muduo网络库学习之muduo_http 库涉及到的类
1、http request：
request line + header + body （header分为普通报头，请求报头与实体报头）
header与body之间有一空行（CRLF）
请求方法有：Get, Post, Head, Put, Delete等协议版本1.0、1.1
常用请求头
Accept：浏览器可接受的媒体（MIME）类型；Accept-Language：浏览器所希望的语言种类Accept-Encoding：浏览器能够解码的编码方法，如gzip，deflate等User-Agent：告诉HTTP服务器， 客户端使用的操作系统和浏览器的名称和版本Connection：表示是否需要持久连接，Keep-Alive表示长连接，close表示短连接
GET / HTTP/1.1
Accept: image/jpeg, application/x-ms-application, image/gif, application/xaml+xml, image/pjpeg, application/x-ms-xbap, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, */*
Accept-Language: zh-CN
User-Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; Trident/4.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; Tablet PC 2.0)
Accept-Encoding: gzip, deflate
Host: 192.168.159.188:8000
Connection: Keep-Alive
一个典型的http 响应：
Accept: image/jpeg, application/x-ms-application, image/gif, application/xaml+xml, image/pjpeg, application/x-ms-xbap, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, */*
Accept-Language: zh-CN
User-Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; Trident/4.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; Tablet PC 2.0)
Accept-Encoding: gzip, deflate
Host: 192.168.159.188:8000
Connection: Keep-Alive
2、http response：
status line + header + body （header分为普通报头，响应报头与实体报头）
header与body之间有一空行（CRLF）
状态响应码
1XX 提示信息 - 表示请求已被成功接收，继续处理2XX 成功 - 表示请求已被成功接收，理解，接受3XX 重定向 - 要完成请求必须进行更进一步的处理4XX 客户端错误 - 请求有语法错误或请求无法实现5XX 服务器端错误 - 服务器执行一个有效请求失败
HTTP/1.1 200 OK
Content-Length: 112
Connection: Keep-Alive
Content-Type: text/html
Server: Muduo
<html><head><title>This is title</title></head><body><h1>Hello</h1>Now is 20130611 02:14:31.518462</body></html>
3、muduo_http 库
HttpRequest：http请求类封装，主要有以下几个成员：
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class HttpRequest :
public muduo::copyable
{ public: void addHeader( const char *start, const char *colon, const char *end); private: Method method_; // 请求方法 Version version_; // 协议版本1.0/1.1 string path_; // 请求路径 Timestamp receiveTime_; // 请求时间 std::map<string, string> headers_; // header列表 } |
HttpResponse：http响应类封装，主要有以下几个成员：
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class HttpResponse :
public muduo::copyable
{ public: void appendToBuffer(Buffer *output) const; // 将HttpResponse添加到Buffer private: std::map<string, string> headers_; // header列表 HttpStatusCode statusCode_; // 状态响应码 // FIXME: add http version string statusMessage_; // 状态响应码对应的文本信息 bool closeConnection_; // 是否关闭连接 string body_; // 实体 }; |
HttpContext：http协议解析类，主要有以下几个成员：
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class HttpContext : public muduo::copyable { private: HttpRequestParseState state_; // 请求解析状态 HttpRequest request_; // http请求 }; |
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/// A simple embeddable HTTP server designed for report status of a program. /// It is not a fully HTTP 1.1 compliant server, but provides minimum features /// that can communicate with HttpClient and Web browser. /// It is synchronous, just like Java Servlet. class HttpServer : boost::noncopyable { public: typedef boost::function < void ( const HttpRequest &, HttpResponse *) > HttpCallback; /// Not thread safe, callback be registered before calling start(). void setHttpCallback( const HttpCallback &cb) { httpCallback_ = cb; } void setThreadNum( int numThreads) { server_.setThreadNum(numThreads); } void start() { server_.start(); } private: void onConnection( const TcpConnectionPtr &conn); void onMessage( const TcpConnectionPtr &conn, Buffer *buf, Timestamp receiveTime); void onRequest( const TcpConnectionPtr &, const HttpRequest &); TcpServer server_; HttpCallback httpCallback_; // 在处理http请求（即调用onRequest）的过程中回调此函数，对请求进行具体的处理 }; |
在HttpServer 构造函数中：
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server_.setConnectionCallback(
boost::bind(&HttpServer::onConnection, this, _1)); server_.setMessageCallback( boost::bind(&HttpServer::onMessage, this, _1, _2, _3)); |
即通过设置server_ ，最终设置到TcpConnection 的回调函数, 当客户端如浏览器连接上来，根据以前的分析可知，调用
HttpServer::onConnection(), 绑定HttpContext到TcpConnection 中的 boost::any context_;
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if (conn->connected())
{ conn->setContext(HttpContext()); // TcpConnection与一个HttpContext绑定 } |
接着客户端发出请求，比如访问服务器的某个路径，调用
HttpServer::onMessage(),
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void HttpServer::onMessage(
const TcpConnectionPtr &conn,
Buffer *buf, Timestamp receiveTime) { HttpContext *context = boost::any_cast<HttpContext>(conn->getMutableContext()); if (!detail::parseRequest(buf, context, receiveTime)) { conn->send( "HTTP/1.1 400 Bad Request\r\n\r\n"); conn->shutdown(); } // 请求消息解析完毕 if (context->gotAll()) { onRequest(conn, context->request()); context->reset(); // 本次请求处理完毕，重置HttpContext，适用于长连接(一个连接多次请求) } } |
其中parseRequest() 会将存放在Buffer 中的请求解析到server_.TcpConnection.context_.request_ 中，最后调用
HttpServer::onRequest(),
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void HttpServer::onRequest(
const TcpConnectionPtr &conn,
const HttpRequest &req)
{ const string &connection = req.getHeader( "Connection"); bool close = connection == "close" || (req.getVersion() == HttpRequest::kHttp10 && connection != "Keep-Alive"); HttpResponse response(close); httpCallback_(req, &response); // 客户代码设置的回调函数，填充response Buffer buf; response.appendToBuffer(&buf); // 将响应填充到buf conn->send(&buf); // 将buf 中的响应发送给客户端 if (response.closeConnection()) { conn->shutdown(); //短连接直接关闭 } } |
即要用客户代码设置的httpCallback_ 函数来填充httpResponse，然后发送给客户端。
测试代码：
HttpServer_test.cc：
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#include <muduo/net/http/HttpServer.h>
#include <muduo/net/http/HttpRequest.h> #include <muduo/net/http/HttpResponse.h> #include <muduo/net/EventLoop.h> #include <muduo/base/Logging.h> #include <iostream> #include <map> using namespace muduo; using namespace muduo::net; extern char favicon[ 555]; bool benchmark = false; // 实际的请求处理 void onRequest( const HttpRequest &req, HttpResponse *resp) { std::cout << "Headers " << req.methodString() << " " << req.path() << std::endl; if (!benchmark) { const std::map<string, string> &headers = req.headers(); for (std::map<string, string>::const_iterator it = headers.begin(); it != headers.end(); ++it) { std::cout << it->first << ": " << it->second << std::endl; } } if (req.path() == "/") { resp->setStatusCode(HttpResponse::k200Ok); resp->setStatusMessage( "OK"); resp->setContentType( "text/html"); resp->addHeader( "Server", "Muduo"); string now = Timestamp::now().toFormattedString(); resp->setBody( "<html><head><title>This is title</title></head>" "<body><h1>Hello</h1>Now is " + now + "</body></html>"); } else if (req.path() == "/favicon.ico") { resp->setStatusCode(HttpResponse::k200Ok); resp->setStatusMessage( "OK"); resp->setContentType( "image/png"); resp->setBody(string(favicon, sizeof favicon)); } else if (req.path() == "/hello") { resp->setStatusCode(HttpResponse::k200Ok); resp->setStatusMessage( "OK"); resp->setContentType( "text/plain"); resp->addHeader( "Server", "Muduo"); resp->setBody( "hello, world!\n"); } else { resp->setStatusCode(HttpResponse::k404NotFound); resp->setStatusMessage( "Not Found"); resp->setCloseConnection( true); } } int main( int argc, char *argv[]) { int numThreads = 0; if (argc > 1) { benchmark = true; Logger::setLogLevel(Logger::WARN); numThreads = atoi(argv[ 1]); } EventLoop loop; HttpServer server(&loop, InetAddress( 8000), "dummy"); server.setHttpCallback(onRequest); server.setThreadNum(numThreads); server.start(); loop.loop(); } // 这是一个图片数据 char favicon[ 555] = { ..... }; |
运行程序，使用浏览器访问目录，如下：
服务器端输出如下：
simba@ubuntu:~/Documents/build/debug/bin$ ./httpserver_test
20131113 08:15:30.110059Z 3637 TRACE IgnoreSigPipe Ignore SIGPIPE - EventLoop.cc:51
20131113 08:15:30.112625Z 3637 TRACE updateChannel fd = 4 events = 3 - EPollPoller.cc:104
20131113 08:15:30.113241Z 3637 TRACE EventLoop EventLoop created 0xBFBC8EF4 in thread 3637 - EventLoop.cc:76
20131113 08:15:30.113677Z 3637 TRACE updateChannel fd = 5 events = 3 - EPollPoller.cc:104
20131113 08:15:30.114767Z 3637 WARN HttpServer[dummy] starts listenning on 0.0.0.0:8000 - HttpServer.cc:155
20131113 08:15:30.115687Z 3637 TRACE updateChannel fd = 6 events = 3 - EPollPoller.cc:104
20131113 08:15:30.116272Z 3637 TRACE loop EventLoop 0xBFBC8EF4 start looping - EventLoop.cc:108
20131113 08:15:32.870784Z 3637 TRACE poll 1 events happended - EPollPoller.cc:65
20131113 08:15:32.871784Z 3637 TRACE printActiveChannels {6: IN } - EventLoop.cc:271
20131113 08:15:32.872287Z 3637 INFO TcpServer::newConnection [dummy] - new connection [dummy:0.0.0.0:8000#1] from 192.168.56.1:2794 - TcpServer.cc:93
20131113 08:15:32.872898Z 3637 DEBUG TcpConnection TcpConnection::ctor[dummy:0.0.0.0:8000#1] at 0x9BD77E0 fd=8 - TcpConnection.cc:65
20131113 08:15:32.873280Z 3637 TRACE newConnection [1] usecount=1 - TcpServer.cc:111
20131113 08:15:32.873640Z 3637 TRACE newConnection [2] usecount=2 - TcpServer.cc:113
20131113 08:15:32.874050Z 3637 TRACE updateChannel fd = 8 events = 3 - EPollPoller.cc:104
20131113 08:15:32.874459Z 3637 TRACE newConnection [5] usecount=2 - TcpServer.cc:123
20131113 08:15:32.890691Z 3637 TRACE poll 1 events happended - EPollPoller.cc:65
20131113 08:15:32.890825Z 3637 TRACE printActiveChannels {8: IN } - EventLoop.cc:271
Headers GET /hello
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Encoding: gzip,deflate,sdch
Accept-Language: zh-CN,zh;q=0.8
Connection: keep-alive
Cookie: Hm_lvt_3d143f0a07b6487f65609d8411e5464f=1380329613
Host: 192.168.56.188:8000
User-Agent: Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/29.0.1547.66 Safari/537.36
20131113 08:15:42.902273Z 3637 TRACE poll nothing happended - EPollPoller.cc:74
20131113 08:15:52.912887Z 3637 TRACE poll nothing happended - EPollPoller.cc:74
......
20131113 08:17:11.421249Z 3637 TRACE poll 1 events happended - EPollPoller.cc:65
20131113 08:17:11.421328Z 3637 TRACE printActiveChannels {8: IN } - EventLoop.cc:271
Headers GET /favicon.ico
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Encoding: gzip,deflate,sdch
Accept-Language: zh-CN,zh;q=0.8
Connection: keep-alive
Cookie: Hm_lvt_3d143f0a07b6487f65609d8411e5464f=1380329613
Host: 192.168.56.188:8000
User-Agent: Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/29.0.1547.66 Safari/537.36
20131113 08:17:21.432017Z 3637 TRACE poll nothing happended - EPollPoller.cc:74
20131113 08:17:31.439508Z 3637 TRACE poll nothing happended - EPollPoller.cc:74
20131113 08:15:30.110059Z 3637 TRACE IgnoreSigPipe Ignore SIGPIPE - EventLoop.cc:51
20131113 08:15:30.112625Z 3637 TRACE updateChannel fd = 4 events = 3 - EPollPoller.cc:104
20131113 08:15:30.113241Z 3637 TRACE EventLoop EventLoop created 0xBFBC8EF4 in thread 3637 - EventLoop.cc:76
20131113 08:15:30.113677Z 3637 TRACE updateChannel fd = 5 events = 3 - EPollPoller.cc:104
20131113 08:15:30.114767Z 3637 WARN HttpServer[dummy] starts listenning on 0.0.0.0:8000 - HttpServer.cc:155
20131113 08:15:30.115687Z 3637 TRACE updateChannel fd = 6 events = 3 - EPollPoller.cc:104
20131113 08:15:30.116272Z 3637 TRACE loop EventLoop 0xBFBC8EF4 start looping - EventLoop.cc:108
20131113 08:15:32.870784Z 3637 TRACE poll 1 events happended - EPollPoller.cc:65
20131113 08:15:32.871784Z 3637 TRACE printActiveChannels {6: IN } - EventLoop.cc:271
20131113 08:15:32.872287Z 3637 INFO TcpServer::newConnection [dummy] - new connection [dummy:0.0.0.0:8000#1] from 192.168.56.1:2794 - TcpServer.cc:93
20131113 08:15:32.872898Z 3637 DEBUG TcpConnection TcpConnection::ctor[dummy:0.0.0.0:8000#1] at 0x9BD77E0 fd=8 - TcpConnection.cc:65
20131113 08:15:32.873280Z 3637 TRACE newConnection [1] usecount=1 - TcpServer.cc:111
20131113 08:15:32.873640Z 3637 TRACE newConnection [2] usecount=2 - TcpServer.cc:113
20131113 08:15:32.874050Z 3637 TRACE updateChannel fd = 8 events = 3 - EPollPoller.cc:104
20131113 08:15:32.874459Z 3637 TRACE newConnection [5] usecount=2 - TcpServer.cc:123
20131113 08:15:32.890691Z 3637 TRACE poll 1 events happended - EPollPoller.cc:65
20131113 08:15:32.890825Z 3637 TRACE printActiveChannels {8: IN } - EventLoop.cc:271
Headers GET /hello
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Encoding: gzip,deflate,sdch
Accept-Language: zh-CN,zh;q=0.8
Connection: keep-alive
Cookie: Hm_lvt_3d143f0a07b6487f65609d8411e5464f=1380329613
Host: 192.168.56.188:8000
User-Agent: Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/29.0.1547.66 Safari/537.36
20131113 08:15:42.902273Z 3637 TRACE poll nothing happended - EPollPoller.cc:74
20131113 08:15:52.912887Z 3637 TRACE poll nothing happended - EPollPoller.cc:74
......
20131113 08:17:11.421249Z 3637 TRACE poll 1 events happended - EPollPoller.cc:65
20131113 08:17:11.421328Z 3637 TRACE printActiveChannels {8: IN } - EventLoop.cc:271
Headers GET /favicon.ico
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Encoding: gzip,deflate,sdch
Accept-Language: zh-CN,zh;q=0.8
Connection: keep-alive
Cookie: Hm_lvt_3d143f0a07b6487f65609d8411e5464f=1380329613
Host: 192.168.56.188:8000
User-Agent: Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/29.0.1547.66 Safari/537.36
20131113 08:17:21.432017Z 3637 TRACE poll nothing happended - EPollPoller.cc:74
20131113 08:17:31.439508Z 3637 TRACE poll nothing happended - EPollPoller.cc:74
从输出中看到，fd=6是监听套接字，fd=8是与服务器连接起来的已连接套接字（fd=7 是idlefd_）。浏览器访问某个目录，fd=8可读事件发生，服务器端最终执行到httpCallback_（onRequest() 函数），首先从HttpRequest中读取解析到的请求头部等信息并打印出来，即Headers GET /hello 开始的几行输出。这是一个长连接，所以第二次切换目录访问时，也是fd=8可读事件发生，只不过填充到HttpResponse 的数据不同，故浏览器端看到的输出就不一样了。
注意：muduo只实现了最简单的http应答功能，并不能处理带有body的http 请求，比如POST。实现http库主要是为了让
muduo inspect 库可以通过HTTP方式为服务器提供监控接口。
参考：
《UNP》
muduo manual.pdf
《linux 多线程服务器编程：使用muduo c++网络库》