Resty Error Handling by the book - can't catch a 404 HTTP status

[BigBoulard]

Hi,

I struggle to understand who error handling is working using Resty.
I make a PUT API call that returns a 404 HTTP status code but I can catch it in the code below.

I've tried to use resp.IsError() without sucess.

I've read some similar topic here which uses the SetError method on a struct (Error or Response depending on the case), but this method is maybe specifically tied to a marshalling error when using the SetResult method.

Do you have king of a simple example to understand the good way to handle error using Resty?
That would be awesome.

Best.

func PutItems( items []string) ([]string, string, rest_errors.RestErr){
  resp, err := client.R().
  SetHeader("Accept", "application/json").
  SetBody(myBody).
  Put(myEndpoint)
  
  if err != nil { // 404 don't happen here apparently
       return nil, rest_errors.NewBadRequestError("API Gateway - http update user cars:" + err.Error())
  }
  
  if resp.IsError() { // 404 is not detected either here
      return nil, errors.New("Unknow error here")
  }

  var createdItems []string
  err2 := json.Unmarshal(resp.Body(), &createdItems)
  if err2 != nil {
     return nil, errors.New("error when unmarshalling items" + err2.Error())
  }
  
  return createdItems, nil
}

[peterjmorgan]

I'm confused by this too.

Right now, instead of using the if err != nil pattern, I'm using:

if test := CheckResponse(resp); test != nil {
    // do stuff with the error
   return nil, errors.New("..."+ test.Error)
}

I have structs for the errors for this API I'm working on so CheckResponse() looks like:

func CheckResponse(resp *resty.Response) *ErrorStruct {
    var jsonER ErrorStruct

    if resp.IsError() {
        err := json.Unmarshall(resp.Body(), &jsonER)
        if err != nil {
             // barf
        }
        return &jsonER
    }
    return nil
}

It feels weird because every other Go library I've used follows the convention of returning errors in a return value.

Curious if anyone has figured this out better.

[segevda]

@BigBoulard
the error return value on the Get/Put/Post/Execute/etc methods indicates whether the request was successfully delivered and a response was returned from the server. This is not different from the native go http client, here quoting from the docs for the Do() method:
An error is returned if caused by client policy (such as CheckRedirect), or failure to speak HTTP (such as a network connectivity problem). A non-2xx status code doesn't cause an error.

IsError() should indeed return true if the returned status code is 4xx or 5xx. Try running the following snippet:

import (
	"fmt"

	"github.com/go-resty/resty/v2"
)

func main() {
	cl := resty.New().SetBaseURL("https://httpbin.org")

	resp, err := cl.R().Put("status/404")
	if err != nil {
		panic(err)
	}

	if resp.IsError() {
		fmt.Println(resp.StatusCode()) // prints 404
	}
}

The way you handled the error in your PutItems function is perfectly fine - if IsError() you should create and return an error.

@peterjmorgan: it seems that what your doing in your CheckResponse function can be achieved by using SetError(&ErrorStruct{}). If this doesn't work, care to elaborate on what happens?