Conditional activities API

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Overview

Conditional Apis allow you to specify , if to show or hide an activity when the conditions associated with it are met/not met.

Files

The main file containing all important conditional stuff is located at lib/conditionlib.php

Functions

The class condition_info defined in lib/conditionlib.php is the main conditional API in Moodle. Following are some important methods of the above mentioned class.

fill_availability_conditions(&$cm)
get_full_course_module()
add_completion_condition($cmid, $requiredcompletion)
add_grade_condition($gradeitemid, $min, $max, $updateinmemory=false)
wipe_conditions()
get_full_information($modinfo=null)
is_available(&$information, $grabthelot=false, $userid=0, $modinfo=null)
show_availability()
update_cm_from_form($cm, $fromform, $wipefirst=true)
completion_value_used_as_condition($course, $cm)

The basic functionality of these methods can be classified as:-

Fetching information related to conditions
Adding/Updating conditional clauses to activities
Deleting conditions attached to activities

Fetching information related to conditions

Following functions are normally used to fetch information regarding conditions associated with activities:- get_full_course_module(); get_full_information($modinfo=null); is_available(&$information, $grabthelot=false, $userid=0, $modinfo=null); show_availability();

get_full_course_module()

This method can fetches and returns all necessary information as a course module object which are required to determine the availability conditions.

Example:-

$cm->id = $id; $test = new condition_info($cm,CONDITION_MISSING_EVERYTHING); $fullcm = $test->get_full_course_module();

get_full_information()

This function returns a string which describes the various conditions in place for the activity in the given context.Some possible outputs can be:-

a) From 13:05 on 14 Oct until 12:10 on 17 Oct (exact, exact)
b) From 14 Oct until 12:11 on 17 Oct (midnight, exact)
c) From 13:05 on 14 Oct until 17 Oct (exact, midnight 18 Oct)

Please refer the inline documentation in the code for detailed explanation of the logic and all possible cases.

Example:- $ci = new condition_info($mod); $fullinfo = $ci->get_full_information();

is_available()

This function is used to check if a given course module is currently available or not. A thing worth noting is that this doesn't take "visibility settings" and "viewhiddenactivities" capability into account. That is these settings should be properly checked after the result of is_available(), before dumping any data to the user.

Example:- $ci = new condition_info((object)array('id'=>$cmid),CONDITION_MISSING_EVERYTHING); $bool = $ci->is_available($text,false,0);

show_availability()

This function is used to check if information regarding availability of the current module should be shown to the user or not.

Example:- $ci = new condition_info((object)array('id'=>$cmid),CONDITION_MISSING_EVERYTHING); $bool = $ci->show_availability();

Adding/Updating conditional clauses to activities

fill_availability_conditions(&$cm); add_completion_condition($cmid, $requiredcompletion);

fill_availability_conditions()

This function adds any extra availability conditions to given course module object. $rawmods = get_course_mods($courseid); if (empty($rawmods)) {

   die;

}
if ($sections = $DB->get_records("course_sections", array("course"=>$courseid), "section ASC")) {

   foreach ($sections as $section) {
       if (!empty($section->sequence)) {
           $sequence = explode(",", $section->sequence);
               foreach ($sequence as $seq) {
                   if (empty($rawmods[$seq])) {
                       continue;
                   }
                   if (!empty($CFG->enableavailability)) {
                        condition_info::fill_availability_conditions($rawmods[$seq]);
                        //do something
                   }
               }
           }
       }
   }

}

add_completion_condition()

In Moodle avaialabilty condition of a Module or activity can depend on another activity. For example activity B will not be unlocked untill activity A is successfully completed. To add such inter-dependent condtions, this funtion is used.

Example:- $test1=new condition_info((object)array('id'=>$cmid),CONDITION_MISSING_EVERYTHING); $test1->add_completion_condition(13,3);

Deleting conditions attached to activities

we have a simple function wipe_conditions() that can erase all conditions associated with the current activity. consider an example:-

$ci = new condition_info($cm, CONDITION_MISSING_EVERYTHING, false); $ci->wipe_conditions();

Documentation