CODEWITHSUNDEEP
breeze
Adam
Adam

Reputation: 28858

Custom DataService adapter saveChanges method to set entities to Unchanged

I've implemented a custom DataService adapter for BreezeJS - I wanted to use Breeze with a RESTful back end service (not OData or ASP.NET Web API).

So far - decent results after a learning curve.

I'm having an issue that when I call save changes - afterwards my entities on the client do not get marked as 'Unchanged'. They keep the same entityState.

I assume it has something to do with the success handler of the AJAX request to the backend service (looking at the source code to the WebAPI adapter):

        success: function(data, textStatus, XHR) {
            if (data.Error) {
                // anticipatable errors on server - concurrency...
                var err = createError(XHR);
                err.message = data.Error;
                deferred.reject(err);
            } else {
                // HACK: need to change the 'case' of properties in the saveResult
                // but KeyMapping properties internally are still ucase. ugh...
                var keyMappings = data.KeyMappings.map(function(km) {
                    var entityTypeName = MetadataStore.normalizeTypeName(km.EntityTypeName);
                    return { entityTypeName: entityTypeName, tempValue: km.TempValue, realValue: km.RealValue };
                });
                var saveResult = { entities: data.Entities, keyMappings: keyMappings, XHR: data.XHR };
                deferred.resolve(saveResult);
            }

        },

It looks like the response includes an array of 'Entities'. What do these 'Entities' look like? It echoes what the client sent with an updated entityAspect.entityState value (server responses with 'Unchanged')?

Is that what should be passed into the deferred.resolve call?

Upvotes: 1

Views: 605

Answers (1)

Adam
Adam

Reputation: 28858

I've got a working solution for this.

In a nutshell here's what is required for the object that is passed to the 

deferred.resolve(saveResult);

Call in the success handler of the save change AJAX request.

  • Server response should include information about how to map from the client generated id to the server generated id (if the server generated one). This can be one keyMapping property returned in the response (like the Breeze API controller does) or what my service does is return a keyMapping property as a child property of a particular resource

    • The client code should create an array of objects that look like:

      { entityTypeName: "fully qualified entity type name", tempValue: "client generated id", realValue: "server generated id" }

    • this array is the keyMappings property of the saveResult object
    • the entities property of the saveResult object is a flat list of all the entities that were modified from the server. Because of the design of my service API, it can return an entity, and child entities embedded in it, which I had to traverse and pull out into a flat list. Additionally these entity objects should be 'raw' and not include the entityAspect property or anything Breeze might interpret as a 'real' entity.

Also - something that can also be helpful is to look at the new sample from the Breeze folks - the MongoDB Breeze sample. They've implemented a custom dataServiceAdapter that hooks up their NodeJS/MongoDB backend. That provided some additional insight as well.

Good luck!

Upvotes: 1

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