![Interceptors Diagram](../assets/images/******@****.***)

### 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`:

```java
OkHttpClient client = new OkHttpClient.Builder()

import okio.Buffer
import okio.BufferedSource
import okio.ByteString

/**
 * A one-shot stream from the origin server to the client application with the raw bytes of the
 * response body. Each response body is supported by an active connection to the webserver. This
 * imposes both obligations and limits on the client application.
 *
 * ### The response body must be closed.
 *

      """
      |--simple boundary
      |
      |abcd
      |--simple boundary--
      """.trimMargin()
        .replace("\n", "\r\n")

    val responseBody =
      multipart.toResponseBody(
        "application/multipart; boundary=\"simple boundary\"".toMediaType(),
      )

    val parts = MultipartReader(responseBody)
    assertThat(parts.boundary).isEqualTo("simple boundary")

    val part = parts.nextPart()!!

import okhttp3.internal.connection.RealCall

/**
 * A concrete interceptor chain that carries the entire interceptor chain: all application
 * interceptors, the OkHttp core, all network interceptors, and finally the network caller.
 *
 * If the chain is for an application interceptor then [exchange] must be null. Otherwise it is for
 * a network interceptor and [exchange] must be non-null.
 */
class RealInterceptorChain(

        val parts = header.split(':', limit = 2)
        if ("Content-Type".equals(parts[0], ignoreCase = true)) {
          return@let parts[1].trim()
        }
      }
      return@let null
    } ?: "application/x-www-form-urlencoded"

  return mimeType.toMediaTypeOrNull()
}

private fun isSpecialHeader(s: String): Boolean {
  return s.equals("Content-Type", ignoreCase = true)
}

fun Main.commonRun() {

        return "application/xml".toMediaType()
      }

      override fun writeTo(sink: BufferedSink) {
        sink.writeUtf8("<el")
        sink.flush()
        throw IOException("failed to stream the XML")
      }
    }

    class ValidRequestBody : RequestBody() {
      override fun contentType(): MediaType {
        return "application/xml".toMediaType()
      }

     * [Request.tag]. Use null to remove any existing tag assigned for [T].
     *
     * Use this API to attach timing, debugging, or other application data to a request so that
     * you may read it in interceptors, event listeners, or callbacks.
     */
    @JvmName("reifiedTag")
    inline fun <reified T : Any> tag(tag: T?): Builder = tag(T::class, tag)

 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package okhttp3.slack;

/** Authorization for an application to make Slack API calls on behalf of a user. */
@SuppressWarnings("checkstyle:membername")
public final class OAuthSession {
  public final boolean ok;
  public final String access_token;
  public final String scope;

   *
   * The initialization time may vary depending on the journal file size and the current actual
   * cache size. The application needs to be aware of calling this function during the
   * initialization phase and preferably in a background worker thread.
   *
   * Note that if the application chooses to not call this method to initialize the cache. By
   * default, OkHttp will perform lazy initialization upon the first usage of the cache.

import java.net.HttpURLConnection
import java.net.Proxy
import okhttp3.HttpUrl
import okhttp3.Request

object RequestLine {
  /**
   * Returns the request status line, like "GET / HTTP/1.1". This is exposed to the application by
   * [HttpURLConnection.getHeaderFields], so it needs to be set even if the transport is
   * HTTP/2.
   */
  fun get(
    request: Request,
    proxyType: Proxy.Type,
  ): String =
    buildString {