Catch ValueError during network discovery for when JSON parsing fails

Observed behavior

When trying to import content channels (from local network or internet), no error message is produced even though the connection isn’t established. (The “trying to connect” message stays on forever) This happens when there is a typo in the address. (I used kolibri-demo.learningequality.omg) When there’s no internet, an error message DOES get produced.

Expected behavior

An error message should’ve been produced.

User-facing consequences

The user will not know how long they have to wait to see if the connection is being established.

Errors and logs

…

Steps to reproduce

Import content channels from local network or internet >input “kolibri-demo.learningequality.omg” or something else with a typo in it.

Context

Kolibri version: 0.14.3 Operating system: Android 5.1 Browser: Android App Device: BLU Advance 5.0

[rtibbles]

The issue is that we do catch requests RequestException here: https://github.com/learningequality/kolibri/blob/develop/kolibri/core/discovery/utils/network/client.py#L56 but are not catching the JSON Decode Error.

We should add ValueError to the tuple of caught exceptions, as a Python 2 compatible way of catching the error.

[jonboiser]

I think one way to fix it is to handle more general Exceptions at this line.

https://github.com/learningequality/kolibri/blob/65c0d60a7b2507337f95b131492e47d0e62e2b47/kolibri/core/discovery/utils/network/client.py#L56-L57

But maybe the problem here is that .omg isn’t a real TLD? It might be something internal to the requests module.