--- loncom/lti/ltiutils.pm	2018/01/04 12:19:25	1.5
+++ loncom/lti/ltiutils.pm	2018/05/15 04:59:22	1.10
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # Utility functions for managing LON-CAPA LTI interactions 
 #
-# $Id: ltiutils.pm,v 1.5 2018/01/04 12:19:25 raeburn Exp $
+# $Id: ltiutils.pm,v 1.10 2018/05/15 04:59:22 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -34,6 +34,7 @@ use Digest::SHA;
 use UUID::Tiny ':std';
 use Apache::lonnet;
 use Apache::loncommon;
+use Math::Round();
 use LONCAPA qw(:DEFAULT :match);
 
 #
@@ -324,6 +325,7 @@ sub sign_params {
     if ($sigmethod eq '') {
         $sigmethod = 'HMAC-SHA1';
     }
+    srand( time() ^ ($$ + ($$ << 15))  ); # Seed rand.
     my $nonce = Digest::SHA::sha1_hex(sprintf("%06x%06x",rand(0xfffff0),rand(0xfffff0)));
     my $request = Net::OAuth->request("request token")->new(
             consumer_key => $key,
@@ -458,4 +460,153 @@ sub release_tool_lock {
     }
 }
 
+#
+# LON-CAPA as LTI Provider
+#
+# Use the part of the launch URL after /adm/lti to determine
+# the scope for the current session (i.e., restricted to a
+# single resource, to a single folder/map, or to an entire
+# course).
+#
+# Returns an array containing scope: resource, map, or course
+# and the LON-CAPA URL that is displayed post-launch, including
+# accommodation of URL encryption, and translation of a tiny URL
+# to the actual URL
+#
+
+sub lti_provider_scope {
+    my ($tail,$cdom,$cnum,$getunenc) = @_;
+    my ($scope,$realuri,$passkey,$unencsymb);
+    if ($tail =~ m{^/?uploaded/$cdom/$cnum/(?:default|supplemental)(?:|_\d+)\.(?:sequence|page)(|___\d+___.+)$}) {
+        my $rest = $1;
+        if ($rest eq '') {
+            $scope = 'map';
+            $realuri = $tail;
+        } else {
+            my ($map,$resid,$url) = &Apache::lonnet::decode_symb($tail);
+            $realuri = &Apache::lonnet::clutter($url);
+            if ($url =~ /\.sequence$/) {
+                $scope = 'map';
+            } else {
+                $scope = 'resource';
+                $realuri .= '?symb='.$tail;
+                $passkey = $tail;
+                if ($getunenc) {
+                    $unencsymb = $tail;
+                }
+            }
+        }
+    } elsif ($tail =~ m{^/?res/$match_domain/$match_username/.+\.(?:sequence|page)(|___\d+___.+)$}) {
+        my $rest = $1;
+        if ($rest eq '') {
+            $scope = 'map';
+            $realuri = $tail;
+        } else {
+            my ($map,$resid,$url) = &Apache::lonnet::decode_symb($tail);
+            $realuri = &Apache::lonnet::clutter($url);
+            if ($url =~ /\.sequence$/) {
+                $scope = 'map';
+            } else {
+                $scope = 'resource';
+                $realuri .= '?symb='.$tail;
+                $passkey = $tail;
+                if ($getunenc) {
+                    $unencsymb = $tail;
+                }
+            }
+        }
+    } elsif ($tail =~ m{^/tiny/$cdom/(\w+)$}) {
+        my $key = $1;
+        my $tinyurl;
+        my ($result,$cached)=&Apache::lonnet::is_cached_new('tiny',$cdom."\0".$key);
+        if (defined($cached)) {
+            $tinyurl = $result;
+        } else {
+            my $configuname = &Apache::lonnet::get_domainconfiguser($cdom);
+            my %currtiny = &Apache::lonnet::get('tiny',[$key],$cdom,$configuname);
+            if ($currtiny{$key} ne '') {
+                $tinyurl = $currtiny{$key};
+                &Apache::lonnet::do_cache_new('tiny',$cdom."\0".$key,$currtiny{$key},600);
+            }
+        }
+        if ($tinyurl ne '') {
+            my ($cnum,$symb) = split(/\&/,$tinyurl,2);
+            my ($map,$resid,$url) = &Apache::lonnet::decode_symb($symb);
+            if ($url =~ /\.(page|sequence)$/) {
+                $scope = 'map';
+            } else {
+                $scope = 'resource';
+            }
+            $passkey = $symb;
+            if ((&Apache::lonnet::EXT('resource.0.encrypturl',$symb) =~ /^yes$/i) &&
+                (!$env{'request.role.adv'})) {
+                $realuri = &Apache::lonenc::encrypted(&Apache::lonnet::clutter($url));
+                if ($scope eq 'resource') {
+                    $realuri .= '?symb='.&Apache::lonenc::encrypted($symb);
+                }
+            } else {
+                $realuri = &Apache::lonnet::clutter($url);
+                if ($scope eq 'resource') {
+                    $realuri .= '?symb='.$symb;
+                }
+            }
+            if ($getunenc) {
+                $unencsymb = $symb;
+            }
+        }
+    } elsif (($tail =~ m{^/$cdom/$cnum$}) || ($tail eq '')) {
+        $scope = 'course';
+        $realuri = '/adm/navmaps';
+        $passkey = $tail;
+    }
+    if ($scope eq 'map') {
+        $passkey = $realuri;
+    }
+    if (wantarray) {
+        return ($scope,$realuri,$unencsymb);
+    } else {
+        return $passkey;
+    }
+}
+
+sub send_grade {
+    my ($id,$url,$ckey,$secret,$scoretype,$total,$possible) = @_;
+    my $score;
+    if ($possible > 0) {
+        if ($scoretype eq 'ratio') {
+            $score = Math::Round::round($total).'/'.Math::Round::round($possible);
+        } elsif ($scoretype eq 'percentage') {
+            $score = (100.0*$total)/$possible;
+            $score = Math::Round::round($score);
+        } else {
+            $score = $total/$possible;
+            $score = sprintf("%.2f",$score);
+        }
+    }
+    my $date = &Apache::loncommon::utc_string(time);
+    my %ltiparams = (
+        lti_version                   => 'LTI-1p0',
+        lti_message_type              => 'basic-lis-updateresult',
+        sourcedid                     => $id,
+        result_resultscore_textstring => $score,
+        result_resultscore_language   => 'en-US',
+        result_resultvaluesourcedid   => $scoretype,
+        result_statusofresult         => 'final',
+        result_date                   => $date,
+    );
+    my $hashref = &sign_params($url,$ckey,$secret,\%ltiparams);
+    if (ref($hashref) eq 'HASH') {
+        my $request=new HTTP::Request('POST',$url);
+        $request->content(join('&',map {
+                          my $name = escape($_);
+                          "$name=" . ( ref($hashref->{$_}) eq 'ARRAY'
+                          ? join("&$name=", map {escape($_) } @{$hashref->{$_}})
+                          : &escape($hashref->{$_}) );
+        } keys(%{$hashref})));
+        my $response = &LONCAPA::LWPReq::makerequest('',$request,'','',10);
+        my $message=$response->status_line;
+#FIXME Handle case where pass back of score to LTI Consumer failed.
+    }
+}
+
 1;