*   }
 * ```
 */
fun interface Interceptor {
  @Throws(IOException::class)
  fun intercept(chain: Chain): Response

  companion object {
    /**
     * Constructs an interceptor for a lambda. This compact syntax is most useful for inline
     * interceptors.
     *
     * ```kotlin
     * val interceptor = Interceptor { chain: Interceptor.Chain ->
     *     chain.proceed(chain.request())
     * }

public final class okhttp3/logging/HttpLoggingInterceptor : okhttp3/Interceptor {
	public static final field Companion Lokhttp3/logging/HttpLoggingInterceptor$Companion;
	public final fun -deprecated_level ()Lokhttp3/logging/HttpLoggingInterceptor$Level;
	public fun <init> ()V
	public fun <init> (Lokhttp3/logging/HttpLoggingInterceptor$Logger;)V
	public synthetic fun <init> (Lokhttp3/logging/HttpLoggingInterceptor$Logger;ILkotlin/jvm/internal/DefaultConstructorMarker;)V

![Interceptors Diagram](../assets/images/interceptors@2x.png)

### Application Interceptors

Interceptors are registered as either _application_ or _network_ interceptors. We'll use the `LoggingInterceptor` defined above to show the difference.

Register an _application_ interceptor by calling `addInterceptor()` on `OkHttpClient.Builder`:

      assertThat(expected.message).isEqualTo(
        "network interceptor $interceptor must call proceed() exactly once",
      )
    }
  }

  @Test
  fun networkInterceptorsCannotChangeServerAddress() {
    server.enqueue(
      MockResponse.Builder()
        .code(500)
        .build(),
    )
    val interceptor =
      Interceptor { chain: Interceptor.Chain ->

Logging Interceptor
===================

An [OkHttp interceptor][interceptors] which logs HTTP request and response data.

```java
HttpLoggingInterceptor logging = new HttpLoggingInterceptor();
logging.setLevel(Level.BASIC);
OkHttpClient client = new OkHttpClient.Builder()
  .addInterceptor(logging)
  .build();
```

You can change the log level at any time by calling `setLevel()`.

 *
 * The format of the logs created by this class should not be considered stable and may
 * change slightly between releases. If you need a stable logging format, use your own interceptor.
 */
class HttpLoggingInterceptor
  @JvmOverloads
  constructor(
    private val logger: Logger = Logger.DEFAULT,
  ) : Interceptor {

    // Call the next interceptor in the chain.
    val next = copy(index = index + 1, request = request)
    val interceptor = interceptors[index]

    @Suppress("USELESS_ELVIS")
    val response =
      interceptor.intercept(next) ?: throw NullPointerException(
        "interceptor $interceptor returned null",
      )

    if (exchange != null) {
      check(index + 1 >= interceptors.size || next.calls == 1) {

  @Test fun clonedInterceptorsListsAreIndependent() {
    val interceptor =
      Interceptor { chain: Interceptor.Chain ->
        chain.proceed(chain.request())
      }
    val original = clientTestRule.newClient()
    original.newBuilder()
      .addInterceptor(interceptor)
      .addNetworkInterceptor(interceptor)
      .build()
    assertThat(original.interceptors.size).isEqualTo(0)

import java.util.Collections;
import java.util.Set;
import okhttp3.CertificatePinner;
import okhttp3.Interceptor;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;

public final class CheckHandshake {
  /** Rejects otherwise-trusted certificates. */
  private static final Interceptor CHECK_HANDSHAKE_INTERCEPTOR = new Interceptor() {
    final Set<String> denylist = Collections.singleton(

import java.io.IOException;
import okhttp3.Cache;
import okhttp3.Interceptor;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;

public final class RewriteResponseCacheControl {
  /** Dangerous interceptor that rewrites the server's cache-control header. */
  private static final Interceptor REWRITE_CACHE_CONTROL_INTERCEPTOR = chain -> {
    Response originalResponse = chain.proceed(chain.request());