finagle/finch

Better errors for missing/wrong JSON properties

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#264 opened on May 6, 2015

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 (3 comments) (1 reaction) (1 assignee)Scala (221 forks)batch import
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Description

It would be nice if we could better understand what's wrong with an incoming JSON body and throw a reasonable error about it. For now, we throw NotParsed(BodyItem, ....). Would be nice if we could promote BodyItem to a case class BodyItem(name: String) and wrap missing/wrongly decoded properties in it.

This is only about the cases when JSON is decoded directly to a case class: body.as[User]. I believe, end users should handle this manually (with custom exceptions like NotFoundJsonProperty) when dealing with raw JSON types directly: body.as[Json] and then parsing them with AST API provided by a JSON library.

See discussion in #261 started by @lderks.

Contributor guide

Research direction
Investigate how body.as[User] works and identify where error messages are generated. Then implement a better error that includes the missing or wrong property name.
Tech stack
scala
Domain
backend api design
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
Half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
Scala
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
40