\Eventsourcingdb\Client;

$client = new Client('http://localhost:3000', 'secret');

Then call the ping function to check whether the instance is reachable. If it is not, the function will throw an exception:

$client->ping();

Note that ping does not require authentication, so the call may succeed even if the API token is invalid.

If you want to verify the API token, call verifyApiToken. If the token is invalid, the function will throw an exception:

$client->verifyApiToken();

Writing Events

Call the writeEvents function and hand over an array with one or more events. You do not have to provide all event fields – some are automatically added by the server.

Specify source, subject, type, and data according to the CloudEvents format.

The function returns the written events, including the fields added by the server:

use Thenativeweb\Eventsourcingdb\EventCandidate;

$writtenEvents = $client->writeEvents([
  new EventCandidate(
    'https://library.eventsourcingdb.io',
    '/books/42',
    'io.eventsourcingdb.library.book-acquired',
    [
      'title' => '2001 – A Space Odyssey',
      'author' => 'Arthur C. Clarke',
      'isbn' => '978-0756906788',
    ],
  ),
]);

Using the isSubjectPristine precondition

If you only want to write events in case a subject (such as /books/42) does not yet have any events, import the IsSubjectPristine class, use it to create a precondition, and pass it in an array as the second argument:

use Thenativeweb\Eventsourcingdb\IsSubjectPristine;

$writtenEvents = $client->writeEvents([
  // ...
], [
  new IsSubjectPristine('/books/42'),
]);

Using the isSubjectOnEventId precondition

If you only want to write events in case the last event of a subject (such as /books/42) has a specific ID (e.g., 0), import the IsSubjectOnEventId class, use it to create a precondition, and pass it in an array as the second argument:

use Thenativeweb\Eventsourcingdb\IsSubjectOnEventId;

$writtenEvents = $client->writeEvents([
  // ...
], [
  new IsSubjectOnEventId('/books/42', '0'),
]);

Note that according to the CloudEvents standard, event IDs must be of type string.

Using Testcontainers

Import the Container class, call the start function to run a test container, get a client, run your test code, and finally call the stop function to stop the test container:

require __DIR__ . '/vendor/autoload.php';

use Thenativeweb\Eventsourcingdb\Container;

$container = new Container();
$container->start();

$client = $container->getClient();

// ...

$container->stop();

To check if the test container is running, call the isRunning function:

$isRunning = $container->isRunning();

Configuring the Container Instance

By default, Container uses the latest tag of the official EventSourcingDB Docker image. To change that, call the withImageTag function:

$container = new Container()
  ->withImageTag('1.0.0');

Similarly, you can configure the port to use and the API token. Call the withPort or the withApiToken function respectively:

$container = new Container()
  ->withPort(4000)
  ->withApiToken('secret');

Configuring the Client Manually

In case you need to set up the client yourself, use the following functions to get details on the container:

• getHost() returns the host name
• getMappedPort() returns the port
• getBaseUrl() returns the full URL of the container
• getApiToken() returns the API token