C++实现含附件的邮件发送功能

C++实现邮件发送程序在vs2013测试通过，一共3个文件，发邮件的程序封装为Csmtp 类。

1.测试用的主函数

//
#include "Csmtp.h"
#pragma comment(lib, "Kernel32.lib") 

int main()
{ 

 Csmtp mail(
  25,
  "smtp.126.com",
  "username@126.com",// 来源邮箱
  "pwd",
  "username@126.com" //目标邮箱
  );

 if (!mail.CReateSocket())
 {
  cout << "ReateSocket failed!" << endl;
  return -1;//
 }
 mail.setTitle("test mail");
 mail.setContent("this is content.");

 mail.addfile("test1.png"); //添加附件
 mail.addfile("test2.png"); //添加附件

 mail.SendMail(); //类主函数

 return 0;
} 

2.Csmtp类定义

#include <iostream>
#include <string>
#include <vector>
#include <fstream> 

#include <WinSock2.h> //适用平台 Windows

#pragma comment(lib, "ws2_32.lib") /*链接ws2_32.lib动态链接库*/
 // POP3服务器（端口：110） Csmtp服务器（端口：25）
using namespace std;
class Csmtp
{ 

 int port;
 string domain;
 string user;
 string pass;
 string target;
 string title; //邮件标题
 string content; //邮件内容

 HOSTENT* pHostent;
 SOCKET sockClient; //客户端的套接字
 vector <string> filename; //存储附件名的向量

public: 

 Csmtp(
  int _port, //端口25
  string _domain,  //域名
  string _user,  //发送者的邮箱
  string _pass,  //密码
  string _target)  //目标邮箱
 :port(_port),domain(_domain),user(_user),pass(_pass), target(_target){};//内容
 bool CReateSocket();
 void setTitle(string tem){title = tem;}
 void setContent(string tem){content = tem;}

 int SendAttachment(SOCKET &sockClient);
 int SendMail();
 void addfile(string str){filename.push_back(str);}

}; 

3. Csmtp 类的实现

#include "Csmtp.h"
//#include <afx.h>//异常类
static const char base64Char[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
char* base64Encode(char const* origSigned, unsigned origLength)
{
 unsigned char const* orig = (unsigned char const*)origSigned; // in case any input bytes have the MSB set
 if (orig == NULL) return NULL; 

 unsigned const numOrig24BitValues = origLength / 3;
 bool havePadding = origLength > numOrig24BitValues * 3;
 bool havePadding2 = origLength == numOrig24BitValues * 3 + 2;
 unsigned const numResultBytes = 4 * (numOrig24BitValues + havePadding);
 char* result = new char[numResultBytes + 3]; // allow for trailing '/0' 

 // Map each full group of 3 input bytes into 4 output base-64 characters:
 unsigned i;
 for (i = 0; i < numOrig24BitValues; ++i)
 {
  result[4 * i + 0] = base64Char[(orig[3 * i] >> 2) & 0x3F];
  result[4 * i + 1] = base64Char[(((orig[3 * i] & 0x3) << 4) | (orig[3 * i + 1] >> 4)) & 0x3F];
  result[4 * i + 2] = base64Char[((orig[3 * i + 1] << 2) | (orig[3 * i + 2] >> 6)) & 0x3F];
  result[4 * i + 3] = base64Char[orig[3 * i + 2] & 0x3F];
 } 

 // Now, take padding into account. (Note: i == numOrig24BitValues)
 if (havePadding)
 {
  result[4 * i + 0] = base64Char[(orig[3 * i] >> 2) & 0x3F];
  if (havePadding2)
  {
   result[4 * i + 1] = base64Char[(((orig[3 * i] & 0x3) << 4) | (orig[3 * i + 1] >> 4)) & 0x3F];
   result[4 * i + 2] = base64Char[(orig[3 * i + 1] << 2) & 0x3F];
  }
  else
  {
   result[4 * i + 1] = base64Char[((orig[3 * i] & 0x3) << 4) & 0x3F];
   result[4 * i + 2] = '=';
  }
  result[4 * i + 3] = '=';
 } 

 result[numResultBytes] = '\0';
 return result;
} 

int Csmtp::SendAttachment(SOCKET &sockClient) /*发送附件*/
{
 for (std::vector<string>::iterator iter = filename.begin();iter != filename.end(); iter++)
 {
  cout << "Attachment is sending··· " << endl; 

  string path=*iter;
  ifstream ifs(path, ios::in | ios::binary); //'或链接2个属性，以输入、二进制打开'
  if (false == ifs.is_open())
  {
   cout<<"无法打开文件！"<<endl;
   return 1;
  } 

  string sendstring;
  sendstring = "--@boundary@\r\nContent-Type: application/octet-stream; name=\"1.jpg\"\r\n";
  sendstring += "Content-Disposition: attachment; filename=\"1.jpg\"\r\n";
  sendstring += "Content-Transfer-Encoding: base64\r\n\r\n";
  send(sockClient, sendstring.c_str(), sendstring.length(), 0); 

  //infile.read((char*)buffer,sizeof(数据类型));

  // get length of file:
  ifs.seekg (0, ifs.end);
  int length = ifs.tellg();
  ifs.seekg (0, ifs.beg);
  cout<<"length:"<<length<<endl;
  // allocate memory:
  char * buffer = new char [length];
  // read data as a block:
  ifs.read (buffer,length);
  ifs.close();
  char *pbase;
  pbase = base64Encode(buffer, length);
  delete[]buffer;
  string str(pbase);
  delete[]pbase;
  str+="\r\n";
  int err =send(sockClient, str.c_str(), strlen(str.c_str()), 0); 

  if (err != strlen(str.c_str()))
  {
   cout << "文件传送出错!" << endl;
   return 1;
  }
 }
 return 0;
} 

bool Csmtp::CReateSocket()
{
 WSADATA wsaData;
 WORD wVersionRequested = MAKEWORD(2, 1);
 //WSAStarup，即WSA(Windows SocKNDs Asynchronous，Windows套接字异步)的启动命令
 int err = WSAStartup(wVersionRequested, &wsaData);
 cout<<"WSAStartup(0:successful):"<<err<<endl;

 char namebuf[128]; //获得本地计算机名
 string ip_list;
 if(0==gethostname(namebuf,128))
 {
  struct hostent* pHost; //获得本地IP地址
  pHost=gethostbyname(namebuf); //pHost返回的是指向主机的列表
  for (int i=0;pHost!=NULL&&pHost->h_addr_list[i]!=NULL;i++)
  {
   string tem = inet_ntoa(*(struct in_addr *)pHost->h_addr_list[i]);
   ip_list += tem;
   ip_list += "\n";
  }
 }
 else
 {
  cout<<"获取主机信息失败..."<<endl ;
 }
 //////////////////////////////////////////////////////////////////////////
 title=namebuf;// 邮件标题
 content=ip_list; //主机ip

 sockClient = socket(AF_INET, SOCK_STREAM, 0); //建立socket对象 

 pHostent = gethostbyname(domain.c_str()); //得到有关于域名的信息

 if (pHostent == NULL)
 {
  printf( "创建连接失败，也许没联网！\n" );
  return false;
 }

 return true;
}

int Csmtp::SendMail()
{
 char *ecode;

 char buff[500]; //recv函数返回的结果
 int err = 0;
 string message; //

 SOCKADDR_IN addrServer; //服务端地址
 addrServer.sin_addr.S_un.S_addr = *((DWORD *)pHostent->h_addr_list[0]); //得到smtp服务器的网络字节序的ip地址  

 addrServer.sin_family = AF_INET;
 addrServer.sin_port = htons(port); //连接端口25
 //int connect (SOCKET s , const struct sockaddr FAR *name , int namelen );
 err = connect(sockClient, (SOCKADDR*)&addrServer, sizeof(SOCKADDR)); //向服务器发送请求
 cout<<"connect:"<<err<<endl;
 //telnet smtp.126.com 25 连接服务器结束
 buff[recv(sockClient, buff, 500, 0)]='\0';
 //cout<<"connect:"<<buff<<endl;

 message="ehlo 126.com\r\n";
 send(sockClient, message.c_str(), message.length(), 0); 

 buff[recv(sockClient, buff, 500, 0)]='\0';
 //cout<<"helo:"<<buff<<endl;

 message="auth login \r\n";
 send(sockClient, message.c_str(), message.length(), 0);
 buff[recv(sockClient, buff, 500, 0)]='\0';
 //cout<<"auth login:"<<buff<<endl;
 //上传邮箱名
 message=user;
 ecode = base64Encode(message.c_str(), strlen(message.c_str()));
 message = ecode;
 message += "\r\n";
 delete[]ecode;
 send(sockClient, message.c_str(), message.length(), 0);
 buff[recv(sockClient, buff, 500, 0)]='\0';
 //cout<<"usrname:"<<buff<<endl;
 //上传邮箱密码
 message=pass;
 ecode = base64Encode(message.c_str(), strlen(message.c_str()));
 message = ecode;
 delete[]ecode;
 message += "\r\n";
 send(sockClient, message.c_str(), message.length(), 0);
 buff[recv(sockClient, buff, 500, 0)]='\0';
 //cout<<"password:"<<buff<<endl;

 message="mail from:<"+user+">\r\nrcpt to:<"+target+">\r\n";
 send(sockClient, message.c_str(), message.length(), 0);
 buff[recv(sockClient, buff, 500, 0)]='\0';
 //cout<<"mail from: "<<buff<<endl;
 buff[recv(sockClient, buff, 500, 0)]='\0';
 //cout<<"rcpt to: "<<buff<<endl;

 message="data\r\n";//data要单独发送一次
 send(sockClient, message.c_str(), message.length(), 0);
 buff[recv(sockClient, buff, 500, 0)]='\0';
 //cout<<"data: "<<buff<<endl;
 ///-----------------------------------------DATA-------------------------------------
 //要使用Csmtp 发送附件, 需要对Csmtp 头信息进行说明, 改变Content-type 及为每一段正文添加BOUNDARY 名,
 cout<<"-------------------DATA------------------------"<<endl;
 // 头
 message="from:"+user+"\r\nto:"+target+"\r\nsubject:"+title+"\r\n";
 message += "MIME-Version: 1.0\r\n";
 message += "Content-Type: multipart/mixed;boundary=@boundary@\r\n\r\n";
 send(sockClient, message.c_str(), message.length(), 0); 

 // 正文
 message = "--@boundary@\r\nContent-Type: text/plain;charset=\"gb2312\"\r\n\r\n"+content+"\r\n\r\n";
 send(sockClient, message.c_str(), message.length(), 0); 

 //------------------------------------------------------------------------------------------------
 // 发送附件

 SendAttachment(sockClient);

 /*发送结尾信息*/
  message = "--@boundary@--\r\n.\r\n";
 send(sockClient, message.c_str(), message.length(), 0);
 buff[recv(sockClient, buff, 500, 0)]='\0';
 //cout<<"end_qwertyuiop:"<<buff<<endl;

 message="QUIT\r\n";
 send(sockClient, message.c_str(), message.length(), 0);
 buff[recv(sockClient, buff, 500, 0)]='\0';
 cout<<"Send mail is finish:"<<buff<<endl;
 return 0;
}

容易理解的简化版可以点击->这里

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