ajax-backed-model-behavior

Pub Travis

A Dart Polymer behavior that provides a Polymer element with a model derived from an ajax request.

Usage

First, make your model class implement AjaxBackedModel and its abstract method setFromJsonString. This method handles deserialization of JSON into an existing instance of the model.

Next, create a Polymer element that will utilize the model, by implementing AjaxBackedModelBehavior. The element must implement

above.  

With the above wiring, the polymer element gains additional attributes
which simplify its use.  For example:

<my-element auto-load ajax-url="http://mydomain/api/data.json"></my-element>


With the usage above, the json returned from ```data.json``` will be
converted to the model object and assigned to the "ajaxModel" attribute
when the element is readied.  The element's html can 
reference model data as ```[[ajaxModel.myField]]```.

## Attributes

 * ```ajax-url```: The url to the data source, e.g. a rest endpoint or data
file 
 *  ```auto-load```: if true, then any changes to ```ajax-url``` will 
result in the model being updated with the result of a new ajax 
request.
 *  ```ajax-model```: may be used to set the model directly for situations 
 where it is not necessary to look up the model via ajax

## Events

AjaxBackedModelBehavior may fire the following three events

 * ajax-model-request, detail: String containing url
 * ajax-model-response, detail: AjaxBackedModel 
 * ajax-model-error, detail: Map containing 'status' and  'statusText'

## Changing the model attribute name

If desired, the model attribute name can be changed from the default 
("ajaxModel").  Override the method ```get modelName```.   See [example](https://github.com/ilikerobots/ajax-backed-model-behavior/blob/master/example/view/country_detail.dart).


## Future improvements

I would like to provide a @AjaxModel annotation, and create a 
transformer automatically provide the wiring described above.


## Example


The following code illustrates a simple example of a model and a custom
Polymer element using it an ajax backed model.

class Country extends Object with AjaxBackedModel, JsProxy {

@reflectable int id; @reflectable String name;

Country();

setFromJsonString(String json) {

id = o['id'];
name = o['country'];

} }



@HtmlImport('country_detail.html')

@PolymerRegister('country-detail') class CountryDetail extends PolymerElement with AjaxBackedModelBehavior {

CountryDetail.created() : super.created();

AjaxBackedModel get modelInstance => new Country();

}



An full example can be found in the [example directory](https://github.com/ilikerobots/ajax-backed-model-behavior/tree/master/example) and run 
via ``pub serve example`` or [viewed online](https://ilikerobots.github.io/ajax-backed-model-behavior/example/)


## Testing

To run on dartium (default): ```pub run test```  As usual, tests can be run on other platforms with ```-p<platform>```

To run tests as javascript, the pub serve and test execution must be performed separately. Run ```pub serve test --port=8080``` from one terminal and ```pub run test -pchrome --pub-serve=8080``` from a second.

Note that tests are specifically blocked from running on Firefox currently in order to utilize [Travis CI](https://travis-ci.org/ilikerobots/ajax-backed-model-behavior).




Libraries

ajax_backed_model.ajax_backed_model
ajax_backed_model.ajax_backed_model