Available keywords should be discoverable and validatable

[ordnungswidrig]

The available resource declaration keywords are only discoverable from the documentation or the source. They should be easily available from a namespace.

Simple typos of a declaration keyword are not detected and lead to hard to find bugs. A validation mechanism should be available, at least optional.

[kanwei]

👍 I've had issues where I've accidentally typed :authorized instead of :authorized?, and you can imagine how bad that could be :)

[ordnungswidrig]

It happens to me as well. I have not settled down on a method how to do this. The possibility to declare arbitrary keywords and attach values to it can come handing for advanced use cases, but as a default, maybe, the keywords should be checked.

[kanwei]

I think just not letting it "compile" would work, or throwing exception, since afaik you can't do anything with non-described keywords anyways. That way you at least won't have silent failures.

[ordnungswidrig]

Currently you can make additional values, e.g. functions or constants, available in liberators resource definition using any key you like. The resource definition itself is available under :resourcein the context and this anything you put in can be looked up in a decision function or handler function.

While this is not officially supported, this is the way, how declarations like :available-media-types were introduced into liberator in the first. Before, you always had to declare a function at :media-type-available? which is obviously more work than returning a list at the other key.

However, I think the drawback of typos and unguided users weights more than this kind of ad hoc extensibility. And I, thus, will change to a more strict resource definition.

[prachetasp]

If liberator is changed to use a strict resource definition there must be a plan to reconcile this with custom decision graphs (#48)? If this functionality is still intended to be implemented that is.

[dchelimsky]

@ordnungswidrig is this on your radar in 2016? It's been 18 months since the last comment and I just ran into a bug caused by :exists instead of :exists?.

[ordnungswidrig]

It is on my radar but I don't see a near term solution. When you abstain from using arbitrary keyword in a resource definition you can easily build a validator yourself. As long as liberator support the use of arbitrary keyword it don't see a way of providing a general validator.