![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`:

interceptors@2x.png...

 *   }
 * ```
 */
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:5.1.0")
```

        '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'

    // Build a full stack of interceptors.
    val interceptors = mutableListOf<Interceptor>()
    interceptors += client.interceptors
    interceptors += RetryAndFollowUpInterceptor(client)
    interceptors += BridgeInterceptor(client.cookieJar)
    interceptors += CacheInterceptor(client.cache)
    interceptors += ConnectInterceptor
    if (!forWebSocket) {
      interceptors += client.networkInterceptors
    }

      }

    /**
     * Returns a modifiable list of interceptors that observe the full span of each call: from
     * before the connection is established (if any) until after the response source is selected
     * (either the origin server, cache, or both).
     */
    fun interceptors(): MutableList<Interceptor> = interceptors

    fun addInterceptor(interceptor: Interceptor) =
      apply {
        interceptors += interceptor

    running SSLv3, you must manually configure your own `ConnectionSpec`.

 *  **OkHttp now offers interceptors.** Interceptors are a powerful mechanism
    that can monitor, rewrite, and retry calls. The [interceptors doc][interceptors] is a full
    introduction to this new API.

 *  New: APIs to iterate and selectively clear the response cache.
 *  New: Support for SOCKS proxies.

  @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)