Apache: The Definitive Guide, Second Edition

Appendix B. The echo Program

The following listing is echo.c :

#include <stdio.h>
#include <stdlib.h>
#define MAX_ENTRIES 10000
typedef struct
    {
    char *name;
    char *val;
    } entry;
char *makeword(char *line, char stop);
char *fmakeword(FILE *f, char stop, int *len);
char x2c(char *what);
void unescape_url(char *url);
void plustospace(char *str);
int main(int argc, char *argv[])
    {
    entry entries[MAX_ENTRIES];
    register int x,m=0;
    int cl;
    char mbuf[200];
    printf("Content-type: text/html\n\n");
    if(strcmp(getenv("REQUEST_METHOD"),"POST"))
        {
        printf("This script should be referenced with a METHOD of POST.\n");
        exit(1);
        }
    if(strcmp(getenv("CONTENT_TYPE"),"application/x-www-form-urlencoded")) 
        {
        printf("This script can only be used to decode form results. \n");
        exit(1);
        }
    cl = atoi(getenv("CONTENT_LENGTH"));
// Returns the length of data to come.
    for(x=0;cl && (!feof(stdin));x++) 
        {
        m=x;
        entries[x].val = fmakeword(stdin,'&',&cl);
        plustospace(entries[x].val);
        unescape_url(entries[x].val);
        entries[x].name = makeword(entries[x].val,'=');
        }
//Reads in the data, breaking at the "&" symbols
    printf("<H1>Query Results</H1>"); 
//Sends the top of the return HTML document.
    printf("You submitted the following name/value pairs:<p>%c",10);
    printf("<ul>%c",10);
    for(x=0; x <= m; x++)
        printf("<li> <code>%s = %s</code>%c",entries[x].name,
               entries[x].val,10);
//Lists the fields in the original form with the values filled in by 
//the customer.
    printf("</ul>%c",10);
}

This listing is the helper program echo2.c