[Freeipa-devel] Extending the IPA-API

[Endi Sukma Dewata]

On 10/27/2011 10:59 AM, Adam Young wrote:
> The web UI can implement a similar mechanism. We do not want end sites
> modifying the .js files shipped with the IPA server RPM, other wise,
> they could inject columns and fields there, but they would be
> susceptible to breaking during upgrade. Instead, we will provide an
> extension mechanism similar to the Library back end:
>
> The Apache server will provide access to the file
> /etc/ipa/html/extensions.json. By default, this file will contain the
> simplest valid JSON possible:
> {}
>
> This file will be fetched via AJAX and evaluated during the
> initialization of Entities. THe format of the file will indicate what
> fields will be hidden in the UI, and what fields to add. As much as
> possible, the format will match the Java script that is used to poulated
> the entities.
>
> Something along the lines of:
>
> {entity:user,
> search:{add:['foo'],
> hide:['manager']},
> details:{add:[ {identity: ['foo','bar']}],
> hide:['manager']},
> }

I'd rather not use a descriptive language to perform object modification 
because it's very limited. For example, the 'add' operation doesn't say 
where the 'foo' should be added, whether it should be at the beginning 
or the end, or before/after certain fields, etc. We could continue 
expanding the language to support more complex logic, but why not just 
use JS directly.

> This would add one field to the search results, and two fields to the
> details page, inside the identity section.
>
> For the first pass, all added fields would be added as text fields.
>
> On the second pass, the JSON listed above can be extended to allow
> custom widgets in the field declarations.
>
> On the third pass, we add in a second file:
> /etc/ipa/html/custom_widgets.js. By default it will be blank.

I'd say we go directly with custom JS file and provide a good extensible 
JS API. It will require the least effort from us.

Somewhere in the code we can define the default entities:

   IPA.register('user', IPA.user.User);
   IPA.register('group', IPA.group.Group);

Then in the custom JS file we can override the default entity:

   IPA.register('user', com.example.user.User);

The custom entity can be defined as follows:

   com.example.user.User = function(spec) {

       // extend the default entity
       var that = IPA.user.User(spec);

       var init = function() {

           // replace the original search facet
           that.add_facet(com.example.user.SearchFacet({
               name: 'search'
           });
       };

       init();

       return that;
   };

   com.example.user.SearchFacet = function(spec) {

       // extend the default search facet
       var that = IPA.user.SearchFacet(spec);

       var init = function() {

           // find phone's position
           var i = that.get_field_index('phone');

           // add fax after phone
           that.add_field(i+1, 'fax');
       };

       init();

       return that;
   };

Then later we can design a descriptive language that will cover most 
common use cases.

> This file will be added to the index.html of the webUI, and evaluated
> after all of the other widgets, but before the entities. This will allow
> the end sites to not only add in their own widgets, but to possibly
> change the definition of some of the baseline widgets as well.

-- 
Endi S. Dewata