Perl with FastCGI authorization example

Perl with FastCGI authorization example:

#!/usr/bin/perl

use strict;

use DBI;

use FCGI;

use constant PATH_NEVER  => 0;

use constant PATH_MAYBE  => 1;

use constant PATH_ALWAYS => 2;

# normally, I would abstract this stuff out into a sitewide config module,

# but for didactic reasons, I’ll just define some constants here:

use constant COOKIE_NAME => ‘AUTH_TOKEN’;

use constant DBI_DSN     => ‘dbi:mysql:hostname=DBHOSTNAME;database=DBNAME’;

use constant DBI_USR     => ‘monty’;

use constant DBI_PWD     => ‘widenius’;

use constant AUTH_ERR => -1;

use constant AUTH_NOK =>  0;

use constant AUTH_OK  =>  1;

use constant AUTH_QUERY => <<AQ_SQL;

select count(*) as authorized

from   login_table

where  user  = ?

and    token = ?

and    expiry > unix_timestamp()

AQ_SQL

use vars qw($DBH $STH $N);

sub _init ();

sub _exit ();

sub authorized ($$$);

sub get_login_cookie ();

sub query_decode (;@);

_init();

for ($N = 0; FCGI::accept() >= 0; $N++)

{

    # check the path to see if we want/need to authorize access:

    my $path_auth = check_path($ENV{REQUEST_URI});

    if($path_auth == PATH_MAYBE)

    {

        my $auth = undef();

        my $user;

        my $token;

        my $cookie;

        # get the login cookie and decompose it into user + token:

        # cookie format: USERNAME:OPAQUETOKENFROMDB

        $cookie = get_login_cookie();

        ($user,$token) = split(/:/,$cookie,2);

        # check to see if an unexpired entry exists in the db:

        $auth = authorized($STH, $user, $token);

        if($auth == AUTH_OK)

        {

            # return 200 Ok, and set the AUTH_USER_NAME env variable

            # in case there is a dynamic content generator:

            # variables you want to set for the requested script/page

            # need to be prefixed w. the string ‘Variable-’,

            # or they will be passed back to the client, not the server.

            print(STDOUT “Status: 200 Authorized\r\n”);

            print(STDOUT “Variable-AUTH_USER_NAME: $user\r\n”);

            print(STDOUT “\r\n”);

        }

        elsif($auth == AUTH_NOK)

        {

            # Not authorized.

            # You can make your login page the default

            # 401 page with the htaccess ErrorDocument 401 directive:

            print(STDOUT “Status: 401 Not Authorized\r\n”);

            print(STDOUT “WWW-Authenticate: basic realm=\”foo\”\r\n”);

            print(STDOUT “\r\n”);

        }

        else

        {

            # Waah. Something blew up.

            print(STDOUT “Status: 500 Internal Auth Error\r\n”);

            print(STDOUT “\r\n”);

        }

    }

    elsif($path_auth == PATH_NEVER)

    {

        # we never allow anyone in to these:

        print(STDOUT “Status: 403 Denied\r\n”);

        print(STDOUT “\r\n”);

    }

    elsif($path_auth == PATH_ALWAYS)

    {

        # these we don’t really care about, just let them in.

        # your error pages, icon, etc should all fall into this

        # category, as should your login page:

        print(STDOUT “Status: 200 Ok\r\n”);

        print(STDOUT “\r\n”);

    }

    else

    {

        # This should not be able to happen: If it does,

        # your site needs attention from you:

        print(STDOUT “Status: 500 Internal Auth Error\r\n”);

        print(STDOUT “\r\n”);

    }

}

_exit();

##############

# Access rules, first match wins:

# /auth/login.cgi is always allowed

# /share

create table login_table (token  char(32) not null,

                          user   char(32) not null,

                          expiry int(11)  not null)

WARNING: unknown config-key: fastcgi.server (ignored)

WARNING: unknown config-key: fastcgi.server (ignored)

This means you need to include the line

server.modules += ( “mod_fastcgi” )

or

include “conf.d/fastcgi.conf”

(which should have the line server.modules += ( “mod_fastcgi” ) by default)

in your lighttpd.conf file. Without this, you’ll get the error

WARNING: unknown config-key: fastcgi.server (ignored)

when trying to use lighttpd with fastcgi and, for example, php.

Wsgiauthorizer Installation

Wsgiauthorizer Installation:

svn checkout http://wsgiauthorizer.googlecode.com/svn/trunk/ wsgiauthorizer-read-only 
cd wsgiauthorizer-read-only 
sudo python setup.py install

Install Django with FastCGI, SCGI

A good tutorial on howto Install Django with FastCGI, SCGI:

Although the current preferred setup for running Django is Apache with mod_wsgi, many people use shared hosting, on which protocols such as FastCGI, SCGI or AJP are the only viable options. In some setups, these protocols may provide better performance than mod_wsgi.

FastCGI Sample Program

FastCGI Sample Program:

FastCGI Prime Number Generator Example

FastCGI Prime Number Generator Example:

Consider a responder application that generates the n-th prime number.

A CGI application would have no efficient way of solving this problem. For example, if the user asks for the 50,000th prime number, a CGI application would have to calculate the first prime number, then the second, and so on, up until the 50,000th. The application would then terminate, taking with it all its hard-earned calculations. If a client then asks for the 49,000th prime number, the server will have to spawn a new CGI application which will have to start calculating prime numbers from scratch.

FastCGI applications can be much more efficient at this sort of problem, since they can maintain state. A FastCGI application can calculate an extensive table of prime numbers in its initialization phase and then keep the table around indefinitely. Whenever a client requests a particular prime number, the response loop merely needs to look it up in the table.

Here is the code for the prime number example:

#include "fcgi_stdio.h"
#include <stdlib.h>
#include <string.h>

#define POTENTIALLY_PRIME 0
#define COMPOSITE 1
#define VALS_IN_SIEVE_TABLE 1000000
#define MAX_NUMBER_OF_PRIME_NUMBERS 78600 


long int  sieve_table[VALS_IN_SIEVE_TABLE];
long int  prime_table[MAX_NUMBER_OF_PRIME_NUMBERS];

void
initialize_prime_table(void)
{
 long int prime_counter=1;
 long int current_prime=2, c, d; 

  prime_table[prime_counter]=current_prime;

  while (current_prime < VALS_IN_SIEVE_TABLE)   {
   
     for (c = current_prime; c <= VALS_IN_SIEVE_TABLE;
          c += current_prime)  {
        sieve_table[c] = COMPOSITE;
     }

   
     for (d=current_prime+1; sieve_table[d] == COMPOSITE; d++);
   
     prime_table[++prime_counter]=d;
     current_prime=d;
  }
}

void main(void)
{
    char *query_string;
    long int n;

    initialize_prime_table();

    while(FCGI_Accept() >= 0) {
        
        printf("Content-type: text/html\r\n"
               "\r\n");
        
        printf("<title>Prime FastCGI</title>\n"
               "<h1>Prime FastCGI</h1>\n");
        
        query_string = getenv("QUERY_STRING");
        if(query_string == NULL) {
            printf("Usage: Specify a positive number in the query string.\n");
        } else {
            query_string = strchr(query_string, `=') + 1;
            n = strtol(query_string);
            if(n < 1) {
                printf("The query string `%s' is not a positive number.\n",
                       query_string);
            } else if(n > MAX_NUMBER_OF_PRIME_NUMBERS) {
                printf("The number %d is too large for this program.\n", n);
            } else
                printf("The %ldth prime number is %ld.\n", n, prime_table[n]);
            }
        }
    } 
}

This application has a noticeable start up cost while it initializes the table, but subsequent accesses are fast.

Building

This section explains how to build and debug FastCGI applications written in C.

The C preprocessor needs to know the location of the fcgi_stdio.h header file, which is at the following pathname:

$toolkit/include/fcgi_stdio.h

where $toolkit symbolizes the directory in which you have installed the Software Development Kit for FastCGI.

The linker needs to know the location of the libfcgi.a library file, which is at the following pathname:

$toolkit/libfcgi/libfcgi.a

If your linker does not search the Berkeley socket library, then you must add linker directives to force this search.

We provide a sample application Makefile at the following pathname:

$toolkit/examples/Makefile

This Makefile contains the necessary rules and pathnames to build the C FastCGI applications accompanying the toolkit. To build all the applications, type:

$ ./configure
$ make