Schema Validation and UX improvements

[dmuhs]

This PR will add:

• magic methods to the analysis list and detected issues response models
• delegated property acces for easier access to a model's underlying Analysis object
• a context handler for the client class to allow easy usage with various accounts
• jsonschema validation for all requests and responses

Furthermore, the *DecodeError exceptions have been deprecated in favour of the *ValidationError ones. This makes it easier to catch internal PythX errors. As discussed before, an example like this is now possible:

with Client(eth_address="0xF00...", password="my-password") as c:
    print(c.analysis_list())

Next up: Further UX improvements, examples in the readme, actual documentation, and then v1.0 🎉

[cache-monet]

Are these the auth JWT's?

[dmuhs]

Yes 👍

[cache-monet]

Whew what an adventure~

[cache-monet]

So even when derived classes call BaseResponse's implementation of validate, cls.schema would be the child's schema right?
ie: VersionResponse would have "version.json" as it's class schema.

[dmuhs]

Exactly. schema is a class property, meaning that it's the same (pointer to) the data for each class. validate then just hooks into that data and interprets it as a schema.
Because the base classes are abstract, we cannot instantiate them directly, so as long as our concrete class definitions override schema with the stuff they need, we should be fine.

[dmuhs]

However, there's a hidden bug here. Classes which don't override schema and don't implement validate will fail, because their schema variable is None and the default validate implementation is executed. So in the default implementation we should add another check for None and raise a validation error to notify the user about a missing schema. WDYT?

[cache-monet]

Good catch

[cache-monet]

Good informative error but I think we could abstract away the extra info. This error will mostly like occur when a derived class tries to call cls.validate(d) without setting the schema.
I'm unsure if we should give reveal too much of our implementation details.
Rephrasing to reveal the most relevant info:

if cls.schema is None:
      raise TypeError("Cannot validate request without a schema. Please load schema")

What do you think?

[dmuhs]

Good point. This error will occur when a domain model doesn't have a JSON body (e.g. logout responses or analysis status requests). Maybe we should also bring this in somehow? Otherwise the user will be confused if we ask them to load a schema even though there can't be one. It's most likely a mistaken validate call

[cache-monet]

Would it be possible to overridevalidate for those models then?

[dmuhs]

Yes. That's always possible in Python, after all we are all consenting adults here. 👍

[cache-monet]

Ohmy that's pretty different from what's taught in class 😂 (The encapsulation part I mean)