http.md

HTTP Client

Calling an HTTP server

use Innmind\Http\{
    Message\Request\Request,
    Message\Method,
    Message\Response,
    ProtocolVersion,
};
use Innmind\Url\Url;

$http = $os->remote()->http();

$response = $http(new Request(
    Url::of('https://github.com'),
    Method::get(),
    new ProtocolVersion(2, 0),
));
$response instanceof Response; // true

All elements of a request/response call is built using objects to enforce correctness of the formatted messages.

Note: since request and responses messages can be viewed either from a client or a server the model is abstracted in the standalone innmind/http library.

Resiliency in a distributed system

One of the first things taught when working with distributed systems is that they will intermittently fail. To prevent your app to crash for an occasional failure a common pattern is the retry pattern with a backoff strategy allowing the client to retry safe requests a certain amount of time before giving up. You can use this pattern like so:

use Innmind\OperatingSystem\OperatingSystem\Resilient;
use Innmind\HttpTransport\ExponentialBackoffTransport;

$os = new Resilient($os);
$http = $os->remote()->http();
$http instanceof ExponentialBackoffTransport; // true

Another strategy you can add on top of that is the circuit breaker pattern that will stop sending request to a server known to have failed.

use Innmind\HttpTransport\CircuitBreakerTransport;
use Innmind\TimeContinuum\Earth\Period\Minute;

$http = new CircuitBreakerTransport(
    $http,
    $os->clock(),
    new Minute(1),
);
$request = new Request(/* ...args */)
$response = $http($request);
// if the previous call failed then the next call wil not even be sent to the
// server and the client will respond immediately unless 1 minute has elapsed
// between the 2 calls
$response = $http($request);

Note: the circuit breaker works on host per host basis meaning if server1.com fails then calls to server2.com will still be sent.