--- loncom/interface/lonnavmaps.pm	2011/09/22 12:48:40	1.464
+++ loncom/interface/lonnavmaps.pm	2011/10/21 10:13:57	1.465
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # Navigate Maps Handler
 #
-# $Id: lonnavmaps.pm,v 1.464 2011/09/22 12:48:40 raeburn Exp $
+# $Id: lonnavmaps.pm,v 1.465 2011/10/21 10:13:57 foxr Exp $
 
 #
 # Copyright Michigan State University Board of Trustees
@@ -478,12 +478,18 @@ use Apache::loncommon();
 use Apache::lonenc();
 use Apache::lonlocal;
 use Apache::lonnet;
+use Apache::lonmap;
 
 use POSIX qw (floor strftime);
 use Time::HiRes qw( gettimeofday tv_interval );
 use LONCAPA;
 use DateTime();
+
+# For debugging
+
 use Data::Dumper;
+
+
 # symbolic constants
 sub SYMB { return 1; }
 sub URL { return 2; }
@@ -1961,10 +1967,13 @@ sub new {
     my $proto = shift;
     my $class = ref($proto) || $proto;
     my $self = {};
+    bless($self);		# So we can call change_user if neceesary
 
     $self->{USERNAME} = shift || $env{'user.name'};
     $self->{DOMAIN}   = shift || $env{'user.domain'};
 
+
+
     # Resource cache stores navmap resources as we reference them. We generate
     # them on-demand so we don't pay for creating resources unless we use them.
     $self->{RESOURCE_CACHE} = {};
@@ -1973,31 +1982,90 @@ sub new {
     # failed
     $self->{NETWORK_FAILURE} = 0;
 
-    # tie the nav hash
+    # We can only tie the nav hash as done below if the username/domain
+    # match the env one. Otherwise change_user does everything we need...since we can't
+    # assume there are course hashes for the specific requested user@domamin:
+    #
 
-    my %navmaphash;
-    my %parmhash;
-    my $courseFn = $env{"request.course.fn"};
-    if (!(tie(%navmaphash, 'GDBM_File', "${courseFn}.db",
-              &GDBM_READER(), 0640))) {
-        return undef;
+    if (($self->{USERNAME} eq $env{'user.name'}) && ($self->{DOMAIN} eq $env{'user.domain'})) {
+	
+	# tie the nav hash
+	
+	my %navmaphash;
+	my %parmhash;
+	my $courseFn = $env{"request.course.fn"};
+	if (!(tie(%navmaphash, 'GDBM_File', "${courseFn}.db",
+		  &GDBM_READER(), 0640))) {
+	    return undef;
+	}
+	
+	if (!(tie(%parmhash, 'GDBM_File', "${courseFn}_parms.db",
+		  &GDBM_READER(), 0640)))
+	{
+	    untie %{$self->{PARM_HASH}};
+	    return undef;
+	}
+	
+	$self->{NAV_HASH} = \%navmaphash;
+	$self->{PARM_HASH} = \%parmhash;
+	$self->{PARM_CACHE} = {};
+    } else {
+	$self->change_user($self->{USERNAME}, $self->{DOMAIN});
     }
+        
+    return $self;
+}
+
+#
+#  In some instances it is useful to be able to dynamically change the
+# username/domain associated with a navmap (e.g. to navigate for someone
+# else besides the current user...if sufficiently privileged.
+# Parameters:
+#    user  - New user.
+#    domain- Domain the user belongs to.
+# Implicit inputs:
+#   
+sub change_user {
+    my $self = shift;
+    $self->{USERNAME} = shift;
+    $self->{DOMAIN}   = shift;
+
+    # If the hashes are already tied make sure to break that bond:
+
+    untie %{$self->{NAV_HASH}}; 
+    untie %{$self->{PARM_HASH}};
+
+    # The assumption is that we have to
+    # use lonmap here to re-read the hash and from it reconstruct
+    # new big and parameter hashes.  An implicit assumption at this time
+    # is that the course file is probably not created locally yet
+    # an that we will therefore just read without tying.
+
+    my ($cdom, $cnum) = split(/\_/, $env{'request.course.id'});
+
+    my %big_hash;
+    &Apache::lonmap::loadmap($cnum, $cdom, $self->{USERNAME}, $self->{DOMAIN}, \%big_hash);
+    $self->{NAV_HASH} = \%big_hash;
+
+    # Now clear the parm cache and reconstruct the parm hash fromt he big_hash
+    # param.xxxx keys.
+
+    $self->{PARM_CACHE} = {};
     
-    if (!(tie(%parmhash, 'GDBM_File', "${courseFn}_parms.db",
-              &GDBM_READER(), 0640)))
-    {
-        untie %{$self->{PARM_HASH}};
-        return undef;
+    my %parm_hash = {};
+    foreach my $key (keys %big_hash) {
+	if ($key =~ /^param\./) {
+	    my $param_key = $key;
+	    $param_key =~ s/^param\.//;
+	    $parm_hash{$param_key} = $big_hash{$key};
+	}
     }
 
-    $self->{NAV_HASH} = \%navmaphash;
-    $self->{PARM_HASH} = \%parmhash;
-    $self->{PARM_CACHE} = {};
+    $self->{PARM_HASH} = \%parm_hash;
 
-    bless($self);
-        
-    return $self;
-}
+
+    
+} 
 
 sub generate_course_user_opt {
     my $self = shift;