--- loncom/homework/structuretags.pm	2006/04/20 02:05:30	1.349
+++ loncom/homework/structuretags.pm	2006/05/23 19:05:42	1.355
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA 
 # definition of tags that give a structure to a document
 #
-# $Id: structuretags.pm,v 1.349 2006/04/20 02:05:30 albertel Exp $
+# $Id: structuretags.pm,v 1.355 2006/05/23 19:05:42 albertel Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -79,7 +79,6 @@ sub page_start {
 	}
     }
 
-
     if ($target eq 'tex') {
 	return
 	    &Apache::londefdef::start_html($target,$token,$tagstack,
@@ -161,8 +160,15 @@ sub page_start {
 	    $form_tag_start.=&Apache::edit::form_change_detection();
 	}
 	$form_tag_start.='>';
-    }
 
+	my $symb=&Apache::lonnet::symbread();
+	if ($symb =~ /\S/) {
+	    $symb=
+		&HTML::Entities::encode(&Apache::lonenc::check_encrypt($symb));
+	    $form_tag_start.=
+		'<input type="hidden" name="symb" value="'.$symb.'" />';
+	}
+    }
     return ($page_start,$form_tag_start);
 }
 
@@ -333,9 +339,16 @@ Feedback Mode:
 }
 
 sub initialize_storage {
-    %Apache::lonhomework::results=();
-    %Apache::lonhomework::history=();
+    undef(%Apache::lonhomework::results);
+    undef(%Apache::lonhomework::history);
     my ($symb,$courseid,$domain,$name) = &Apache::lonxml::whichuser();
+    
+    # anonymous users (CODEd exams) have no data
+    if ($name eq 'anonymous' 
+	&& !defined($domain)) {
+	return;
+    }
+
     if ($env{'request.state'} eq 'construct' 
 	|| $symb eq ''
 	|| $Apache::lonhomework::type eq 'practice') {
@@ -355,6 +368,7 @@ sub initialize_storage {
 	%Apache::lonhomework::history=
 	    &Apache::lonnet::restore($symb,$courseid,$domain,$name);
     }
+
     #ignore error conditions
     my ($temp)=keys %Apache::lonhomework::history ;
     if ($temp =~ m/^error:.*/) { %Apache::lonhomework::history=(); }
@@ -442,13 +456,14 @@ sub checkout_msg {
                 'warning'=>'Checking out resources is subject to course policies, and may exclude future credit even if done erroneously.',
                 'checkout'=>'Check out Exam for Viewing',
 		'checkout?'=>'Check out Exam?');
+    my $uri = &Apache::lonenc::check_encrypt($env{'request.uri'});
     return (<<ENDCHECKOUT);
 <h2>$lt{'resource'}</h2>
     <p>$lt{'id_expln'}</p>
 <font color="red">
 <p>$lt{'warning'}</p>
 </font>
-<form name="checkout" method="POST" action="$env{'request.uri'}">
+<form name="checkout" method="POST" action="$uri">
 <input type="hidden" name="doescheckout" value="yes" />
 <input type="button" name="checkoutbutton" value="$lt{'checkout'}" onClick="javascript:if (confirm('$lt{'checkout?'}')) { document.checkout.submit(); }" />
 </form>
@@ -460,9 +475,10 @@ sub firstaccess_msg {
     my ($map)=&Apache::lonnet::decode_symb($symb);
     my $foldertitle=&Apache::lonnet::gettitle($map);
     &Apache::lonxml::debug("map is $map title is $foldertitle");
+    my $uri = &Apache::lonenc::check_encrypt($env{'request.uri'});
     return (<<ENDCHECKOUT);
 <h2>The resources in "$foldertitle" are open for a limited time. Once you click the 'Show Resource' button below you have $time to complete all resources "$foldertitle".</h2>
-<form name="markaccess" method="POST" action="$env{'request.uri'}">
+<form name="markaccess" method="POST" action="$uri">
 <input type="hidden" name="markaccess" value="yes" />
 <input type="button" name="accessbutton" value="Show Resource" onClick="javascript:if (confirm('Start Timer?')) { document.markaccess.submit(); }" />
 </form>
@@ -597,9 +613,14 @@ sub start_problem {
     my $accessmsg;
 
     my $name= &get_resource_name($parstack,$safeeval);
-    my ($result,$form_tag_start)=
-	&page_start($target,$token,$tagstack,$parstack,$parser,$safeeval,
-		    $name);
+    my ($result,$form_tag_start);
+    if ($target eq 'web' || $target eq 'webgrade' || $target eq 'tex'
+	|| $target eq 'edit') {
+	($result,$form_tag_start) =
+	    &page_start($target,$token,$tagstack,$parstack,$parser,$safeeval,
+			$name);
+    }
+
     if ($target eq 'tex' and $env{'request.symb'} =~ m/\.page_/) {$result='';}
 
     if ($target eq 'analyze') { my $rndseed=&setup_rndseed($safeeval); }