if (errorExceptionToDeliver == null &&
                unacknowledgedBytesRead >= connection.okHttpSettings.initialWindowSize / 2
              ) {
                // Flow control: notify the peer that we're ready for more data! Only send a
                // WINDOW_UPDATE if the stream isn't in error.
                connection.writeWindowUpdateLater(id, unacknowledgedBytesRead)

    executeSynchronously("/")
      .assertFailureMatches("(?s)Hostname localhost not verified.*")
  }

  /**
   * Anonymous cipher suites were disabled in OpenJDK because they're rarely used and permit
   * man-in-the-middle attacks. https://bugs.openjdk.java.net/browse/JDK-8212823
   */
  @Test
  fun anonCipherSuiteUnsupported() {
    platform.assumeNotConscrypt()

    internal var lockingSourceCount = 0

    /** The sequence number of the most recently committed edit to this entry. */
    internal var sequenceNumber: Long = 0

    init {
      // The names are repetitive so re-use the same builder to avoid allocations.
      val fileBuilder = StringBuilder(key).append('.')
      val truncateTo = fileBuilder.length
      for (i in 0 until valueCount) {
        fileBuilder.append(i)

with Java.

We spent a lot of time and energy on retaining strict compatibility with OkHttp 3.x. We’re even
keeping the package name the same: `okhttp3`!

There are three kinds of compatibility we’re tracking:

 * **Binary compatibility** is the ability to compile a program against OkHttp 3.x, and then to run
   it against OkHttp 4.x. We’re using the excellent [japicmp][japicmp] library via its

      if (!response.isSuccessful) throw IOException("Unexpected code $response")

      println(response.body.string())
    }
  }

  companion object {
    /**
     * The imgur client ID for OkHttp recipes. If you're using imgur for anything other than running
     * these examples, please request your own client ID! https://api.imgur.com/oauth2
     */
    private const val IMGUR_CLIENT_ID = "9199fdef135c122"

      // Fail fast if there's no response queued up.
      return failFastResponse!!
    }

    val result = responseQueue.take()

    // If take() returned because we're shutting down, then enqueue another dead letter so that any
    // other threads waiting on take() will also return.
    if (result == DEAD_LETTER) responseQueue.add(DEAD_LETTER)

    return result
  }

      "FINE: Q10000 starting              : task",
      "FINE: Q10000 finished run in   0 µs: task",
    )
  }

  /** Inspect how many runnables have been enqueued. If none then we're truly sequential. */
  @Test fun singleQueueIsSerial() {
    redQueue.execute("task one", 100.µs) {
      log += "one:run@${taskFaker.nanoTime} parallel=${taskFaker.isParallel}"
    }

    }

    if (userRequest.header("Connection") == null) {
      requestBuilder.header("Connection", "Keep-Alive")
    }

    // If we add an "Accept-Encoding: gzip" header field we're responsible for also decompressing
    // the transfer stream.
    var transparentGzip = false
    if (userRequest.header("Accept-Encoding") == null && userRequest.header("Range") == null) {
      transparentGzip = true

---


# Recipes

We've written some recipes that demonstrate how to solve common problems with OkHttp. Read through them to learn about how everything works together. Cut-and-paste these examples freely; that's what they're for.

### Synchronous Get ([.kt][SynchronousGetKotlin], [.java][SynchronousGetJava])

Download a file, print its headers, and print its response body as a string.

organization-specific certificate authority.

By default `HeldCertificate` instances expire after 24 hours. Use `duration()` to adjust.

By default server certificates need to identify which hostnames they're trusted for. You may add as
many as necessary with `addSubjectAlternativeName()`. This mechanism also supports a very limited
form of wildcards `*.example.com` where the `*` must be first and doesn't match nested subdomains.