Allow errors to send an error code in the response extension #246

DJLemkes · 2020-02-27T19:39:54Z

A first attempt to allow errors to define an error code which is renderd in the extensions section of error elements. Closely related to #158

I have no idea whether this is solution is on the right track. If not, no hard feelings on rejections :). If it is on the right track, I can put in a little more effort to include more error information as mentioned in #158

Closes #158

ghostdogpr · 2020-02-28T00:40:13Z

@DJLemkes thanks for volunteering on this! I think the idea of using a trait extending Throwable works. But I would make the function return a Option[ObjectValue] (the same type we used for extensions in GraphQLResponse). That way, users are able to return a Map containing anything they want, instead of us forcing them to return something specific (extensions have no specified fields, anything could be used).

I had another approach in mind, let me explain it and you can tell me what you think. If we added Option[ObjectValue] (or maybe directly ObjectValue) directly in CalibanError (and each of the 3 case classes), users would be able to use mapError on the interpreter and put anything they want into it without having to use a custom Throwable and modify their business code. They could easily remove the items Caliban adds (e.g. explanation text for validation errors) or add their own based on the type of innerThrowable which could be their own business error type. What do you think?

Tip: run fmt in sbt to format sources and allow the CI to run the tests

DJLemkes · 2020-03-01T14:15:51Z

@ghostdogpr Like your idea better! Will give it a shot in the next couple of days.

DJLemkes · 2020-03-06T11:41:17Z

@ghostdogpr sorry, had the flue hence the delay. Could you have a look and tell me if this is what you had in mind?

ghostdogpr · 2020-03-06T11:55:27Z

@DJLemkes no problem, I'll have a closer look tomorrow!

ghostdogpr

Looking good! Just have some minor remarks.

ghostdogpr · 2020-03-07T02:15:14Z

core/src/main/scala/caliban/CalibanError.scala

      Json
        .obj(
          "message" -> s"Parsing Error: $msg".asJson,
          "locations" -> Some(locationInfo).collect {
            case Some(li) => Json.arr(locationToJson(li))
-          }.asJson
+          }.asJson,
+          "extensions" -> extensions.asInstanceOf[Option[ResponseValue]].asJson.dropNullValues


(extensions: Option[ResponseValue]) would be better than asInstanceOf (here and below)

Makes a lot of sense but I can't seem to get the encoder for an Option[ResponseValue] in implicit scope such that .asJson works. Thought that the implicit circeEncoder of ResponseValue would be able to pick this one up? I got the .asInstanceOf[ResponseValue] trick from GraphQLResponse actually.

(extensions: Option[ResponseValue]).asJson.dropNullValues doesn't work? We were about to remove the asInstanceOf in this PR by using that same trick: https://github.com/ghostdogpr/caliban/pull/234/files#diff-16ab822f0162e843af921d1e9d0c34dfR23

Aha, I was trying to put it in the match clause. Apparently didn't fully understand what you meant. Changed it now and it works!

examples/src/main/scala/caliban/http4s/ExampleApp.scala

ghostdogpr

Awesome!

ghostdogpr · 2020-03-11T00:22:56Z

core/src/main/scala/caliban/CalibanError.scala

      Json
        .obj(
          "message" -> s"Parsing Error: $msg".asJson,
          "locations" -> Some(locationInfo).collect {
            case Some(li) => Json.arr(locationToJson(li))
-          }.asJson
+          }.asJson,
+          "extensions" -> extensions.asInstanceOf[Option[ResponseValue]].asJson.dropNullValues


(extensions: Option[ResponseValue]).asJson.dropNullValues doesn't work? We were about to remove the asInstanceOf in this PR by using that same trick: https://github.com/ghostdogpr/caliban/pull/234/files#diff-16ab822f0162e843af921d1e9d0c34dfR23

ghostdogpr · 2020-03-11T00:25:39Z

vuepress/docs/docs/middleware.md

+
+## Customizing error responses
+
+During various phases of executing a query, an error may occur. Caliban renders the different instances of `CalibanError` to a GraphQL spec compliant response. As a user, you will most likely encounter `ExecutionError` at some point because this will encapsulate the errors in the error channel of your effects. For Caliban to be able to render some basic message about the error that occured during query execution, it is important that your errror extends `Throwable`.


typo: errror

ghostdogpr · 2020-03-11T00:26:31Z

vuepress/docs/docs/middleware.md

+
+During various phases of executing a query, an error may occur. Caliban renders the different instances of `CalibanError` to a GraphQL spec compliant response. As a user, you will most likely encounter `ExecutionError` at some point because this will encapsulate the errors in the error channel of your effects. For Caliban to be able to render some basic message about the error that occured during query execution, it is important that your errror extends `Throwable`.
+
+For more meaningful error handling, GraphQL spec allows for an [`extension`](http://spec.graphql.org/June2018/#example-fce18) object in the error response. This object may include, for instance, `code` information to model enum-like error codes that can be handled by a front-end. In order to generate this information, one can use the `mapError` function on a `GraphQLInterpreter`. An example is provided below in which we map a custom domain error within an `ExecutionError` to a meaningful error code.


ghostdogpr · 2020-03-11T09:35:36Z

@DJLemkes thanks for your contribution!

DJLemkes · 2020-03-11T13:09:57Z

@ghostdogpr Thanks for you reviews and patience! And for creating the library of course :)

DJLemkes force-pushed the error-extension branch from d060434 to d68458e Compare March 6, 2020 11:17

ghostdogpr reviewed Mar 7, 2020

View reviewed changes

DJLemkes added 2 commits March 10, 2020 22:27

Make error extension section an ObjectValue for arbitrary k,v support

f66fa4a

Update docs with example on error extension usage

b9ca4b5

DJLemkes force-pushed the error-extension branch from d68458e to b9ca4b5 Compare March 10, 2020 22:19

ghostdogpr reviewed Mar 11, 2020

View reviewed changes

Remove .asInstanceOf and fix typo

d9b5950

ghostdogpr merged commit 7e82950 into ghostdogpr:master Mar 11, 2020

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Allow errors to send an error code in the response extension #246

Allow errors to send an error code in the response extension #246

DJLemkes commented Feb 27, 2020 •

edited by ghostdogpr

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DJLemkes commented Mar 11, 2020


		## Customizing error responses

		During various phases of executing a query, an error may occur. Caliban renders the different instances of `CalibanError` to a GraphQL spec compliant response. As a user, you will most likely encounter `ExecutionError` at some point because this will encapsulate the errors in the error channel of your effects. For Caliban to be able to render some basic message about the error that occured during query execution, it is important that your errror extends `Throwable`.


		During various phases of executing a query, an error may occur. Caliban renders the different instances of `CalibanError` to a GraphQL spec compliant response. As a user, you will most likely encounter `ExecutionError` at some point because this will encapsulate the errors in the error channel of your effects. For Caliban to be able to render some basic message about the error that occured during query execution, it is important that your errror extends `Throwable`.

		For more meaningful error handling, GraphQL spec allows for an [`extension`](http://spec.graphql.org/June2018/#example-fce18) object in the error response. This object may include, for instance, `code` information to model enum-like error codes that can be handled by a front-end. In order to generate this information, one can use the `mapError` function on a `GraphQLInterpreter`. An example is provided below in which we map a custom domain error within an `ExecutionError` to a meaningful error code.

Allow errors to send an error code in the response extension #246

Allow errors to send an error code in the response extension #246

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DJLemkes commented Feb 27, 2020 • edited by ghostdogpr Loading

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ghostdogpr commented Mar 11, 2020

DJLemkes commented Mar 11, 2020

DJLemkes commented Feb 27, 2020 •

edited by ghostdogpr

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