np_pizza.c

this gives details of the network programming

/* COOKIE version of CGI program that handles multiple forms */
/* Uses a cookie to keep user name and password on the client */
/* CGI program that handles multiple forms */
/* Each for includes a hidden field that specifies the name of the form */

#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <time.h>
#include <stdlib.h>
#include <ctype.h>

#include "cgilib.h"	/* simple CGI request parsing routines */
#include "cookies.h"    /* some stuff for handling cookies */

/* print HTML error message and exit */

void fatal_error( char *s) {
  printf("\n\n<H1 ALIGN=CENTER><FONT COLOR=RED>\n");
  printf("%s</FONT></H1>\n",s);
  exit(1);
}


/* Here is a routine that simply prints the contents of a file 
   This is used so we can save most of the HTML we need to generate 
   in files, so we can change the appearance of the pizza system
   without recompiling */

void sendfile( char *filename ) {
  FILE *f;
  char buf[1000];
  
  if ( (f=fopen(filename,"r")) == NULL) {
    fatal_error("can't find a file");
  }

  while (fgets(buf,1000,f)) {
    printf("%s",buf);
  }
  fclose(f);
}





#define MAXFIELDS 10 	/* Max number of fields we will handle */


/* see if a string contains any nonblank chars */
int empty( char *s) {
  return(strlen(s)==strspn( s, " \t\n"));
}


/* Some file names */

char *logo = "logo";	         /* the file containing the pizza logo */
char *login = "loginform.tmpl";  /* the file with the login form */
char *order = "orderform.tmpl";  /* most of the order form */
char *baduser = "baduser";       /* Nasty bad user message */
char *nicetry = "nicetry";       /* another bad user message */


char *pwfile="passwords";

/* The passwords file now includes name, password and cookie
   (each on a seperate line) for each valid user.
*/

int validate_user(char *name, char *password, char *cookie) {
  FILE *pw;
  char u[100],p[100], c[100];

  if ((empty(name)) || (empty(password)))
      return(0);

  if ( (pw=fopen(pwfile,"r"))==NULL)
    fatal_error("Sorry we lost our password file");

  while (!feof(pw)) {
    /* read a username and password from the database */
    if (!fgets(u,100,pw)) { fclose(pw); return(0); }
    if (!fgets(p,100,pw)) { fclose(pw); return(0); }
    if (!fgets(c,100,pw)) { fclose(pw); return(0); }

    /* Eliminate trailing whitespace */
    while (isspace((int)u[strlen(u)-1]))
      u[strlen(u)-1]=0;

    while (isspace((int)p[strlen(p)-1]))
      p[strlen(p)-1]=0;

    while (isspace((int)c[strlen(c)-1]))
      c[strlen(c)-1]=0;

    /* see if we got a match */
    if ( (strcmp(u,name)==0) && (strcmp(p,password)==0) ) {
      strcpy(cookie,c);
      fclose(pw);
      return(1);	/* we found it! */
    }
  }
  fclose(pw);
  return(0);
}

/* get the user name and password corresponding to a cookie */

int user_lookup(char *name, char *password, char *cookie) {
  FILE *pw;
  char u[100],p[100], c[100];

  if ((cookie==NULL) || (strlen(cookie)==0))
    return(0);

  if ( (pw=fopen(pwfile,"r"))==NULL)
    fatal_error("Sorry we lost our password file");

  while (!feof(pw)) {
    /* read a username and password from the database */
    if (!fgets(u,100,pw)) { fclose(pw); return(0); }
    if (!fgets(p,100,pw)) { fclose(pw); return(0); }
    if (!fgets(c,100,pw)) { fclose(pw); return(0); }

    /* Eliminate trailing whitespace */
    while (isspace((int)u[strlen(u)-1]))
      u[strlen(u)-1]=0;

    while (isspace((int)p[strlen(p)-1]))
      p[strlen(p)-1]=0;

    while (isspace((int)c[strlen(c)-1]))
      c[strlen(c)-1]=0;

    /* see if we got a match */
    if (strcmp(c,cookie)==0) {
      strcpy(name,u);
      strcpy(password,p);
      fclose(pw);
      return(1);	/* we found it! */
    }
  }
  fclose(pw);
  return(0);
}
 

void handle_login( char **names, char **vals, int n) {
  char *name;
  char *password;
  char cookie[100];
  int i;

  /* find the name and password entered */
  name=password=NULL;

  for (i=0;i<n;i++) {
    if (strcasecmp(names[i],"name")==0) {
      name = vals[i];
    } else if (strcasecmp(names[i],"password")==0) {
      password = vals[i];
    }
  }

  /* validate the user name and password here */
  if (!validate_user(name,password,cookie)) {
    printf("\n");
    sendfile(logo);
    sendfile(baduser);
    sendfile(login);
    return;
  }
    

  /* Set the cookie so this user doesn't need to log in again */
  printf("Set-cookie: NPPIZZA=%s;\n\n",cookie);

  sendfile(logo);

  /* Valid username and password - we need to send back the
     order form. We need to insert some hidden fields in the
     order form so when we get it we know who it's for!

     Most of the order form is in the file order, we need to
     take care of the form declaration and the hidden fields
     first
  */
  printf("<H2 ALIGN=CENTER>Hello ");
  printf("<FONT COLOR=BLUE>%s</FONT>, place your order</H2>\n",name);
  printf("<FORM METHOD=POST ACTION=np_pizza.cgi>\n");
  printf("<INPUT TYPE=HIDDEN NAME=name VALUE=\"%s\">\n",name);
  printf("<INPUT TYPE=HIDDEN NAME=password VALUE=\"%s\">\n",password);

  /* the rest of the form is in a file */
  sendfile(order);

}

char *validpizzas[] = { "Cheese", "Veggie", "Pepperoni", "Sausage" };
int n_validpizzas = sizeof(validpizzas)/sizeof(char *);

int validate_pizza(char *p) {
  int i;

  if ((p==NULL) || (empty(p)))
    return(0);

  for (i=0;i<n_validpizzas;i++) {
    if (strcmp(validpizzas[i],p)==0) 
      return(1);
  }
  return(0);
}

char *validsizes[] = { "large", "medium", "small" };
int n_validsizes = sizeof(validsizes)/sizeof(char *);

int validate_size(char *p) {
  int i;

  if ((p==NULL) || (empty(p)))
    return(0);

  for (i=0;i<n_validsizes;i++) {
    if (strcmp(validsizes[i],p)==0) 
      return(1);
  }
  return(0);
}


void handle_order(char **names,char **vals, int n) {
  char *name;
  char *password;
  char *pizza;
  char *size;
  char cookie[100];
  int i;
  struct tm *timerec;
  time_t t;

  /* get the current time and date */

  t = time(NULL);
  timerec = localtime( &t );

  printf("\n");
  sendfile(logo);

  /* find the name and password entered */
  name=password=pizza=size=NULL;

  for (i=0;i<n;i++) {
    if (strcasecmp(names[i],"name")==0) {
      name = vals[i];
    } else if (strcasecmp(names[i],"password")==0) {
      password = vals[i];
    } else if (strcasecmp(names[i],"pizza")==0) {
      pizza = vals[i];
    } else if (strcasecmp(names[i],"size")==0) {
      size = vals[i];
    }
  }

  /* validate the user name and password here */
  if (!validate_user(name,password,cookie)) {
    sendfile(nicetry);
    sendfile(baduser);
    sendfile(login);
    return;
  }


  /* Make sure the pizza is valid */
  if (! validate_pizza(pizza)) {
    sendfile(nicetry);
    printf("<H3 ALIGN=CENTER><FONT COLOR=BLUE>\n");
    printf("Your pizza selection is invalid! (%s)\n",pizza);
    printf("<H2 ALIGN=CENTER>Hello ");
    printf("<FONT COLOR=BLUE>%s</FONT>, place your order</H2>\n",name);
    printf("<FORM METHOD=POST ACTION=np_pizza.cgi>\n");
    printf("<INPUT TYPE=HIDDEN NAME=name VALUE=\"%s\">\n",name);
    printf("<INPUT TYPE=HIDDEN NAME=password VALUE=\"%s\">\n",password);
    sendfile(order);
    return;
  }

  /* Make sure the size is valid */
  if (! validate_size(size)) {
    sendfile(nicetry);
    printf("<H3 ALIGN=CENTER><FONT COLOR=BLUE>\n");
    printf("Your size selection is invalid! (%s)\n",size);
    printf("<H2 ALIGN=CENTER>Hello ");
    printf("<FONT COLOR=BLUE>%s</FONT>, place your order</H2>\n",name);
    printf("<FORM METHOD=POST ACTION=np_pizza.cgi>\n");
    printf("<INPUT TYPE=HIDDEN NAME=name VALUE=\"%s\">\n",name);
    printf("<INPUT TYPE=HIDDEN NAME=password VALUE=\"%s\">\n",password);
    sendfile(order);
    return;
  }

  /* Valid order - send back a receipt */

  printf("<H2 ALIGN=CENTER>Thanks for your order %s</H2><P>\n",name);



  printf("<TABLE BORDER=0><TR>\n");
  printf("<TR><TH COLSPAN=2 ALIGN=CENTER>RECEIPT</TH></TR>\n");
  printf("<TR><TH ALIGN=RIGHT>Name:</TH><TD>%s</TD></TR>\n",name);

  printf("<TR><TH ALIGN=RIGHT>Date:</TH>");
  printf("<TD>%d/%d/%d</TD></TR>\n",
	    timerec->tm_mon+1,timerec->tm_mday,timerec->tm_year+1900);

  printf("<TR><TH ALIGN=RIGHT>Time:</TH>");
  printf("<TD>%d:%d</TD></TR>\n",
	    timerec->tm_hour,timerec->tm_min);

  printf("<TR><TH ALIGN=RIGHT>Pizza:</TH><TD>%s</TD></TR>\n",pizza);
  printf("<TR><TH ALIGN=RIGHT>Size:</TH><TD>%s</TD></TR>\n",size);
  printf("<TH>Time Ready:</TH>");
  printf("<TD>%d:%d</TD></TR>\n",
	    timerec->tm_hour+1,timerec->tm_min);
  printf("<TR><TH ALIGN=RIGHT>Amount Due:</TH>");
  if (strcmp(size,"small")==0)
      printf("<TD>$6.50</TD></TR>\n");
  else if (strcmp(size,"medium")==0)
      printf("<TD>$8.50</TD></TR>\n");
  else
      printf("<TD>$10.50</TD></TR>\n");
  printf("</TABLE>\n");
}


/* Cookie version of the pizza server (perhaps this should
   be a cookie server instead?) 
*/

int main() {

  char *query;
  char *names[MAXFIELDS];	/* form field names */
  char *vals[MAXFIELDS];	/* form field values */
  char *form;
  char *cnames[MAXFIELDS];	/* cookie names */
  char *cvals[MAXFIELDS];	/* cookie values */
  char *cookie;

  char name[100],password[100];
  int i,n,n_cookies;

  /* always tell the browser what kind of document we are sending */
  /* NOTE: the web server that started the CGI program will send
     back the appropriate HTTP header !!! */

  printf("Content-type: text/html\n");

  /* Can't send any content yet, since we might want to send a
     cookie header (to set a cookie on the client). 
  */

  /* get the query */
  query = get_request();

  /* get all the cookies that came with the request */
  n_cookies=get_cookies(cnames, cvals, MAXFIELDS);

  /* find the cookie we are interested in */
  cookie = cookie_lookup(cnames,cvals,n_cookies,"NPPIZZA");


  if ((query==NULL)||(strlen(query)==0)) {

    /* we got nothing - see if we got a cookie that identifies the user */
    if (user_lookup(name,password,cookie)) {
      /* we found a cookie that identifies the user
	 send back an order form 
	 I'm lasy - I just create a names,vals array as if the user
	 just sent us a login request (so I don't have to write
	 a function to handle cookie logins 
      */
      names[0]="name";
      vals[0]=name;
      names[1]="password";
      vals[1]=password;
      handle_login(names,vals,2);
    } else {
      /* null query and no valid cookie - need to send a login form */
      printf("\n");
      sendfile(logo);
      sendfile(login);
    }
  } else {
    /* we got a query, for now just figure out which form we 
       are handling */

    /* parse the request string and chop into fields */
    n = split_and_parse(query,names,vals,MAXFIELDS);

    form=NULL;

    for (i=0;i<n;i++) {
      if (strcasecmp(names[i],"formname")==0) {
	form = vals[i];
	break;
      }
    }

    if (form==NULL) {
      /* We did not get a formname - this request is invalid! */
      fatal_error("ERROR - Invalid request");
    }

    /* now figure out which form and call the appropriate routine */
    if (strcmp("login",form)==0) {
      /* handling the login form */
      handle_login(names,vals,n);
    } else if (strcmp("order",form)==0) {
      /* handling the order form */
      handle_order(names,vals,n);
    } else {
      /* something is wrong - invalid form name */
      fatal_error("ERROR - Invalid request");
    }
  }
  return(0);
}