S3UI v1 - ExtJS based UI for Eden

S3XRC being a powerful backend that serves XML and JSON in a RESTful manner has now got a front-end framework that can exploit its positives. S3UI - the new ExtJS based front-end help us not only utilize S3XRC but also save a lot of bandwidth by exchanging information in JSON instead of full page reloads. This in turn aims to create an easy and quick workflow for different tasks that a user does with Sahana Eden.

Architecture

S3UI Framework is has 4 major components

• Custom views - these views contain appropriate javascript and html required to render the S3UI widgets, however they are minimal and look almost similar to old views for matter of simplicity and similarity.

• Javascript -
  • _s3ui_list.js - generates the grid view, included by _s3ui_list and _s3ui_list_create views -
    • Setting up metadata
    • fetching column model
    • Parsing json data from s3xrc into an Ext Datastore
    • Configuring and rendering a Grid widget on desired DOM element

• core.js -
  • Provides S3UI objects and S3UI_Elements list
  • Manages creation of different widgets - used in custom views
  • Naming convention -
    • data_FunctionName - any function pertaining to parsing, formatting or manipulating data, nothing that affects UI
    • tools_FunctionName - various helpers that aid larger widgets - Eg. plugin implementors, micro-widget generators (date picker, checkbox, combo box)
    • widget_FunctionName - Larger widgets that can be used directly to create new visible UI elements
• plugins - various ExtJS based plugins used by core.js

• Extcrud.py
  • is used to override necessary functions of 01_crud.py that are useful to S3UI
  • Alters flow through pre, post hooks to plug in code required by new UI
  • list_fields is no longer relevant, the modified S3XRC has a url/listfileds.json handler that gives back list of fields needed by a resource, it is implemented in the post processing hook here.
  • Implements xrc_list - a replacement for shn_list. It doesn't do as much work as shn_list, but leaves the rendering of datagrid to the frontend, page loads fast but rest of the processing is done by core.js
  • contains S3XRC_FRONTEND switch. Whats that? setting S3XRC_FRONTEND = false results in disabling all S3UI functionalities and lets one fall back to old UI. Useful when S3UI fails, or for testing.
  • overrides shn_rest_controller to setup hooks.

Widgets

• Grid View widget -
  • Seen in _s3ui_list , _s3ui_list_create views
  • Utilized in _s3ui_list.js
  • Produced by core.js -
    • once all required metadata is setup (see _s3ui_list.js), the following are called up in order -
      • widgets_getGridView()
      • widgets_gridView.create(dom element id)
      • widgets_gridView.show()

• Rheader tabs -
  • Seen in _s3ui_update , _s3ui_display views as they are found to be primary to record's default view
  • Utilized in _s3ui_update and _s3ui_display views itself
  • Produced by core.js -
    • once base_url, update_url, uid_prefix, setupElementNames() is set, following are called to produce tabs
      • widgets_tabs_parseHtml() [ subject to change in version 2 ]
      • widgets_tabs_render()

• widgets_formPanel -
  • Seen in grid view widget, views where there are no records in the list
  • widgets_formPanel parameters
    • action - either of 'create' or 'update' indication which type of form window to generate
    • window title - caption for form window
  • also has ability to generate buttons for actions - widgets_formPanel_createButton(action, caption, title, dom element id)
  • handles form submission, has very basic error indicaton as of now.

Roadmap

Wishlist for S3UI v2 -

• Frontend validation
• Exploiting more ExtJS power
• New Rheader tabs, non IFrame implementation
• SQLFORM2 as a replacement of SQLFORM to give out json form configuration
• More speed, less load on backend, free the logic layer of presentation tasks

FAQ

Q. How to turn off S3UI and fall back to old UI?

A. In models/01_extcrud.py change -

S3XRC_FRONTEND = True

into

S3XRC_FRONTEND = False