How to handle paginated endpoints with no Link header

[bennettscience]

I'm working on #565 right now and have run into an issue with paginating the responses.

LiveAssessments are a tool in Canvas to give feedback on Learning Outcomes in your course. The Magic Marker app used to use this, but Instructure hasn't done anything with it in ages. The problem is in how the endpoint returns paginated responses.

Instead of using a Link header that the PaginatedList class can use, the links to paginated responses are in the body of the response. This happens for any live_assessment endpoint, including for results.

{
  "links": {
    "assessments.results": "http://example.com/courses/1/live_assessments/1/results"
  },
  "meta": {
      "pagination": {
          "per_page": 10,
          "next":"https://www.example.com/api/v1/courses/1/live_assessments/results?page=2&per_page=10"
          "last": "https://example.com/api/v1/courses/1/live_assessments/1/results?page=2&per_page=10",
          "current":"https://example.com/api/v1/courses/1/live_assessments/1/results?page=1&per_page=10",
          "first":"https://example.com/api/v1/courses/1/live_assessments/1/results?page=1&per_page=10",
          "page":1,
          "template":"https://example.com/api/v1/courses/1/live_assessments/1/results?page={page}&per_page=10",
          "count": 20,
          "page_count":2
      }
  }
}

There are a couple ways I could handle this:

1. Make the LiveAssessment class an iterable on its own. The user could use it just the same as the PaginatedList responses.
2. Iterate all of the responses and returning a list of live assessments or results, but not make the class itself iterable.
3. Return JSON and note in the docs that the user needs to iterate themselves.

Does one of these stand out as better or worse than another? Given how little it's actually used in Canvas, I don't have a strong opinion one way or another.

[Thetwam]

It's been a while since I've looked at the PaginatedList code, so this is theoretical...

It might be possible to first try to get the info from Link headers, but if none are found, check for a meta in the body, before ultimately raising an error.

[bennettscience]

Ok, I'll work ok a patch for PaginatedList because this would help a couple different endpoints and see if I can get something manageable. #565 is such a niche endpoint, that I don't think it's worth doing a custom implementation here.

[Thetwam]

Looks to be resolved in #614