Fetching Data with winapi - winapi

Question

I've found on google this code and adapted somewhat. As far as that goes without problems. However, I have much in the output file at the very beginning of a blank line to. I do not know how I can get off this.
I try to get data from a php.
$echo "hello file";
And the C++
int main()
{
HINTERNET connect = InternetOpen("MyBrowser",0 ,0, 0, 0);
if(!connect){
cout<<"Connection Failed or Syntax error";
return 0;
}
HINTERNET OpenAddress = InternetOpenUrl(connect, http://www.myurl.com/winapi.php", 0, 0, 0, 0);
if ( !OpenAddress )
{
DWORD ErrorNum = GetLastError();
cout<<"Failed to open URL \nError No: "<<ErrorNum;
InternetCloseHandle(connect);
return 0;
}
char DataReceived[4096];
DWORD NumberOfBytesRead = 0;
ofstream data;
data.open("output.txt");
while(InternetReadFile(OpenAddress, DataReceived, 4096,
&NumberOfBytesRead) && NumberOfBytesRead) {
DataReceived[NumberOfBytesRead]='\x00';
data<< DataReceived;
}
system( "pause" );
}
In the file at the beginning of a blank line is too much. How do I remove them?

Answer 1

You have a buffer overflow if InternetReadFile() actually reads 4096 bytes. You do not need to null-terminate the buffer, just write the buffer as-is up to the number of bytes actually read by using the write() method instead of the << operator:
int main()
{
HINTERNET connect = InternetOpen("MyBrowser",0 ,0, 0, 0);
if (!connect)
{
cout << "Connection Failed or Syntax error";
return 0;
}
HINTERNET OpenAddress = InternetOpenUrl(connect, "http://www.myurl.com/winapi.php", 0, 0, 0, 0);
if (!OpenAddress)
{
DWORD ErrorNum = GetLastError();
cout << "Failed to open URL" << endl << " Error No: " << ErrorNum;
InternetCloseHandle(connect);
return 0;
}
ofstream data("output.txt");
if (!data)
{
cout << "Failed to open txt file";
InternetCloseHandle(OpenAddress);
InternetCloseHandle(connect);
return 0;
}
char DataReceived[4096];
DWORD NumberOfBytesRead = 0;
do
{
if (!InternetReadFile(OpenAddress, DataReceived, 4096, &NumberOfBytesRead))
{
DWORD ErrorNum = GetLastError();
cout << "Failed to read from URL" << endl << " Error No: " << ErrorNum;
InternetCloseHandle(OpenAddress);
InternetCloseHandle(connect);
return 0;
}
if (NumberOfBytesRead == 0)
break;
data.write(DataReceived, NumberOfBytesRead);
}
while (true);
cout << "Finished reading from URL";
system( "pause" );
return 0;
}
With that said, if you are still seeing the extra line appear in the file, then use a packet sniffer to check the data actually being transmitted by PHP and make sure it is not sending an extra blank line to begin with. If it is, then you need to address the issue on the PHP side, not the client side.