Document that an exception thrown in a Path param unmarshaller is a rejection

[akka-ci]

Issue by ktoso
Sunday Jul 10, 2016 at 14:01 GMT
Originally opened as akka/akka#20929

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... and the next path will be attempted to be resolved.

This is different than exceptions inside of a route already (which would render as 500 usually then)

[ilke-zilci]

Hey, I'd like to take this one, is anyone working on it already?

[ktoso]

No, seems no one has picked it up yet, thanks for looking into it! :)
(Feel free to ask if not sure about things with it etc)

[jrudolph]

I agree, might be a good starting contribution!

However, I find the ticket description a bit unclear. I think it's about using parameter("age".as(xyzUnmarshaller)) and this xyzUnmarshaller throws an exception? Do you remember if that was the case here, @ktoso?

In that case, this code here seems to convert the exception into a rejection: https://github.com/akka/akka-http/blob/master/akka-http/src/main/scala/akka/http/scaladsl/server/directives/ParameterDirectives.scala#L115

It should probably be documented in the documentation of the parameters directive here: https://github.com/akka/akka-http/blob/master/docs/src/main/paradox/scala/http/routing-dsl/directives/parameter-directives/parameters.md

[ktoso]

Yes, it was about that; AFAIR someone expected "well it's an exception so should be an error page!", but indeed there we interpret it as "well, unable to extract, let's try another one", so as a rejection :)

[jlprat]

Good to see you here @ilke-zilci!

[ilke-zilci]

Great! I will work on it then. It goes here, right? https://github.com/akka/akka-http/blob/master/docs/src/main/paradox/scala/http/routing-dsl/rejections.md

[jlprat]

As @jrudolph mentioned, I would document it next to the Path Parameter documentation pages (https://github.com/akka/akka-http/blob/master/docs/src/main/paradox/scala/http/routing-dsl/directives/parameter-directives/parameters.md) and then link to the rejection doc page as a "see for further info".

And don't forget to document it for both Scala and Java docs :)

[ilke-zilci]

Ok thanks. And sorry missed that line on the first read.

[jrudolph]

Fixed in #1285.