CHttpFile::QueryInfo的BUG

来源：互联网发布：淘宝店铺开店资料编辑：程序博客网时间：2024/06/18 14:01

MFC对WinINet封装时的BUG，导致无法完整查到的协议头中的字段。懒得上报，谁有空了帮我报告，感谢。

以下是代码：（注意特别注释部分）

BOOL CHttpFile::QueryInfo(DWORD dwInfoLevel, CString& str,LPDWORD lpdwIndex) const{ASSERT(dwInfoLevel <= HTTP_QUERY_MAX);ASSERT_VALID(this);ASSERT(m_hFile != NULL);BOOL bRet;DWORD dwLen = 0;// ask for nothing to see how long the return really isstr.Empty();if (HttpQueryInfo(m_hFile, dwInfoLevel, NULL, &dwLen, 0/* 这里应该传入 lpdwIndex，而非0*/))bRet = TRUE;else{// now that we know how long it is, ask for exactly that much// space and really request the header from the APILPTSTR pstr = str.GetBufferSetLength(dwLen / sizeof(TCHAR));bRet = HttpQueryInfo(m_hFile, dwInfoLevel, pstr, &dwLen, lpdwIndex);if (bRet)str.ReleaseBuffer(dwLen / sizeof(TCHAR));elsestr.ReleaseBuffer(0);}return bRet;}

如何重现：

用以下串作为HTTP请求头：

GET https://www.baidu.com/ HTTP/1.1

Accept-Encoding: gzip; q=1.0

Accept-Encoding: defalte;q=0.5

Host: www.baidu.com

然后调用 CHttpFile::QueryInfo（假设 p指向一个有效的CHttpFile对象）：

CString s;DWORD dwIndex = 0;while( p->QueryInfo( s, &dwIndex ) )TRACE( _T("%s\n"), (LPCTSTR)s );

你会发现只输出了 gzip; q=1.0 ，而第2个Accept-encoding 的 defalte;q=0.5没有输出。

因为CHttpFile::QueryInfo函数里第一次调用HttpQueryInfo时没有指示要获取第几个名称相同的属性，哇啦哇啦一大堆，原因看MSDN吧：

https://msdn.microsoft.com/en-us/library/aa384238(VS.85).aspx

以下是改正后的代码：

BOOL CHttpFile::QueryInfo(DWORD dwInfoLevel, CString& str,LPDWORD lpdwIndex) const{ASSERT(dwInfoLevel <= HTTP_QUERY_MAX);ASSERT_VALID(this);ASSERT(m_hFile != NULL);BOOL bRet;DWORD dwLen = 0;// ask for nothing to see how long the return really isstr.Empty();if( HttpQueryInfo( m_hFile, dwInfoLevel, NULL, &dwLen, lpdwIndex/*改正*/) )bRet = TRUE;else{// now that we know how long it is, ask for exactly that much// space and really request the header from the APILPTSTR pstr = str.GetBufferSetLength(dwLen / sizeof(TCHAR));bRet = HttpQueryInfo(m_hFile, dwInfoLevel, pstr, &dwLen, lpdwIndex);if (bRet)str.ReleaseBuffer(dwLen / sizeof(TCHAR));elsestr.ReleaseBuffer(0);}return bRet;}

阅读全文

0 0