Light, concurrent RPC framework for PHP(see also: Yar C framework, Yar Java framework)

• PHP 7.0 (master branch))
• PHP 5.2 (php5 branch)
• Curl
• Json
• Msgpack (Optional)

Yar is a RPC framework which provides a simple and easy way to do communication between PHP applications, it also offers an ability of doing multiple calls to remote services concurrently.

• Fast, Easy, Simple
• Concurrent RPC calls
• Multiple data packager supported (php, json, msgpack built-in)
• Multiple transfer protocols supported (http, https, TCP)
• Detailed debug informations

Yar is an PECL extension, could be installed simply by:

pecl install yar

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

Available instructions to configure are

--with-curl=DIR
--enable(disable)-msgpack
--enable(disable)-epoll (require Yar 2.1.2)

1. Install msgpack for PHP extension:

pecl install msgpack

or for ubuntu user

apt-get install msgpack-php

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

2. configuration:

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

• 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, which was measured in seconds before 1.2.1.

• YAR_VERSION
• YAR_OPT_PACKAGER
• YAR_OPT_PERSISTENT
• YAR_OPT_TIMEOUT
• YAR_OPT_CONNECT_TIMEOUT
• YAR_OPT_HEADER // Since 2.0.4
• YAR_OPT_PROXY //Since 2.2.0
• YAR_OPT_PROVIDER //Since 2.3.0
• YAR_OPT_TOKEN //Since 2.3.0

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 are issued as HTTP POST requests.

If a HTTP GET request is issued to the uri(access the api address directly via a browser), the service information (commented section above) will be returned, like:

Since 2.3.0, Yar allows you to custom the output in above example by defining "__info" magic method:

<?php
class API {
    protected function __info($markup) {
         return "Hello world";
    }
}

then If a HTTP GET request is issued, "hello world" will be sent instead.

Since 2.3.0, Yar allows server to authentic client request by Provider/Token fileds in header, for achieve this, you should define a protected magic method named "__auth" in server side:

<?php
class API {
     protected function __auth($provider, $token) {
          return verify($provider, $token);
     }

NOTE __auth method should always be defined as protected

if a Yar server has __auth defined, then __auth will be called at the very first time for any request,

if __auth method return true, the request will be processed further, otherwise the request will be terminated by an error of "authentication failed"

in clent side, you can specific the provider/token by:

<?php
    $client->setOpt(YAR_OPT_PROVIDER, "provider");
    $client->setOpt(YAR_OPT_TOKEN, "token");
    $client->call();

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

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

$client->SetOpt(YAR_OPT_HEADER, array("hd1: val", "hd2: val"));  //Custom headers, Since 2.0.4

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

<?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
?>

After Yar 2.1.0, if YAR_OPT_PERSISTENT is set to true, then Yar is able to use HTTP keep-alive to speedup repeated calls to a same address, the link will be released at the end of the PHP request lifecycle.

<?php
$client = new Yar_Client("http://host/api/");
$client->SetOpt(YAR_OPT_PERSISTENT, 1);

$result = $client->some_method("parameter");

/* The following calls will speed up due to keep-alive */
$result = $client->some_other_method1("parameter");
$result = $client->some_other_method2("parameter");
$result = $client->some_other_method3("parameter");
?>

After Yar 2.1.0, if Yar runs on HTTP protocol, YAR_OPT_RESOLVE could be used to define custom hostname resolving.

<?php
$client = new Yar_Client("http://host/api/");

$client->SetOpt(YAR_OPT_RESOLVE, array("host:80:127.0.0.1"));

/* call goes to 127.0.0.1 */
$result = $client->some_method("parameter");

After Yar 2.2.1, if Yar runs on HTTP protocol, YAR_OPT_PROXY could be used to define http proxy , such as fidder or charles.

<?php
$client = new Yar_Client("http://host/api/");

$client->SetOpt(YAR_OPT_PROXY,"127.0.0.1:8888"); //http proxy , Since 2.2.0

/* call goes to 127.0.0.1 */
$result = $client->some_method("parameter"); 

Yar is no only designed for PHP only, all RPC request and response are transferred by binary data stream.

Key messages are exchanged by a struct called "Yar Header":

#ifdef PHP_WIN32
#pragma pack(push)
#pragma pack(1)
#endif
typedef struct _yar_header {
    uint32_t       id;            // transaction id
    uint16_t       version;       // protocol version
    uint32_t       magic_num;     // default is: 0x80DFEC60
    uint32_t       reserved;
    unsigned char  provider[32];  // reqeust from who
    unsigned char  token[32];     // request token, used for authentication
    uint32_t       body_len;      // request body len
}
#ifndef PHP_WIN32
__attribute__ ((packed))
#endif
yar_header_t;
#ifdef PHP_WIN32
#pragma pack(pop)
#endif

Yar also supports multi packager protocols, which is a char[8] before the header struct, to identicate which packager the body is packaged by.

When a Client do an RPC request , the request is sent as an array(in PHP) like:

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

When a server responses, the response is sent also as an array (in PHP) like:

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