* ## Preemptive Authentication
 *
 * To make HTTPS calls using an HTTP proxy server OkHttp must first negotiate a connection with
 * 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

              .build(),
        ),
      )
    val response = call.execute()
    assertThat(response.isSuccessful).isTrue()

    server.takeRequest() // Discard the CONNECT tunnel.
    return server.takeRequest()
  }

    and `www.squareup.com`. If a server refuses such sharing it will return HTTP 421 and OkHttp will
    automatically retry on an unshared connection.
 *  Fix: Don't crash if a TLS tunnel's response body is truncated.
 *  Fix: Don't track unusable routes beyond their usefulness. We had a bug where we could track
    certain bad routes indefinitely; now we only track the ones that could be necessary.

    val get = server.takeRequest()
    assertThat(get.requestLine).isEqualTo("GET /foo HTTP/1.1")
    assertThat(get.headers["Proxy-Authorization"]).isNull()
  }

  // Don't disconnect after building a tunnel with CONNECT
  // http://code.google.com/p/android/issues/detail?id=37221
  @Test
  fun proxyWithConnectionClose() {
    server.useHttps(handshakeCertificates.sslSocketFactory())

    // Make an SSL Tunnel on the first message pair of each SSL + proxy connection.
    val url = route.address.url
    val requestLine = "CONNECT ${url.toHostHeader(includeDefaultPort = true)} HTTP/1.1"
    while (true) {
      val source = this.source!!
      val sink = this.sink!!
      val tunnelCodec =
        Http1ExchangeCodec(
          // No client for CONNECT tunnels:
          client = null,

     * doing HTTPS through an HTTP proxy, or HTTP/2 prior knowledge through an HTTP proxy.
     *
     * When a new connection is received, all in-tunnel responses are served before the connection is
     * upgraded to HTTPS or HTTP/2.
     */
    fun inTunnel() =
      apply {
        removeHeader("Content-Length")
        inTunnel = true
      }

 * [newFixedLengthSource(0)][newFixedLengthSource] and may skip reading and closing that source.
 */
class Http1ExchangeCodec(
  /** The client that configures this stream. May be null for HTTPS proxy tunnels. */
  private val client: OkHttpClient?,
  override val carrier: ExchangeCodec.Carrier,
  private val source: BufferedSource,
  private val sink: BufferedSink,
) : ExchangeCodec {
  private var state = STATE_IDLE

    assertThat(get2.headers["Proxy-Authorization"]).isEqualTo("password")
  }

  /**
   * OkHttp has a bug where a `Connection: close` response header is not honored when establishing a
   * TLS tunnel. https://github.com/square/okhttp/issues/2426
   */
  @Test
  fun proxyAuthenticateOnConnectWithConnectionClose() {
    server.useHttps(handshakeCertificates.sslSocketFactory())

 4. If it's a new route, it connects by building either a direct socket connection, a TLS tunnel (for HTTPS over an HTTP proxy), or a direct TLS connection. It does TLS handshakes as necessary. This step may be retried for tunnel challenges and TLS handshake failures.
 5. It sends the HTTP request and reads the response.

 *  **OkHttp now supports TLS 1.3.** This requires either Conscrypt or Java 11+.

 *  **Proxy authenticators are now asked for preemptive authentication.** OkHttp will now request
    authentication credentials before creating TLS tunnels through HTTP proxies (HTTP `CONNECT`).
    Authenticators should identify preemptive authentications by the presence of a challenge whose
    scheme is "OkHttp-Preemptive".