### Rewriting Requests

Interceptors can add, remove, or replace request headers. They can also transform the body of those requests that have one. For example, you can use an application interceptor to add request body compression if you're connecting to a webserver known to support it.

```java
/** This interceptor compresses the HTTP request body. Many webservers can't handle this! */
final class GzipRequestInterceptor implements Interceptor {

 * They don't specify whether a specific proxy server should be used or how to authenticate with that proxy server.

They're also concrete: each URL identifies a specific path (like `/square/okhttp`) and query (like `?q=sharks&lang=en`). Each webserver hosts many URLs.

### [Addresses](https://square.github.io/okhttp/4.x/okhttp/okhttp3/-address/)

 *  Fix: Don't throw when converting an `HttpUrl` to a `java.net.URI`.
    Previously URLs with special characters like `|` and `[` would break when
    subjected to URI’s overly-strict validation.
 *  Fix: Don't re-encode `+` as `%20` in encoded URL query strings. OkHttp
    prefers `%20` when doing its own encoding, but will retain `+` when that is
    provided.
 *  Fix: Enforce that callers call `WebSocket.close()` on IO errors. Error

   * the String used to construct them is no longer strongly referenced outside of the CipherSuite.
   */
  @Test
  fun instancesAreInterned_survivesGarbageCollection() {
    // We're not holding onto a reference to this String instance outside of the CipherSuite...
    val cs = forJavaName("FakeCipherSuite_instancesAreInterned")

    to OkHttp's default TLS options.

 *  New: Upgrade to Conscrypt 2.0.0. OkHttp works with other versions of Conscrypt but this is the
    version we're testing against.

    ```kotlin
    implementation("org.conscrypt:conscrypt-openjdk-uber:2.0.0")
    ```

 *  New: Update the embedded public suffixes list.


## Version 3.13.1

_2019-02-05_

          parameter.groups[3]!!.value
        }
        token.startsWith("'") && token.endsWith("'") && token.length > 2 -> {
          // If the token is 'single-quoted' it's invalid! But we're lenient and strip the quotes.
          token.substring(1, token.length - 1)
        }
        else -> token
      }

    parameterNamesAndValues += name
    parameterNamesAndValues += value

import okhttp3.RequestBody;
import okhttp3.Response;
import okio.BufferedSink;
import okio.GzipSink;
import okio.Okio;

public final class RequestBodyCompression {
  /**
   * The Google API KEY for OkHttp recipes. If you're using Google APIs for anything other than
   * running these examples, please request your own client ID!
   *
   * https://console.developers.google.com/project
   */

      } catch (_: IOException) {
        // The cache cannot be written.
      }
      return null
    }

    if (requestMethod != "GET") {
      // Don't cache non-GET responses. We're technically allowed to cache HEAD requests and some
      // POST requests, but the complexity of doing so is high and the benefit is low.
      return null
    }

    if (response.hasVaryAll()) {
      return null

import org.junit.jupiter.api.Disabled
import org.junit.jupiter.api.Test

/**
 * Access every declaration that is deprecated with [DeprecationLevel.ERROR]. Although new Kotlin
 * code shouldn't use these, they're necessary for clients migrating from OkHttp 3.x and this test
 * ensures the symbols remain available and with the expected parameter and return types.
 */
@Suppress(
  "DEPRECATION_ERROR",
  "UNUSED_VALUE",

      // Confirm the connection is healthy and return it.
      if (connection.isHealthy(doExtensiveHealthChecks)) return connection

      // In the second synchronized block, release the unhealthy acquired connection. We're also on
      // the hook to close this connection if it's no longer in use.
      val noNewExchangesEvent: Boolean
      val toClose: Socket? =
        connection.withLock {