--- loncom/lti/ltiutils.pm	2019/03/31 18:48:33	1.16
+++ loncom/lti/ltiutils.pm	2019/07/18 18:28:46	1.17
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # Utility functions for managing LON-CAPA LTI interactions 
 #
-# $Id: ltiutils.pm,v 1.16 2019/03/31 18:48:33 raeburn Exp $
+# $Id: ltiutils.pm,v 1.17 2019/07/18 18:28:46 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -31,6 +31,7 @@ package LONCAPA::ltiutils;
 use strict;
 use Net::OAuth;
 use Digest::SHA;
+use Digest::MD5 qw(md5_hex);
 use UUID::Tiny ':std';
 use Apache::lonnet;
 use Apache::loncommon;
@@ -339,14 +340,20 @@ sub verify_lis_item {
 # 
 
 sub sign_params {
-    my ($url,$key,$secret,$sigmethod,$paramsref) = @_;
+    my ($url,$key,$secret,$paramsref,$sigmethod,$type,$callback,$post) = @_;
     return unless (ref($paramsref) eq 'HASH');
     if ($sigmethod eq '') {
         $sigmethod = 'HMAC-SHA1';
     }
+    if ($type eq '') {
+        $type = 'request token';
+    }
+    if ($callback eq '') {
+        $callback = 'about:blank',
+    }
     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(
+    my $request = Net::OAuth->request($type)->new(
             consumer_key => $key,
             consumer_secret => $secret,
             request_url => $url,
@@ -354,12 +361,16 @@ sub sign_params {
             signature_method => $sigmethod,
             timestamp => time,
             nonce => $nonce,
-            callback => 'about:blank',
+            callback => $callback,
             extra_params => $paramsref,
             version      => '1.0',
             );
     $request->sign();
-    return $request->to_hash();
+    if ($post) {
+        return $request->to_post_body();
+    } else {
+        return $request->to_hash();
+    }
 }
 
 #
@@ -647,7 +658,7 @@ sub get_roster {
         lti_message_type           => 'basic-lis-readmembershipsforcontext',
         ext_ims_lis_memberships_id => $id,
     );
-    my $hashref = &sign_params($url,$ckey,$secret,'',\%ltiparams);
+    my $hashref = &sign_params($url,$ckey,$secret,\%ltiparams);
     if (ref($hashref) eq 'HASH') {
         my $request=new HTTP::Request('POST',$url);
         $request->content(join('&',map {
@@ -735,7 +746,7 @@ sub send_grade {
             result_statusofresult         => 'final',
             result_date                   => $date,
         );
-        my $hashref = &sign_params($url,$ckey,$secret,$sigmethod,\%ltiparams);
+        my $hashref = &sign_params($url,$ckey,$secret,\%ltiparams,$sigmethod);
         if (ref($hashref) eq 'HASH') {
             $request=new HTTP::Request('POST',$url);
             $request->content(join('&',map {
@@ -807,6 +818,28 @@ END
 #FIXME Handle case where pass back of score to LTI Consumer failed.
 }
 
+sub setup_logout_callback {
+    my ($uname,$udom,$server,$ckey,$secret,$service_url,$idsdir,$protocol,$hostname) = @_;
+    if ($service_url =~ m{^https?://[^/]+/}) {
+        my $digest_user = &Encode::decode_utf8($uname.':'.$udom);
+        my $loginfile = &Digest::SHA::sha1_hex($digest_user).&md5_hex(&md5_hex(time.{}.rand().$$));
+        if ((-d $idsdir) && (open(my $fh,'>',"$idsdir/$loginfile"))) {
+            print $fh "$uname,$udom,$server\n";
+            close($fh);
+            my $callback = 'http://'.$hostname.'/adm/service/logout/'.$loginfile;
+            my %ltiparams = (
+                callback   => $callback,
+            );
+            my $post = &sign_params($service_url,$ckey,$secret,\%ltiparams,
+                                    '','','',1);
+            my $request=new HTTP::Request('POST',$service_url);
+            $request->content($post);
+            my $response = &LONCAPA::LWPReq::makerequest('',$request,'','',10);
+        }
+    }
+    return;
+}
+
 #
 # LON-CAPA as LTI Provider
 #