Moodle Development Best Practices

Presented by:Justin Filip

Presentation outline

Intro / development environment

Best practices

Peer reviews

Working with the Moodle tracker

Maintaining a plugin with Github

Submitting a core patch to Moodle HQ

Development environment

Web server:Apache

Lighttpd

Nginx

Database server:MySQL

PostgreSQL

PHP (5.3.2 or later for Moodle 2.2)

Code editor:Console (vim, Emacs)

IDE (Eclipse,Netbeans,Sublime Text)

Console editor - Emacs

IDE - Netbeans

General development settings

Enable developer debugging from Debugging section of the Development section of the Site administration menu

If working with real user data, prevent emails from being sent out by adding $CFG->noemailever = true; to your config.php file

If working on theme / CSS changes, enable Theme designer mode from the Theme settings section of the Site administration menuImportant! Do not leave this setting enabled on production sites as it has a large performance hit

Best practices

Correct usage of plugins and APIs

Security

Performance

Testing

Coding style

Key concepts: Correct usage of plugins and APIs

Correct usage of plugins and APIs

Key concepts:Plugin types

Core APIs

Database system

Key concepts: Moodle plugins

http://docs.moodle.org/dev/PluginsActivity modules

Authentication plugins

Blocks

Course formats

Enrolment plugins

Filters

Local plugins

Reports

Repository plugins

Themes

Extra: Moodle 2.3 plugin changes

Assignment module/mod/assign/submission/

/mod/assign/feedback/

Repository pluginsSupport for alias / shortcut to external content

supported_returntypes() should add FILE_REFERENCE to the return values to indicate this

Key concepts: database system

http://docs.moodle.org/dev/Data_definition_API

Plugin specific documentation http://tinyurl.com/a3gvpjj

Always use a primary key column called id

Add indexes and foreign keys to your database tables

If writing full SQL queries make sure to put table names within braces without the prefix{assignment_submissions} instead of mdl_assignment_submissions

Use the built-in XMLDB editor in Moodle for managing your XML install files

Key concepts: Moodle core APIs

Access

Data manipulation (DML)

File

Form

Logging

Navigation

Page

Strings

Upgrade

Extra: data definition (DDL)

Correct usage of plugins and APIs: Summary

Key concepts:Plugin types

Core APIs

Database system

Security

Security

Key concepts:Authentication

Roles and capabilities

User input

Key concepts: authentication

How users get into the system

Can connect to external systems:Problems if that system is unavailable

SSO & SSI

Confirming users and deletion

Key concepts: roles and capabilities

Context levels:CONTEXT_SYSTEM, CONTEXT_COURSE, CONTEXT_USER, etc.

Roles:Definitions

Applicable contexts

CapabilitiesUse the most specific capability possible

Check in the most specific context level

Extra: context hierarchy

Key concepts: user input

Never ever trust user input!!!Common web application problem

Always sanitise input data

required_param() & optional_param()

required_param_array() & optional_param_array()

Input parameter types:PARAM_ALPHA, PARAM_ALPHANUM, PARAM_NOTAGS, PARAM_CLEANHTML

PARAM_EMAIL, PARAM_URL, PARAM_SAFEDIR

Moodle form API (formslib) and SESSKEY validation

Extra: protecting access to your code

Command-line only scripts:define('CLI_SCRIPT', true);

Preventing directly loading a PHP file:defined('MDL_INTERNAL') || die();

Security: Summary

Authentication

Roles and capabilities

User input

Performance

Performance

Key concepts:Database IO

Profiling

Key concepts: database IO

Limit returned dataset using $fields parameter

Use result set paging with $limitfrom and $limitnum

Use record sets to not load all returned data into memory

Writing custom SQL queriesDatabase agnostic

Caution when using JOINs and subqueries

Key concepts: profiling

Use good testing dataTry to use a large dataset

If at all available, use a copy of data from a production siteSet $CFG->noemailever = true; in your Moodle config.php file

Enable performance output on each Moodle pageDisplays execution time, memory usage, DB read / write, etc.

http://tinyurl.com/axkuqjz

Key concepts: profiling with XHProf

Facebook-developed live profiling of PHP code

Built into Moodle

Quantitative analysis of results from a page execution

Pin-pointing performance problems

Critical execution path

http://techportal.inviqa.com/2009/12/01/profiling-with-xhprof/Ignore everything before the How to use XHProf section

XHProf: summary data

XHProf: execution call graph

Performance: Summary

Database IO

Profiling

Testing

Testing

Key concepts:Unit testing

Functional testing

Performance testing

Key concepts: unit testing

PHPUnithttps://github.com/sebastianbergmann/phpunit/

Testing single functions and methods in isolation

Added to Moodle core in 2.3.0

PHPUnit tests menu in the Development section of the Site administration menu contains more information how to setup and use them

See examples from other core code and plugins

Key concepts: functional testing

Testing interaction with your code via web browser or a simulated web browser

Can be used to find UI display problems across multiple browsers / OSs

Selenium http://seleniumhq.org/

Moodle HQ Behat testinghttps://moodle.org/mod/forum/discuss.php?d=221638

To be available for plugin authors as well as used in core Moodle

Key concepts: performance testing

Jmeterhttp://jmeter.apache.org/

Stress testing

Simulates load from many concurrent users

Extra: Moodle Universal Cache (MUC)

http://tinyurl.com/by7gs3p

A generic caching system that any code can use

Can plug into different back-end caching systems

Introduced in Moodle 2.4.0

Available to add-ons now, core components to use it in Moodle 2.0

Testing: Summary

Unit testing

Functional testing

Performance testing

Coding style

Coding style

More about how you write your code, not necessarily what you write

Consistency allows for familiarity when looking at new areas

Can prevent bad or sub-optimal code from being released

CodeChecker plugin:http://tinyurl.com/a9z9d8o

Best practices: Summary

Correct usage of plugins and APIs

Security

Performance

Testing

Coding style

Peer reviews

Attempt to find problems before testing

Ensure consistency in new code

Make sure required information is present and correct

Teaching tool for new developers

Enforces style and correctness of solution

Verify that new code is not using deprecated functionality

Peer review checklist

Syntax

Whitespace

Output

Language

Databases

Testing

Security

Documentation

Git

Sanity check

Working with the Moodle tracker

Key concepts:Creating new issues

Working on an existing issue

Key concepts: creating new issues

Always make sure to see if the issue you want to create already exists

Make sure to report as much information as possibleAffects Version/s

Database

Testing instructions

Workaround

Important! Always include debugging messages and screenshots if reporting a bug

Key concepts: working on an existing issue

Make sure nobody is working on it already

Put in a comment to ask for the issue to be assigned to you

Put your work in a publicly available Git repository and provide this information in the issue

Make sure that you provide testing instructions for your work

Request peer review when your work is finished

Maintaing a plugin with Github

Use correct repository name (see Moodle Frankenstyle)http://docs.moodle.org/dev/Frankenstyle

Create branches for supported Moodle versions (e.g. MOODLE_23_STABLE, MOODLE_24_STABLE)

Provide documentation in the MoodleDocs wiki

Submit the plugin to the Moodle.org plugins database

Keep track of bugs and new features in the official trackerRequest a component be created for your plugin in the Non-core contributed modules project

http://tinyurl.com/b7xc7nv

Submitting core patches to HQ

Fork the Moodle Github repositoryhttps://github.com/moodle/moodle

Create branches for affected versions

If this is for an existing issue, post the information for your repository into the issue

If this is for something new, create a new issue and start a discussion in the Moodle.org forums

Thank you

This presentation is available on SlideSharehttp://tinyurl.com/a3w7m2f

Find me on Twitter@jfilip

Click to edit the title text formatClick to edit Master title style

Click to edit the title text formatClick to edit Master title style

Click to edit the outline text formatSecond Outline LevelThird Outline LevelFourth Outline LevelFifth Outline LevelSixth Outline Level

Seventh Outline LevelClick to edit Master text styles

Second level

Third level

Fourth level

Fifth level