user/index: Show enrolment and group/grouping data in Participants page MDL-12311

The participants page will now show (to users that have
moodle/role:assign) the relevant enrolments for each participant.

This is done with a second SELECT using a WHERE id IN() so we are
limited to doing it with small datasets. This is for 2 reasons

 - we cannot retrieve all teh data in the "main" SELECT because
   the outer joins will bring dup rows, breaking LIMIT

 - we cannot use the main SELECT as a subselect because we cannot
   retrieve the LIMIT part of the statement with the current dmllib

 - on large courses / sitecourse performance would be horrible

so it is limited to paginated datasets. It is doing 20 recs at a time,
the "extra" SELECT takes ~7ms on a some large Pg databases).

This will generate an extra DB query on Oracle (and any other DB that
cannot rewind the recordset) because we walk the main rs twice.

While at it, ensure we mark the unsortable columns thus...

diff --git a/user/index.php b/user/index.php
index b8e250429d464329fc203de3bc8ff581d3051a72..8293328951d6cb15999e588f87e483e2205f7f5c 100644 (file)
--- a/user/index.php
+++ b/user/index.php
@@ -268,6 +268,19 @@
         }
     }
 
+    // Decide wheteher we will fetch extra enrolment/groups data.
+    //
+    // If the listing is small (at or below DEFAULT_PAGE_SIZE)
+    // and $USER can enrol/unenrol, display extra enrolments & groups information.
+    // (will take 1 extra DB query - 2 on Oracle)
+    //
+    if ($fullmode === false &&
+        $perpage <= DEFAULT_PAGE_SIZE && has_capability('moodle/role:assign',$context)) {
+        $showenroldata = true;
+    } else {
+        $showenroldata = false;
+    }
+
     /// Define a table showing a list of users in the current role selection
 
     $tablecolumns = array('userpic', 'fullname');
@@ -290,8 +303,19 @@
         $tableheaders[] = get_string('enrolmentend');
     }
 
+    if ($showenroldata) {
+        $tablecolumns[] = 'roles';
+        $tableheaders[] = get_string('roles');
+        $tablecolumns[] = 'groups';
+        $tableheaders[] = get_string('groups');
+        if (!empty($CFG->enablegroupings)) {
+            $tablecolumns[] = 'groupings';
+            $tableheaders[] = get_string('groupings', 'group');
+        }
+    }
+
     if ($bulkoperations) {
-        $tablecolumns[] = '';
+        $tablecolumns[] = 'select';
         $tableheaders[] = get_string('select');
     }
 
@@ -302,6 +326,10 @@
     $table->define_baseurl($baseurl);
 
     $table->sortable(true, 'lastaccess', SORT_DESC);
+    $table->no_sorting('roles');
+    $table->no_sorting('groups');
+    $table->no_sorting('groupings');
+    $table->no_sorting('select');
 
     $table->set_attribute('cellspacing', '0');
     $table->set_attribute('id', 'participants');
@@ -426,6 +454,30 @@
     $userlist = get_recordset_sql($select.$from.$where.$wheresearch.$sort,
             $table->get_page_start(),  $table->get_page_size());
 
+    //
+    // The SELECT behind get_participants_extra() is cheaper if we pass an array
+    // if IDs. We could pass the SELECT we did before (with the limit bits - tricky!)
+    // but this is much cheaper. And in any case, it is only doable with limited numbers
+    // of rows anyway. On a large course it will explode badly...
+    //
+    if ($showenroldata) {
+        $userids = array();
+
+        while ($user = rs_fetch_next_record($userlist)) {
+            $userids[] = $user->id;
+        }
+        $userlist_extra = get_participants_extra($userids, $avoidroles, $course, $context);
+
+        // Only Oracle cannot seek backwards
+        // and must re-query...
+        if ($userlist->canSeek === true) {
+            $userlist->MoveFirst();
+        } else {
+            $userlist = get_recordset_sql($select.$from.$where.$wheresearch.$sort,
+                                          $table->get_page_start(),  $table->get_page_size());
+        }
+    }
+
     /// If there are multiple Roles in the course, then show a drop down menu for switching
 
     if (count($rolenames) > 1) {
@@ -566,6 +618,15 @@
 
 
         if ($userlist)  {
+
+            // only show the plugin if multiple enrolment plugins
+            // are enabled...
+            if (strpos($CFG->enrol_plugins_enabled, ',')=== false) {
+                $showenrolplugin = true;
+            } else {
+                $showenrolplugin = false;
+            }
+            
             while ($user = rs_fetch_next_record($userlist)) {
                 $user = make_context_subobj($user);
                 if ($user->hidden) {
@@ -625,6 +686,36 @@
                         $data[] = get_string('unlimited');
                     }
                 }
+
+                if (isset($userlist_extra) && isset($userlist_extra[$user->id])) {
+                    $ras = $userlist_extra[$user->id]['ra'];
+                    $rastring = '';
+                    foreach ($ras AS $key=>$ra) {
+                        $rolename = $rolenames [ $ra['roleid'] ] ;
+                        if ($ra['ctxlevel'] == CONTEXT_COURSECAT) {
+                            $rastring .= $rolename. ' @ ' . s($ra['ccname']);
+                        } elseif ($ra['ctxlevel'] == CONTEXT_SYSTEM) {
+                            $rastring .= $rolename. ' @ ' . get_string('globalrole','role');
+                        } else {
+                            $rastring .= $rolename;
+                        }
+                        if ($showenrolplugin) {
+                            $rastring .= '<br />';
+                        } else {
+                            $rastring .= ' ('. $ra['enrolplugin'] .')<br />';
+                        }
+                    }
+                    $data[] = $rastring; 
+                    if ($course->groupmode != 0) {
+                        // htmlescape with s() and implode the array
+                        $data[] = implode(', ', array_map('s',$userlist_extra[$user->id]['group']));
+                    }
+                    if (!empty($CFG->enablegroupings)) {
+                        $data[] = implode(', ', array_map('s', $userlist_extra[$user->id]['gping']));
+                    }
+
+                }
+
                 if ($bulkoperations) {
                     $data[] = '<input type="checkbox" name="user'.$user->id.'" />';
                 }
@@ -694,4 +785,116 @@ function get_lastaccess_sql($accesssince='') {
     }
 }
 
+function get_participants_extra ($userids, $avoidroles, $course, $context) {
+
+    global $CFG;
+
+    if (count($userids) === 0 || count($avoidroles) === 0) {
+        return array();
+    }
+
+    $userids = implode(',', $userids);
+
+    // turn the path into a list of context ids
+    $contextids = substr($context->path, 1); // kill leading slash
+    $contextids = str_replace('/', ',', $contextids);;
+
+    if (count($avoidroles) > 0) {
+        $avoidroles = implode(',', $avoidroles);
+        $avoidrolescond = " AND ra.roleid NOT IN ($avoidroles) ";
+    } else {
+        $avoidrolescond = '';
+    }
+
+    if (!empty($CFG->enablegroupings)) {
+        $gpjoin = "LEFT OUTER JOIN {$CFG->prefix}groupings_groups gpg
+                     ON gpg.groupid=g.id
+                   LEFT OUTER JOIN {$CFG->prefix}groupings gp
+                     ON (gp.courseid={$course->id} AND gp.id=gpg.groupingid)";
+        $gpselect = ',gp.id AS gpid, gp.name AS gpname ';
+    } else {
+        $gpjoin   = '';
+        $gpselect = '';
+    }
+
+    // Note: this returns strange redundant rows, perhaps
+    // due to the multiple OUTER JOINs. If we can tweak the
+    // JOINs to avoid it ot
+    $sql = "SELECT DISTINCT ra.userid, 
+                   ctx.id AS ctxid, ctx.path AS ctxpath, ctx.depth AS ctxdepth, 
+                   ctx.contextlevel AS ctxlevel, ctx.instanceid AS ctxinstanceid,
+                   cc.name  AS ccname, 
+                   ra.roleid AS roleid,
+                   ra.enrol AS enrolplugin,
+                   g.id     AS gid, g.name AS gname
+                   $gpselect
+            FROM {$CFG->prefix}role_assignments ra
+            JOIN {$CFG->prefix}context ctx
+              ON (ra.contextid=ctx.id)
+            LEFT OUTER JOIN {$CFG->prefix}course_categories cc
+              ON (ctx.contextlevel=40 AND ctx.instanceid=cc.id)
+
+            /* only if groups active */
+            LEFT OUTER JOIN {$CFG->prefix}groups_members gm
+              ON (ra.userid=gm.userid)
+            LEFT OUTER JOIN {$CFG->prefix}groups g
+              ON (gm.groupid=g.id AND g.courseid={$course->id})
+            /* and if groupings is enabled... */
+            $gpjoin
+
+            WHERE ra.userid IN ( $userids ) 
+                  AND ra.contextid in ( $contextids ) 
+                  $avoidrolescond
+
+            ORDER BY ra.userid, ctx.depth DESC";
+
+    $rs = get_recordset_sql($sql);
+    $extra = array();
+
+    // Data structure -
+    // $extra [ $userid ] [ 'group' ] [ $groupid => 'group name']
+    //                    [ 'gping' ] [ $gpingid => 'gping name']
+    //                    [ 'ra' ] [  [ "$ctxid:$roleid" => [ctxid => $ctxid
+    //                                                       ctxdepth =>  $ctxdepth, 
+    //                                                       ctxpath => $ctxpath,
+    //                                                       ctxname => 'name' (categories only)
+    //                                                       ctxinstid => 
+    //                                                       roleid => $roleid
+    //                                                       enrol => $pluginname
+    //
+    // Might be interesting to add to RA timestart, timeend, timemodified,
+    // and modifierid (with an outer join to mdl_user!
+    //
+
+    while ($rec = rs_fetch_next_record($rs)) {
+        $userid = $rec->userid;
+
+        // Prime an initial user rec...
+        if (!isset($extra[$userid])) {
+            $extra[$userid] = array( 'group' => array(),
+                                     'gping' => array(),
+                                     'ra'    => array() );
+        }
+
+        if (!empty($rec->gid)) {
+            $extra[$userid]['group'][$rec->gid]= $rec->gname;
+        }
+        if (!empty($rec->gpid)) {
+            $extra[$userid]['gping'][$rec->gpid]= $rec->gpname;
+        }
+        $rakey = $rec->ctxid . ':' . $rec->roleid;
+        if (!isset($extra[$userid]['ra'][$rakey])) {
+            $extra[$userid]['ra'][$rakey] = array('ctxid'         => $rec->ctxid,
+                                                  'ctxlevel'       => $rec->ctxlevel,
+                                                  'ctxinstanceid' => $rec->ctxinstanceid,
+                                                  'ccname'        => $rec->ccname,
+                                                  'roleid'        => $rec->roleid,
+                                                  'enrolplugin'   => $rec->enrolplugin);
+
+        }
+    }
+    return $extra;
+
+}
+
 ?>