Development:Comments 2.0
Objectives
The goals of comments 2.0:
- Manage comments centrally
- Use a consistent approach for all comments throughout Moodle
- Easily integrate comments 2.0 with existing modules
- Works no matter Javascript is enabled or not
Overview
The comments 2.0 provides APIs to:
- Add comments
- Manage comments
- Delete comments
And provides a fancy ajax interface to add/delete comments without loading a new page.
Comments database table
| Field | Type | Default | Info |
|---|---|---|---|
| id | int(10) | auto-incrementing | The unique ID for this comment. |
| userid | int(10) | who wrote this comment | |
| contextid | int(10) | The context id defined in context table - identifies the instance of plugin owning the comment. | |
| itemid | int(10) | Some plugin specific item id (eg. forum post, blog entry or assignment submission) | |
| commentarea | int(10) | for example, in user profile, you can comment user's description or interests, but they share the same itemid(==userid), we need comment_area to separate them | |
| timecreated | int(10) | ||
| timemodified | int(10) | ||
| content | text | content of comment |
Use Comments API
Add an option to format_text function
Using this format_text function will add a comment icon automatically at the end of the text:
For example, using the following code in the forum module will add a comment icon to every post:
$to = new stdclass;
$cmt->contextid = $modcontext->id;
$cmt->area = 'format_post';
$cmt->itemid = $post->id;
$options->comments = $cmt;
echo format_text($post->message, $post->messageformat, $options, $course->id)."
";
Use comment class
To use Comments API elsewhere, using following code:
$options->area = 'database_entry';
$options->context = $context;
$options->itemid = $record->id;
$options->showcount = true;
$comment = new comment($options);
$comment->output(false);
Comments API overview
Generally speaking, only two functions you need to know to get comments 2.0 worked:
- Use comment::init to initialize comments 2.0
- Use $comment->output to display comments
The comment class has been implemented in comment/lib.php.
class comment()
__construct($contextid, $comment_area, $itemid))
Initialize class members
init()
It is a static function used to initialize comments, setting up languages, which must be called before html head printed
output($return = false)
Will print the html snippet for commenting interface, if set $return as true, it will return html string instead of printing out.
print_comments($params = array())
Used by non-javascript comment interface, will print a list of comments.
add($content)
Public instance funciton, add a comment to database, used in comment/comment_ajax.php
count()
Counting the number of comments
delete($id)
Delete a comment from database, used in comment/comment_ajax.php
delete_comments
Delete all comments in a specific contexts (like all comments belonging to a forum post)
Javascript API
Comments 2.0 implemented a YUI3 module M.core_comment to deal with the communication between browsers and moodle. It can be found in comment/comment.js
Call M.core_comment.init will create an instance of CommentHelper class. You don't need to make any calls to this instance, it simply works out of box.
Moodle modules callback
Comments API allows modules/blocks/blog to how comments display.
Permission control
Modules can implement a function named modname_comment_permissions to control post and view permission.
Blocks need to overwrite comment_permissions function of block_base.
Blog need to implement blog_comment_permissions function.
This function will return an array: array('post'=>true, 'view'=>true)
Check new added comment
The callback function allows you to change the comment content before inserting into database or reject this comment.
Modules can implement a function named modname_comment_add.
Blocks need to overwrite comment_add function.
Blog need to implement blog_comment_add function.
Filter/format comments
This callback allows modules check/format comments when user request to display comments.
Modules can implement a function named modname_comment_display.
Blocks need to overwrite comment_display function.
Blog need to implement blog_comment_display function.
Define a comment template
Modules can implement a function named modname_comment_template, which allow modules define a comment template. The template must have 4 embedding variables, ___id___, ___content___, ___time___, ___name___, they will be replaced with html id, comments content, comment time and commenter name
See also
- MDL-19118 - Comments 2.0 issue
