Inter-Widget Communication (IWC)

Common API Action: bulkGet()

Applies to All IWC APIs

Retrieves a collection of nodes

In some cases, gathering multiple resources at once is desired. The bulkGet action takes a reference to a partial node path, and returns the values for all of the API's nodes that match.

For example, the Names API has a collection of resources on the various APIs connected to the IWC. These resources are labeled as /api/{address} (/api/data.api, /api/names.api, ...). Referencing the partial path /api/ means that when calling bulkGet, all resource pathed under /api/ will be returned.

var apiRef = new iwc.names.Reference("/api");
var apiMap = {}

apiRef.bulkGet().then(function(values){
    for(var i in values){
        var resource = values[i].resource;
        var apiEntity = values[i].entity;

        apiMap[resource] = apiEntity;
    }
});

Differance in promise response to other actions

Since this action is doing a lookup with a partial resource path, values of multiple node resources may be returned. In order distinguish which node provided which value, a more detailed response is used when calling bulkGet. Similar to the format of responses in the Comprehensive IWC Requests, bulk get returns an array of full-detail response messages.

While most of the properties in the response packet aren't utilized in general IWC use, two properties of the response are important:

1. entity - the value of the node.
2. resource - the path of the node.

   [
    {
        "entity": {
            "actions": [
                "get",
                "set",
                "delete",
                "watch",
                "unwatch",
                "list",
                "bulkGet",
                "addChild",
                "removeChild"
            ]
        },
        "lifespan": {
            "type": "Ephemeral"
        },
        "contentType": "application/vnd.ozp-iwc-api-v1+json",
        "permissions": {},
        "eTag": 1,
        "resource": "/api/data.api",
        "collection": []
    },
    {
        "entity": {
            "actions": [
                "get",
                "set",
                "delete",
                "watch",
                "unwatch",
                "list",
                "bulkGet"
            ]
        },
        "lifespan": {
            "type": "Ephemeral"
        },
        "contentType": "application/vnd.ozp-iwc-api-v1+json",
        "permissions": {},
        "eTag": 1,
        "resource": "/api/names.api",
        "collection": []
    },
    // Omitted additional entries due to size...
   ];
   

Requesting a Bulk Get that Finds no Matching Nodes

While a get request for a node that does not exist returns a noResource error, a bulkGet with a partial key reference that matches no node is a valid action because the IWC checks its nodes without failure. The response would be an empty array:

[]