[META] Basic architecture discussion

Issues: https://www.drupal.org/project/issues/search/entity_browser?project_issu...

Basic structure

Components

• Entity browser: Config entity that stores entire configuration for a given EB instance, provides communication interface to other systems, implemets any business logic and glues all pieces of the system together.
• Browser display: Plugins that bring EB into different contexts in UI: entity_embed uses modal implementation; a field widget could use EB in an iFrame; a system that pushes content to 3rd party systems could use a standalone form to select entities that need to be pushed over; ...
• Browser widget: Plugins that provide different ways of selecting content (views, custom form, entity form, uploader, field widgets, ...).
• Widget selector: Plugins that define how different widgets are displayed and selected. Can be tabs, dropdown, buttons, ...
• Selection display: Plugin that handles display and logic around currently selected entities (before they are actually sent over). Can be something as a grid of rendered entities that were selected - allows user to go into different widgets and select entities in multiple steps or something very simple that pushes entities over as soon as something is selected on one of the widgets.

Basic flows

Initial form load

External system requests a specific EB. EB config entity works with all plugins and delivers a form/selection interface.

Selection of entities when using simple (single step) selection display

User selects entities on one of the widgets. SelectionDisplay plugin relizes that we're not doing any further steps which results in EB emmiting an event with all selected entities attached. It is then up to subscribers to decide what to do with them and where to go from there.

Selection of entities when using "multi step" selection display

Very similar to single step selection. The only difference are multple steps that we can take to select entities. On every step we add selected entities to selection display, which renders them as a grid, table, list, ... Along with that we provide another UI element that ends the selection process. From here on we have same flow as with single step: selection display realizes that we've reached the final step, which results in EB emmiting an event.

Browser widget examples

Tabs display

Dropdown display

Buttons display

Specially useful if we have small number of browser widgets (2 or 3).

Selection display examples

Note: "Simple" (single step) selection display is not includded. However, all examples in previous section can be understood as such.

Grid selection display

Table selection display

Unordered list selection display

Diagrams and wireframes in other formats

ODG version: https://box.zabica.org/public.php?service=files&t=4ccf1e062ad26cde37f308...
PDF version: https://box.zabica.org/public.php?service=files&t=7a734038ecdbf7d8dc8abf...