Hello guys, I’m pretty new to KTOR and Kotlin in g...

# ktor

[Goku]

Hello guys, I’m pretty new to KTOR and Kotlin in general…

I’ve created a simple multiplatform project, and I’m calling the following endpoint from the iOS side: <https://api.github.com/projects/columns/42> in order to receive 401, which is intended.

Unfortunately, the program crashes with the following explanation:

Exception doesn't match @Throws-specified class list and thus isn't propagated from Kotlin to Objective-C/Swift as NSError.
It is considered unexpected and unhandled instead. Program will be terminated.
Uncaught Kotlin exception: io.ktor.client.features.ClientRequestException: Client request(<https://api.github.com/projects/columns/42>) invalid: 401 Unauthorized. Text: "{"message":"Requires authentication","documentation_url":"<https://docs.github.com/rest/reference/projects#get-a-project-column>"}"

I get back the response and everything gets logged properly.

Any idea on how to fix this?

Thanks!

[Rustam Siniukov]

you can disable default request validation by setting expectSuccess = false on client or per-request level

[Goku]

Yeah, I figured that one out, thanks 🙂

[Goku]

I also need help with the following:

this.install(HttpSend) {
            intercept { httpClientCall, httpRequestBuilder ->
                val statusCode = httpClientCall.response.status.value

                if (statusCode !in 100..399) {
                    val delayBetweenRequests = retryStrategy.retryDelay(httpClientCall) ?: 0.0
                    delay(maxOf(delayBetweenRequests, 0.0).toLong())
                    execute(httpRequestBuilder)
                } else {
                    httpClientCall
                }
            }

            maxSendCount = retryStrategy.retryCount
        }
    }

For some reason I keep getting the following exception:

Uncaught Kotlin exception: io.ktor.client.features.SendCountExceedException: Max send count 3 exceeded

But I don’t understand how this is possible

[Goku]

Also, sorry for being so pushy 😄

I have this:

install(Auth) {
        basic {
            username = "myUsername"
            password = "myPassword"
            // sendWithoutRequest = true
        }
    }

/**
* Send credentials in without waiting for [HttpStatusCode.Unauthorized].
*/
var sendWithoutRequest: Boolean = false

The request that gets executed returns 401 (Unauthorized) but it doesn’t get re-executed with the Authorization header…

I can only send it once I set sendWithoutRequest = true which I really don’t want to do for every request.

Any help would be greatly appreciated!

Thanks!

[Rustam Siniukov]

for SendCountExceedException what exactly is wrong? It seems like you send more then 3 retries, and it’s your current limit

[Goku]

This is what I see in HttpSend.kt class:

if (sentCount >= maxSendCount) {
    throw SendCountExceedException("Max send count $maxSendCount exceeded")
}

So once it reaches 3 it will throw an exception, so I don’t understand how I can fix this on my side?

All I do is set the maxSendCount = 3 in here:

this.install(HttpSend) { 
    intercept { httpClientCall, httpRequestBuilder ->
        ...
    }

    maxSendCount = 3
}

[Goku]

I’m probably doing something wrong here I just don’t see it

[Rustam Siniukov]

what is your expected behavior?

[Goku]

To retry it n times and then just stop retrying.

Throwing an exception crashes it on iOS, that’s why this is a problem for me

[Goku]

Exception doesn't match @Throws-specified class list and thus isn't propagated from Kotlin to Objective-C/Swift as NSError.
It is considered unexpected and unhandled instead. Program will be terminated.
Uncaught Kotlin exception: io.ktor.client.features.SendCountExceedException: Max send count 3 exceeded

[Goku]

I don’t mind the exception actually. Just need to figure out how to stop the app from crashing once it’s thrown.

I’m really new to KMM so sorry if these are stupid questions.

[Rustam Siniukov]

you can create a counter on your side and stop calling execute in your interceptor once it reaches desired value

[Rustam Siniukov]

something like

this.install(HttpSend) {
            var couter = 0
            intercept { httpClientCall, httpRequestBuilder ->
                val statusCode = httpClientCall.response.status.value

                if (counter < 3 && statusCode !in 100..399) {
                    ...
                    execute(httpRequestBuilder)
                    counter++
                } else {
                    httpClientCall
                }
            }
        }

[Goku]

Yeah got you, that works.

Just to clarify how this mechanism works.

It will keep repeating the request until it gets a success response?

[Rustam Siniukov]

or you reach desired retry count

[Goku]

👍 thanks for your help

[rsetkus]

Hi @Rustam Siniukov. Have very similar case so, will drop my question in this thread.

I am using HttpSend to intercept response for authentication purposes. On 401/Unauthorized response intercepting and performing actions to refresh token and retry request. When expectSuccess is turned on (value true), 401 response is not intercepted. I guess it happens due to ExpectSuccess feature, which throws exception just before HttpSend feature and stops proceeding ktor pipeline.

When I turn off expectSuccess (value false), response is intercepted in HttpSend and authentication works as expected. However, none of the HttpResponseValidator functions (validateResponse and handleResponseException) are called.

Can you suggest or what is preferred way to map http errors to custom errors when expectSuccess is off?

[Rustam Siniukov]

hi @rsetkus. What version of Ktor do you use? We had a bug that expectSuccess=false will disable all validators, and not only the default one. It was fixed in 1.5.2 https://youtrack.jetbrains.com/issue/KTOR-2007.
Another point, please consider using Auth feature and implementing custom AuthProvider instead of intercepting HttpSend . Internally it will do the same, but it is more idiomatic way. Not a big deal, though

[rsetkus]

Thank you for prompt response @Rustam Siniukov.

This is it, I’m using version 1.5.0. Will try to switch to 1.5.2 to see if the issue disappears.

Can see that HttpSend is marked as experimental so, definitely will consider option re-implement authentication using AuthProvider .

[Rustam Siniukov]

If you are updating anyway, update to 1.5.3 😃

[rsetkus]

Hi @Rustam Siniukov. Updated to 1.5.3. Like you said, it does fix/trigger custom validators but HttpSend doesn’t intercept response anymore.

[Rustam Siniukov]

@rsetkus can you share example, please?

[rsetkus]

@Rustam Siniukov working an a private project but can try to make a minimal reproducable example.

[rsetkus]

Hi @Rustam Siniukov. If that helps, then example I followed is this https://github.com/icerockdev/moko-network/issues/37#issuecomment-709420620. Can make complete example if necessary. Let me know.

[Rustam Siniukov]

The best is if you create youtrack issue and put reproducer there