Why you shouldn’tedit SilverStripe

core files(and how to do it anyway)

By Loz Calver / @kinglozzer

What do you mean “editingcore files”?

Modifying someone else’s codeCode outside the scope of “your project”Applies to framework, cms and any other modules

Why would I edit core files?Bugs - SilverStripe isn’t (quite) perfectSecurity

need urgent/immediate fixemail us!

Missing/upcoming features - time delay between minor versionsClients!

security@silverstripe.org

Why shouldn’t I edit core files?Other developers don’t know what you’ve doneUpdates are harder

(you should all be keeping up to date!)eventually you’ll get bored or frustrated and give up

You might accidentally introduce other issues

How can I avoid editing core?

Workaround 1: ExtensionsExample 1: adding database fields & extra methods

MyMemberExtension.php

<?php

class MyMemberExtension extends DataExtension {

private static $db = array( 'DateOfBirth' => 'SS_Datetime' );

public function SayHi() { return "Hi " . $this->owner->Name; }

}

_config.yml

Member: extensions: - MyMemberExtension

Workaround 1: ExtensionsExample 2: augmenting database queries

BlogPostFilter.php

<?php

class BlogPostFilter extends DataExtension {

public function augmentSQL(SQLQuery &$query) { $stage = Versioned::current_stage();

if ($stage == 'Live' || !Permission::check('VIEW_DRAFT_CONTENT')) { $sqlNow = Convert::raw2sql(SS_Datetime::now()); $query->addWhere(sprintf('"PublishDate" < \'%s\'', $sqlNow)); } }

}

_config.yml

BlogPost: extensions: - BlogPostFilter

Workaround 1: ExtensionsPros

Can be used to add things to built-in classesReusable: package them up, release them as modules!

Cons/CaveatsReliant on extension pointsExtensions have limited power

Workaround 2: InjectorExample: adding an extension hook

ManyManyListWithHook.php

<?php

class ManyManyListWithHook extends ManyManyList {

public function add($item, $extraFields = null) { parent::add($item, $extraFields);

if($item instanceof DataObject) { $item->extend('onAfterManyManyAdd', $this); } }

}

_config.yml

Injector: ManyManyList: class: ManyManyListWithHook

Credit to / module@camspiers silverstripe-cacheinclude

Workaround 2: InjectorExample: using the extension hook

MemberExtension.php

<?php

class MemberExtension extends Extension {

public function onAfterManyManyAdd(ManyManyList $list) { Debug::log('Member added to many_many relation'); }

}

_config.yml

Member: extensions: - MemberExtension

Workaround 2: InjectorPros

Can “replace” an entire classSuper powerful

Cons/CaveatsWith great power comes great responsibilityMust be instantiated with one of:

Class::create()Injector::inst()->get('Class')Injector::inst()->create('Class')Injector::inst()->createWithArgs('Class')

When all else fails, fork it!

Create a fork, apply your fixUse Git to periodically rebase from “upstream”Composer helps to make this easier!

Examplecomposer.json

{ "require": { "silverstripe/cms": "3.1.15", "silverstripe/framework": "3.1.15" }, "repositories": [ { "type": "vcs", "url": "git@github.com:kinglozzer/sapphire.git" } ]}

Examplecomposer.json

{ "require": { "silverstripe/cms": "3.1.15", "silverstripe/framework": "dev-hotfix" }, "repositories": [ { "type": "vcs", "url": "git@github.com:kinglozzer/sapphire.git" } ]}

Not quite...

Fixed!composer.json

{ "require": { "silverstripe/cms": "3.1.15", "silverstripe/framework": "dev-hotfix" }, "repositories": [ { "type": "vcs", "url": "git@github.com:kinglozzer/sapphire.git" } ]}

Fixed!composer.json

{ "require": { "silverstripe/cms": "3.1.15", "silverstripe/framework": "dev-hotfix as 3.1.15" }, "repositories": [ { "type": "vcs", "url": "git@github.com:kinglozzer/sapphire.git" } ]}

ForkingPros

Easier to:keep track of modifications madere-apply changes during updates - rebase/cherry-pickcreate a PR!

Cons/CaveatsWhile easier, it’s still extra effort!Slows down composer updates

SummaryUse extensions where possibleFor simple additions/fixes to methods, Injector should be okayFor anything else you can’t work around, fork as last resortUse Composer!

Thanks/questionsFeedback welcomed!

@kinglozzer @kinglozzer lozcalver@bigfork.co.uk