No additional error message in case of 4xx responses

[piotr-iohk]

Release	Operating System	Cause
next	Linux	Code

Context

For some 4xx response codes returned by the API we do deliver additional error message indicating what is wrong with the request (These are mainly true for 400 responses which are most often due to invalid request parameters - additional message often explains what is wrong with particular message, like passphrase is too long...). Some of the 4xx responses however are missing those additional messages.

No additional message is delivered in the following cases:

• 409 creating wallet that already exists: POST v2/wallets -> no additional message, could be "Wallet already exists"
• 404 in case of accessing non-existing wallet id GET, PUT, DELETE v2/wallets/{wallet-id} -> no additional message, could be "Wallet with given id not found"
• 403 in case of providing incorrect old_passphrase (e.g. PUT v2/wallets/{wallet-id}/passphrase) -> no message, could be "Provided old_passphrase is incorrect"
• 405 (e.g. DELETE v2/wallets) -> could be "HTTP Method not allowed" (if there's option to fine tune it could be "DELETE method not allowed for endpoint v2/wallets)
• 406 (e.g. http header Accept: text/plain) -> could be "Content not acceptable. Acceptable content is application/json. Check your request's Accept header."
• 415 (e.g. no Content-Type header for POST and PUT requests) -> could be "Unsupported media type, check Content-Type and Content-Encoding headers of your request"

Although 405, 406, 415 messages would not be so common and may be considered as nice to have I think that having messages for 403, 404 and 409 would be improvement in user experience.

Steps to Reproduce

Look at the cases in the Context above.

Expected behavior

Additional error message could be presented in case of the mentioned 4xx responses.

Actual behavior

There is no additional error message.

---

Resolution Plan

• Add proper error description to errors
• Review error return type to be a JSON object containing both a { "code": ..., "message": ... }

PR

Number	Base
#298	master
#299	KtorZ/260/more-descriptive-errors
#308	master
#304	master

QA

• We now return more descriptive error messages for all errors we do catch and handle in the wallet layer.

• Also, with a small middleware sitting between Servant and Warp, we now catch "raw" errors thrown directly by servant and provide a helpful payload to them to make them more descriptives too.

• See also: Cardano.Wallet.Api.Server

[piotr-iohk]

well done :) 👍