added JSON Topic for use with micropython-upip

[awachtler]

This patch adds a json-info url to pypiserver, which is needed for micropython-upip.

The change enables pypi-server to be used as local package server for micropython projects.

If server is queried like this: http://gretel-2:8080/pypiserver/json it returns this JSON data:

{
"info": {"version": "2.0.0.dev1"}, 
"releases": {
  "2.0.0.dev1": [{"url": "http://gretel-2:8080/packages/pypiserver-2.0.0.dev1.zip"}], 
  "2.0.0dev1aw": [{"url": "http://gretel-2:8080/packages/pypiserver-2.0.0dev1aw.zip"}]
 }
}

I would be happy, if this change can make it to the master branch.

Best Regards, Axel.

[dee-me-tree-or-love]

Hi @awachtler! Great, thanks a lot for your proposal. I am not sure when exactly I will have a moment to give a review, but I will try to take a good look at it in the coming days. The functionality looks nice already :)
In case of anything, @mplanchard, please feel free to take a second look

[dee-me-tree-or-love]

Hi @awachtler! Sorry getting back to it only after such a delay, but I've taken a look and had to look a bit into Micropython to get slightly more familiar, but it looks like a nice addition in my opinion ;). I will add a few comments, but I think it'll make it nicely into master :). @mplanchard, if you'd have some time, could you give a second opinion?

But to give a better idea and mention this feature to the world, you could add an example of using this endpoint with upip? I think a nice spot for it would be in the readme as a new section in Recipes.

[dee-me-tree-or-love]

Looks good, but I have left a couple of comments :)

1. could you align with PEP 503?
2. if you could add a unit test, would be very grateful!

[awachtler]

@dee-me-tree-or-love, I just added normalized package name redirecting.

While testing I found that I should raise 404 error in case of invalid package name.
Currently 3 tests are added, let me know, if more test coverage is required.

The use-case documentation for micropython I will add within the next days.

[awachtler]

Just updated README.rst

[dee-me-tree-or-love]

@awachtler great! Thanks a lot, I've seen the newly added changes! Looks great to me! :)
I've spotted a small typo in the README and after that I'd be glad to approve :)

[dee-me-tree-or-love]

Spotted a typo ;)

[awachtler]

Hallo, @dee-me-tree-or-love, thanks for your careful review, the typo was just fixed.

[dee-me-tree-or-love]

@awachtler hey great! Thanks a lot for the fixes and the friendly bump to review, merging it 👍