Hydrate object fields - rally

Question

I want to get Feature object for User Stories that I got from lookback API.
But when I try to hydrate Feature I get only UnFormatted feature ID.
Can I get real Feature objects for User Stories from lookback result set?
Below the example of code that I use for retrieving data:
storeConfig: {
find: {
"_TypeHierarchy": { '$in' : [-51038] },
"Children": null
},
fetch: ["ScheduleState", "PlanEstimate", "ObjectID", "_ValidFrom", "_ValidTo", "c_BaselineDeliveryConfidence", "Name", "Feature"],
hydrate: ["ScheduleState", "c_BaselineDeliveryConfidence", "Name", "Feature"],
sort: {
"_ValidFrom": 1
},
compress: true,
useHttpPost: true

Answer 1

It is not possible to hydrate objects straight out of the LBAPI. However, I have been working on a helper class to do just that, using a method similar to what Nick suggested.
https://github.com/ConnerReeves/RallyHelpers/blob/master/RecordHydrator/RecordHydrator.js
Here's an example of how it's used. I'm gathering all leaf User Stories (that have an iteration assignment) and then hydrating that Initiative field:
launch: function() {
var self = this;
Ext.create('Rally.data.lookback.SnapshotStore', {
limit : Infinity,
fetch : ['Name','Iteration'],
filters : [{
property : '__At',
value : 'current'
},{
property : '_TypeHierarchy',
value : 'HierarchicalRequirement'
},{
property : 'Iteration',
operator : '!=',
value : null
},{
property : 'Children',
value : null
}]
}).load({
params : {
compress : true,
removeUnauthorizedSnapshots : true
},
callback : function(records, operation, success) {
self._hydrateRecords(records);
}
});
},
_hydrateRecords: function(records) {
Ext.create('CustomApp.RecordHydrator', {
fields: [{
name : 'Iteration',
hydrate : ['Name','StartDate','EndDate']
}]
}).hydrate(records).then({
success: function(hydratedRecords) {
console.log(_.groupBy(hydratedRecords, function(record) {
return record.get('Iteration') && record.get('Iteration').get('Name');
}));
}
});
}

Answer 2

Feature is a full object to which a user story has a reference to (via Feature attribute).
Your code which is similar to this query:
https://rally1.rallydev.com/analytics/v2.0/service/rally/workspace/111/artifact/snapshot/query.js?find={"_TypeHierarchy":"HierarchicalRequirement"}&fields=["Name","ScheduleState","PlanEstimate","Feature"]&hydrate=["ScheduleState"]
will return something like this:
{
Feature: 12483739639,
Name: "my story",
ScheduleState: "Defined",
PlanEstimate: 3
}
where 12483739639 is ObjectID of the Feature. Adding "Feature" to the hydrate will not make a difference.
If you want to get the full Feature object or some of its attributes, in your code you may use the OID of the feature and issue a separate query. You may also push those OIDs into an array and use $in operator in that second query.