rpc_call.md

Client. RPC call

The client's quick tour describes how to get the client object. Here we'll use Enqueue\SimpleClient\SimpleClient though it is not required. You can get all that stuff from manually built client or get objects from a container (Symfony).

The simple client could be created like this:

The client side

There is a handy class RpcClient shipped with the client component. It allows you to easily perform RPC calls. It send a message and wait for a reply.

<?php
use Enqueue\Client\RpcClient;
use Enqueue\SimpleClient\SimpleClient;

$client = new SimpleClient('amqp://');

$rpcClient = new RpcClient($client->getProducer(), $context);

$replyMessage = $rpcClient->call('greeting_topic', 'Hi Thomas!', 5);

You can perform several requests asynchronously with callAsync and request replays later.

<?php
use Enqueue\Client\RpcClient;
use Enqueue\SimpleClient\SimpleClient;

$client = new SimpleClient('amqp://');

$rpcClient = new RpcClient($client->getProducer(), $context);

$promises = [];
$promises[] = $rpcClient->callAsync('greeting_topic', 'Hi Thomas!', 5);
$promises[] = $rpcClient->callAsync('greeting_topic', 'Hi Thomas!', 5);
$promises[] = $rpcClient->callAsync('greeting_topic', 'Hi Thomas!', 5);
$promises[] = $rpcClient->callAsync('greeting_topic', 'Hi Thomas!', 5);

$replyMessages = [];
foreach ($promises as $promise) {
    $replyMessages[] = $promise->receive();
}

The server side

On the server side you may register a processor which returns a result object with a reply message set. Of course it is possible to implement rpc server side based on transport classes only. That would require a bit more work to do.

<?php

use Interop\Queue\PsrMessage;
use Interop\Queue\PsrContext;
use Enqueue\Consumption\Result;
use Enqueue\Consumption\ChainExtension;
use Enqueue\Consumption\Extension\ReplyExtension;
use Enqueue\SimpleClient\SimpleClient;

/** @var \Enqueue\Psr\PsrContext $context */

$client = new SimpleClient('amqp://');

$client->bind('greeting_topic', 'greeting_processor', function (PsrMessage $message, PsrContext $context) use (&$requestMessage) {
    echo $message->getBody();
    
    return Result::reply($context->createMessage('Hi there! I am John.'));
});

$client->consume(new ChainExtension([new ReplyExtension()]));

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