Add-On Development: EE Expects that Every Developer will do his Duty

Add-On Development: EE Expects that Every Developer will do his Duty Paul Burdick, Lead Developer solspace http://solspace.com/downloads/eeci2009/presentation.txt

Summary of Talk • What are Add-Ons? • The Three Types of Add-Ons in EE • Overview of Accessories in EE 2.x • Add-On Development Skills • Developing Add-Ons in ExpressionEngine • Writing Code • Debugging & Improving Performance

I. What are Add-Ons?

Three Types of Add-Ons in EE 1.x and 2.x • Extensions • Modules • Plugins

Extensions

• Extends the base functionality of ExpressionEngine • Allows developers to interpose their own code into EE's codebase. • Restrained by where hooks are placed in the code and what arguments are sent with the extension call

• More and more Third Party developers are adding hooks to their own code, allowing extensions for Third Party Add-Ons. Pretty darn cool. • Typically no DB tables, but there are always exceptions • Settings Form CP

function settings() { $settings = array(); $settings['butter'] = "Quite Tasty"; $settings['buttery'] = array('r', array('yes' => "yes", 'no' => "no"), 'no'); // Complex: // [variable_name] => array(type, values, default value) // variable_name => short name for setting and key for language file variable // types: t - textarea // r - radio buttons // s - select // ms - multiselect // f - function calls // values: can be array (r, s, ms), string (t), function name (f) // default: name of array member, string, nothing // // Simple: // [variable_name] => 'Butter' // Text input, with 'Butter' as the default. return $settings; }

Modules

• The Mighty Workhorses of EE • Complete and expansive Control Panels. • Database Tables • Template Tags • Own extensions possible

Plugins

• No settings, no tables, no CP, no install • Text manipulation either via Template Tags or Custom Fields • Or, functionality "plugged" into your Templates.

Add-On Quantities @ devot-ee.com 18 October 2009 Extensions: 170 Modules: 73 Plugins: 248

Examples of Extensions • Edit Tab AJAX - AJAX enabled search for Control Panel's Edit area • FieldFrame - Easily create new custom ﬁeld types for ExpressionEngine. • LG Add Sitename - Site Label in upper left of your CP

Examples of Modules • Structure - Create Static and Listing pages, editable via a tree sitemap • Tag - Folksonomy functionality for Weblog and Gallery Entries • User - EE's Member Functionality in Templates

Examples of Plugins • EE Gravatar - Global Avatars for site members • Image Sizer - Resizes and caches images on the ﬂy • Markdown - Markdown formatting in EE Custom Weblog Fields

Accessories in EE 2.0

• Accessories provide tools, references, or abilities at the bottom of your EE Control Panel in ExpressionEngine 2.0 • No CP page for each Accessory • Can have own DB tables • View ﬁles! Lovely lovely View ﬁles!

II. Add-On Development Skills

• Duh... • PHP: Hypertext Preprocessor. You really have to love recursive acronyms. • Server side programming language. Processed at runtime. • No Compiling! Viewable Source!

• PHP ﬁles contain code, but they can also have HTML, JS, XML, et cetera inside them. • Extremely widespread on hosting environments.

PHP Learning References PHP Docs: http://php.net/manual/ W3C Tutorial: http://www.w3schools.com/PHP/php_intro.asp Zend Tutorial: http://devzone.zend.com/article/627

• Required for advanced Add-On development • Active Record only *helps* build queries

MySQL • Popular, open-source, relational database. • Simple to setup and administrate. • Fast for reading, decent for writing • Dominant on hosted environments

MySQL Learning References • MySQL Docs: http://dev.mysql.com/doc/ • Buy a book. ( O'Reilly Books are well done ) • Learn JOINs • http://www.informit.com/articles/article.aspx? p=30875&seqNum=5 • http://en.wikipedia.org/wiki/Join_(SQL)

HTML/CSS

View Files • Essentially HTML ﬁles with PHP inside for outputting data • Part of ExpressionEngine 2.0 by default • Available in ExpressionEngine1.x using Hermes or custom include code

<?php echo $this->view('header.html');?> <h4 class="alertHeadingCenter"><?php echo $LANG->line('error');?></h4> <div class='defaultCenter' > <div class="box"> <strong><?=$error_message?></strong> <br /><br /> <strong> <a href='javascript:history.go(-1)'>« <?=$LANG->line('back')?></a> </strong> </div> </div> <?php echo $this->view('footer.html'); ?>

User Interfaces • Build in static HTML, CSS, JS files before converting to View files. • Easier development. • Easier bug testing. • No need to create data variables/objects first. • UI developer does not need to understand PHP.

jQuery/JavaScript

• jQuery available in EE 1.x via an extension (not enabled by default) • jQuery available in EE 2.x with no additional work • Relatively easy to add other libraries or custom JS if need be.

global $EXT; if ( ! isset($EXT->version_numbers['Cp_jquery'])) { return $OUT->show_user_error('general', $LANG->line('cp_jquery_requred'))); }

III. Developing Add-Ons in ExpressionEngine

Never, Ever Just Start Coding!

Research • Previous Approaches • Required Features • Alternative Approach in ExpressionEngine? • Can this be done in EE in any other way? • Is a Module required? Could an Extension do it? • Could a Plugin output weblog data in the way you need?

Tell a Story • How will Person A do Task 1? • Question Previous Approaches. • Is X Really the BEST way to do it? • What Would Apple Do? • Eliminate Steps, Make Process Intuitive. • Follow your instincts.

Map Out Features • Major • Functionality required for module to serve its market/purpose • Minor • Not Necessarily Required. • Features are cuttable for a 1.0 release. • Icing • For speciﬁc clients or users • Think and consider them

Database Structure • Tables for your Major and Minor Features • Normalization: Eliminate Data Duplication • http://en.wikipedia.org/wiki/Database_normalization • Indexes! • Speciﬁc, Sensical Field Names • 'event_title' vs 'event' • 'event_short_name' vs 'name'

Tags Structure • The Naming and Functionality of Template tags • For Each Tag • Describe • Name • Parameters • Variable Pairs and Single Variables • Consider this a precursor to your documentation

Tags Structure: Describe • Descriptions for each Tag, Parameter, and Variable. • Explain what each one does.

Tags Structure: Tag Name • Simple and Obvious • No Abbreviations, No Ambiguity • {exp:module:g_entries} vs {exp:module:gallery_entries}

Tags Structure: Parameters • Preﬁx? • form:id="" or form_id="" • Use preﬁxes to break up parameters into "groups" of functionality. • notify:admin_email="" • notify:user_email=""

Tags Structure: Variables • No Ambiguity, No Abbreviations • {group}{/group} vs {category_group}{/category_group} • {title} vs {event_title} • Prevent collisions in nested tags • Underscores recommended

Tags Structure: Show to Other People • Get Feedback • Revise until the Spec feels solid.

Building a Control Panel

Workﬂow Module’s CP

Control Panel: Break Up into Sections • Data Adding, Deleting, and Manipulation • Create/Modify/Delete Items • Ex: Calendar, Wiki, Forum • Build only one main interface • Preferences/Settings/Permissions • Per Site, Per Weblog, Per Member Group, Per X • Actions • Ex: Recount, Re-Cache, Clear Caches • Version Number and Documentation Link

KISS: Keep It Simple, Stupid

Control Panel: Design • Build an HTML/CSS/JS mockup first • Put into a View file • PHP into HTML, Not HTML into PHP • documentDOM in Hermes - Builds HTML in PHP, specifically form fields • Ignore IE6 • EE 2.x no longer supports it • Solspace no longer supports it • Neither should you.

Time Wasted on IE6 Making Software Support IE6 vs. Upgrading Users

Time Wasted on IE6 Making Software Support IE6 vs. Upgrading Users 92% 8%

Have Goals, Even Milestones, Never Deadlines

IV. Writing Code

Follow the EllisLab Development Guidelines! http://expressionengine.com/docs/development/guidelines/index.html

"Proliﬁc and informative commenting using proper comment style" • We want to know your thinking! Why this way? • Expect people to learn from your code. • Helps you understand your *own* logic

Sanitize and Escape Everything • Be Paranoid! Nothing is Immune! Constant Vigilance! • If you DID NOT set or get data yourself, assume it is tainted, even EE variables • If you DID set or get yourself, but not within ten lines of code, assume it is tainted. • Sanitize and Escape at the Query • No Security Exceptions for SuperAdmins

Abstraction • Use Twice, Write Once • Create Libraries! • Reduces Work and Mistakes • Purpose of Hermes

Simplify, Simplify, Simplify

Simplify: Reduce Code Work • Do the Least Amount of Effort to produce results • Bail Out First, Work Second • Invalid variable type? Bail. • No Permissions? Bail. • Error? Bail. • Don’t Do Serious Work Until You Know You Have Work To Do

Simplify: Reduce DB Work • Performing Multiple Queries are OK. • Validate, Check Pagination, Then Retrieve Data

Simplify: Models • Abstract common SELECTs into separate methods • INSERTs/UPDATEs for a DB Table in one method • Hermes has per Add-On model caching caching built into it. • Speaking of caching...

Per Page Load Caching • Use $SESS->cache • Suggested: • $SESS->cache['modules']['module_name']['some_cache'] = array(); • Alternative: • $SESS->cache['Solspace']['module_name']['some_cache'] = array() • Try a Reference! • $this->cache =& $SESS->cache['modules']['module_name']; • $this->cache[‘some_cache’] = array();

Weblog Module Class • Very powerful code, no need to write your own. • Code was written so that it could be used elsewhere. • Returns Results based on tag parameters • You can modify $TMPL->tagparams!

require_once PATH_CORE.'core.typography'.EXT; require_once PATH_MOD.'/weblog/mod.weblog'.EXT; $TMPL->tagparams['entry_id'] = '1|2|3|4'; $TMPL->tagparams['dynamic'] = 'off'; $TMPL->tagdata = $TMPL->assign_relationship_data( $TMPL->tagdata ); $TMPL->var_single = array_merge( $TMPL->var_single, $TMPL->related_markers ); $weblog_object = new Weblog; $weblog_object->fetch_custom_weblog_fields(); $weblog_object->fetch_custom_member_fields(); $weblog_object->fetch_pagination_data(); $weblog_object->create_pagination(); $weblog_object->build_sql_query(); if ($weblog_object->sql == '') return $this->return_data = $TMPL->no_results(); $weblog_object->query = $DB->query($weblog_object->sql); if ($weblog_object->query->num_rows == 0) return $this->return_data = $TMPL->no_results(); $weblog_object->TYPE = new Typography; $weblog_object->fetch_categories(); $weblog_object->parse_weblog_entries(); $weblog_object->add_pagination_data(); return $this->return_data = $weblog_object->return_data;

Provide Tools for Keeping Things Tidy • Removal of Old Data. • Removal of Old Caches • Optimize Tables - Reduce DB Overhead

V. Debugging and Improving Performance

Consider Performance an Aspect of Add-On Debugging

Turn on PHP Debugging • Insure Display Errors Setting is On in php.ini • Error Reporting is E_ALL • No PHP Errors! Ever! • Remove All Deprecated PHP Functions.

Turn on SQL Queries • Admin => System Preferences => Output and Debugging • Queries appear on both CP and User side of EE • Review Queries • Check the Add-On's CP • Extensions: Check areas of usage in CP • Check EVERY single tag in a Template. • Eliminate Duplicates!

Turn on SQL Queries • Are Certain Queries Necessary on EVERY load? • Settings/Preferences • Caching (Checks, Re-caching, Emptying) • Statistics • Evaluate Queries for Performance • Run in phpMyAdmin or similar • Try Making the Query More Efﬁcient • Add a WHERE clause on indexed ﬁeld • Remove Extraneous JOINs when possible

Turn on SQL Queries • De-Normalization. • Duplicating Data or Grouping It to Reduce Work • http://en.wikipedia.org/wiki/Denormalization • Best example? Statistics: Hit count. • Abstract methods for data consistency (i.e. correct values) • Learn About Optimizing MySQL • MySQL Performance Blog • http://mysqlperformanceblog.com

SuperSearch SQL Queries

Turn on Template Debugging • Admin => System Preferences => Output and Debugging • Outputs Elapsed Time during Add-On processing • What Code is Taking the Longest to Process? • $TMPL->log_item() • $TMPL->log_item('Freeform Module: Run Query'); • Disable Processing • Disable Parameter ( disable="feng_shui" ) • Auto-detect Variables and Remove Queries and Processing

Vanilla Template Log

SuperSearch Processing

Knowing is Half the Battle!

Automated Actions • Example: Caching or Retrieving Remote Data • Can Seriously Slow Down an Add-On • Try AJAX

Deprecated Code • Consider using trigger_error() • trigger_error('Favorites Module: The Favorites Count tag has been deprecated. Use the Entry Count tag instead'); • Don't Leave It Around Forever, Discontinue Support, Then Remove It

Ask for Help • Plenty of EE, PHP, SQL Knowledge out there. Use it. • Often just discussing a problem will lead to a solution.

V. Presentation Over, So Let's Talk

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Add-On Development: EE Expects that Every Developer will do his Duty

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Add-On Development: EE Expects that Every Developer will do his Duty — Presentation Transcript