MFC之Http POST请求

作者：@渔阳俊俊
本文为作者原创，转载请注明出处：https://www.cnblogs.com/wjq13752525588/p/12188487.html

　　一、建立会话（session）对象

　　CInternetSession mysession；

　　二、连接到HTTP服务器

　　CHttpConnection *mysession=mysession.GetHttpConnection("www.baidu.com");

　　三、打开HTTP请求

　　CHttpFile *myfile = myconn->OpenRequest("GET","/index.html");

　　四、发送HTTP请求

　　myfile->SendRequest();

　　五、从服务器读取字节流(bytes)

　　CString mystr;

　　CString tmp;

　　while(myfile->ReadString(tmp))

　　{

　　　　mystr+=tmp;

　　}

　　六、释放资源

　　myfile->Close();

　　myconn->Close();

　　mysession->Close();

　　delete myfile;

　　delete myconn;

　　myfile=0;

　　myconn=0;

　　步骤基本如上，上列各函数主要使用默认参数，具体函数声明请查阅MSDN。另外别忘了异常处理！

1、下载文件
Download(const CString& strFileURLInServer, //待下载文件的URL
const CString & strFileLocalFullPath)//存放到本地的路径
{
ASSERT(strFileURLInServer != "");
ASSERT(strFileLocalFullPath != "");
CInternetSession session;
CHttpConnection* pHttpConnection = NULL;
CHttpFile* pHttpFile = NULL;
CString strServer, strObject;
INTERNET_PORT wPort;

DWORD dwType;
const int nTimeOut = 2000;
session.SetOption(INTERNET_OPTION_CONNECT_TIMEOUT, nTimeOut); //重试之间的等待延时
session.SetOption(INTERNET_OPTION_CONNECT_RETRIES, 1); //重试次数
char* pszBuffer = NULL;

try
{
  AfxParseURL(strFileURLInServer, dwType, strServer, strObject, wPort);
  pHttpConnection = session.GetHttpConnection(strServer, wPort);
  pHttpFile = pHttpConnection->OpenRequest(CHttpConnection::HTTP_VERB_GET, strObject);
  if(pHttpFile->SendRequest() == FALSE)
   return false;
  DWORD dwStateCode;

  pHttpFile->QueryInfoStatusCode(dwStateCode);
  if(dwStateCode == HTTP_STATUS_OK)
  {
    HANDLE hFile = CreateFile(strFileLocalFullPath, GENERIC_WRITE,
         FILE_SHARE_WRITE, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL,
         NULL);  //创建本地文件
   if(hFile == INVALID_HANDLE_VALUE)
   {
    pHttpFile->Close();
    pHttpConnection->Close();
    session.Close();
    return false;
   }

   char szInfoBuffer[1000];  //返回消息
   DWORD dwFileSize = 0;   //文件长度
   DWORD dwInfoBufferSize = sizeof(szInfoBuffer);
   BOOL bResult = FALSE;
   bResult = pHttpFile->QueryInfo(HTTP_QUERY_CONTENT_LENGTH,
           (void*)szInfoBuffer,&dwInfoBufferSize,NULL);

   dwFileSize = atoi(szInfoBuffer);
   const int BUFFER_LENGTH = 1024 * 10;
   pszBuffer = new char[BUFFER_LENGTH];  //读取文件的缓冲
   DWORD dwWrite, dwTotalWrite;
   dwWrite = dwTotalWrite = 0;
   UINT nRead = pHttpFile->Read(pszBuffer, BUFFER_LENGTH); //读取服务器上数据

   while(nRead> 0)
   {
    WriteFile(hFile, pszBuffer, nRead, &dwWrite, NULL);  //写到本地文件
    dwTotalWrite += dwWrite;
    nRead = pHttpFile->Read(pszBuffer, BUFFER_LENGTH);
   }

   delete[]pszBuffer;
   pszBuffer = NULL;
   CloseHandle(hFile);
  }
  else
  {
   delete[]pszBuffer;
   pszBuffer = NULL;
   if(pHttpFile != NULL)
   {
    pHttpFile->Close();
    delete pHttpFile;
    pHttpFile = NULL;
   }
   if(pHttpConnection != NULL)
   {
    pHttpConnection->Close();
    delete pHttpConnection;
    pHttpConnection = NULL;
   }
   session.Close();
    return false;
  }
}
catch(...)
{
  delete[]pszBuffer;
  pszBuffer = NULL;
  if(pHttpFile != NULL)
  {
   pHttpFile->Close();
   delete pHttpFile;
   pHttpFile = NULL;
  }
  if(pHttpConnection != NULL)
  {
   pHttpConnection->Close();
   delete pHttpConnection;
   pHttpConnection = NULL;
  }
  session.Close();
  return false;
}

if(pHttpFile != NULL)
pHttpFile->Close();
if(pHttpConnection != NULL)
pHttpConnection->Close();
session.Close();
return true;
}

2、上传文件
bool Download(const CString& strFileURLInServer, //待下载文件的URL
const CString & strFileLocalFullPath)//存放到本地的路径
{
ASSERT(strFileURLInServer != "");
ASSERT(strFileLocalFullPath != "");
CInternetSession session;
CHttpConnection* pHttpConnection = NULL;
CHttpFile* pHttpFile = NULL;
CString strServer, strObject;
INTERNET_PORT wPort;
bool bReturn = false;

DWORD dwType;
const int nTimeOut = 2000;
session.SetOption(INTERNET_OPTION_CONNECT_TIMEOUT, nTimeOut); //重试之间的等待延时
session.SetOption(INTERNET_OPTION_CONNECT_RETRIES, 1); //重试次数
char* pszBuffer = NULL;

try
{
AfxParseURL(strFileURLInServer, dwType, strServer, strObject, wPort);
pHttpConnection = session.GetHttpConnection(strServer, wPort);
pHttpFile = pHttpConnection->OpenRequest(CHttpConnection::HTTP_VERB_GET, strObject);
if(pHttpFile->SendRequest() == FALSE)
return false;
DWORD dwStateCode;

pHttpFile->QueryInfoStatusCode(dwStateCode);
if(dwStateCode == HTTP_STATUS_OK)
{
HANDLE hFile = CreateFile(strFileLocalFullPath, GENERIC_WRITE,
FILE_SHARE_WRITE, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL,
NULL); //创建本地文件
if(hFile == INVALID_HANDLE_VALUE)
{
pHttpFile->Close();
pHttpConnection->Close();
session.Close();
return false;
}

char szInfoBuffer[1000]; //返回消息
DWORD dwFileSize = 0; //文件长度
DWORD dwInfoBufferSize = sizeof(szInfoBuffer);
BOOL bResult = FALSE;
bResult = pHttpFile->QueryInfo(HTTP_QUERY_CONTENT_LENGTH,
(void*)szInfoBuffer,&dwInfoBufferSize,NULL);

dwFileSize = atoi(szInfoBuffer);
const int BUFFER_LENGTH = 1024 * 10;
pszBuffer = new char[BUFFER_LENGTH]; //读取文件的缓冲
DWORD dwWrite, dwTotalWrite;
dwWrite = dwTotalWrite = 0;
UINT nRead = pHttpFile->Read(pszBuffer, BUFFER_LENGTH); //读取服务器上数据

while(nRead > 0)
{
WriteFile(hFile, pszBuffer, nRead, &dwWrite, NULL); //写到本地文件
dwTotalWrite += dwWrite;
nRead = pHttpFile->Read(pszBuffer, BUFFER_LENGTH);
}

delete[]pszBuffer;
pszBuffer = NULL;
CloseHandle(hFile);
bReturn = true;
}
}
catch(CInternetException* e)
{
TCHAR tszErrString[256];
e->GetErrorMessage(tszErrString, ArraySize(tszErrString));
TRACE(_T("Download XSL error! URL: %s,Error: %s"), strFileURLInServer, tszErrString);
e->Delete();
}
catch(...)
{
}

if(pszBuffer != NULL)
{
delete[]pszBuffer;
}
if(pHttpFile != NULL)
{
pHttpFile->Close();
delete pHttpFile;
}
if(pHttpConnection != NULL)
{
pHttpConnection->Close();
delete pHttpConnection;
}
session.Close();
return bReturn;
}