Error message not returned to client, get empty JSON instead

[traturne]

Issue Description

See the following code:

if err := c.Bind(req); err != nil {
		msg := "Unable to bind DataAPISearchProductsRequest: " + err.Error()
		return echo.NewHTTPError(http.StatusBadRequest, errors.New(msg))
	}

I do not see the error message in the response from the server for the following invalid request.

PAYLOAD=$(cat <<-END
{
  query": "wrench"
}
END
)

curl -v -H "Content-Type: application/json" \
 -X POST http://localhost:8080/search_products -d $PAYLOAD
Note: Unnecessary use of -X or --request, POST is already inferred.
*   Trying ::1:8080...
* TCP_NODELAY set
* Connected to localhost (::1) port 8080 (#0)
> POST /search_products HTTP/1.1
> Host: localhost:8080
> User-Agent: curl/7.65.3
> Accept: */*
> Content-Type: application/json
> Content-Length: 22
>
* upload completely sent off: 22 out of 22 bytes
* Mark bundle as not supporting multiuse
< HTTP/1.1 400 Bad Request
< Content-Type: application/json; charset=UTF-8
< Date: Sat, 27 Jun 2020 03:32:24 GMT
< Content-Length: 3
<
{}
* Connection #0 to host localhost left intact

The error is logged just fine:

{"time":"2020-06-26T20:32:01.452707-07:00","id":"","remote_ip":"::1","host":"localhost:8080","method":"POST","uri":"/search_products","user_agent":"curl/7.65.3","status":400,"error":"code=400, message=Unable to bind DataAPISearchProductsRequest: code=400, message=Syntax error: offset=5, error=invalid character 'q' looking for beginning of object key string","latency":41355283633,"latency_human":"41.355283633s","bytes_in":22,"bytes_out":3}

Expected behaviour

I expect to see the error message int he response.

Actual behaviour

I do not see the error message in the response.

Steps to reproduce

I'm not doing anything fancy here, just trying to use the default HTTP error handler.

Version/commit

v3.3.10-dev

[sm4ll-3gg]

Hello!
You see that behavior because returned by errors.New error couldn't be marshaled in JSON correctly. It's not a bug in echo.

Look at this example: https://play.golang.org/p/d8eStiK3z1R

To fix this you can just pass a string to echo.NewHTTPError as a message instead of result of errors.New calling.

Hope it'll help you ;)

[lammel]

I guess this is fixed in v4 where the error is unwrapped actually.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[lammel]

An error with incorrect handling of errors was fixed for v4.2.
So this should work with the latest release. Please close/confirm @traturne

[Meowzz95]

I'm using github.com/labstack/echo/v4 v4.6.1

return c.JSON(401,body)
This returns empty object {} when body is error type, is this expected?

Error is generated by errors.New

---

Edit:

type AuthError struct {
	Message string
}

I tried to use a custom error type with a public member, it works. However, from the above discussion, it seems that errors.New should work too. Did I misunderstand something?

[lammel]

This has probably been fixed by PR #1666 (see also #1477).
Closing.