ios怎样使用multipart from方式上传网络数据

在网络编程过程中需要向服务器上传文件。Multipart/form-data是上传文件的一种方式。

Multipart/form-data其实就是浏览器用表单上传文件的方式。最常见的情境是：在写邮件时，向邮件后添加附件，附件通常使用表单添培罩加，态孝也就是用multipart/form-data格式上传到服务器。

表单形式上传附件

具体的步骤是怎样的呢？

首先，客户端和服务器建立连接（TCP协议）。

第二，客户端可以向服务器端发送数据。因为上传文件实质上也是向服务器端发送请求。

第三，客户端按照符合“multipart/form-data”的格式向服务器端发送数帆中稿据。

Multipart/form-data的格式是怎样的呢？

既然Multipart/form-data格式就是浏览器用表单提交数据的格式，我们就来看看文件经过浏览器编码后是什么样子。

//---------------------------------------

// this is the demo code of using multipart/form-data to upload text and

photos.

// -use WinInet APIs.

//

//

// connection handlers.

//

HRESULT hr

HINTERNET m_hOpen

HINTERNET m_hConnect

HINTERNET m_hRequest

//

// make connection.

//

...

//

// form the content.

//

std::wstring strBoundary = std::wstring(L"------------------")

std::wstring wstrHeader(L"Content-Type: multipart/form-data, boundary=")

wstrHeader += strBoundary

HttpAddRequestHeaders(m_hRequest, wstrHeader.c_str(),

DWORD(wstrHeader.size()), HTTP_ADDREQ_FLAG_ADD)

//

// "std::wstring strPhotoPath" is the name of photo to upload.

//

//

// uploaded photo form-part begin.

//

std::wstring strMultipartFirst(L"--")

strMultipartFirst += strBoundary

strMultipartFirst += L"\r\nContent-Disposition: form-dataname=\"pic\"

filename="

strMultipartFirst += L"\"" + strPhotoPath + L"\""

strMultipartFirst += L"\r\nContent-Type: image/jpeg\r\n\r\n"

//

// "std::wstring strTextContent" is the text to uploaded.

//

//

// uploaded text form-part begin.

//

std::wstring strMultipartInter(L"\r\n--")

strMultipartInter += strBoundary

strMultipartInter += L"\r\nContent-Disposition: form-data

name=\"status\"\r\n\r\n"

std::wstring

wstrPostDataUrlEncode(CEncodeTool::Encode_Url(strTextContent))

// add text content to send.

strMultipartInter += wstrPostDataUrlEncode

std::wstring strMultipartEnd(L"\r\n--")

strMultipartEnd += strBoundary

strMultipartEnd += L"--\r\n"

//

// open photo file.

//

// ws2s(std::wstring)

// -transform "strPhotopath" from unicode to ansi.

std::ifstream *pstdofsPicInput = new std::ifstream

pstdofsPicInput->open((ws2s(strPhotoPath)).c_str(),

std::ios::binary|std::ios::in)

pstdofsPicInput->seekg(0, std::ios::end)

int nFileSize = pstdofsPicInput->tellg()

if(nPicFileLen == 0)

{

return E_ACCESSDENIED

}

char *pchPicFileBuf = NULL

try

{

pchPicFileBuf = new char[nPicFileLen]

}

catch(std::bad_alloc)

{

hr = E_FAIL

}

if(FAILED(hr))

{

return hr

}

pstdofsPicInput->seekg(0, std::ios::beg)

pstdofsPicInput->read(pchPicFileBuf, nPicFileLen)

if(pstdofsPicInput->bad())

{

pstdofsPicInput->close()

hr = E_FAIL

}

delete pstdofsPicInput

if(FAILED(hr))

{

return hr

}

// Calculate the length of data to send.

std::string straMultipartFirst = CEncodeTool::ws2s(strMultipartFirst)

std::string straMultipartInter = CEncodeTool::ws2s(strMultipartInter)

std::string straMultipartEnd = CEncodeTool::ws2s(strMultipartEnd)

int cSendBufLen = straMultipartFirst.size() + nPicFileLen +

straMultipartInter.size() + straMultipartEnd.size()

// Allocate the buffer to temporary store the data to send.

PCHAR pchSendBuf = new CHAR[cSendBufLen]

memcpy(pchSendBuf, straMultipartFirst.c_str(),

straMultipartFirst.size())

memcpy(pchSendBuf + straMultipartFirst.size(), (const char *)pchPicFileBuf,

nPicFileLen)

memcpy(pchSendBuf + straMultipartFirst.size() + nPicFileLen,

straMultipartInter.c_str(), straMultipartInter.size())

memcpy(pchSendBuf + straMultipartFirst.size() + nPicFileLen +

straMultipartInter.size(), straMultipartEnd.c_str(),

straMultipartEnd.size())

//

// send the request data.

//

HttpSendRequest(m_hRequest, NULL, 0, (LPVOID)pchSendBuf, cSendBufLen)

建议你每次打开淘宝助理都要先更新下数据，同步下系统

淘宝助理5的版本系统比较不稳定，经常会出现一些无法解辩棚释的系统性问题

所以，一定要用淘宝助理5的版本的话，一定要养成习惯， *** 作几个步骤就更新同步一次

个人推荐使用旧的版本，淘宝助理4，系统会比较稳定一些

有时候用数据包导入的宝贝，每个宝贝都要稍微修改下桥搜，然后点击确定保存下，

每个宝贝都这样 *** 作，就算不修改，只要每个宝贝都点击下保存敏灶历也会提高上传的成功率

希望可以帮到你，望采纳，有其他问题可以继续提问。。。

BOOL InternetWriteFile(

IN HINTERNET hFile,

IN LPCVOID lpBuffer,

IN DWORD dwNumberOfBytesToWrite,

OUT LPDWORD lpdwNumberOfBytesWritten

)

hFile

Valid handle returned from a previous call to FtpOpenFile or an HINTERNET handle sent by HttpSendRequestEx.

lpBuffer

Address of a buffer that contains the data to be written to the file.

dwNumberOfBytesToWrite

Number of bytes to write to the file.

lpdwNumberOfBytesWritten

Address of a variable that receives the number of bytes written to the buffer. InternetWriteFile sets this value to zero before doing any work or error checking.

给个例子：

#include <Windows.h>

#include <WinINet.h>

#include <stdio.h>

BOOL UseHttpSendReqEx(HINTERNET hRequest, DWORD dwPostSize)

#define BUFFSIZE 500

void main( int argc, char **argv )

{

DWORD dwPostSize

if (argc <4)

{

printf("Usage: Bigpost <Size><敏雹庆Server><Path>\n")

printf("<Size>is the number of KB to POST\n")

printf("<Server>is the server to POST to\n")

printf("<Path>is the virtual path to POST to\n")

exit(0)

}

if ( ((dwPostSize = strtoul(argv[1],NULL,10)) == 0) || (dwPostSize >=) )

{

printf("%s is invalid size. Valid sizes are from 1 to 2047999\n",[1])

exit(0)

}

printf( "Test of POSTing %luKB with WinInet\肆昌n", dwPostSize)

dwPostSize *= 1024// Convert KB to bytes

HINTERNET hSession = InternetOpen( "HttpSendRequestEx",,

NULL, NULL, 0)

if(!hSession)

{

printf("Failed to open session\n")

exit(0)

}

HINTERNET hConnect = InternetConnect(hSession, argv[2],,

NULL, NULL, INTERNET_SERVICE_HTTP,NULL, NULL)

if (!hConnect)

printf( "Failed to connect\n"桥握 )

else

{

HINTERNET hRequest = HttpOpenRequest(hConnect, "POST", argv[3],

NULL, NULL, NULL, INTERNET_FLAG_NO_CACHE_WRITE, 0)

if (!hRequest)

printf( "Failed to open request handle\n" )

else

{

if(UseHttpSendReqEx(hRequest, dwPostSize))

{

char pcBuffer[BUFFSIZE]

DWORD dwBytesRead

printf("\nThe following was returned by the server:\n")

do

{dwBytesRead=0

if(InternetReadFile(hRequest, pcBuffer, BUFFSIZE-1,&dwBytesRead))

{

pcBuffer[dwBytesRead]=0x00// Null-terminate buffer

printf("%s", pcBuffer)

}

else

printf("\nInternetReadFile failed")

}while(dwBytesRead>0)

printf("\n")

}

if (!InternetCloseHandle(hRequest))

printf( "Failed to close Request handle\n" )

}

if(!InternetCloseHandle(hConnect))

printf("Failed to close Connect handle\n")

}

if( InternetCloseHandle( hSession ) == FALSE )

printf( "Failed to close Session handle\n" )

printf( "\nFinished.\n" )

}

BOOL UseHttpSendReqEx(HINTERNET hRequest, DWORD dwPostSize)

{

INTERNET_BUFFERS BufferIn

DWORD dwBytesWritten

int n

BYTE pBuffer[1024]

BOOL bRet

BufferIn.dwStructSize = sizeof( INTERNET_BUFFERS )// Must be set or error will occur

BufferIn.Next = NULL

BufferIn.lpcszHeader = NULL

BufferIn.dwHeadersLength = 0

BufferIn.dwHeadersTotal = 0

BufferIn.lpvBuffer = NULL

BufferIn.dwBufferLength = 0

BufferIn.dwBufferTotal = dwPostSize// This is the only member used other than dwStructSize

BufferIn.dwOffsetLow = 0

BufferIn.dwOffsetHigh = 0

if(!HttpSendRequestEx( hRequest, &BufferIn, NULL, 0, 0))

{

printf( "Error on HttpSendRequestEx %d\n",GetLastError() )

return FALSE

}

FillMemory(pBuffer, 1024, 'D')// Fill buffer with data

bRet=TRUE

for(n=1n<=(int)dwPostSize/1024 &&bRetn++)

{

if(bRet=InternetWriteFile( hRequest, pBuffer, 1024, &dwBytesWritten))

printf( "\r%d bytes sent.", n*1024)

}

if(!bRet)

{

printf( "\nError on InternetWriteFile %lu\n",GetLastError() )

return FALSE

}

if(!HttpEndRequest(hRequest, NULL, 0, 0))

{

printf( "Error on HttpEndRequest %lu \n", GetLastError())

return FALSE

}

return TRUE

}

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