OkHttp interceptors in Android Kotlin - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to add a logging interceptor to the OkHttpClient builder.

Android Kotlin

val client = OkHttpClient.Builder()
    .addInterceptor({ chain ->
        val request = chain.request()
        println("Request URL: ${request.url}")
        chain.proceed(request)
    })
    .[1]()

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Abuild

Brun

Cexecute

Dstart

Attempts:

3 left

💡 Hint

Common Mistakes

Using start() or execute() instead of build()

Forgetting to call any method after adding the interceptor

The OkHttpClient.Builder requires calling build() to create the OkHttpClient instance.

2fill in blank

medium

Complete the code to create an interceptor that adds a custom header "X-Auth" with value "token123".

Android Kotlin

val interceptor = Interceptor { chain ->
    val newRequest = chain.request().newBuilder()
        .[1]("X-Auth", "token123")
        .build()
    chain.proceed(newRequest)
}

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AsetHeader

BaddHeader

CremoveHeader

Dheader

Attempts:

3 left

💡 Hint

Common Mistakes

Using setHeader which does not exist

Using header which is a getter, not a setter

To add a header in OkHttp request builder, use addHeader().

3fill in blank

hard

Fix the error in the interceptor code to correctly log the response body as a string.

Android Kotlin

val loggingInterceptor = Interceptor { chain ->
    val response = chain.proceed(chain.request())
    val bodyString = response.body?.string() ?: ""
    println("Response: ${bodyString}")
    [1]
}

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Aresponse.newBuilder().body(response.body).build()

Bresponse

Cresponse.newBuilder().body(ResponseBody.create(null, bodyString)).build()

Dresponse.newBuilder().body(ResponseBody.create(response.body?.contentType(), bodyString)).build()

Attempts:

3 left

💡 Hint

Common Mistakes

Returning the original response after consuming the body causes errors

Using null content type loses the original content type

Reading response.body.string() consumes the body, so we must create a new response with a new body containing the same content.

4fill in blank

hard

Fill both blanks to create an interceptor that retries the request once if the response code is 500.

Android Kotlin

val retryInterceptor = Interceptor { chain ->
    var response = chain.proceed(chain.request())
    if (response.code == [1]) {
        response.close()
        response = chain.proceed(chain.request())
    }
    response
}

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A500

B404

C200

D503

Attempts:

3 left

💡 Hint

Common Mistakes

Using 404 which means not found

Not closing the original response before retrying

HTTP status code 500 means server error; retrying on 500 is common.

5fill in blank

hard

Fill all three blanks to create a custom interceptor that adds a query parameter "lang" with value "en" to every request URL.

Android Kotlin

val langInterceptor = Interceptor { chain ->
    val originalRequest = chain.request()
    val originalUrl = originalRequest.url
    val newUrl = originalUrl.newBuilder()
        .[1]("lang", "en")
        .build()
    val newRequest = originalRequest.newBuilder()
        .[2](newUrl)
        .build()
    chain.[3](newRequest)
}

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AaddQueryParameter

Burl

Cproceed

DaddHeader

Attempts:

3 left

💡 Hint

Common Mistakes

Using addHeader instead of addQueryParameter

Not updating the request URL properly

Calling chain.proceed with the original request

To add a query parameter, use addQueryParameter on the URL builder, set the new URL with url(), and proceed with the new request.