Custom HTTP error on Cornice view predicate

[Thierry Florac]

Hi,

I'm building a REST API using Pyramid and Cornice for which I defined custom view predicates. By default, an HTTP NotFound error is raised when a predicate is not verified. Is there a way to raise a custom error, like an HTTP Unauthorized or HTTP Forbidden?

Best regards,

Thierry

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  https://www.ulthar.net -- http://pyams.readthedocs.io

[Theron Luhn]

You might be looking for something like view derivers https://docs.pylonsproject.org/projects/pyramid/en/latest/narr/hooks.html#custom-view-derivers

That will allow you to accept additional parameters in `add_view`/`@view_config` and wrap the view in customer behavior, such as raising an HTTPForbidden if a certain condition isn’t met.

e.g. `permission` is implemented using a view deriver https://github.com/Pylons/pyramid/blob/eb0e01a0fd7aff84c345b1c43bd4fa9d2fe04441/src/pyramid/viewderivers.py#L286-L333

— Theron

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[Thierry Florac]

I tried to use permission predicate/deriver, but an HTTP NotFound exception is raised if the permission is not granted to the current request!

I think that an HTTP Forbidden exception would be more appropriate to handle automatic redirection to a login form from the client application...

Best regards,

Thierry

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  https://www.ulthar.net -- http://pyams.readthedocs.io

To view this discussion visit https://groups.google.com/d/msgid/pylons-discuss/4612BE66-D7F2-49FA-8B74-9FAC908097A1%40luhn.com.

[Theron Luhn]

You say “predicate/deriver” but those are two different things.

Predicates will influence what view matches the request but do not modify the behavior of the view callable.  If no view is found a 404 is raised.

View derivers do the opposite:  They modify the behavior of the view callable but do not influence choosing the view.

The default Pyramid permission view deriver will raise HTTP Forbidden if the permission check fails.  I’m not familiar with Cornice so I can’t speak to anything there.

— Theron

To view this discussion visit https://groups.google.com/d/msgid/pylons-discuss/CAPX_VWC12Yp0kkoKsX5LwDJ6vBVSqMKeKErm0%3DR4Zn-W0_SD_g%40mail.gmail.com.