Returning Content-Type from a filename

Our server code uses a series of if statements to determine the proper media type based only on the requested file's extension. This isn't a perfect solution, but it is a common one, and it works for our purposes.

The code to determine a file's media type is as follows:

/*web_server.c except*/

const char *get_content_type(const char* path) {
    const char *last_dot = strrchr(path, '.');
    if (last_dot) {
        if (strcmp(last_dot, ".css") == 0) return "text/css";
        if (strcmp(last_dot, ".csv") == 0) return "text/csv";
        if (strcmp(last_dot, ".gif") == 0) return "image/gif";
        if (strcmp(last_dot, ".htm") == 0) return "text/html";
        if (strcmp(last_dot, ".html") == 0) return "text/html";
        if (strcmp(last_dot, ".ico") == 0) return "image/x-icon";
        if (strcmp(last_dot, ".jpeg") == 0) return "image/jpeg";
        if (strcmp(last_dot, ".jpg") == 0) return "image/jpeg";
        if (strcmp(last_dot, ".js") == 0) return "application/javascript";
        if (strcmp(last_dot, ".json") == 0) return "application/json";
        if (strcmp(last_dot, ".png") == 0) return "image/png";
        if (strcmp(last_dot, ".pdf") == 0) return "application/pdf";
        if (strcmp(last_dot, ".svg") == 0) return "image/svg+xml";
        if (strcmp(last_dot, ".txt") == 0) return "text/plain";
    }

    return "application/octet-stream";
}

The get_content_type() function works by matching the filename extension to a list of known extensions. This is done by using the strrchr() function to find the last dot (.) in the filename. If a dot is found, then strcmp() is used to check for a match on each extension. When a match is found, the proper media type is returned. Otherwise, the default of application/octet-stream is returned instead.

Let's continue building helper functions for our server.