is there any Interceptor equivalent in Ktor like OkHttp?

# android

[Tuan Kiet]

is there any Interceptor equivalent in Ktor like OkHttp?

[tseisel]

When configuring Ktor HttpClient with the OkHttp engine, you have the opportunity to configure OkHttp to use interceptors.

[Tuan Kiet]

what about other platform?

[Dias]

I haven't used OkHttp, but I assume interceptor is something like a ktor client feature that can intercept calls at various stages

[tseisel]

By inspecting the JsonFeature, I noticed that it is possible to define interceptors with the following syntax :

// Transformation on the request
httpClient.requestPipeline.intercept(HttpRequestPipeline.Transform) { playload ->
    // Do some things with the request, then send it to the next level
    val result = transformMyRequest(payload)
    proceedWith(result)
}

// Transformations on the response
httpClient.responsePipeline.intercept(HttpResponsePipeline.Transform) { (info, body) ->
    // Do some things with the response, then send it to the next level
    val result = transformMyResponse(info, body)
    proceedWith(result)
}

More details on Ktor Pipelining : https://ktor.io/advanced/pipeline.html#interceptors-and-the-pipelinecontext

[Tobi]

You can also use this to install an `interceptor`:

private fun HttpClientConfig<*>.authenticatedRequestsEngine() {
        engine {
            [e-mail](KEY_AUTH_INTERCEPTOR) {
                [e-mail] {
                    parameter(KEY_API_SECRET, BuildKonfig.API_KEY)
                }
            }
        }
    }

[Tobi]

I use it to authenticate each request by adding a parameter with an API_KEY

[Tobi]

https://api.ktor.io/0.9.4/io.ktor.client/-http-client-config/install.html

[Tobi]

Installs an interceptor defined by block. The key parameter is used as a unique name, that also prevents installing duplicated interceptors.