Handling polymorphic references for records

[morganick]

• Build test data
• Identify the problem
• Fix it

This addresses issue #24

[morganick]

So, I think I know where I went wrong. I made the assumption that you would have a model for every content type inside of Contentful. In that assumption, I also assumed that the name of your model would be pulled from the content_type when it appears that you'd rather have the model name you give it inside the hasMany reference. (e.g. section from the test data above.)

Does that sound correct @bretmorris?

/cc @davidpett

[davidpett]

@morganick i just pushed a failing polymorphic demo to https://github.com/davidpett/ember-data-contentful/tree/failing-polymorphic if you ember s and visit http://localhost:4200/test-page and look at the ember inspector, you will see 1 module all with undefined values and 1 'module-contentwith actual values. logging the contentType of each module rendersundefined`

{{#each model.modules as |module|}}
  {{log module.contentType}}
{{/each}}

[morganick]

@davidpett Thanks for doing that. I'll take a look.

[morganick]

I finally got some time to dive into this and try to find a solution to this issue. Here are a couple of things that I have noticed; let me know if I'm missing something.

When we are parsing the relationships for the page model, we pass in the relationship name of module. So at that point I have a type of module and an id of the entity inside Contentful. This is, currently, all I have for the resource linkage. (http://jsonapi.org/format/#document-resource-object-linkage) That's all fine and good until we parse the includes which is where the related models are loaded. (e.g. module-content in the case of the dummy app)

When we parse the includes, we use the contentType from Contentful to tell ember-data which model it is and push it into the store. With a non-polymorphic hasMany this works as intended. This is how module model gets initialized but there is no data, and model-content gets data but is not linked to the page via the hasMany.

I've also looked through the 0.2.1 code to see what the differences where and where I broke this since it appears to work in 0.2.1. So far it has eluded me. My next step here will be to pull in the 0.2.1 serializer up to where we have the test suite and see if my tests pass there.

The other thing I was looking at doing was supporting true polymorphic hasMany for this. This used to be something that ember-data handled out of the box but seems to have been removed when they switched over to JSONAPI. I've read a couple of closed PRs with grumblings towards that.

Also, if we don't support polymorphic then you lose the ability to do findRecord and queryRecord on the related content types. module-content is what you would use for those not the generic module which has no meaning outside of the page model in Contentful.

@davidpett & @bretmorris just wanted to give you an update on the status of this issue. Let me know if you have other ideas or suggestions.

[jkeen]

@morganick @davidpett Were y'all able to get any further with this issue? I'm in the same boat of needing polymorphic references.