上一篇文章《仿nginx Http服务器的设计与实现(一)——多进程和多路IO的实现》中实现了一个仿照nginx的支持高并发的服务器,但只是实现了端口监听和数据接收,并没有实现对http协议的解析,下面就对如何解析http协议进行说明。
我们可以通过浏览器访问之前所搭建的http服务器,可以看到终端输出如下:
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- GET / HTTP/1.1
- Host: 127.0.0.1:8080
- Connection: keep-alive
- Cache-Control: max-age=0
- Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
- User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_9_0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/34.0.1847.131 Safari/537.36
- Accept-Encoding: gzip,deflate,sdch
- Accept-Language: zh-CN,zh;q=0.8
参考一些网上的资料可以知道,http协议主要有三部分组成,即请求行、若干请求字段、请求体。请求行主要包括所使用的http方法,访问的路径以及http的版本。请求字段主要包括若干个详细说明本次http请求的字段,每个字段由字段名+冒号+空格+字段值组成。请求体主要包括发送到客户端的数据。其中请求行和请求字段之间是连续的,而请求字段与请求体之间会有两个空白行(\r\n)分隔。
在明确了这些内容之后,我们就可以开始对接收到的http请求进行解析了。本文将使用两个类,CHttpRequest和CHttpResponse来实现这一功能。下面首先修改上一篇文章中的
handleRequest方法:
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- //处理http请求
- bool handleRequest(int connFd) {
- if (connFd<=0) return false;
- //读取缓存
- char buff[4096];
- //读取http header
- int len = (int)recv(connFd, buff, sizeof(buff), 0);
- if (len<=0) {
- return false;
- }
- buff[len] = '\0';
- std::cout<<buff<<std::endl;
- CHttpRequest *httpRequest = new CHttpRequest();
- httpRequest->handleRequest(buff);
- CHttpResponse *httpResponse = new CHttpResponse(httpRequest);
- bool result = httpResponse->response(connFd);
- //返回是否需要中断连接
- std::string transformConnection(httpRequest->connection);
- std::transform(transformConnection.begin(), transformConnection.end(), transformConnection.begin(), ::tolower);
- return transformConnection == "Keep-Alive" && result;
- }
该代码中采用了一个长度为4096的缓冲区接收http头,接收完成之后,调用CHttpRequest进行解析。下面来看看CHttpRequest的代码:
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- #include "CHttpRequest.h"
- #include "define.h"
- using namespace std;
- CHttpRequest::CHttpRequest() {
- connection = "Close";
- modifiedTime = "";
- fileStart = 0;
- fileEnd = 0;
- fieldMap[TS_HTTP_HEADER_CONNECTION] = &CHttpRequest::handleConnection;
- fieldMap[TS_HTTP_HEADER_AUTHORIZATION] = &CHttpRequest::handleAuthorization;
- fieldMap[TS_HTTP_HEADER_RANGE] = &CHttpRequest::handleRange;
- fieldMap[TS_HTTP_HEADER_IF_MOD_SINCE] = &CHttpRequest::handleIfModSince;
- }
- void CHttpRequest::handleRequest(char *header) {
- stringstream stream;
- stream<<header;
- int count = 0;
- while (1) {
- if (stream.eof()) {
- break;
- }
- char line[1024];
- stream.getline(line, sizeof(line));
- if (strcmp(line, "")==0) {
- continue;
- }
- stringstream lineStream;
- lineStream<<line;
- //first line
- if (count == 0) {
- lineStream>>method;
- lineStream>>path;
- lineStream>>version;
- }else {
- string fieldName;
- lineStream>>fieldName;
- //remove \r
- line[strlen(line)-1] = '\0';
- void(CHttpRequest::*func)(char*) = fieldMap[fieldName];
- if (func!=NULL) {
- (this->*func)(line+fieldName.length()+1);
- }
- }
- count++;
- }
- }
- void CHttpRequest::handleConnection(char *field) {
- if (ENABLE_KEEP_ALIVE) {
- connection = string(field);
- }
- }
- void CHttpRequest::handleAuthorization(char *field) {
- char authName[10], authInfo[256];
- sscanf(field, "%s %s", authName, authInfo);
- authorize = string(authInfo);
- }
- void CHttpRequest::handleRange(char *field) {
- if (strstr(field, "bytes=")==field) {
- char *start = strtok(field+strlen("bytes="), "-");
- fileStart = start==NULL?0:atol(start);
- char *end = strtok(NULL, "-");
- fileEnd = end==NULL?0:atol(end);
- }
- }
- void CHttpRequest::handleIfModSince(char *field) {
- modifiedTime = string(field);
- }
为了保证http解析的效率,本文采用了与nginx中类似的做法,将字段名与解析函数放到了map中(nginx中使用的是hash表,在这里简化为map)。在解析完成之后,调用CHttpResponse构造响应。CHttpResponse代码如下:
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- #include "CHttpResponse.h"
- #include "CHttpRequest.h"
- #include <sys/socket.h>
- #include "define.h"
- #include <string.h>
- #define HTTP_RESPONSE_404 "<html><head><title>404 Not Found</title></head><body><h1>Not Found</h1><p>The requested URL was not found on this server.</p></body></html>"
- std::string getStringFromTime(time_t time) {
- char timeBuff[64];
- struct tm tm = *gmtime(&time);
- strftime(timeBuff, sizeof timeBuff, "%a, %d %b %Y %H:%M:%S %Z", &tm);
- return std::string(timeBuff);
- }
- CHttpResponse::CHttpResponse(CHttpRequest *request) {
- m_request = request;
- if (m_request->method.compare(TS_HTTP_METHOD_GET_S)==0 || m_request->method.compare(TS_HTTP_METHOD_HEAD_S)==0) {
- std::string path = ROOT_PATH;
- if (m_request->path.compare("/")==0) {
- path += ROOT_HTML;
- }else {
- path += m_request->path;
- }
- m_statusCode = 0;
- //if file exist
- if (isFileExist(path.c_str())) {
- //if receive modified time
- if (!m_request->modifiedTime.empty()) {
- time_t time = fileModifiedTime(path.c_str());
- if (getStringFromTime(time) == m_request->modifiedTime) {
- m_statusCode = TS_HTTP_STATUS_NOT_MODIFIED;
- m_statusMsg = TS_HTTP_STATUS_NOT_MODIFIED_S;
- }
- }
- //if file modified
- if (m_statusCode == 0) {
- if (m_request->fileStart || m_request->fileEnd) {
- long long fileSize = getFileSize(path.c_str());
- //if request range satisfied
- if (m_request->fileStart<fileSize && m_request->fileEnd<fileSize) {
- m_statusCode = TS_HTTP_STATUS_PARTIAL_CONTENT;
- m_statusMsg = TS_HTTP_STATUS_PARTIAL_CONTENT_S;
- m_sendFilePath = path;
- }else {
- m_statusCode = TS_HTTP_STATUS_REQUEST_RANGE_NOT_SATISFIABLE;
- m_statusMsg = TS_HTTP_STATUS_REQUEST_RANGE_NOT_SATISFIABLE_S;
- }
- }else {
- m_statusCode = TS_HTTP_STATUS_OK;
- m_statusMsg = TS_HTTP_STATUS_OK_S;
- m_sendFilePath = path;
- }
- }
- } else {
- m_statusCode = TS_HTTP_STATUS_NOT_FOUND;
- m_statusMsg = TS_HTTP_STATUS_NOT_FOUND_S;
- m_sendStr = HTTP_RESPONSE_404;
- }
- }
- }
- bool CHttpResponse::response(int connFd) {
- bool result = true;
- std::stringstream responseStream;
- responseStream<<m_request->version<<" "<<m_statusMsg<<"\r\n";
- //time
- responseStream<<"Date: "<<getStringFromTime(time(0))<<"\r\n";
- //server name
- responseStream<<"Server: "<<SERVER_NAME<<"\r\n";
- //keep alive
- responseStream<<"Connection: "<<m_request->connection<<"\r\n";
- //content length
- long long contentLength = 0;
- //if file exist
- if (!m_sendFilePath.empty()) {
- //if define file end
- if (m_request->fileEnd) {
- contentLength = m_request->fileEnd - m_request->fileStart + 1;
- }
- //if define file start
- else if (m_request->fileStart) {
- contentLength = getFileSize(m_sendFilePath.c_str()) - m_request->fileStart + 1;
- }
- //if undefine start or end
- else {
- contentLength = getFileSize(m_sendFilePath.c_str());
- }
- } else if (!m_sendStr.empty()) {
- contentLength = m_sendStr.length();
- }
- if (contentLength) {
- responseStream<<"Content-Length: "<<contentLength<<"\r\n";
- }
- //last modified
- if (!m_sendFilePath.empty()) {
- responseStream<<"Last-Modified: "<<getStringFromTime(fileModifiedTime(m_sendFilePath.c_str()))<<"\r\n";
- responseStream<<"Accept-Ranges: "<<"bytes"<<"\r\n";
- }
- //content type
- if (!m_sendFilePath.empty()) {
- char path[256];
- strcpy(path, m_sendFilePath.c_str());
- char *ext = strtok(path, ".");
- char *lastExt = ext;
- while (ext!=NULL) {
- ext = strtok(NULL, ".");
- if (ext) lastExt = ext;
- }
- for (int i=0; i<38; i++) {
- if (strcmp(mmt[i].ext, lastExt)==0) {
- responseStream<<"Content-Type: "<<mmt[i].type<<"\r\n";
- break;
- }
- }
- }
- //other
- switch (m_statusCode) {
- case TS_HTTP_STATUS_UNAUTHORIZED:
- responseStream<<"WWW-Authenticate: Basic realm=\"zhaoxy.com\"\r\n";
- break;
- case TS_HTTP_STATUS_FOUND:
- responseStream<<"Location: /index.html\r\n";
- break;
- case TS_HTTP_STATUS_PARTIAL_CONTENT:
- responseStream<<"Content-Range: "<<"bytes "<<m_request->fileStart<<"-"<<(m_request->fileEnd==0?contentLength:m_request->fileEnd)<<"/"<<getFileSize(m_sendFilePath.c_str())<<"\r\n";
- break;
- default:
- break;
- }
- //seperator
- responseStream<<"\r\n";
- //send response header
- std::string responseStr = responseStream.str();
- std::cout<<responseStr<<std::endl;
- send(connFd, responseStr.c_str(), responseStr.length(), 0);
- //content
- //if not head method
- if (m_request->method.compare(TS_HTTP_METHOD_HEAD_S)!=0) {
- if (!m_sendFilePath.empty()) {
- std::ifstream file(m_sendFilePath);
- file.seekg(m_request->fileStart, std::ifstream::beg);
- while(file.tellg() != -1)
- {
- char *p = new char[1024];
- bzero(p, 1024);
- file.read(p, 1024);
- int n = (int)send(connFd, p, 1024, 0);
- if (n < 0) {
- std::cout<<"ERROR writing to socket"<<std::endl;
- result = false;
- break;
- }
- delete p;
- }
- file.close();
- }else {
- send(connFd, m_sendStr.c_str(), m_sendStr.length(), 0);
- }
- }
- return result;
- }
该代码支持断点续传、last modified和authorization字段。具体的逻辑不作详细说明,有疑问的可以留言。
该Http服务器的代码已经上传到GitHub上,大家可以直接下载。
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如果大家觉得对自己有帮助的话,还希望能帮顶一下,谢谢:)
个人博客: blog.csdn.net/zhaoxy2850
本文地址: blog.csdn.net/zhaoxy_thu/…
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