最近要写一个代理程序，软件最终要跑在嵌入式设备上，其中一部分是需要做一个简单爬虫程序，用来和嵌入式设备上的Web做信息交互。我不想用第三方的任何库，如是简单看了下http协议，用一天时间实现了http协议的客户端，实现Get、Post、UpFile（文件上传）等常用操作，需要完善的部分是Cookie没有自动提取和传输，需要自己手动处理，朋友们可以完善吧！写个日志，便于日后参考！希望对朋友有参考。

由于最终要在嵌入式设备上运行，所以用 #define Windows 来区分，Socket部分Window和Linux还是有差别的，程序兼容了Windows和Liunx。

通信类头文件

#pragma once
#include<string>
#ifndef WINDOWS
#define WINDOWS
#endif 
 
#ifdef WINDOWS
  #include<WINSOCK2.H>
  #include <WS2tcpip.h>  
#else
    #include <iconv.h>
  #include <netinet/in.h>
  #include <stdio.h>
  #include <sys/types.h>
  #include <sys/socket.h>
  #include <arpa/inet.h>
  #include <string.h>
  #include <stdlib.h>
  #include <sys/stat.h>
  #include <unistd.h>
  #include <fcntl.h>
   
#endif // WINDOWS
using namespace std;
class TCPClient
{
public:
  
  TCPClient(string host);
  ~TCPClient();
 
 
  bool ConnectToServer();
  bool SendData(const char * sendBuffer,int dataLen);
  string RecvData();
private:
 
  #ifdef WINDOWS
    SOCKET  clientSocket;
  #else
  int  clientSocket;
  #endif
  string hostAddr;
  bool isConnected;
};

封装基础通信类cpp

#include "TCPClient.h"
#include<vector>
#include<errno.h>
 
#ifdef WINDOWS
#pragma warning(disable:4996) 
#pragma comment(lib, "WS2_32.lib")
#endif // WINDOWS
 
#ifdef  WINDOWS
 
TCPClient::TCPClient(string host)
{
  hostAddr = host;
  isConnected = false;
#ifdef WINDOWS
  WSAData wsdata;
  if (WSAStartup(MAKEWORD(2, 2), &wsdata) != 0)
  {
    WSACleanup();
    printf("WSAStartup failured \r\n");
  }
  else
  {
    printf("WSAStartup OK\r\n");
  }
 
#endif
}
 
bool TCPClient::ConnectToServer()
{
  if (isConnected)
    return true;
 
  clientSocket = socket(AF_INET, SOCK_STREAM, 0);
  if (clientSocket == -1)
  {
    printf("sockclient create fail ! \n");
    return false;
  }
 
  struct sockaddr_in dest_addr;     /* 目的地址*/
  dest_addr.sin_family = AF_INET;   /* host byte order */
  dest_addr.sin_port = htons(80);   /* short, network byte order */
 
#ifdef WINDOWS
  dest_addr.sin_addr.s_addr = inet_addr(this->hostAddr.c_str());
#else
  inet_pton(AF_INET, this->hostAddr.c_str(), &dest_addr.sin_addr.s_addr);
#endif // WINDOWS
 
  if (connect(clientSocket, (struct sockaddr *)&dest_addr, sizeof(struct sockaddr)) < 0)
  {
 
#ifdef WINDOWS
    closesocket(clientSocket);
    printf("connect controlServer failured%d\r\n", GetLastError());
 
#else
    close(clientSocket);
    printf("connect controlServer failured\r\n");
 
#endif
 
    return false;
  }
  isConnected = true;
  return true;
}
 
TCPClient::~TCPClient()
{
#ifdef WINDOWS
  closesocket(clientSocket);
  WSACleanup();
#else
  close(clientSocket);
#endif
}
 
bool TCPClient::SendData(const char *sendBuffer, int dataLen)
{
  if (!ConnectToServer())
    return false;
  int sendLen = 0;
  int oneLen = 0;
  while (sendLen < dataLen)
  {
    oneLen = send(this->clientSocket, sendBuffer + sendLen, dataLen - sendLen, 0);
    if (oneLen <= 0)
    {
      if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR)
      {
        //这几种错误码，认为连接是正常的，继续接收
      }
      else {
        //printf("%d", WSAGetLastError());
        return 0;
      }
 
      break;
    }
    else
      sendLen += oneLen;
  }
  return true;
}
 
string TCPClient::RecvData()
{
  char  recvData[1000] = { 0 };
  string responseData = "";
  int recLen = 0;
  int recLenOfAll = 0;
  while ((recLen = recv(this->clientSocket, recvData, sizeof(recvData) - 1, 0)) > 0)
  {
    responseData.append(recvData);
    memset(recvData, 0, 1000);
    //ZeroMemory(recvData, 1000);
    recLenOfAll += recLen;
  }
  string resp;
#ifdef WINDOWS
  resp =responseData.c_str();
  closesocket(this->clientSocket);
#else
  resp = (responseData.c_str());
  close(this->clientSocket);
#endif
  isConnected = false;
  return resp;
}

WebRequest头文件

#pragma once
 
#include<iostream>
#include<thread>
#include<mutex>
#include<map>
#include<string>
#include "TCPClient.h"
 
using namespace std;
 
enum  RequestType
{
  Post, Get
};
 
class WebRequest
{
private:
  string SendData(string method, string path, map<string, string> paramters, string referUrl);
  string SendData(string method, string path, string bodyInfo, string referUrl);
  string SendData(string method, string path, string referUrl);
public:
  WebRequest(string host);
  ~WebRequest();
  
  string GetData(string path, map<string, string> paramters, string referUrl);
  string GetData(string path, string referUrl);
  string PostData(string path, map<string, string> paramters, string referUrl);
  string PostData(string path, string referUrl);
  string GetData(string path, string bodyInfo, string referUrl);
  string PostData(string path, string bodyInfo, string referUrl);
 
  string UpFile(string path, string FileName);
public:
  map<string, string>  Headers;
  RequestType requestType;
private:
  string GetHeadContent();
  TCPClient *tcpClient;
  string hostAddr;
};

webrequest.cpp

#include "WebRequest.h"
#include<vector>
#include<fstream>
WebRequest::WebRequest(string host)
{
  this->hostAddr = host;
  //Headers.insert(pair<string,string>("A", "B"));
  map<string, string> *HeadersTest = new map<string, string>();
  Headers["Accept"]="*/*";
  Headers["Host"] = host;
  Headers["Accept-Language"] = "zh-CN";
  Headers["Accept-Encoding"] = "gzip, deflate";
  Headers["User-Agent"] = "Mozilla/5.0 (Windows NT 10.0; WOW64; Trident/7.0; rv:11.0) like Gecko";
  Headers["Connection"] = "Keep-Alive";
  tcpClient = new TCPClient(host);
}
 
WebRequest::~WebRequest()
{
  delete tcpClient;
}
 
 
string WebRequest::GetHeadContent()
{
  string headContent = "";
  for (const auto& kv : this->Headers)
  {
    if (kv.second.size() == 0)
      continue;
    headContent.append(kv.first);
    headContent.append(": ");
    headContent.append(kv.second);
    headContent.append("\r\n");
  }
  return headContent;
}
 
string WebRequest::SendData( string method, string path, string bodyInfo, string referUrl)
{
  string headStr = "";
  headStr.append(method+" " + path + " HTTP/1.1\r\n");
  headStr.append(GetHeadContent());
  if (referUrl.length() > 0)
    headStr.append("Referer: http://"+hostAddr + referUrl +"\r\n");
  headStr.append("Content-Length: " + to_string(bodyInfo.size()));
  headStr.append("\r\n\r\n");
  headStr.append(bodyInfo);
  if (tcpClient->SendData(headStr.c_str(), headStr.length()))
    return tcpClient->RecvData();
  else
    return "发送请求失败！";
}
string WebRequest::GetData(string path, map<string, string> paramters, string referUrl)
{
  string recstr = this->SendData("GET", path, paramters, referUrl);
  //this->temRecStr = recstr;
  return recstr;
}
string WebRequest::PostData(string path, map<string, string> paramters, string referUrl)
{
  return this->SendData("POST", path, paramters, referUrl);
}
string WebRequest::GetData(string path, string referUrl)
{
  return this->SendData("GET", path, referUrl);
}
string WebRequest::PostData(string path,  string referUrl)
{
  return this->SendData("POST", path, referUrl);
}
 
string WebRequest::GetData(string path, string bodyInfo, string referUrl)
{
  return this->SendData("GET", path, bodyInfo, referUrl);
}
string WebRequest::PostData(string path, string bodyInfo, string referUrl)
{
  return this->SendData("POST", path, bodyInfo, referUrl);
}
string WebRequest::SendData(string method, string path, map<string,string> paramters,string referUrl)
{
  string headStr = "";
  headStr.append(method+" "+ path+" HTTP/1.1\r\n");
  headStr.append(GetHeadContent());
  if (referUrl.length() > 0)
    headStr.append("Referer: http://" +hostAddr+ referUrl + "\r\n");
  string bodyInfo = "";
  
  for (const auto& kv : paramters)
  {
    //if(TString::endsWith(path,"&"))
    if (bodyInfo.length() > 0)
      bodyInfo.append("&");
    bodyInfo.append(kv.first);
    bodyInfo.append("=");
    bodyInfo.append(kv.second);
  }
 
  headStr.append("Content-Length: " + to_string(bodyInfo.size()));
  headStr.append("\r\n\r\n");
  headStr.append(bodyInfo);
 
  if (this->tcpClient->SendData(headStr.c_str(), headStr.length()))
    return tcpClient->RecvData();
  else
    return"请求失败！";
}
string WebRequest::SendData(string method, string path,  string referUrl)
{
  string headStr = "";
  headStr.append(method + " " + path + " HTTP/1.1\r\n");
  headStr.append(GetHeadContent());
  if (referUrl.length() > 0)
    headStr.append("Referer: http://" + hostAddr + referUrl + "\r\n");
  headStr.append("Content-Length:0" );
  headStr.append("\r\n\r\n");
 
  if (this->tcpClient->SendData(headStr.c_str(), headStr.length()))
    return tcpClient->RecvData();
  else
    return"请求失败！";
}
string WebRequest::UpFile(string path, string fileName)
{
  string boundary = "---------------------------7d33a816d302b6\r\n";
  this->Headers["Content-Type"] = "multipart/form-data;boundary=---------------------------7d33a816d302b6";// +boundary;
 
  string bodyInfo = "";
  fstream fs;
  fs.open(fileName, ios::binary | ios::in);
  if (!fs)
  {
    cout << "文件不存在！" << fileName << endl;
    return  "上传文件不存在！";
  }
 
  fs.seekg(0, fs.end);
  int fsLen=fs.tellg();
  bodyInfo.append(boundary);//文件内容开始，
  bodyInfo.append("Content-Disposition: form-data; name=\"fx_19V_11.10.128.14.uot\"; filename=\"" + fileName + "\"\r\n");
  bodyInfo.append("Content-Type: application/octet-stream\r\n");
  
  string sendContent = "";
  sendContent.append("POST " + path + " HTTP/1.1\r\n");
  sendContent.append(GetHeadContent());
  sendContent.append("Content-Length: " + to_string(fsLen + bodyInfo.length() + boundary.length()));
  sendContent.append("\r\n\r\n");
  sendContent.append(bodyInfo);
 
  const char* sendBuffer = sendContent.c_str();
  if (!tcpClient->SendData(sendBuffer, sendContent.length()))
    return "发送请求失败";
 
  //这里读取文件，发送文件
  fs.seekg(0, fs.beg);
  char fsBuffer[2000];
  int readLen = 0;
  int sendAll = 0;
  while (!fs.eof())
  {
    fs.read(fsBuffer, 2000);
    readLen=fs.gcount();
    if (!tcpClient->SendData(fsBuffer, readLen))
      break;
    else
    {
      sendAll += readLen;
      cout <<"已发送:"<< sendAll << endl;
    }
  }
  fs.close();
  if(!tcpClient->SendData(("\r\n"+boundary).c_str(), boundary.length()))//协议结束
    return "发送请求失败";
  return tcpClient->RecvData();
}