Custom JSON-based HTTPError

[joarleymoraes]

Hey guys,

I have been using Falcon for some REST-API projects. And I have the following use case I wanted an input from you guys. I would like to respond to clients custom json-based error messages as follow:

{
"error":"A error occurred"
"type":"database.error"
"code":13
}

I know I could build error responses from scratch (using a Middleware, for example), but it would be great if I could accomplish it by elegantly raising an HTTPError like:

raise HTTPBadRequest(title, desc, code)

The problem with this solution is basically the field names that seems not appropriate for error message (title, desc, code). Is there any recommended way to change those names ? Or maybe extend HTTPError somehow ?

Thanks in advance.
Joarley

[kgriffs]

Hi @joarleymoraes, there are a few ways you could approach this. The first one would be to raise a custom error type (or child thereof) and then serialize it with a custom error handler. Another approach would be to inherit from HTTPError but only use the fields from the base class that you need, adding additional ones in the child class. In this second approach, you would also need to implement a custom error serializer to render the JSON result.

[joarleymoraes]

Thanks @kgriffs. I ended up implementing custom error handler together with a JSON-Translator middleware to prepare the response.

[vvvhung]

I found an example. Allow me to post here for anyone who still looking for one:

https://stackoverflow.com/questions/41103069/custom-response-during-falcon-middleware-exception/45685353#45685353

[rwagnergit]

Thenks @vvvhung. Struggled with this for days. Your solution is exactly what I was looking for.

[vytas7]

@rwagnergit, see also https://gist.github.com/vytas7/068ac5bd8a0fd118052d32e30be67792