php-rpc-client

Web Service RPC client implementation for PHP., _(*1)

This is a project I worked on a while back, so there are probably much better implementations out there at present., _(*2)

The library aims to provide a simple, transparent means of working with RPC-based web services, using Guzzle as the underlying HTTP client library. At present, it supports: 1. JSON-RPC (versions 1.0 and 2.0); 2. XML-RPC; 3. The RPC format used by the Transmission BitTorrent engine., _(*3)

Making a request

Generally this library takes advantage of magic methods in PHP (specifically __get and __call), in much the same way as the PHP SOAP client to invoke web service methods under multiple levels of namespace., _(*4)

Example: Updating XBMC's media library

The popular XBMC media centre makes use of JSON-RPC v2 in the extensive web service it offers for remote control purposes., _(*5)

To invoke it's VideoLibrary.Scan method with an empty string parameter, on a server running on :, _(*6)

<?php

use Guzzle\Http\Client;
use Mdjward\RpcApi\RequestInitiator;
use Mdjward\RpcApi\RequestEncoder\JsonRpc\JsonRpcV2Encoder;

// Initialise the Guzzle client to the JSON RPC endpoint offered by XBMC
$client = new Client("http://xbmc.myhomenetwork.org:8080/jsonrpc");

// Initialise an object of the prescribed class for encoding/decoding JSON RPC v2 messages
$encoder = new JsonRpcV2Encoder();

// Initialise the initiator!
$initiator = new RequestInitiator($client, $encoder);

// Invoke the Scan method and store the response in variable $response
$response = $initiator->VideoLibrary->Scan("");

This should produce a string "OK", as the principle result of the method., _(*7)

However, since magic method resolution is well known to have extremely poor performance, you are advised to extend the RequestInitiator class for purpose-specific APIs and create purpose-specific methods (and, potentially, fields/properties), as in the example below (although probably not with a public property, and possibly with dependency injection as opposed to tight coupling)., _(*8)

<?php

// ...

class XbmcRequestInitiator extends RequestInitiator {

    public $videoLibrary;

    public function __construct(Client $client, JsonRpcV2Encoder $encoder) {
        parent::__construct($client, $encoder, "");

        $this->videoLibrary = new VideoLibraryRequestInitiator($client, $encoder);
    }

}

// ...

class VideoLibraryRequestInitiator extends RequestInitiator {

    public function __construct(Client $client, JsonRpcV2Encoder $encoder) {
        parent::__construct($client, $encoder, "VideoLibrary");
    }

    public function scan($directory = "") {
        return $this->__call("Scan", array("directory" => $directory);
    }

}

// ...

// Initialise the XBMC initiator!
$initiator = new XbmcRequestInitiator($client, $encoder);

// Invoke the Scan method and store the response in variable $response
$response = $initiator->videoLibrary->scan("");

In this way, it is possible to build an entire client library for the XBMC RPC API or any supported RPC API., _(*9)