Yar

Introduction

Yar is a RPC framework which aims to provide a simple and easy way to do communication between PHP applications

It has the ability to concurrently call multiple remote services.

Features

• Fast, Easy, Simple
• Concurrent RPC calls
• Multiple data packager supported (php, json, msgpack built-in)
• Multiple transfer protocols supported (http implemented, tcp/unix will be supported later)
• Detailed debug informations

Install

Install Yar

Yar is an PECL extension, thus you can simply install it by:

pecl install yar

Compile Yar in Linux

$/path/to/phpize
$./configure --with-php-config=/path/to/php-config/
$make && make install

Install Yar with msgpack

first you should install msgpack-ext

pecl install msgpack

or , you can get the github source here: https://github.com/msgpack/msgpack-php

then:

$phpize
$configure --with-php-config=/path/to/php-config/ --enable-msgpack
$make && make install

Runtime Configure

• yar.timeout //default 5000 (ms)
• yar.connect_timeout //default 1000 (ms)
• yar.packager //default "php", when built with --enable-msgpack then default "msgpack", it should be one of "php", "json", "msgpack"
• yar.debug //default Off
• yar.expose_info // default On, whether output the API info for GET requests
• yar.content_type // default "application/octet-stream"
• yar.allow_persistent // default Off

NOTE yar.connect_time is a value in milliseconds, and was measured in seconds in 1.2.1 and before.

Constants

• YAR_VERSION
• YAR_OPT_PACKAGER
• YAR_OPT_PERSISTENT
• YAR_OPT_TIMEOUT
• YAR_OPT_CONNECT_TIMEOUT

Server

It's very easy to setup a Yar HTTP RPC Server

<?php
class API {
    /**
     * the doc info will be generated automatically into service info page.
     * @params 
     * @return
     */
    public function some_method($parameter, $option = "foo") {
    }

    protected function client_can_not_see() {
    }
}

$service = new Yar_Server(new API());
$service->handle();
?>

Usual RPC calls will be issued as HTTP POST requests. If a HTTP GET request is issued to the uri, the service information (commented section above) will be printed on the page:

Client

It's very easy for a PHP client to call remote RPC:

Synchronous call

<?php
$client = new Yar_Client("http://host/api/");
/* the following setopt is optinal */
$client->SetOpt(YAR_OPT_CONNECT_TIMEOUT, 1000);

/* call remote service */
$result = $client->some_method("parameter");
?>

Concurrent call

<?php
function callback($retval, $callinfo) {
     var_dump($retval);
}

function error_callback($type, $error, $callinfo) {
    error_log($error);
}

Yar_Concurrent_Client::call("http://host/api/", "some_method", array("parameters"), "callback");
Yar_Concurrent_Client::call("http://host/api/", "some_method", array("parameters"));   // if the callback is not specificed, 
                                                                               // callback in loop will be used
Yar_Concurrent_Client::call("http://host/api/", "some_method", array("parameters"), "callback", "error_callback", array(YAR_OPT_PACKAGER => "json"));
                                                                               //this server accept json packager
Yar_Concurrent_Client::call("http://host/api/", "some_method", array("parameters"), "callback", "error_callback", array(YAR_OPT_TIMEOUT=>1));
                                                                               //custom timeout 

Yar_Concurrent_Client::loop("callback", "error_callback"); //send the requests, 
                                                           //the error_callback is optional
?>

Protocols

Yar Header

Since Yar will support multi transfer protocols, so there is a Header struct, I call it Yar Header

#ifdef PHP_WIN32
#pragma pack(push)
#pragma pack(1)
#endif
typedef struct _yar_header {
    unsigned int   id;            // transaction id
    unsigned short version;       // protocl version
    unsigned int   magic_num;     // default is: 0x80DFEC60
    unsigned int   reserved;
    unsigned char  provider[32];  // reqeust from who
    unsigned char  token[32];     // request token, used for authentication
    unsigned int   body_len;      // request body len
}
#ifndef PHP_WIN32
__attribute__ ((packed))
#endif
yar_header_t;
#ifdef PHP_WIN32
#pragma pack(pop)
#endif

Packager Header

Since Yar also supports multi packager protocl, so there is a char[8] at the begining of body, to identicate which packager the body is packaged by.

Request

When a Client request a remote server, it will send a struct (in PHP):

<?php
array(
   "i" => '', //transaction id
   "m" => '', //the method which being called
   "p" => array(), //parameters
)

Server

When a server response a result, it will send a struct (in PHP):

<?php
array(
   "i" => '',
   "s" => '', //status
   "r" => '', //return value 
   "o" => '', //output 
   "e" => '', //error or exception
)