Comet

Comet is a modern PHP framework for building fast REST APIs and microservices.

Superpowers

Comet gets all superpowers from Slim and Workerman as well as adds its own magic.

Slim is a micro-framework that helps write simple yet powerful web applications and APIs based on modern PSR standards.

Workerman is an asynchronous event-driven framework. It delivers high performance to build fast and scalable network applications.

Comet is a hybrid app server that allows you natively use all methods of Slim: http://www.slimframework.com/docs/v4/

Performance

PHP is often criticized for its low throughput and high latency. But that is not necessarily true for modern frameworks. Let's see how Comet outperforms others.

As you can see, the right architecture provides it with tenfold advantage over Symfony and other popular frameworks.

Latency

How long it takes to get response from API is even more important than overall service throughput. And that is were Comet really shines!

Comet provides sub-millisecond latency for typical scenarios. Even under hard pressure of thousand concurrent connections it can compete with frameworks of compiled platforms like Go and Java.

Basics

Installation

It is recommended that you use Composer to install Comet.

$ composer require gotzmann/comet

This will install framework itself and all required dependencies. Comet requires PHP 7.1 or newer.

Hello Comet

Create single app.php file at project root folder with content:

<?php

use Comet\Comet;

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

$app = new Comet();

$app->get('/hello', function ($request, $response, $args) {
    $response->getBody()->write("Hello, Comet!");      
    return $response;
});

$app->run();

Start it from command line:

$ php app.php start

Then open browser and type in default address http://localhost:80 - you'll see hello from Comet!

Simple JSON Response

Let's start Comet server listening on custom port and returning JSON payload.

<?php

use Comet\Comet;

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

$app = new Comet([
    'host' => 'localhost',
    'port' => 8080
]);

$app->get('/json', function ($request, $response, $args) {    
    $object = new stdClass();
    $object->data = [ "code" => 200, "message" => "Hello, Comet!" ];
    $payload = json_encode($object);
    $response->getBody()->write($payload);
    return $response
        ->withHeader('Content-Type', 'application/json');
});

$app->run();

Start Postman and see the JSON resonse from GET http://localhost:8080

Advanced Topics

PSR-4 and Autoloading

Before you proceed with complex examples, be sure that your composer.json contains autoload section like this:

    "autoload": {
        "psr-4": { "\\": "src/" }
    }

If not, you should add the section mentioned above and update all vendor packages and autoload logic by command:

$ composer install

Controllers for MVC apps

Create src/Controllers/SimpleController.php:

<?php

namespace Controllers;

use Slim\Psr7\Request;
use Slim\Psr7\Response;

class SimpleController
{    
    private static $counter = 0;

    public function getCounter(Request $request, Response $response, $args)
    {
        $response->getBody()->write(self::$counter);  
        return $response->withStatus(200);
    }

    public function setCounter(Request $request, Response $response, $args)    
    {        
        $body = (string) $request->getBody();
        $json = json_decode($json);
        if (!$json) {
            return $response->withStatus(500);
        }  
        self::$counter = $json->counter;
        return $response;        
    }
}  

Then create Comet server app.php at project root folder:

<?php

use Comet\Comet;
use Controllers\SimpleController;

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

$app = new Comet([
    'host' => 'localhost',
    'port' => 8080
]);

$app->setBasePath("/api/v1"); 

$app->get('/counter',
    'Controllers\SimpleController:getCounter');

$app->post('/counter',    
    'Controllers\SimpleController:setCounter');

$app->run();

Now you are ready to get counter value with API GET endpoint:

GET http://localhost:8080/counter

You can change counter sending JSON request for POST method:

POST http://localhost:8080/counter with body { "counter": 100 } and 'application/json' header.

Any call with mailformed body will be replied with HTTP 500 code, as defined at controller logic.

Docker and Nginx

Please see Dockerfile at this repo as starting point for creating your own app images and containers.

If you would like to use Nginx as reverse proxy or load balancer for your Comet app, insert into nginx.conf these lines:

http {
 
    upstream app {
        server http://path.to.your.app:port;
    }
  
    server {
        listen 80;
         location / {
            proxy_pass         http://app;
            proxy_redirect     off;
        }
    }
}