Poco C++库网络模块例子解析2-------HttpServer

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//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 1class 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ServerApplicationclass 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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