Jayrock: JSON and JSON-RPC for .NET
Joyrock是一个LGPL的开源的软件，实现了JSON和JSON-RPC，支持微软ASP.NET框架。
看看服务器端的写法：
<%@ WebHandler Class="JayrockWeb.HelloWorld" %>
namespace JayrockWeb
{
using System;
using System.Web;
using Jayrock.Json;
using Jayrock.JsonRpc;
using Jayrock.JsonRpc.Web;
public class HelloWorld : JsonRpcHandler
{
[ JsonRpcMethod("greetings") ]
public string Greetings()
{
return "Welcome to Jayrock!";
}
}
}
[ JsonRpcMethod("greetings") ]恰好对应于ASP.NET 的[WebMethod],深入理解一下就知道，这两个自定义属性就是起到标记作用，用来声明方法是可以远程调用的。
客户端调用：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en">
<head>
<title>Hello Jayrock</title>
<script type="text/javascript" src="json.js"></script>
<script type="text/javascript" src="helloworld.ashx?proxy"></script>
<script type="text/javascript">
/* <![CDATA[ */
window.onload = function()
{
var s = new HelloWorld();
alert("sync:" + s.greetings());
s.greetings(function(response) {
alert("async:" + response.result)
});
}
/* ]]> */
</script>
</head>
<body>
<p>This page tests the HelloWorld service with Jayrock.</p>
</body>
可以看到helloworld.ashx?proxy指向了一个JS文件，他的内容就是：
// This JavaScript was automatically generated by
// Jayrock.Json.Rpc.Web.JsonRpcProxyGenerator, Jayrock, Version=0.9.7507.0, Culture=neutral, PublicKeyToken=null
// on 2006年12月5日 at 8:46:27 (中国标准时间)
// Proxy version 1.0
function HelloWorld(url)
{
/* Returns a summary about the JSON-RPC server implementation for display purposes. */
this["system.about"] = function(callback)
{
return call("system.about", [ ], callback);
}
/* Returns the version JSON-RPC server implementation using the major, minor, build and revision format. */
this["system.version"] = function(callback)
{
return call("system.version", [ ], callback);
}
/* Returns an array of method names implemented by this service. */
this["system.listMethods"] = function(callback)
{
return call("system.listMethods", [ ], callback);
}
this["greetings"] = function(callback)
{
return call("greetings", [ ], callback);
}
var url = typeof(url) === 'string' ? url : 'http://localhost:3409/Web/HelloWorld.ashx';
var self = this;
var nextId = 0;
function call(method, params, callback)
{
var request = { id : nextId++, method : method, params : params };
return callback == null ?
callSync(method, request) : callAsync(method, request, callback);
}
function callSync(method, request)
{
var http = newHTTP();
http.open('POST', url, false, self.httpUserName, self.httpPassword);
setupHeaders(http, method);
http.send(JSON.stringify(request));
if (http.status != 200)
throw { message : http.status + ' ' + http.statusText, toString : function() { return message; } };
var response = JSON.eval(http.responseText);
if (response.error != null) throw response.error;
return response.result;
}
function callAsync(method, request, callback)
{
var http = newHTTP();
http.open('POST', url, true, self.httpUserName, self.httpPassword);
setupHeaders(http, method);
http.onreadystatechange = function() { http_onreadystatechange(http, callback); }
http.send(JSON.stringify(request));
return request.id;
}
function setupHeaders(http, method)
{
http.setRequestHeader('Content-Type', 'text/plain; charset=utf-8');
http.setRequestHeader('X-JSON-RPC', method);
}
function http_onreadystatechange(sender, callback)
{
if (sender.readyState == /* complete */ 4)
{
var response = sender.status == 200 ?
JSON.eval(sender.responseText) : {};
response.xmlHTTP = sender;
callback(response);
}
}
function newHTTP()
{
return typeof(ActiveXObject) === 'function' ?
new ActiveXObject('Microsoft.XMLHTTP') : /* IE 5 */
new XMLHttpRequest(); /* Safari 1.2, Mozilla 1.0/Firefox, and Netscape 7 */
}
}
HelloWorld.rpcMethods = ["system.about","system.version","system.listMethods","greetings"];
上面JS文档是自动生成的，ASP.NET AJAX也有自动生成客户端访问对象的功能
Jayrock 远程方法要求写在一个ashx中，页面请求这个ashx的时候，在ProcessRequest 中根据Request对象中的参数信息，确定请求的服务器端方法名称和参数，然后进行调用，并返回结果。
