Select Transform

The select request transform allows authors to construct the query param, to include fields whose values need to be included, in the response. Example, the built-in Business Objects based transforms creates a 'fields' query parameter.

The select criteria provided via the options parameter is an Object with properties { attributes, type }. The type is the response type structure typically specified on the ServiceDataProvider and Call Rest action configurations. The attributes are provided by the caller, such as the component, through a fetch call. See JET Data Provider docs for details on the fetch methods and the parameters. particularly 'attributes' (JET FetchAttribute). When attributes and type are present, how these are combined is left to the discretion of the transforms' implementation.

Examples

select criteria with type transforms to "fields=PartyId,PartyStatus,PartyType;PrimaryAddress:AddressId,FormattedAddress"

{
  "attributes": null,
  "type": [
    {
      "PartyId": "number",
      "PartyStatus": "string",
      "PartyType": "string",
      "PrimaryAddress": [
        {
          "AddressId": "number",
          "FormattedAddress": "string"
        }
      ]
    }
  ]
}

select criteria with attributes transforms to fields=a;b:b1,b2;c:c2;c.c1:c1a,c1b'

{
  "attributes": [
    "a",
    {
      "name": "b",
      "attributes": [
        "b1",
        "b2"
      ]
    },
    {
      "name": "c",
      "attributes": [
        {
          "name": "c1",
          "attributes": [
            "c1a",
            "c1b"
          ]
        },
        "c2"
      ]
    }
  ],
  "type": null
}

select criteria with both type and attributes transforms to fields=PartyId,PartyStatus,PartyType,a;PrimaryAddress:AddressId,FormattedAddress,b;PrimaryAddress.FormattedAddress:c

{
  "attributes": [
    "PartyId",
    {
      "name": "PrimaryAddress",
      "attributes": [
        "AddressId",
        {
          "name": "FormattedAddress",
          "attributes": [
            "c"
          ]
        },
        "b"
      ]
    },
    "a"
  ],
  "type": {
    "items": [
      {
        "PartyId": "number",
        "PartyStatus": "string",
        "PartyType": "string",
        "PrimaryAddress": [
          {
            "AddressId": "number",
            "FormattedAddress": "string"
          }
        ]
      }
    ]
  }
}

For 3rd party services the author can provide a custom select transforms implementation.

Signature

The filter transform function can be declared like this:

function(configuration, options, transformsContext) {

  var c = configuration;
  // use the select criteria provided on 'options' parameter to generate the query param
  // update c.url as needed

  return c;
}

This function has the following parameters:

configuration an object with the following properties:
- Refer to the signature in Request Transformation Functions for details on the various properties.
options select the fields whose data is requested:
- type: an Object that is configured as responseType property on the Service Data Provider or Rest Action
- attributes: a structure defined by JET that is an Array<(string|FetchAttribute)>. See JET docs for details.
transformsContext is an object that is set by the author (ServiceDataProvider, RestHelper, Call Rest action) to then be passed as is to all transforms for the current fetch cycle.

The function returns the updated configuration object.

Usage

The examples below illustrate the arguments passed to the select transform, as well as the effect its code has on the fetch performed by the RestHelper.

The example below uses a service fixitfast that has a GET endpoint to retrieve the list of customers.

Example 1-13 ServiceDataProvider variable

Assume that the following variable of type vb/ServiceDataProvider is defined in a page that refers to the above GET /customers endpoint. The SDP variable includes a response type that it expects the response to be in, set via the property responseType.

{
  "types": {
    "customerResponse": {
      "PartyId": "number",
      "PartyStatus": "string",
      "PartyType": "string",
      "PrimaryAddress": [
        {
          "AddressId": "number",
          "FormattedAddress": "string"
        }
      ]
    }
  },
  "variables": {
    "customersSDP": {
      "type": "vb/ServiceDataProvider",
      "defaultValue": {
        "endpoint": "fixitfast-service/getCustomers",
        "keyAttributes": "PartyId",
        "itemsPath": "result",
        "responseType": {
          "items": "customerResponse"
        }
      }
    }
  }
}

When a caller such as a component bound to the above SDP initiates a fetch call, it can also provide additional attributes. These are combined with the configured responseType above and the combined select criteria is provided to the select transforms function.

The select request transforms function uses the criteria passed in via the options parameter to build a query param on the configuration url. The select transform is implemented in the service transforms as follows:

define([], function () {
  class Request {

    static select(configuration, options, transformsContext) {
      const c = configuration;
      const selectOpts = options;

      // process options to build the query param for the fields requested in the response
      if (selectOpts && (selectOpts.type || selectOpts.attributes)) {
        // ...
      }

      // update the c.url
      return c;
    }
  }

  var Response = function() {};
  var Metadata = function() {};

  // Note: as an example, the Request object is expanded to include just the select property
  return {
    metadata: Metadata,
    request: { select: Request.select },
    response: Response
  };
});