Segregate nested objects

[vddesai1871]

Fixes #248

Checklist

• My branch is up-to-date with upstream/develop branch.
• Everything works and tested for Python 3.5.2 and above.

Description

Segregates objects returned in a response

Test Logs

(h) vishal@vishal:~/oss/hydrus$ pytest hydrus/tests/
============================================================ test session starts ============================================================
platform linux -- Python 3.5.2, pytest-3.4.2, py-1.5.2, pluggy-0.6.0
rootdir: /home/vishal/oss/hydrus, inifile:
collected 51 items                                                                                                                          

hydrus/tests/test_app.py ................                                                                                             [ 31%]
hydrus/tests/test_auth.py ..........                                                                                                  [ 50%]
hydrus/tests/test_crud.py ............                                                                                                [ 74%]
hydrus/tests/test_doc_writer.py ....                                                                                                  [ 82%]
hydrus/tests/test_parser.py .........                                                                                                 [100%]

========================================================= 51 passed in 3.50 seconds =========================================================
(h) vishal@vishal:~/oss/hydrus$ 

Changes log

Added a new resource names 'NestedItem' in app.py which handles the requests for nested objects

Added

• Feature 1
  Segregates objects returned in a response.
  Only segregates the objects nested at the first level, if the nested object has other nested objects in it then they will be returned in the same response.

Changed

Fixed

Removed

[vddesai1871]

Response for Drone object

Response for State object

[vddesai1871]

Should we add POST method in NestedItem so clients can modify the particular nested object directly?
Regarding to changes in flock-demo documentation, some primarily nested classes like State do not have any operations defined, I should define GET as supported operation for those classes and check in app.py if the nested class supports the GET operation before returning it. What other chnages need to be made in ApiDoc?

[chrizandr]

HTTP-APIs/hydra-flock-demo#34 (comment)

[chrizandr]

As far as I can understand, if there are mutliple nestings the old method of retrieving objects is followed right?

Please read the comment I posted, I think we can handle multiple nestings and single level nestings using only the modifications in crud, we might not need to add new endpoints for it.

[Mec-iS]

This improvement may save different reads as in the place of the full object should appear only its link to the proper URI. Any Hydra Resource has by definition its own endpoint, so State does.

[vddesai1871]

Response for Drone object

Response for State object

[vddesai1871]

(h) vishal@vishal:~/oss/hydrus$ pytest hydrus/tests
============================================================ test session starts ============================================================
platform linux -- Python 3.5.2, pytest-3.4.2, py-1.5.2, pluggy-0.6.0
rootdir: /home/vishal/oss/hydrus, inifile:
collected 51 items                                                                                                                          

hydrus/tests/test_app.py ................                                                                                             [ 31%]
hydrus/tests/test_auth.py ..........                                                                                                  [ 50%]
hydrus/tests/test_crud.py ............                                                                                                [ 74%]
hydrus/tests/test_doc_writer.py ....                                                                                                  [ 82%]
hydrus/tests/test_parser.py .........                                                                                                 [100%]

========================================================= 51 passed in 3.67 seconds =========================================================
(h) vishal@vishal:~/oss/hydrus$ 

[vddesai1871]

Other classes besides State in flock-demo-api-doc, which can be returned as nested object are Datastream and Command, both already have collections defined over them and support GET requests. So I have to just add collection for State and define GET operation for State objects in flock-demo-vocab, right?

[Mec-iS]

Every object that is a Resource and it's present inside another Resource should be referencing via its URI. So yes for Datastream and Command in flock-demo and in general for any other object that is instance of HydraResource.
This is the defining part of an hypermedia API, nested objects have to be accessed via URI dereferencing.

[vddesai1871]

This is the defining part of an hypermedia API, nested objects have to be accessed via URI dereferencing.

Yes I know that, and maybe that's why we prefer HTTP-APIs as org name instead of REST-APIs cause REST constraint of hypermedia as the engine of application state is not fulfilled by many self-proclaimed RESTful APIs.
As you can see from the screenshot now server just returns a URI for the nested object, I have also checked it for other examples as well. So the changes needed to be made in the server are done and I have to update the flock-vocab in hydra-flock-vocab repo.
The question I am having is about the changes I have to make in flock-vocab. The repo for drone vocab hydra-flock-vocab has different vocab than one available in the hydrus/examples/drones folder in this repo. Different in the sense that it doesn't define classes like Area, LogEntry, Message and their collections. Why is this the case?

[Mec-iS]

the official vocabulary is the one in the server, nobody updated the version in Github.
HTTP-APIs/hydra-flock-vocab#1 is meant for that.

REST patadigm has a principle called HATEOAS that is rarely applied.

[Mec-iS]

@vddesai1871 I dont see tests for this feature in th ePR.

[vddesai1871]

Initially I was only handling collection classes as nested objects. After following your comment

Every object that is a Resource and it's present inside another Resource should be referencing via its URI.

Now code also handlescollection classes and non collection classes alike which may be present at nested classes in api_doc.
Extended sample doc to have both collection class and non collection class as nested classes (property).
Wrote tests and ran with sample doc and flock-drone doc.