XMLRPC

　　XMLRPC 为以http为传输协议，使用xml格式化数据来执行远程过程调用， 区别于本地过程调用， 即发生在不同主机之间。

　　属于分布式计算的一种简单实现，比web service简单易用。xml语言被多种语言广泛支持，是一种可扩展的标记语言，

 xmlrpc被多种平台实现，以此提供的服务可以客户端和服务器端使用不同语言，

具有平台无关性，比socket发送网络字节序具有优势， 不用考虑大小端问题， 且报文内容遵循规定格式， 易于处理和阅读。 

　　此为UseLand公司制定的一套标准，http://xmlrpc.scripting.com/default.html， 角色分服务器端和客户端， 可以被不同语言实现，

c --- http://xmlrpc-c.sourceforge.net/

lua --- https://github.com/timn/lua-xmlrpc

php --- https://github.com/gggeek/phpxmlrpc/releases/tag/2.2.2

java --- http://ws.apache.org/xmlrpc/

luaXMLRPC

　　luaXMLRPC是lua语言实现的一套软件包， 可以访问 和 提供 xmlrpc服务， 即服务器和客户端角色都支持。

https://github.com/timn/lua-xmlrpc

　　客户端主要实现功能， 将lua table数据转换为 XML RPC message，

然后通过luaSocket库以http协议发送出去，

对于响应回来的XML RPC message 使用XML解析器 luaExpat 反向解析为 lua table，和返回值。

The http.lua file implements a simple stand-alone client based on LuaSocket 2.0.2. The following function is provided:

call (url, method [, params])

Execute the call to method at location url with the given params (if any). The method and params parameters will be just passed to clEncode function. The result is the same as clDecode function: a boolean indicating whether the call was successful or not, followed by the response value (if successful) or by the faultString and the faultCode (if the call fails).

　　服务器端， CGILUA接收到XML RPC message后， 使用luaExpat解析为lua table， 后调用相应方法，

将执行结果组装成XML RPC response message， 发送回客户端。

 　　服务器端注册方法接口：

srvMethods (tab_or_func)Register the methods on the server. The parameter can be a table or a dispatching function. If a table is given it can have one level of objects with the corresponding methods. If a function is given, it will replace the dispatcher.

　　luaXMLRPC提供的一些库函数，参见来自下载包帮助文档：

　　

Library functions

The xmlrpc.lua file implements the functions that encode and decode XML-RPC messages and transform data types between the Lua and XML-RPC. The functions are:

clEncode (method_name [, params]) => method_call

Build a XML-RPC document containing a methodCall element. It receives a string with the method‘s name and an optional list of parameters. The result is a string containing the XML-RPC document.

clDecode (method_response) => ok, results

Disassemble the server response into a Lua object. It receives a string containing the XML-RPC document representing the methodResponse element. The result is a boolean indicating wether the call was successful or not followed by the resulting objects (typically a methodResponse has only one value so only one Lua object will be returned). In case of error the false value is followed by the XMLRPC faultString and the faultCode. This values are extracted from the fault element.

srvDecode (method_call) => method_name, list_params

Disassemble the client request into a method‘s name and a table with the list of parameters. It receives a string containing the XML-RPC document representing the methodCall element. The result is a string with the name of the method to be called and a Lua table with the arguments to the call.

srvEncode (object, is_fault) => method_response

Build a XML-RPC document containing a methodResponse element. It receives a Lua object (a number, a string, a table, a "created typed value" etc.) with the return value of the call. The result is a string containing the XML-RPC document. Note that XML-RPC defines that a response only returns one value so a Lua function that returns more than one value has to pack them into a table to guarantee that all of them will be returned. The second parameter (is_fault) can be used to force a fault element to be generated instead of a params. In this case, the Lua object must be a table with the members faultCode and faultString.

srvMethods (tab_or_func)

Register the methods on the server. The parameter can be a table or a dispatching function. If a table is given it can have one level of objects with the corresponding methods. If a function is given, it will replace the dispatcher.

dispatch (method_name) => function

Returns a Lua function that implements the method call. Note that the object is encapsulated into that function so that the call will be turned into a real method call.

 

luaXMLRPC client + phpXMLRPC server 实例

　　php服务器端运行环境， 需要先行安装 xamp 软件包（https://www.apachefriends.org/zh_cn/index.html），

xamp为 x系统（包括 Linux windows mac） + a （Apache web server）+ m （MySql database）+ p （php server script interpretor），

为流行的php开发环境。

　　phpXMLRPC服务器端， xmlrpc还不是php的原始库，需要下载，下载地址 http://phpxmlrpc.sourceforge.net/。

下载后，解压后，将其的lib目录拷贝出来并命名为libphpxmlrpc， 拷贝到 php 的 xamp/php/pear（珍珠）目录。

使用下面博客中 加法 服务例子（http://blog.csdn.net/flyingfalcon/article/details/2229488），

在\xampp\htdocs目录下建立一个php文件 xmlrpc_server.php：

<?php

include ("libphpxmlrpc/xmlrpc.inc");
include ("libphpxmlrpc/xmlrpcs.inc");

if ($_SERVER[‘REQUEST_METHOD‘] != ‘POST‘)
        exit(0);

$add_sig = array(array($xmlrpcString, $xmlrpcInt, $xmlrpcInt));
$add_doc = "Add the two integer together";

function add($params)
{
        global $xmlrpcerruser;

        $val = php_xmlrpc_decode($params);

        $ret = $val[0] + $val[1];

        return new xmlrpcresp(new xmlrpcval($ret, "int"));
}

$server = new xmlrpc_server(array(
        "add" => array(
                "function" => "add",
                "signature" => $add_sig,
                "docstring" => $add_doc
        )));

?>

　　luaXMLRPC 客户端，按照github下载的压缩包中的帮助文档， 将 src文件夹命名为 xmlrpc，

拷贝到 LUA_PATH 目录即可， 即与 lua.exe 平级。

Lua XML-RPC is composed by three Lua files:

init.lua

Main source file providing the API

http.lua

API to call XML-RPC via HTTP

server.lua

Server side API

 

These files should be copied to a directory named xmlrpc created in your LUA_PATH.

　　luaXMLRPC客户端代码，放到test.lua中， 与lua.exe平级，功能 实现 加法 XMLRPC 请求， 

require "xmlrpc.http"

local ok, res = xmlrpc.http.call ("http://127.0.0.1/xmlrpc_server.php", "add", 1, 2)

if not ok then 
    print ("not ok")
    print("error="..res) 
else
    print ("ok")
    print("sum ="..res); 
end

　　客户端运行结果