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Poco C++库网络模块例子解析2-------HttpServer

2014-11-26 02:06 351 查看
//下面程序取自 Poco 库的Net模块例子----HTTPServer  下面开始解析代码

#include "Poco/Net/HTTPServer.h"   //继承自TCPServer 实现了一个完整的HTTP多线程服务器
#include "Poco/Net/HTTPRequestHandler.h"   //抽象基类类 被HttpServer所创建 用来处理Http的请求
#include "Poco/Net/HTTPRequestHandlerFactory.h" //HTTPRequestHandler的工厂 给予工厂设计模式
#include "Poco/Net/HTTPServerParams.h"    //被用来指定httpserver以及HTTPRequestHandler的参数
#include "Poco/Net/HTTPServerRequest.h"  //ServerRequest的抽象子类用来指定 服务器端的 http请求
#include "Poco/Net/HTTPServerResponse.h" //ServerResponse的抽象子类用来指定服务器端的http响应
#include "Poco/Net/ServerSocket.h"  //提供了一个TCP服务器套接字接口
#include "Poco/Net/WebSocket.h"  //这个类实现了RFC 6455 web套接字接口  专门针对web服务器用
#include "Poco/Net/NetException.h"  //网络异常
#include "Poco/Util/ServerApplication.h" //Application的子类 所有服务器程序 包括 Reactor FTP HTTP等都用到 算是服务器的启动类
#include "Poco/Util/Option.h"  //存储了命令行选项
#include "Poco/Util/OptionSet.h"  //一个Opention对象的集合
#include "Poco/Util/HelpFormatter.h" //从OptionSet格式化帮助信息
#include "Poco/Format.h"  //格式化函数的实现类似于 C的 sprintf函数 具体看文档
#include <iostream>

using Poco::Net::ServerSocket;
using Poco::Net::WebSocket;
using Poco::Net::WebSocketException;
using Poco::Net::HTTPRequestHandler;
using Poco::Net::HTTPRequestHandlerFactory;
using Poco::Net::HTTPServer;
using Poco::Net::HTTPServerRequest;
using Poco::Net::HTTPResponse;
using Poco::Net::HTTPServerResponse;
using Poco::Net::HTTPServerParams;
using Poco::Timestamp;
using Poco::ThreadPool;
using Poco::Util::ServerApplication;
using Poco::Util::Application;
using Poco::Util::Option;
using Poco::Util::OptionSet;
using Poco::Util::HelpFormatter;

//////页面处理器 链接到来的时候 直接打印html内容
class PageRequestHandler: public HTTPRequestHandler
/// Return a HTML document with some JavaScript creating
/// a WebSocket connection.
{
public:
void handleRequest(HTTPServerRequest& request, HTTPServerResponse& response)
{

response.setChunkedTransferEncoding(true);
response.setContentType("text/html");
std::ostream& ostr = response.send();
ostr << "<html>";
ostr << "<head>";
ostr << "<title>WebSocketServer</title>";
ostr << "<script type=\"text/javascript\">";
ostr << "function WebSocketTest()";
ostr << "{";
ostr << "  if (\"WebSocket\" in window)";
ostr << "  {";
ostr << "    var ws = new WebSocket(\"ws://" << request.serverAddress().toString() << "/ws\");";
ostr << "    ws.onopen = function()";
ostr << "      {";
ostr << "        ws.send(\"Hello, world!\");";
ostr << "      };";
ostr << "    ws.onmessage = function(evt)";
ostr << "      { ";
ostr << "        var msg = evt.data;";
ostr << "        alert(\"Message received: \" + msg);";
ostr << "        ws.close();";
ostr << "      };";
ostr << "    ws.onclose = function()";
ostr << "      { ";
ostr << "        alert(\"WebSocket closed.\");";
ostr << "      };";
ostr << "  }";
ostr << "  else";
ostr << "  {";
ostr << "     alert(\"This browser does not support WebSockets.\");";
ostr << "  }";
ostr << "}";
ostr << "</script>";
ostr << "</head>";
ostr << "<body>";
ostr << "  <h1>WebSocket Server</h1>";
ostr << "  <p><a href=\"javascript:WebSocketTest()\">Run WebSocket Script</a></p>";
ostr << "</body>";
ostr << "</html>";
}
};

/////////http请求处理器 1
class WebSocketRequestHandler: public HTTPRequestHandler
/// Handle a WebSocket connection.
{
public:
void handleRequest(HTTPServerRequest& request, HTTPServerResponse& response)
{
Application& app = Application::instance();
try
{
WebSocket ws(request, response);
app.logger().information("WebSocket connection established.");
char buffer[1024];
int flags;
int n;
do
{
n = ws.receiveFrame(buffer, sizeof(buffer), flags);
app.logger().information(Poco::format("Frame received (length=%d, flags=0x%x).", n, unsigned(flags)));
ws.sendFrame(buffer, n, flags);
}
while (n > 0 || (flags & WebSocket::FRAME_OP_BITMASK) != WebSocket::FRAME_OP_CLOSE);
app.logger().information("WebSocket connection closed.");
}
catch (WebSocketException& exc)
{
app.logger().log(exc);
switch (exc.code())
{
case WebSocket::WS_ERR_HANDSHAKE_UNSUPPORTED_VERSION:
response.set("Sec-WebSocket-Version", WebSocket::WEBSOCKET_VERSION);
// fallthrough
case WebSocket::WS_ERR_NO_HANDSHAKE:
case WebSocket::WS_ERR_HANDSHAKE_NO_VERSION:
case WebSocket::WS_ERR_HANDSHAKE_NO_KEY:
response.setStatusAndReason(HTTPResponse::HTTP_BAD_REQUEST);
response.setContentLength(0);
response.send();
break;
}
}
}
};

//HTTP请求处理器工厂
class RequestHandlerFactory: public HTTPRequestHandlerFactory
{
public:
HTTPRequestHandler* createRequestHandler(const HTTPServerRequest& request) //覆盖方法
{
Application& app = Application::instance();
app.logger().information("Request from "
+ request.clientAddress().toString()
+ ": "
+ request.getMethod()
+ " "
+ request.getURI()
+ " "
+ request.getVersion());

//打印所有链接请求
for (HTTPServerRequest::ConstIterator it = request.begin(); it != request.end(); ++it)
{
app.logger().information(it->first + ": " + it->second);
}
//可以选择输出html页面 或者不输出  通过http请求参数
if(request.find("Upgrade") != request.end() && request["Upgrade"] == "websocket")
return new WebSocketRequestHandler;
else
return new PageRequestHandler;
}
};

//////////网络应用程序的启动器 都是ServerApplication
class WebSocketServer: public Poco::Util::ServerApplication
{
public:
WebSocketServer(): _helpRequested(false)
{
}

~WebSocketServer()
{
}

protected:
///再启动的时候先调用
void initialize(Application& self)
{
loadConfiguration(); // load default configuration files, if present
ServerApplication::initialize(self);
}
//在释放的时候调用
void uninitialize()
{
ServerApplication::uninitialize();
}

///覆盖基类的函数 定义一些命令选项
void defineOptions(OptionSet& options)
{
ServerApplication::defineOptions(options);

options.addOption(
Option("help", "h", "display help information on command line arguments")
.required(false)
.repeatable(false));
}
///处理命令行选项
void handleOption(const std::string& name, const std::string& value)
{
ServerApplication::handleOption(name, value);

if (name == "help")
_helpRequested = true;
}

//打印帮助
void displayHelp()
{
HelpFormatter helpFormatter(options());
helpFormatter.setCommand(commandName());
helpFormatter.setUsage("OPTIONS");
helpFormatter.setHeader("A sample HTTP server supporting the WebSocket protocol.");
helpFormatter.format(std::cout);
}
//在初始化完毕之后调用
int main(const std::vector<std::string>& args)
{
if (_helpRequested)
{
displayHelp();
}
else
{
// get parameters from configuration file
//从配置文件中获取端口
unsigned short port = (unsigned short) config().getInt("WebSocketServer.port", 9980);

// 安装一个ServerSocket
ServerSocket svs(port);
// s安装一个HttpServer实例  并且传递 请求处理器工厂  和一个HttpServerParams对象
HTTPServer srv(new RequestHandlerFactory, svs, new HTTPServerParams);
// 启动服务器
srv.start();
// 等待kill 或者控制台CTRL+C
waitForTerminationRequest();
// 停止HTTP服务器
srv.stop();
}
return Application::EXIT_OK;  //返回正常退出状态
}

private:
bool _helpRequested;
};

//启动web 服务器
POCO_SERVER_MAIN(WebSocketServer)
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