View of /trunk/webwork2/lib/Apache/WeBWorK.pm

    1 ################################################################################
    2 # WeBWorK mod_perl (c) 2000-2002 WeBWorK Project
    3 # $Id$
    4 ################################################################################
    5 
    6 package Apache::WeBWorK;
    7 
    8 =head1 NAME
    9 
   10 Apache::WeBWorK - The WeBWorK dispatcher module.
   11 
   12 =cut
   13 
   14 use strict;
   15 use warnings;
   16 use Apache::Constants qw(:common REDIRECT);
   17 use Apache::Request;
   18 use WeBWorK::Authen;
   19 use WeBWorK::Authz;
   20 use WeBWorK::ContentGenerator::Feedback;
   21 use WeBWorK::ContentGenerator::Login;
   22 use WeBWorK::ContentGenerator::Logout;
   23 use WeBWorK::ContentGenerator::Hardcopy;
   24 use WeBWorK::ContentGenerator::Options;
   25 use WeBWorK::ContentGenerator::Problem;
   26 use WeBWorK::ContentGenerator::ProblemSet;
   27 use WeBWorK::ContentGenerator::ProblemSets;
   28 use WeBWorK::ContentGenerator::Professor;
   29 use WeBWorK::ContentGenerator::Test;
   30 use WeBWorK::CourseEnvironment;
   31 
   32 # This module should be installed as a Handler for the location selected for
   33 # WeBWorK on your webserver. Here is an example of a stanza that can be added
   34 # to your httpd.conf file to achieve this:
   35 #
   36 # <IfModule mod_perl.c>
   37 #     PerlFreshRestart On
   38 #     <Location /modperl-sam>
   39 #         SetHandler perl-script
   40 #         PerlSetVar webwork_root /opt/webwork
   41 #         <Perl>
   42 #             use lib '/opt/webwork/lib';
   43 #         </Perl>
   44 #         PerlHandler Apache::WeBWorK
   45 #     </Location>
   46 # </IfModule>
   47 
   48 sub handler() {
   49   my $r = Apache::Request->new(shift); # have to deal with unpredictable GET or POST data, and sift through it for the key.  So use Apache::Request
   50 
   51   # This stuff is pretty much copied out of the O'Reilly mod_perl book.
   52   # It's for figuring out the basepath.  I may change this up if I
   53   # find a better way to do it.
   54   my $path_info = $r->path_info || "";
   55   my $current_uri = $r->uri;
   56   my $args = $r->args;
   57 
   58   # If it's a valid WeBWorK URI, it ends in a /.  This is assumed
   59   # alllll over the place.
   60   unless (substr($current_uri,-1) eq '/') {
   61     $r->header_out(Location => "$current_uri/" . ($args ? "?$args" : ""));
   62     return REDIRECT;
   63     # *** any post data gets lost here -- fix that.
   64   }
   65 
   66   # Create the @components array, which contains the path specified in the URL
   67   my($junk, @components) = split "/", $path_info;
   68   my $webwork_root = $r->dir_config('webwork_root'); # From a PerlSetVar in httpd.conf
   69   my $course = shift @components;
   70 
   71   # If no course was specified, phreak out.
   72   # Eventually, display a list of courses, or something.
   73   unless (defined $course) {
   74     warn "No course specified.\n";
   75     return DECLINED;
   76     # *** we should either write a "Courses" module, or redirect to a static page.
   77   }
   78 
   79   # Try to get the course environment.
   80   my $course_env = eval {WeBWorK::CourseEnvironment->new($webwork_root, $course);};
   81   if ($@) { # If there was an error getting the requested course
   82     # TODO: display an error page.  For now, 404 it.
   83     warn $@;
   84     return DECLINED;
   85   }
   86 
   87   # Freak out if the requested course doesn't exist.  For now, this is just a
   88   # check to see if the course directory exists.
   89   if (!-e $course_env->{webworkDirs}->{courses} . "/$course") {
   90     warn "Course directory for $course not found at "
   91       . $course_env->{webworkDirs}->{courses} . "/$course" ."\n";
   92     return DECLINED;
   93   }
   94 
   95   ### Begin dispatching ###
   96 
   97   # WeBWorK::Authen::verify erases the passwd field and sets the key field
   98   # if login is successful.
   99   if (!WeBWorK::Authen->new($r, $course_env)->verify) {
  100     # *** &verify should throw a descriptive exception on weird failures
  101     return WeBWorK::ContentGenerator::Login->new($r, $course_env)->go;
  102   } else {
  103     # After we are authenticated, there are some things that need to be
  104     # sorted out, Authorization-wize, before we start dispatching to individual
  105     # content generators.
  106     my $effectiveUser = $r->param("effectiveUser") || "";
  107     my $user = $r->param("user");
  108     my $su_authorized = WeBWorK::Authz->new($r, $course_env)->hasPermissions($user, "become_student", $effectiveUser);
  109     # This hoary statement has the effect of forcing effectiveUser to equal user unless
  110     # the user is otherwise authorized.
  111     if (!($user ne $effectiveUser && $su_authorized) || !defined $effectiveUser) {
  112       $r->param("effectiveUser",$user);
  113     }
  114 
  115     my $arg = shift @components;
  116     if (!defined $arg) { # We want the list of problem sets
  117       return WeBWorK::ContentGenerator::ProblemSets->new($r, $course_env)->go;
  118     } elsif ($arg eq "hardcopy") {
  119       my $hardcopyArgument = shift @components;
  120       $hardcopyArgument = "" unless defined $hardcopyArgument;
  121       # *** can i say go(shift || "") here?
  122       return WeBWorK::ContentGenerator::Hardcopy->new($r, $course_env)->go($hardcopyArgument);
  123     } elsif ($arg eq "prof") {
  124       return WeBWorK::ContentGenerator::Professor->new($r, $course_env)->go;
  125     } elsif ($arg eq "options") {
  126       return WeBWorK::ContentGenerator::Options->new($r, $course_env)->go;
  127     } elsif ($arg eq "feedback") {
  128       return WeBWorK::ContentGenerator::Feedback->new($r, $course_env)->go;
  129     } elsif ($arg eq "logout") {
  130       return WeBWorK::ContentGenerator::Logout->new($r, $course_env)->go;
  131     } elsif ($arg eq "test") {
  132       # *** we should change this name, or remove it altogether.
  133       return WeBWorK::ContentGenerator::Test->new($r, $course_env)->go;
  134     } else { # We've got the name of a problem set.
  135       my $problem_set = $arg;
  136       my $ps_arg = shift @components;
  137 
  138       if (!defined $ps_arg) {
  139         # list the problems in the problem set
  140         return WeBWorK::ContentGenerator::ProblemSet->new($r, $course_env)->go($problem_set);
  141       } elsif ($ps_arg eq "hardcopy") {
  142         # *** do we need this? hardcopy is not being called this way
  143       }
  144       else {
  145         # We've got the name of a problem
  146         my $problem = $ps_arg;
  147         return WeBWorK::ContentGenerator::Problem->new($r, $course_env)->go($problem_set, $problem);
  148       }
  149     }
  150 
  151   }
  152 
  153   # If the dispatcher doesn't know any modules that want to handle
  154   # the current path, it'll claim that the path does not exist by
  155   # declining the request.
  156   return DECLINED;
  157 }
  158 
  159 1;