6.2. Comprehensive Theming

Any application, including Otto, can be loosely divided into two parts:

  • the user interface (“how it looks”), and

  • the application logic (“how it works”).

Considerations of the Otto user interface include, for example, how the products are laid out on the page, how the selectors look, how the checkout button is labelled, what sort of fonts and colors are used to display the text, and so on. Considerations of Otto’s application logic includes how Otto adjusts product price based on discount coupons, and how it records that information to be displayed in the future.

Theming consists of changing the user interface without changing the application logic. When you set up an E-Commerce website for use with your Open edX site, you probably want to use your organization’s own logo, modify the color scheme, change links in the header and footer for SEO (search engine optimization) purposes, and so on.

However, although the user interface might look different, the application logic must remain the same so that Otto continues to work properly. A well- designed theme preserves the general layout and structure of the user interface, so that users of the website still find it familiar and easy to use. Be careful about making sweeping changes to the user interface without warning: your users will be very confused!

The default Open edX theme is named “Comprehensive Theming”. You can disable Comprehensive Theming by setting ENABLE_COMPREHENSIVE_THEMING to False, as shown in this example, then applying your custom theme.

ENABLE_COMPREHENSIVE_THEMING = False

6.2.1. Theme Structure

From a technical perspective, theming consists of overriding core templates, static assets, and Sass with themed versions of those resources.

Every theme must conform to a directory structure that mirrors the Otto directory structure.

my-theme
    ├── README.rst
    ├── static
    |      └── images
    |      |     └── logo.png
    |      |
    |      └── sass
    |            └── partials
    |                   └── utilities
    |                           └── _variables.scss
    |
    └── templates
            └── oscar
            |     └── dashboard
            |             └── index.html
            └── 404.html

6.2.1.1. Templates

Any template included in ecommerce/templates directory can be “themed”. However, make sure not to override class names or ID values of HTML elements within a template, as these are used by JavaScript or CSS. Overriding these names and values can cause unwanted behavior.

6.2.1.2. Static Assets

Any static asset included in ecommerce/static can be overridden except for the CSS files in the ecommerce/static/css directory. CSS styles can be overridden via Sass overrides explained below.

Caution

Theme names must be unique. The names of static assets or directories must not be same as the theme’s name, otherwise static assets will not work correctly.

6.2.1.3. Sass

Sass overrides are a little different from static asset or template overrides. There are two types of styles included in ecommerce/static/sass:

  • base

  • partials

Caution

Styles present in ecommerce/static/sass/base should not be overridden as overriding these could result in an unexpected behavior.

Any styles included in ecommerce/static/sass/partials can be overridden. Styles included in this directory contain variable definitions that are used by main Sass files. Elements of the user interface such as header/footer, background, fonts, and so on, can be updated in this directory.

6.2.2. Enabling a Theme

To enable a theme, you must first install your theme onto the same server that is running Otto. If you are using devstack or fullstack to run Otto, you must be sure that the theme is present on the Vagrant virtual machine. It is up to you where to install the theme on the server, but a good default location is /edx/app/ecommerce/ecommerce/themes.

Note

All themes must reside in the same physical directory.

In order for Otto to use the installed themes, you must specify the location of the theme directory in Django settings by defining COMPREHENSIVE_THEME_DIRS in your settings file, as shown in the example, where /edx/app/ecommerce/ecommerce/themes is the path to where you have installed the themes on your server.

COMPREHENSIVE_THEME_DIRS = ["/edx/app/ecommerce/ecommerce/themes", ]

You can list all theme directories using this setting.

After you install a theme, you associate it with your site by adding appropriate entries to the following tables.

  • Site

  • Site Themes

For local devstack, if the Otto server is running at localhost:8002 you can enable a my-theme by following these steps.

  1. Add a new site with the domain localhost:8002 and the name “Otto My Theme”.

  2. Add a site theme with the theme dir name my-theme, selecting localhost:8002 from the site dropdown.

The Otto server can now be started, and you should see that my-theme has been applied. If you have overridden Sass styles and you are not seeing those overrides, then you need to compile Sass files as described in Compiling Theme Sass.

6.2.3. Disabling a Theme

A theme can be disabled by removing its corresponding Site Theme entry using django admin.

6.2.3.1. Creating or Updating Site and SiteTheme

If you have already set up COMPREHENSIVE_THEME_DIRS, you can use the management command for adding Site and SiteTheme directly from the terminal.

python manage.py create_or_update_site_theme --site-domain=localhost:8002 --site-name=localhost:8002 --site-theme=my-theme

The create_or_update_site_theme command accepts the following optional arguments, listed below with examples.

  • settings: The settings file to use. The default file is ecommerce.settings.devstack.

python manage.py create_or_update_site_theme --settings=ecommerce.settings.production
  • site-id: The ID of the site that you want to update.

# update domain of the site with id 1 and add a new theme
# ``my-theme`` for this site
python manage.py create_or_update_site_theme --site-id=1 --site-domain=my-theme.localhost:8002 --site-name=my-theme.localhost:8002 --site-theme=my-theme
  • site-domain: The domain of the site to be created.

python manage.py create_or_update_site_theme --site-domain=localhost:8002 --site-theme=my-theme
  • site-name: The name of the site to be created. The default setting is ''.

python manage.py create_or_update_site_theme --site-domain=localhost:8002 --site-name=localhost:8002 --site-theme=my-theme
  • site-theme: The theme dir for the new theme.

python manage.py create_or_update_site_theme --site-domain=localhost:8002 --site-name=localhost:8002 --site-theme=my-theme

6.2.3.2. Compiling Theme Sass

You use the management command update_assets to compile and collect themed Sass.

python manage.py update_assets

The update_assets command accepts the following optional arguments, listed below with examples.

  • settings: The settings file to use. The default file is ecommerce.settings.devstack.

python manage.py update_assets --settings=ecommerce.settings.production
  • themes: The space-separated list of themes to compile Sass for. Possible options are all for all themes, no to skip Sass compilation for themes. The default option is all.

# compile Sass for all themes
python manage.py update_assets --theme=all

# compile Sass for only given themes, useful for situations if you have
# installed a new theme and want to compile Sass for just this theme

python manage.py update_assets --themes my-theme second-theme third-theme

# skip Sass compilation for themes, useful for testing changes to system
# Sass, keeping theme styles unchanged

python manage.py update_assets --theme=no
  • output-style: The coding style for compiled CSS files. Possible options are nested, expanded, compact and compressed. The default option is nested.

python manage.py update_assets --output-style='compressed'
  • skip-system: This flag disables system Sass compilation.

# useful in cases where you have updated theme Sass, and system Sass is
# unchanged.

python manage.py update_assets --skip-system
  • enable-source-comments: This flag enables source comments in generated CSS files.

python manage.py update_assets --enable-source-comments
  • skip-collect: Use this flag to skip the collectstatic call after Sass compilation.

# useful if you just want to compile Sass, and call ``collectstatic`` later,
# possibly by a script

python manage.py update_assets --skip-collect

6.2.4. Troubleshooting

If you have gone through the preceding procedures and you are not seeing theme overrides, check the following areas.

  • COMPREHENSIVE_THEME_DIRS must contain the path for the directory containing themes. For example, if your theme is /edx/app/ecommerce/ecommerce/themes/my- theme then the correct value for COMPREHENSIVE_THEME_DIRS is ['/edx/app/ecommerce/ecommerce/themes'].

  • The domain name for site is the name that users will put in the browser to access the site, and includes the port number. For example, if Otto is running on localhost:8002 then the value for domain should be localhost:8002.

  • The theme dir name is the name of the directory of your theme. For example, for our ongoing example, my-theme is the correct theme dir name.