BreezeJS create complex enity - entity

Question

I am using ServiceStack to get JSON data to the client. I have setup for BreezeJS to map the ServiceStack calls.
Data return by web service is in format like this:
Meta: {Path:[{"Name":"Root","Id":"00000000000000000000000000000000"}], Duration:145}
Duration: "145"
Path: "[{"Name":"Root","Id":"00000000000000000000000000000000"}]"
Offset: 0
Results: [,…]
0: {Description:SLO, InternalKey:SLO, IsActive:true, Name:SLO, ParentId:00000000000000000000000000000000,…}
ChildCount: 2
CreatedById: "ed85f2b9c0bf46729cbb17cee25e3287"
CreatedDate: "2014-09-06T06:23:16.6000000"
Description: "SLO"
HasChildren: true
Id: "9b636028e3f04535a5147a2df375adaa"
InstanceType: "Container"
InternalKey: "SLO"
IsActive: true
ModifiedDate: "2014-09-17T11:04:23.1553432"
Name: "SLO"
ParentId: "00000000000000000000000000000000"
Total: 1
If I create entity manually for node "Result" the data gets mapped and I can read it in my view.
Entity definition:
define(function (require) {
var breeze = require('breeze');
var ctor = function () {
var self = this;
self.DT = breeze.DataType;
};
ctor.prototype.instanceCreate = function (nameSpace) {
var self = this;
return self.instance = {
shortName: "instances",
namespace: nameSpace,
autoGeneratedKeyType: breeze.AutoGeneratedKeyType.Identity,
defaultResourceName: "instances",
dataProperties: {
ConnectionString: { dataType: self.String },
Description: { dataType: self.String },
InternalKey: { dataType: self.String },
IsActive: { dataType: self.Boolean },
Name: { dataType: self.String },
ParentId: { dataType: self.Int32 },
InstanceType: { dataType: self.String },
ChildCount: { dataType: self.Int32 },
HasChildren: { dataType: self.Boolean },
Uid: { dataType: self.Guid },
ETag: { dataType: self.String },
Id: { dataType: self.Int32, isPartOfKey: true },
CreatedDate: { dataType: self.DateTime },
CreatedById: { dataType: self.String },
ModifiedDate: { dataType: self.DateTime },
ModifiedById: { dataType: self.String },
DeletedDate: { dataType: self.DateTime },
DeletedById: { dataType: self.Int32 },
}
};
};
return new ctor();
});
The question is: is it possible in Breeze to define entity so I can read both the "Result" node and the "Meta" from JSON into single entity definition. So I can access data something like:
data.results and data.Meta? Or is there any other way to solve this problem.

Answer 1

I am not sure I fully understand your question. I THINK you're asking if there is a way to map the JSON into an entity by flattening out some of the data and cherry-picking from different nodes.
If so, the answer is ... absolutely. You'll want to create a custom JsonResultsAdapter and probably a custom DataServiceAdapter (which has its own JsonResultsAdapter for handling server responses to a save such as a new instance).
You'll find examples of both adapters in breeze.js itself and in various of the Breeze Labs.
I wish I could point you to documentation and a guide to writing these adapters. It's on our backlog.
FWIW, I would NOT locate persistence metadata such as etag among the entity properties. That's metadata that you need under the covers to make persistence work; it's not "business data" and not something the application developer should see or care about. Which is why in our OData and SharePoint DataService Adapters, we move that kind of thing to the node's result.extraMetadata property. Breeze picks that up and moves it to the entityAspect which is the place to keep persistence info (e.g., change state). Breeze recognizes entityAspect.extraMetadata as a property bag to which you can add anything that you can JSON.stringify.