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THE ANATOMY OF AN EXTENSION

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WHO IS THIS GUY?

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A family man

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WHO IS THIS GUY?

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Jesus is my homeboy

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WHO IS THIS GUY?

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World famous (I’m on the internet)

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WHO IS THIS GUY?

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EE Reactor team member

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WHO IS THIS GUY?

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Partner & Technical Director

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THE ANATOMY OF AN EXTENSION

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GOALS• Extensions in the context of Add-ons

• What are Hooks?

• How do Hooks relate to Extensions?

• How are Extensions called by EE?

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GOALS• Caveats in using Extensions

• end_script explanation & use

• Returning data back to EE

• Better Debugging Processes

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ADD-ONS OVERVIEW• Plugins

• Accessories

• Modules

• Fieldtypes

• Extensions

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PLUGINS• Runtime add-ons

• No settings interface

• No installation required

• No unique db tables (typically)

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PLUGINS• No language file requirement

• Can format custom text fields

• Can provide Template tags

• Small learning curve

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ACCESSORIES• Only shown in Control Panel

• EE handles installation & settings for you

• Small learning curve

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MODULES• Can have a Control Panel interface

• Requires Language file

• Must be installed in the Control Panel

• Can utilize "actions"

• Can provide Template tags

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FIELDTYPES• Fairly self-explanatory

• Fieldtypes for channel publish form

• Have corresponding Template tags

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EXTENSIONS• Must be installed in the CP

• Can use EE's built-in simple settings builder

• Requires language file when you have settings

• Can have unique database tables (but they o!en don’t)

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EXTENSIONS• Manipulates data or processing during a given point

in a page load

• Must behave nicely with other extensions

• Probably the steepest learning curve in add-ons

• Can only be used with existing system "hooks"

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WHAT ARE HOOKS?

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Hooks are used to alter or augment the behavior of an operating system, of applications, or of other so!ware components.

Wikipedia article on “Hooking”

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How do hooks relate to Extensions?

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How do hooks relate to Extensions?

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HOOK PROCESSING1. ExpressionEngine encounters a "hook" in the system

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HOOK PROCESSING2. It checks the exp_extensions table to see if there is a

record with the "hook" where the "enabled" column is set to "y" (yes)

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HOOK PROCESSING3.If there is, then EE looks at the "class" column to

determine which add-on to look in for this extension

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HOOK PROCESSING4.If the add-on Extension file exists, it is loaded

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HOOK PROCESSING5.Within that Extension class, the method listed is

executed.

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How do hooks relate to Extensions?

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HOOK PROCESSINGLow Seg2Cat Example Applied

1. ExpressionEngine encounters the sessions_end hook in the system

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HOOK PROCESSINGLow Seg2Cat Example Applied

2. It checks the already-loaded extensions dataset for an extension using the sessions_end hook which is enabled

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HOOK PROCESSINGLow Seg2Cat Example Applied

3.EE looks at the class "Low_seg2cat_ext" and knows to look for a folder called third_party/low_seg2cat

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HOOK PROCESSINGLow Seg2Cat Example Applied

4.If third_party/low_seg2cat/ext.low_seg2cat.php exists, the file is loaded and an object is created

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HOOK PROCESSINGLow Seg2Cat Example Applied

5.Finally EE executes the sessions_end method within the ext.low_seg2cat.php file

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EXTENSION PROCESSING

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HOOK EXAMPLE

/* -------------------------------------------/* 'delete_entries_start' hook./* - Perform actions prior to entry deletion / take over deletion*/ $edata = $this->extensions->call('delete_entries_start'); if ($this->extensions->end_script === TRUE) return;/*/* -------------------------------------------*/

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The “delete_entries_start” hook

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HOOK EXAMPLE

/* -------------------------------------------/* 'delete_entries_start' hook./* - Perform actions prior to entry deletion / take over deletion*/ $edata = $this->extensions->call('delete_entries_start'); if ($this->extensions->end_script === TRUE) return;/*/* -------------------------------------------*/

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The “delete_entries_start” hook

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HOOKS QUERY

SELECT DISTINCT ee.*FROM exp_extensions eeWHERE enabled = 'y'ORDER BY hook, priority ASC, class

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From libraries/Extensions.php

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HOOK EXAMPLE

/* -------------------------------------------/* 'delete_entries_start' hook./* - Perform actions prior to entry deletion / take over deletion*/ $edata = $this->extensions->call('delete_entries_start'); if ($this->extensions->end_script === TRUE) return;/*/* -------------------------------------------*/

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The “delete_entries_start” hook

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HOOK EXAMPLE

/* -------------------------------------------/* 'delete_entries_start' hook./* - Perform actions prior to entry deletion / take over deletion*/ $edata = $this->extensions->call('delete_entries_start'); if ($this->extensions->end_script === TRUE) return;/*/* -------------------------------------------*/

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The “delete_entries_start” hook

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Extensions playing well with others

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HOOK EXAMPLE

/* -------------------------------------------/* 'delete_entries_start' hook./* - Perform actions prior to entry deletion / take over deletion*/ $edata = $this->extensions->call('delete_entries_start'); if ($this->extensions->end_script === TRUE) return;/*/* -------------------------------------------*/

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The “delete_entries_start” hook

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DEBUGGING METHODS• Disable all extensions in the CP

• Disable all extensions in the config.php file

• Disable one extension at a time in the database

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Add-ons → Extensions

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config.php override

/*|-------------------------------------------------------| ExpressionEngine Config Items|-------------------------------------------------------|| The following items are for use with ExpressionEngine.| The rest of the config items are for use with| CodeIgniter.|*/

$config['app_version'] = "250";$config['is_system_on'] = "y";$config['allow_extensions'] = "y";

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config.php override

/*|----------------------------------------------------------| ExpressionEngine Config Items|----------------------------------------------------------|| The following items are for use with ExpressionEngine.| The rest of the config items are for use with| CodeIgniter.|*/

$config['app_version'] = "250";$config['is_system_on'] = "y";$config['allow_extensions'] = "n";

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exp_extensions table

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All content available online at:

focuslabllc.com/blog

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!ERIKREAGANPartner"#Focus#Lab"#LLC!FocusLabLLC

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