![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`:

 *   }
 * ```
 */
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())
     * }

    // 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) {

```java
logging.redactHeader("Authorization");
logging.redactHeader("Cookie");
```

Download
--------

```kotlin
implementation("com.squareup.okhttp3:logging-interceptor:4.12.0")
```

        'calls.md': 'features/calls.md'
        'connections.md': 'features/connections.md'
        'events.md': 'features/events.md'
        'https.md': 'features/events.md'
        'interceptors.md': 'features/interceptors.md'
        'r8_proguard.md': 'features/r8_proguard.md'
        # Redirect all Security pages to security/*
        'security.md': 'security/security.md'

import java.net.ProtocolException
import okhttp3.Interceptor
import okhttp3.Response
import okhttp3.internal.connection.Exchange
import okhttp3.internal.http2.ConnectionShutdownException
import okhttp3.internal.stripBody
import okio.buffer

/** This is the last interceptor in the chain. It makes a network call to the server. */
class CallServerInterceptor(private val forWebSocket: Boolean) : Interceptor {
  @Throws(IOException::class)

 * the proxy. This proxy connection is called a "TLS Tunnel" and is specified by
 * [RFC 2817][1]. The HTTP CONNECT request that creates this tunnel connection is special: it
 * does not participate in any [interceptors][Interceptor] or [event listeners][EventListener]. It
 * doesn't include the motivating request's HTTP headers or even its full URL; only the target
 * server's hostname is sent to the proxy.
 *

import okio.IOException
import org.junit.jupiter.api.Assertions

open class RecordingConnectionListener(
  /**
   * An override to ignore the normal order that is enforced.
   * EventListeners added by Interceptors will not see all events.
   */
  private val enforceOrder: Boolean = true,
) : ConnectionListener() {
  val eventSequence: Deque<ConnectionEvent> = ConcurrentLinkedDeque()

      proxy = proxy,
      socketAddress = socketAddress,
    )
  }

  fun newChain(call: RealCall): RealInterceptorChain {
    return RealInterceptorChain(
      call = call,
      interceptors = listOf(),
      index = 0,
      exchange = null,
      request = call.request(),
      connectTimeoutMillis = 10_000,
      readTimeoutMillis = 10_000,
      writeTimeoutMillis = 10_000,
    )
  }

import okhttp3.CallEvent.SecureConnectStart
import org.junit.jupiter.api.Assertions.fail

open class RecordingEventListener(
  /**
   * An override to ignore the normal order that is enforced.
   * EventListeners added by Interceptors will not see all events.
   */
  private val enforceOrder: Boolean = true,
) : EventListener() {
  val eventSequence: Deque<CallEvent> = ConcurrentLinkedDeque()

  private val forbiddenLocks = mutableListOf<Any>()