CODEWITHSUNDEEP
c++imagesocketswebserver
Emil
Emil

Reputation: 1045

How do I read an image to be sent through a socket?

I am creating a very simple webserver, as practice in C++ and sockets. I use OSX.

The code sample is from inside the while(1) loop, a connection has been made and I am starting to process the header. This code works for all text-files but it dosn't work with images. And I figure that I can't use the same method to read text-files and images since images isn't separeted with lines. But how do I read the image data to send through the socket? I might not even be able to use a string, do I have to use char*?

    string strFile  = "htdocs" + getFileFromHeader(httpRequestHeader);
    string strExt   = getFileExtension(strFile);

    string httpContent = "";
    ifstream fileIn(strFile.c_str(), ios::in); // <-- do I have to use ios::binary ?

    if(!fileIn)
    {
        // 404
        cout << "File could not be opened" << endl;
        httpContent = httpHeader404;
    }
    else
    {
        // 200
        string contentType = getContentType(strExt);
        cout << "Sending " << strFile << " -- " << contentType << endl;
        string textInFile = "";

        while (fileIn.good())
        {
            getline (fileIn, textInFile); // replace with what?
            httpContent = httpContent + textInFile + "\n";
        }

        httpContent = httpHeader200 + newLine + contentType + newLine + newLine + httpContent;
    }
    // Sending httpContent through the socket

The question is about how to read the image data.

*EDIT 2011-05-19 *

So, this is an updated version of my code. The file have been opened with ios::binary, however, there are more problems.

httpContent = httpHeader200 + newLine + contentType + newLine + newLine;
char* fileContents = (char*)httpContent.c_str();
char a[1];
int i = 0;

while(!fileIn.eof())
{
    fileIn.read(a, 1);

    std::size_t len = std::strlen (fileContents);
    char *ret = new char[len + 2];

    std::strcpy ( ret, fileContents );
    ret[len] = a[0];
    ret[len + 1] = '\0';

    fileContents = ret;

    cout << fileContents << endl << endl << endl;

    delete [] ret;

    i++;
}

The problem is that is seems that the char * fileContents empty itself every ~240 chars. How can that be? Is there some sort of limit to some of theese functions that they only accept certain length?

Upvotes: 0

Views: 340

Answers (2)

Hyperboreus
Hyperboreus

Reputation: 126

As @Blackbear said, but don't forget to send the corresponding HTML-Headers like contentEncoding, transferEncoding, etc. For simplicity try to send the binary Data of the image encoded in base64.

Upvotes: 0

BlackBear
BlackBear

Reputation: 22979

Open the file for binary read, store the data in a char* array large enough, then send that array.

Upvotes: 2

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