Get distinct capabilities of the nodes registered with a hub as JSON

[dnillia]

Currently, there is no way to retrieve the list (in a form of JSON) of distinct capabilities across all nodes registered with a hub, even though it is possible to see them as HTML by navigating to "/grid/console". It would be helpful to avoid any attempts to parse HTML in order to get capabilities and instead expose a path like "/grid/capabilities" that will result in JSON representing distinct capabilities. This may be helpful if one wants to dynamically create drivers without providing explicit details.

EDIT: the CLA has been signed.

[cschooler]

This look really cool. I can see some interesting usages for this functionality.

[alex-savchuk]

Hi!

Thank you for submitting this pull request!

But i have some suggestions:

1. full feature is expected to include tests covers this feature. Could you implement it? Please take a look at existed set, e.g. https://code.google.com/p/selenium/source/browse/java/server/test/org/openqa/grid/e2e/node/SmokeTest.java
2. i'd suggest to register servlet at /grid/api/console path.
   Such path mentions that it's API and in future can be extended for returned information w/o URL change.
3. for what purpose you need distinct set of grid capabilities ?
   why not return all capabilities in format (just for example): {'nodes': {'proxyid' => [ { test slot capabilities }, .. ], ..}} ?
   It could be extended w/o affecting existed users.
4. (future request) what's about node ? could you implement the similar API point for node?

[andreastt]

Closing this for lack of response. Please comment if you'd like us to reopen.