Allow exceptions in actions

[hypeJunction]

Perhaps we could considering wrapping action() with try() and catch exceptions. Users would get generic messages based on exception type, admins would get full exception messages.

I realize that I spend too much time checking instances, canEdit(), canWriteToContainer() permissions and inventing smart error messages. Would be helpful to have an easy way out by throwing an exception from one of the classes.

[ewinslow]

+1

[mrclay]

I agree that there's too much boilerplate around validation, and the idea seems somewhat easy to implement. Only hesitation is that it feels like an abuse of exceptions (goto).

[Srokap]

Fine with me if we stick to specific type of exceptions to be caught and handled as generic messages. We should perhaps differentiate explicitly here between 400 errors and 500, when first ones are caused by bad input data and the latter are server side issues (DB unreachable etc.)

[hypeJunction]

@mrclay Classes already throw exceptions that unless are caught in the action result in inconveniences for admins and users, e.g. calling ->save() with a container guid that the user has no write permissions to will result in an Exception (something about can't save base entity information). So, we keep repeating canEdit() and canWriteToContainer() calls in every action. These could easily be thrown as Exceptions from ->save() with a generic message that include entity info or type/subtype info.

[jdalsem]

@hypeJunction was this fixed somewhere along the line?

[hypeJunction]

HttpException can be thrown and will result in error response out of action. I don't think we need anything else at the moment