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How to extend the CMS interface

Introduction

The CMS interface works just like any other part of your website: It consists of PHP controllers, templates, CSS stylesheets and JavaScript. Because it uses the same base elements, it is relatively easy to extend.

As an example, we're going to add a permanent "bookmarks" link list to popular pages into the main CMS menu. A page can be bookmarked by a CMS author through a simple checkbox.

For a deeper introduction to the inner workings of the CMS, please refer to our guide on CMS Architecture.

Redux Devtools

It's important to be able to view the state of the React application when you're debugging and building the interface.

To be able to view the state, you'll need to be in a dev environment and have the Redux Devtools installed on Google Chrome or Firefox, which can be found by searching with your favourite search engine.

Overload a CMS template

If you place a template with an identical name into your application template directory (usually mysite/templates/), it'll take priority over the built-in one.

CMS templates are inherited based on their controllers, similar to subclasses of the common Page object (a new PHP class MyPage will look for a MyPage.ss template). We can use this to create a different base template with LeftAndMain.ss (which corresponds to the LeftAndMain PHP controller class).

Copy the template markup of the base implementation at framework/admin/templates/Includes/LeftAndMain_Menu.ss into mysite/templates/Includes/LeftAndMain_Menu.ss. It will automatically be picked up by the CMS logic. Add a new section into the <ul class="cms-menu-list">

:::ss
...
<ul class="cms-menu-list">
	<!-- ... -->
	<li class="bookmarked-link first">
		<a href="{$AdminURL}pages/edit/show/1">Edit "My popular page"</a>
	</li>
	<li class="bookmarked-link last">
		<a href="{$AdminURL}pages/edit/show/99">Edit "My other page"</a>
	</li>
</ul>
...

Refresh the CMS interface with admin/?flush=all, and you should see those hardcoded links underneath the left-hand menu. We'll make these dynamic further down.

Include custom CSS in the CMS

In order to show the links a bit separated from the other menu entries, we'll add some CSS, and get it to load with the CMS interface. Paste the following content into a new file called mysite/css/BookmarkedPages.css:

:::css
.bookmarked-link.first {margin-top: 1em;}

Load the new CSS file into the CMS, by setting the LeftAndMain.extra_requirements_css configuration value.

:::yml
LeftAndMain:
  extra_requirements_css:
    - mysite/css/BookmarkedPages.css

Create a "bookmark" flag on pages

Now we'll define which pages are actually bookmarked, a flag that is stored in the database. For this we need to decorate the page record with a DataExtension. Create a new file called mysite/code/BookmarkedPageExtension.php and insert the following code.

:::php
<?php

class BookmarkedPageExtension extends DataExtension {

	private static $db = array(
		'IsBookmarked' => 'Boolean'
	);

	public function updateCMSFields(FieldList $fields) {
		$fields->addFieldToTab('Root.Main',
			new CheckboxField('IsBookmarked', "Show in CMS bookmarks?")
		);
	}
}

Enable the extension in your configuration file

:::yml
SiteTree:
  extensions:
    - BookmarkedPageExtension

In order to add the field to the database, run a dev/build/?flush=all. Refresh the CMS, open a page for editing and you should see the new checkbox.

Retrieve the list of bookmarks from the database

One piece in the puzzle is still missing: How do we get the list of bookmarked pages from the database into the template we've already created (with hardcoded links)? Again, we extend a core class: The main CMS controller called LeftAndMain.

Add the following code to a new file mysite/code/BookmarkedLeftAndMainExtension.php;

:::php
<?php

class BookmarkedPagesLeftAndMainExtension extends LeftAndMainExtension {

	public function BookmarkedPages() {
		return Page::get()->filter("IsBookmarked", 1);
	}
}

Enable the extension in your configuration file

:::yml
LeftAndMain:
  extensions:
    - BookmarkedPagesLeftAndMainExtension

As the last step, replace the hardcoded links with our list from the database. Find the <ul> you created earlier in mysite/admin/templates/LeftAndMain.ss and replace it with the following:

:::ss
<ul class="cms-menu-list">
	<!-- ... -->
	<% loop $BookmarkedPages %>
	<li class="bookmarked-link $FirstLast">
		<li><a href="{$AdminURL}pages/edit/show/$ID">Edit "$Title"</a></li>
	</li>
	<% end_loop %>
</ul>

Extending the CMS actions

CMS actions follow a principle similar to the CMS fields: they are built in the backend with the help of FormFields and FormActions, and the frontend is responsible for applying a consistent styling.

The following conventions apply:

New actions can be added by redefining getCMSActions, or adding an extension with updateCMSActions.
It is required the actions are contained in a FieldSet (getCMSActions returns this already).
Standalone buttons are created by adding a top-level FormAction (no such button is added by default).
Button groups are created by adding a top-level CompositeField with FormActions in it.
A MajorActions button group is already provided as a default.
Drop ups with additional actions that appear as links are created via a TabSet and Tabs with FormActions inside.
A ActionMenus.MoreOptions tab is already provided as a default and contains some minor actions.
You can override the actions completely by providing your own getAllCMSFields.

Let's walk through a couple of examples of adding new CMS actions in getCMSActions.

First of all we can add a regular standalone button anywhere in the set. Here we are inserting it in the front of all other actions. We could also add a button group (CompositeField) in a similar fashion.

:::php
$fields->unshift(FormAction::create('normal', 'Normal button'));

We can affect the existing button group by manipulating the CompositeField already present in the FieldList.

:::php
$fields->fieldByName('MajorActions')->push(FormAction::create('grouped', 'New group button'));

Another option is adding actions into the drop-up - best place for placing infrequently used minor actions.

:::php
$fields->addFieldToTab('ActionMenus.MoreOptions', FormAction::create('minor', 'Minor action'));

We can also easily create new drop-up menus by defining new tabs within the TabSet.

:::php
$fields->addFieldToTab('ActionMenus.MyDropUp', FormAction::create('minor', 'Minor action in a new drop-up'));

Empty tabs will be automatically removed from the `FieldList` to prevent clutter.

To make the actions more user-friendly you can also use alternating buttons as detailed in the CMS Alternating Button how-to.

ReactJS in SilverStripe

SilverStripeComponent

The base class for SilverStripe React components. If you're building React components for the CMS, this is the class you want to extend. SilverStripeComponent extends React.Component and adds some handy CMS specific behaviour.

Creating a component

my-component.js

import SilverStripeComponent from 'silverstripe-component';

class MyComponent extends SilverStripeComponent {

}

export default MyComponent;

That's how you create a SilverStripe React component!

Interfacing with legacy CMS JavaScript

One of the great things about ReactJS is that it works great with DOM based libraries like jQuery and Entwine. To allow legacy-land scripts to notify your React component about changes, add the following.

my-component.js

import SilverStripeComponent from 'silverstripe-component';

class MyComponent extends SilverStripeComponent {
	componentDidMount() {
		super.componentDidMount();
	}
	
	componentWillUnmount() {
		super.componentWillUnmount();
	}
}

export default MyComponent;

This is functionally no different from the first example. But it's a good idea to be explicit and add these super calls now. You will inevitably add componentDidMount and componentWillUnmount hooks to your component and it's easy to forget to call super then.

So what's going on when we call those? Glad you asked. If you've passed cmsEvents into your component's props, wonderful things will happen.

Let's take a look at some examples.

Getting data into a component

Sometimes you'll want to call component methods when things change in legacy-land. For example when a CMS tab changes you might want to update some component state.

main.js

import $ from 'jquery';
import React, { PropTypes, Component } from 'react';
import MyComponent from './my-component';

$.entwine('ss', function ($) {
	$('.my-component-wrapper').entwine({
		getProps: function (props) {
			var defaults = {
				cmsEvents: {
					'cms.tabchanged': function (event, title) {
						// Call a Redux action to update state.
					}
				}
			};
			
			return $.extend(true, defaults, props);
		},
		onadd: function () {
			var props = this.getProps();
			
			React.render(
				<MyComponent {...props} />,
				this[0]
			);
		}
	});
});

legacy.js

(function ($) {
	$.entwine('ss', function ($) {
		$('.cms-tab').entwine({
			onclick: function () {
				$(document).trigger('cms.tabchanged', this.find('.title').text());
			}
		});
	});
}(jQuery));

Each key in props.cmsEvents gets turned into an event listener by SilverStripeComponent.componentDidMount. When a legacy-land script triggers that event on document, the associated component callback is invoked, with the component's context bound to it.

All SilverStripeComponent.componentWillUnmount does is clean up the event listeners when they're no longer required.

There are a couple of important things to note here:

Both files are using the same ss namespace.
Default properties are defined using the getProps method.

This gives us the flexibility to add and override event listeners from legacy-land. We're currently updating the current tab's title when .cms-tab is clicked. But say we also wanted to highlight the tab. We could do something like this.

legacy.js

(function ($) {
	$.entwine('ss', function ($) {
		$('.main .my-component-wrapper').entwine({
			getProps: function (props) {
				return this._super({
					cmsEvents: {
						'cms.tabchanged': function (event, title) {
							// Call a Redux action to update state.
						}
					}
				});
			}
		});
		
		$('.cms-tab').entwine({
			onclick: function () {
				$(document).trigger('cms.tabchanged', this.find('.title').text());
			}
		});
	});
}(jQuery));

Here we're using Entwine to override the getProps method in main.js. Note we've made the selector more specific .main .my-component-wrapper. The most specific selector comes first in Entwine, so here our new getProps gets called, which passes the new callback to the getProps method defined in main.js.

Getting data out of a component

There are times you'll want to update things in legacy-land when something changes in you component.

SilverStripeComponent has a handly method emitCmsEvents to help with this.

my-component.js

import SilverStripeComponent from 'silverstripe-component';

class MyComponent extends SilverStripeComponent {
	componentDidMount() {
		super.componentDidMount();
	}
	
	componentWillUnmount() {
		super.componentWillUnmount();
	}
	
	componentDidUpdate() {
		this.emitCmsEvent('my-component.title-changed', this.state.title);
	}
}

export default MyComponent;

legacy.js

(function ($) {
	$.entwine('ss', function ($) {
		$('.cms-tab').entwine({
			onmatch: function () {
				var self = this;

				$(document).on('my-component.title-changed', function (event, title) {
					self.find('.title').text(title);
				});
			},
			onunmatch: function () {
				$(document).off('my-component.title-changed');
			}
		});
	});
}(jQuery));

Implementing handlers

Your newly created buttons need handlers to bind to before they will do anything. To implement these handlers, you will need to create a LeftAndMainExtension and add applicable controller actions to it:

:::php
class CustomActionsExtension extends LeftAndMainExtension {
	
	private static $allowed_actions = array(
    	'sampleAction'
	);
	
	public function sampleAction()
	{
		// Create the web
	}
	
}

The extension then needs to be registered:

:::yaml
LeftAndMain:
	extensions:
		- CustomActionsExtension

You can now use these handlers with your buttons:

:::php
$fields->push(FormAction::create('sampleAction', 'Perform Sample Action'));

Summary

In a few lines of code, we've customised the look and feel of the CMS.

While this example is only scratching the surface, it includes most building blocks and concepts for more complex extensions as well.

13 KiB Raw Blame History

How to extend the CMS interface

Introduction

Redux Devtools

Overload a CMS template

Include custom CSS in the CMS

Create a "bookmark" flag on pages

Retrieve the list of bookmarks from the database

Extending the CMS actions

ReactJS in SilverStripe

SilverStripeComponent

Creating a component

Interfacing with legacy CMS JavaScript

Getting data into a component

Getting data out of a component

Implementing handlers

Summary

Related

13 KiB

Raw Blame History