`gotInstanceData` method wiring is missing from the data/callbacks behavior

[pmgmendes]

How often can you reproduce it?

• [x] Always
• [ ] Sometimes
• [ ] Rarely
• [ ] Unable
• [ ] I didn’t try

Description: Although the documentation can-connect references a callback named gotData this method is not being wired to getData in the data/callbacks pairs so it can be overwritten by other behaviors. The pairs object in can-connect/data/callbacks/callbacks.js is expected to also have

var pairs = {
  ...
  getData: "gotInstanceData",
  ...
};

[nlundquist]

The reference you see to gotData on the main can-connect documentation index page is outdated. This will be corrected shortly with a major documentation update that is underway.

The docs for can-connect/data/callbacks here correctly show createdData, destroyedData, gotListData & updatedData. These are the only callbacks that expected to be part of this behavior at this time.

I'll report back if we have a timeline for adding a gotData callback to the data/callbacks behavior. In the meantime the best workaround would be to create your own behavior that wraps getData and does whatever transformation to the request or response you require.

[justinbmeyer]

@pmgmendes or ... submit a pull request with it fixed and we can have a release out immediately :-)

[pmgmendes]

@justinbmeyer So it should be there? Yeah, I'll do it.

[justinbmeyer]

yeah, should be there. Btw, what are you using it for?

[pmgmendes]

I'm accessing a resource modeled as /api/resource/{id} which returns a simple key value map

{ "keyA": "valueA", "keyB": "valueB", ... }

This is a resource that returns only static data from the server (but might change after new re-deploys) and I want to cache the response in localStorage but the returned map doesn't have a unique identifier. So I've created the instance type as a define map with the following props

{ 
id: "string",
data: {}
}

And in gotInstanceData I intend to do something like

gotInstanceData: (response, params) => {
  return {
    id: params.id
    data: response
  }
}

This way I can make use of the behaviors that use instanceStore too. It might appear that I could be better off using cacheRequests behavior but I still want to perform those requests to the server so I'm using fallThroughCache strategy.

[pmgmendes]

@justinbmeyer I've added the gotData getData pair to data/callbacks and also included the getDatain the method list for validation. Some tests in real-time behavior fail

Error: can-connect: Extending behavior "data/callbacks" found base behavior "real-time" was missing required properties: ["getData"]

Should real-time implement getData? I've done it but I'm struggling a bit to have the tests properly evolved to support getData. Help needed.

[justinbmeyer]

For this use case, would parse-data do what you need?

Sent from my iPhone

On Jun 6, 2017, at 4:03 PM, Pedro Mendes notifications@github.com wrote:

I'm accessing a resource modeled as /api/resource/{id} which returns a simple key value map

{ "keyA": "valueA", "keyB": "valueB", ... } This is a resource that returns only static data from the server (but might change after new re-deploys) and I want to cache the response in localStorage but the returned map doesn't have a unique identifier. So I've created the instance type as define map with props

{ id: "string", data: {} } And in gotInstanceData I intend to do something like

gotInstanceData: (response, params) => { return { id: params.id data: response } } This way I can make use of the behaviors that use instanceStore too. It might appear that I could be better off using cacheRequests behavior but I still want to perform those requests to the server so I'm using fallThroughCache strategy.

— You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub, or mute the thread.

[pmgmendes]

I need the request params and parseData just provides the response data. In the meantime I was able to overwrite getData as suggested by @bmomberger-bitovi and @nlundquist in Gitter to attain the same purpose.

const customBehavior = function (baseConnection) {
  return {
    getData: function (params) {
      return baseConnection.getData(params).then(function (instanceData) {
        return {
          id: params.id,
          data: instanceData
        };
      });
    }
  };
};

Todo.connection = connect([ ..., dataUrl, customBehavior, dataParse, ...], {...});

[nlundquist]

Good to hear @pmgmendes! If you want to open a PR for your branch I can help you resolve the problems you're having with the tests. I suspect the issue you're seeing is due to the test for the real-time behavior using a "stub" behavior that only implements getListData instead of the full DataInterface. Adding an empty function called getData to that stub behavior should fix the test.