Changes to API for discussion

Remove redudancy in responses

Many returned objects repeat properties that are redundant, usually due as a result of a query. For example,

GET http://waterml2.csiro.au/rgs-api/v1/gauging/?monitoring-point=419009

returns gaugings with the FOI encoded for every object.

e.g.

{
    "count": 325, 
    "next": "http://waterml2.csiro.au/rgs-api/v1/gauging/?monitoring-point=419009&page=2", 
    "previous": null, 
    "results": [
        {
            "id": 18953, 
            "phenomenonTime": "2011-04-14T00:00:00", 
            "featureOfInterest": "http://waterml2.csiro.au/rgs-api/v1/monitoring-point/419009/", 
            "observedPropertyFrom": {
                "id": "100", 
                "description": "", 
                "external_definition": ""
            }, 
            "observedPropertyTo": {
                "id": "141", 
                "description": "", 
                "external_definition": "http://neiivocab.bom.gov.au/std/water/xml/wio0.2/property/wdtf-parameters/WaterCourseDischarge_m3s"
            }, 
            "quality": 12, 
            "fromValue": "-0.31600", 
            "toValue": "110.02000"
        }, 

An improvement would be to more the FOI up one level:

{
     "count": 325, 
     "next": "http://waterml2.csiro.au/rgs-api/v1/gauging/?monitoring-point=419009&page=2", 
     "previous": null,
     "default": {
       "featureOfInterest": "http://waterml2.csiro.au/rgs-api/v1/monitoring-point/419009/"
      },
     "results": [
         {
             "id": 18953, 
             "phenomenonTime": "2011-04-14T00:00:00", 
             "observedPropertyFrom": {
                 "id": "100", 
                 "description": "", 
                 "external_definition": ""
             }, 
             "observedPropertyTo": {
                 "id": "141", 
                 "description": "", 
                 "external_definition": "http://neiivocab.bom.gov.au/std/water/xml/wio0.2/property/wdtf-parameters/WaterCourseDischarge_m3s"
             }, 
             "quality": 12, 
             "fromValue": "-0.31600", 
             "toValue": "110.02000"
         }, 

Here I've included in a "default" object. What exactly can be defaulted obviously depends on the type of objects being returned AND the allowed query parameters.

Do we:

1. Default only if a property is included as a query parameter?
2. Default by inspecting the properties in the collection to determine what should be defaulted?

Obviously 2 requires more work. With option 1, there will be cases where defaults get missed. E.g. the example above, it would be desirable to default the parameterTo/From combination but we can't guarantee that the collection won't conain multiple paramFrom/To combinations, so the property can't be defaulted.

-- PeterTaylor - 26 Jun 2014