Decoding your arguments

When the server sends you a query string, it encodes them in URL format. This means:

spaces are changed into '+'
Special characters are encoded by %xx, where xx is the hexadecimal number of their ASCII equivalent

What we provide

NCSA has written C functions to do this for you. Hopefully, you can translate these into whatever shell or interpreter language you are using.

void plustospace(char *str)
{
    register int x;

    for(x = 0; str[x]; x++) 
        if(str[x] == '+')
            str[x] = ' ';
}

void unescape_url(char *url) 
{
    register int x, y;

    for(x=0, y=0; url[y]; ++x, ++y) 
    {
        if((url[x] = url[y]) == '%') 
        {
            url[x] = x2c(&url[y+1]);
            y+=2;
        }
    }
    url[x] = '\0';
}

char x2c(char *what) 
{
    register char digit;

    digit = ((what[0] >= 'A') ? ((what[0] & 0xdf) - 'A')+10 : (what[0] - '0'));
    digit *= 16;
    digit += (what[1] >= 'A' ? ((what[1] & 0xdf) - 'A')+10 : (what[1] - '0'));
    return(digit);
}

Move on to output headers

Return to GET script overview

Robert B. Denny <rdenny@netcom.com>