Merge pull request #438 from adriancole/consolidate-protocol

consolidate protocol constants

mockwebserver/src/main/java/com/squareup/okhttp/internal/spdy/SpdyServer.java

@@ -17,6 +17,7 @@
 package com.squareup.okhttp.internal.spdy;
 
 import com.squareup.okhttp.internal.ByteString;
+import com.squareup.okhttp.Protocol;
 import com.squareup.okhttp.internal.SslContextBuilder;
 import java.io.File;
 import java.io.FileInputStream;
@@ -71,7 +72,7 @@ public final class SpdyServer implements IncomingStreamHandler {
         System.out.println("UNSUPPORTED");
       }
       @Override public List<String> protocols() {
-        return Arrays.asList("spdy/3");
+        return Arrays.asList(Protocol.SPDY_3.name.utf8());
       }
       @Override public void protocolSelected(String protocol) {
         System.out.println("PROTOCOL SELECTED: " + protocol);

mockwebserver/src/main/java/com/squareup/okhttp/mockwebserver/MockWebServer.java

@@ -20,6 +20,7 @@ package com.squareup.okhttp.mockwebserver;
 import com.squareup.okhttp.internal.ByteString;
 import com.squareup.okhttp.internal.NamedRunnable;
 import com.squareup.okhttp.internal.Platform;
+import com.squareup.okhttp.Protocol;
 import com.squareup.okhttp.internal.Util;
 import com.squareup.okhttp.internal.spdy.IncomingStreamHandler;
 import com.squareup.okhttp.internal.spdy.SpdyConnection;
@@ -43,7 +44,6 @@ import java.security.SecureRandom;
 import java.security.cert.CertificateException;
 import java.security.cert.X509Certificate;
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
@@ -71,29 +71,6 @@ import static com.squareup.okhttp.mockwebserver.SocketPolicy.FAIL_HANDSHAKE;
  * replays them upon request in sequence.
  */
 public final class MockWebServer {
-  private static final byte[] HTTP_20_DRAFT_09 = new byte[] {
-      'H', 'T', 'T', 'P', '-', 'd', 'r', 'a', 'f', 't', '-', '0', '9', '/', '2', '.', '0'
-  };
-  private static final byte[] SPDY3 = new byte[] {
-      's', 'p', 'd', 'y', '/', '3'
-  };
-  private static final byte[] HTTP_11 = new byte[] {
-      'h', 't', 't', 'p', '/', '1', '.', '1'
-  };
-  private static final byte[] NPN_PROTOCOLS = joinNpnProtocols(HTTP_20_DRAFT_09, SPDY3, HTTP_11);
-
-  private static byte[] joinNpnProtocols(byte[]... protocols) {
-    try {
-      ByteArrayOutputStream baos = new ByteArrayOutputStream();
-      for (byte[] protocol : protocols) {
-        baos.write(protocol.length);
-        baos.write(protocol);
-      }
-      return baos.toByteArray();
-    } catch (IOException e) {
-      throw new AssertionError(e);
-    }
-  }
 
   private static final X509TrustManager UNTRUSTED_TRUST_MANAGER = new X509TrustManager() {
     @Override public void checkClientTrusted(X509Certificate[] chain, String authType)
@@ -181,7 +158,7 @@ public final class MockWebServer {
 
   /**
    * Sets whether NPN is used on incoming HTTPS connections to negotiate a
-   * transport like HTTP/1.1 or SPDY/3. Call this method to disable NPN and
+   * protocol like HTTP/1.1 or SPDY/3. Call this method to disable NPN and
    * SPDY.
    */
   public void setNpnEnabled(boolean npnEnabled) {
@@ -308,7 +285,7 @@ public final class MockWebServer {
       }
 
       public void processConnection() throws Exception {
-        Transport transport = Transport.HTTP_11;
+        Protocol protocol = Protocol.HTTP_11;
         Socket socket;
         if (sslSocketFactory != null) {
           if (tunnelProxy) {
@@ -327,39 +304,26 @@ public final class MockWebServer {
           openClientSockets.put(socket, true);
 
           if (npnEnabled) {
-            Platform.get().setNpnProtocols(sslSocket, NPN_PROTOCOLS);
+            // TODO: expose means to select which protocols to advertise.
+            Platform.get().setNpnProtocols(sslSocket, Protocol.HTTP2_SPDY3_AND_HTTP);
           }
 
           sslSocket.startHandshake();
 
           if (npnEnabled) {
-            byte[] selectedProtocol = Platform.get().getNpnSelectedProtocol(sslSocket);
-            if (selectedProtocol == null || Arrays.equals(selectedProtocol, HTTP_11)) {
-              transport = Transport.HTTP_11;
-            } else if (Arrays.equals(selectedProtocol, HTTP_20_DRAFT_09)) {
-              transport = Transport.HTTP_20_DRAFT_09;
-            } else if (Arrays.equals(selectedProtocol, SPDY3)) {
-              transport = Transport.SPDY_3;
-            } else {
-              throw new IllegalStateException(
-                  "Unexpected transport: " + new String(selectedProtocol, Util.US_ASCII));
-            }
+            ByteString selectedProtocol = Platform.get().getNpnSelectedProtocol(sslSocket);
+            protocol = Protocol.find(selectedProtocol);
           }
           openClientSockets.remove(raw);
         } else {
           socket = raw;
         }
 
-        if (transport == Transport.HTTP_20_DRAFT_09 || transport == Transport.SPDY_3) {
-          SpdySocketHandler spdySocketHandler = new SpdySocketHandler(socket, transport);
-          SpdyConnection.Builder builder = new SpdyConnection.Builder(false, socket)
-              .handler(spdySocketHandler);
-          if (transport == Transport.HTTP_20_DRAFT_09) {
-            builder.http20Draft09();
-          } else {
-            builder.spdy3();
-          }
-          SpdyConnection spdyConnection = builder.build();
+        if (protocol.spdyVariant) {
+          SpdySocketHandler spdySocketHandler = new SpdySocketHandler(socket, protocol);
+          SpdyConnection spdyConnection = new SpdyConnection.Builder(false, socket)
+              .protocol(protocol)
+              .handler(spdySocketHandler).build();
           openSpdyConnections.put(spdyConnection, Boolean.TRUE);
           openClientSockets.remove(socket);
           spdyConnection.readConnectionHeader();
@@ -628,12 +592,12 @@ public final class MockWebServer {
   /** Processes HTTP requests layered over SPDY/3. */
   private class SpdySocketHandler implements IncomingStreamHandler {
     private final Socket socket;
-    private final Transport transport;
+    private final Protocol protocol;
     private final AtomicInteger sequenceNumber = new AtomicInteger();
 
-    private SpdySocketHandler(Socket socket, Transport transport) {
+    private SpdySocketHandler(Socket socket, Protocol protocol) {
       this.socket = socket;
-      this.transport = transport;
+      this.protocol = protocol;
     }
 
     @Override public void receive(SpdyStream stream) throws IOException {
@@ -647,7 +611,7 @@ public final class MockWebServer {
       }
       writeResponse(stream, response);
       logger.info("Received request: " + request + " and responded: " + response
-          + " transport is " + transport);
+          + " protocol is " + protocol.name.utf8());
     }
 
     private RecordedRequest readRequest(SpdyStream stream) throws IOException {
@@ -724,8 +688,4 @@ public final class MockWebServer {
       }
     }
   }
-
-  enum Transport {
-    HTTP_11, SPDY_3, HTTP_20_DRAFT_09
-  }
 }

okhttp-protocols/src/main/java/com/squareup/okhttp/Protocol.java

@@ -0,0 +1,75 @@
+/*
+ * Copyright (C) 2014 Square, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.squareup.okhttp;
+
+import com.squareup.okhttp.internal.ByteString;
+import com.squareup.okhttp.internal.Util;
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.List;
+
+/**
+ * Contains protocols that OkHttp supports
+ * <a href="http://tools.ietf.org/html/draft-agl-tls-nextprotoneg-04">NPN</a> or
+ * <a href="http://tools.ietf.org/html/draft-ietf-tls-applayerprotoneg">ALPN</a> selection.
+ *
+ * <p/>
+ * <h3>Protocol vs Scheme</h3>
+ * Despite its name, {@link java.net.URL#getProtocol()} returns the
+ * {@link java.net.URI#getScheme() scheme} (http, https, etc.) of the URL, not
+ * the protocol (http/1.1, spdy/3, etc.).  OkHttp uses the word protocol to
+ * indicate how HTTP messages are framed.
+ */
+public enum Protocol {
+  HTTP_2("HTTP-draft-09/2.0", true),
+  SPDY_3("spdy/3", true),
+  HTTP_11("http/1.1", false);
+
+  public static final List<Protocol> HTTP2_SPDY3_AND_HTTP =
+      Util.immutableList(Arrays.asList(HTTP_2, SPDY_3, HTTP_11));
+  public static final List<Protocol> SPDY3_AND_HTTP11 =
+      Util.immutableList(Arrays.asList(SPDY_3, HTTP_11));
+  public static final List<Protocol> HTTP2_AND_HTTP_11 =
+      Util.immutableList(Arrays.asList(HTTP_2, HTTP_11));
+
+  /** Identifier string used in NPN or ALPN selection. */
+  public final ByteString name;
+
+  /**
+   * When true the protocol is binary framed and derived from SPDY.
+   *
+   * @see com.squareup.okhttp.internal.spdy.Variant
+   */
+  public final boolean spdyVariant;
+
+  Protocol(String name, boolean spdyVariant) {
+    this.name = ByteString.encodeUtf8(name);
+    this.spdyVariant = spdyVariant;
+  }
+
+  /**
+   * Returns the protocol matching {@code input} or {@link #HTTP_11} is on
+   * {@code null}. Throws an {@link IOException} when {@code input} doesn't
+   * match the {@link #name} of a supported protocol.
+   */
+  public static Protocol find(ByteString input) throws IOException {
+    if (input == null) return HTTP_11;
+    for (Protocol protocol : values()) {
+      if (protocol.name.equals(input)) return protocol;
+    }
+    throw new IOException("Unexpected protocol: " + input.utf8());
+  }
+}

okhttp-protocols/src/main/java/com/squareup/okhttp/internal/ByteString.java

@@ -115,7 +115,7 @@ public final class ByteString {
       System.arraycopy(byteString.data, 0, result, pos, byteString.size());
       pos += byteString.size();
     }
-    return ByteString.of(result);
+    return new ByteString(result);
   }
 
   private ByteString(byte[] data) {
@@ -141,11 +141,6 @@ public final class ByteString {
     out.write(data);
   }
 
-  /** Writes a subsequence of this byte string to {@code out}. */
-  public void write(OutputStream out, int offset, int count) throws IOException {
-    out.write(data, offset, count);
-  }
-
   @Override public boolean equals(Object o) {
     return o == this || o instanceof ByteString && Arrays.equals(((ByteString) o).data, data);
   }

okhttp-protocols/src/main/java/com/squareup/okhttp/internal/Platform.java

@@ -16,9 +16,9 @@
  */
 package com.squareup.okhttp.internal;
 
+import com.squareup.okhttp.Protocol;
 import java.io.IOException;
 import java.io.OutputStream;
-import java.io.UnsupportedEncodingException;
 import java.lang.reflect.Constructor;
 import java.lang.reflect.InvocationHandler;
 import java.lang.reflect.InvocationTargetException;
@@ -106,7 +106,7 @@ public class Platform {
   }
 
   /** Returns the negotiated protocol, or null if no protocol was negotiated. */
-  public byte[] getNpnSelectedProtocol(SSLSocket socket) {
+  public ByteString getNpnSelectedProtocol(SSLSocket socket) {
     return null;
   }
 
@@ -114,7 +114,7 @@ public class Platform {
    * Sets client-supported protocols on a socket to send to a server. The
    * protocols are only sent if the socket implementation supports NPN.
    */
-  public void setNpnProtocols(SSLSocket socket, byte[] npnProtocols) {
+  public void setNpnProtocols(SSLSocket socket, List<Protocol> npnProtocols) {
   }
 
   public void connectSocket(Socket socket, InetSocketAddress address,
@@ -267,11 +267,11 @@ public class Platform {
       }
     }
 
-    @Override public void setNpnProtocols(SSLSocket socket, byte[] npnProtocols) {
+    @Override public void setNpnProtocols(SSLSocket socket, List<Protocol> npnProtocols) {
       if (setNpnProtocols == null) return;
       if (!openSslSocketClass.isInstance(socket)) return;
       try {
-        Object[] parameters = { npnProtocols };
+        Object[] parameters = { concatLengthPrefixed(npnProtocols) };
         if (setAlpnProtocols != null) {
           setAlpnProtocols.invoke(socket, parameters);
         }
@@ -283,16 +283,16 @@ public class Platform {
       }
     }
 
-    @Override public byte[] getNpnSelectedProtocol(SSLSocket socket) {
+    @Override public ByteString getNpnSelectedProtocol(SSLSocket socket) {
       if (getNpnSelectedProtocol == null) return null;
       if (!openSslSocketClass.isInstance(socket)) return null;
       try {
         if (getAlpnSelectedProtocol != null) {
           // Prefer ALPN's result if it is present.
           byte[] alpnResult = (byte[]) getAlpnSelectedProtocol.invoke(socket);
-          if (alpnResult != null) return alpnResult;
+          if (alpnResult != null) return ByteString.of(alpnResult);
         }
-        return (byte[]) getNpnSelectedProtocol.invoke(socket);
+        return ByteString.of((byte[]) getNpnSelectedProtocol.invoke(socket));
       } catch (InvocationTargetException e) {
         throw new RuntimeException(e);
       } catch (IllegalAccessException e) {
@@ -316,20 +316,15 @@ public class Platform {
       this.serverProviderClass = serverProviderClass;
     }
 
-    @Override public void setNpnProtocols(SSLSocket socket, byte[] npnProtocols) {
+    @Override public void setNpnProtocols(SSLSocket socket, List<Protocol> npnProtocols) {
       try {
-        List<String> strings = new ArrayList<String>();
-        for (int i = 0; i < npnProtocols.length; ) {
-          int length = npnProtocols[i++];
-          strings.add(new String(npnProtocols, i, length, "US-ASCII"));
-          i += length;
+        List<String> names = new ArrayList<String>(npnProtocols.size());
+        for (int i = 0, size = npnProtocols.size(); i < size; i++) {
+          names.add(npnProtocols.get(i).name.utf8());
         }
         Object provider = Proxy.newProxyInstance(Platform.class.getClassLoader(),
-            new Class[] {clientProviderClass, serverProviderClass},
-            new JettyNpnProvider(strings));
+            new Class[] { clientProviderClass, serverProviderClass }, new JettyNpnProvider(names));
         putMethod.invoke(null, socket, provider);
-      } catch (UnsupportedEncodingException e) {
-        throw new AssertionError(e);
       } catch (InvocationTargetException e) {
         throw new AssertionError(e);
       } catch (IllegalAccessException e) {
@@ -337,7 +332,7 @@ public class Platform {
       }
     }
 
-    @Override public byte[] getNpnSelectedProtocol(SSLSocket socket) {
+    @Override public ByteString getNpnSelectedProtocol(SSLSocket socket) {
       try {
         JettyNpnProvider provider =
             (JettyNpnProvider) Proxy.getInvocationHandler(getMethod.invoke(null, socket));
@@ -347,9 +342,7 @@ public class Platform {
               "NPN callback dropped so SPDY is disabled. " + "Is npn-boot on the boot class path?");
           return null;
         }
-        return provider.unsupported ? null : provider.selected.getBytes("US-ASCII");
-      } catch (UnsupportedEncodingException e) {
-        throw new AssertionError();
+        return provider.unsupported ? null : ByteString.encodeUtf8(provider.selected);
       } catch (InvocationTargetException e) {
         throw new AssertionError();
       } catch (IllegalAccessException e) {
@@ -400,4 +393,26 @@ public class Platform {
       }
     }
   }
+
+  /**
+   * Concatenation of 8-bit, length prefixed protocol names.
+   *
+   * http://tools.ietf.org/html/draft-agl-tls-nextprotoneg-04#page-4
+   */
+  static byte[] concatLengthPrefixed(List<Protocol> protocols) {
+    int size = 0;
+    for (Protocol protocol : protocols) {
+      size += protocol.name.size() + 1; // add a byte for 8-bit length prefix.
+    }
+    byte[] result = new byte[size];
+    int pos = 0;
+    for (Protocol protocol : protocols) {
+      int nameSize = protocol.name.size();
+      result[pos++] = (byte) nameSize;
+      // toByteArray allocates an array, but this is only called on new connections.
+      System.arraycopy(protocol.name.toByteArray(), 0, result, pos, nameSize);
+      pos += nameSize;
+    }
+    return result;
+  }
 }

okhttp-protocols/src/main/java/com/squareup/okhttp/internal/Util.java

@@ -400,11 +400,19 @@ public final class Util {
     };
   }
 
-  public static List<ByteString> byteStringList(String... strings) {
-    List<ByteString> result = new ArrayList<ByteString>(strings.length);
-    for (String string : strings) {
+  public static List<ByteString> byteStringList(String... elements) {
+    List<ByteString> result = new ArrayList<ByteString>(elements.length);
+    for (String string : elements) {
       result.add(ByteString.encodeUtf8(string));
     }
     return result;
   }
+
+  public static List<ByteString> byteStringList(List<String> elements) {
+    List<ByteString> result = new ArrayList<ByteString>(elements.size());
+    for (int i = 0, size = elements.size(); i < size; i++) {
+      result.add(ByteString.encodeUtf8(elements.get(i)));
+    }
+    return result;
+  }
 }

okhttp-protocols/src/main/java/com/squareup/okhttp/internal/spdy/HpackDraft05.java

@@ -405,6 +405,7 @@ final class HpackDraft05 {
       }
     }
 
+    // http://tools.ietf.org/html/draft-ietf-httpbis-header-compression-05#section-4.1.1
     public void writeInt(int value, int prefixMask, int bits) throws IOException {
       // Write the raw value for a single byte value.
       if (value < prefixMask) {

okhttp-protocols/src/main/java/com/squareup/okhttp/internal/spdy/Http20Draft09.java

@@ -16,6 +16,7 @@
 package com.squareup.okhttp.internal.spdy;
 
 import com.squareup.okhttp.internal.ByteString;
+import com.squareup.okhttp.Protocol;
 import com.squareup.okhttp.internal.Util;
 import java.io.ByteArrayOutputStream;
 import java.io.DataInputStream;
@@ -33,8 +34,8 @@ import java.util.List;
  */
 public final class Http20Draft09 implements Variant {
 
-  @Override public String getProtocol() {
-    return "HTTP-draft-09/2.0";
+  @Override public Protocol getProtocol() {
+    return Protocol.HTTP_2;
   }
 
   private static final byte[] CONNECTION_HEADER;

okhttp-protocols/src/main/java/com/squareup/okhttp/internal/spdy/Spdy3.java

@@ -17,6 +17,7 @@ package com.squareup.okhttp.internal.spdy;
 
 import com.squareup.okhttp.internal.ByteString;
 import com.squareup.okhttp.internal.Platform;
+import com.squareup.okhttp.Protocol;
 import com.squareup.okhttp.internal.Util;
 import java.io.ByteArrayOutputStream;
 import java.io.DataInputStream;
@@ -31,8 +32,8 @@ import java.util.zip.Deflater;
 
 final class Spdy3 implements Variant {
 
-  @Override public String getProtocol() {
-    return "spdy/3";
+  @Override public Protocol getProtocol() {
+    return Protocol.SPDY_3;
   }
 
   static final int TYPE_DATA = 0x0;

okhttp-protocols/src/main/java/com/squareup/okhttp/internal/spdy/SpdyConnection.java

@@ -18,6 +18,7 @@ package com.squareup.okhttp.internal.spdy;
 
 import com.squareup.okhttp.internal.ByteString;
 import com.squareup.okhttp.internal.NamedRunnable;
+import com.squareup.okhttp.Protocol;
 import com.squareup.okhttp.internal.Util;
 import java.io.Closeable;
 import java.io.IOException;
@@ -60,7 +61,7 @@ public final class SpdyConnection implements Closeable {
       Integer.MAX_VALUE, 60, TimeUnit.SECONDS, new SynchronousQueue<Runnable>(),
       Util.threadFactory("OkHttp SpdyConnection", true));
 
-  /** The protocol variant, like SPDY/3 or HTTP-draft-09/2.0. */
+  /** The protocol variant, like {@link com.squareup.okhttp.internal.spdy.Spdy3}. */
   final Variant variant;
 
   /** True if this peer initiated the connection. */
@@ -104,12 +105,8 @@ public final class SpdyConnection implements Closeable {
     new Thread(new Reader()).start(); // Not a daemon thread.
   }
 
-  /**
-   * The protocol name, like {@code spdy/3} or {@code HTTP-draft-09/2.0}.
-   *
-   * @see com.squareup.okhttp.internal.spdy.Variant#getProtocol()
-   */
-  public String getProtocol() {
+  /** The protocol as selected using NPN or ALPN. */
+  public Protocol getProtocol() {
      return variant.getProtocol();
   }
 
@@ -423,13 +420,15 @@ public final class SpdyConnection implements Closeable {
       return this;
     }
 
-    public Builder spdy3() {
-      this.variant = Variant.SPDY3;
-      return this;
-    }
-
-    public Builder http20Draft09() {
-      this.variant = Variant.HTTP_20_DRAFT_09;
+    public Builder protocol(Protocol protocol) {
+      // TODO: protocol == variant.getProtocol, so we could map this.
+      if (protocol == Protocol.HTTP_2) {
+        this.variant = Variant.HTTP_20_DRAFT_09;
+      } else if (protocol == Protocol.SPDY_3) {
+        this.variant = Variant.SPDY3;
+      } else {
+        throw new AssertionError(protocol);
+      }
       return this;
     }
 

okhttp-protocols/src/main/java/com/squareup/okhttp/internal/spdy/Variant.java

@@ -15,6 +15,7 @@
  */
 package com.squareup.okhttp.internal.spdy;
 
+import com.squareup.okhttp.Protocol;
 import java.io.InputStream;
 import java.io.OutputStream;
 
@@ -23,8 +24,8 @@ interface Variant {
   Variant SPDY3 = new Spdy3();
   Variant HTTP_20_DRAFT_09 = new Http20Draft09();
 
-  /** The protocol name, like {@code spdy/3} or {@code HTTP-draft-09/2.0}. */
-  String getProtocol();
+  /** The protocol as selected using NPN or ALPN. */
+  Protocol getProtocol();
 
   /**
    * @param client true if this is the HTTP client's reader, reading frames from

okhttp-protocols/src/test/java/com/squareup/okhttp/internal/ByteStringTest.java

@@ -66,12 +66,6 @@ public class ByteStringTest {
     assertByteArraysEquals(new byte[] { 0x61, 0x62, 0x63 }, out.toByteArray());
   }
 
-  @Test public void writeWithOffset() throws Exception {
-    ByteArrayOutputStream out = new ByteArrayOutputStream();
-    ByteString.of((byte) 0x61, (byte) 0x62, (byte) 0x63).write(out, 1, 2);
-    assertByteArraysEquals(new byte[] { 0x62, 0x63 }, out.toByteArray());
-  }
-
   @Test public void concat() {
     assertEquals(ByteString.of(), ByteString.concat());
     assertEquals(ByteString.of(), ByteString.concat(ByteString.EMPTY));

okhttp/src/main/java/com/squareup/okhttp/Address.java

@@ -41,22 +41,22 @@ public final class Address {
   final SSLSocketFactory sslSocketFactory;
   final HostnameVerifier hostnameVerifier;
   final OkAuthenticator authenticator;
-  final List<String> transports;
+  final List<Protocol> protocols;
 
   public Address(String uriHost, int uriPort, SSLSocketFactory sslSocketFactory,
       HostnameVerifier hostnameVerifier, OkAuthenticator authenticator, Proxy proxy,
-      List<String> transports) throws UnknownHostException {
+      List<Protocol> protocols) throws UnknownHostException {
     if (uriHost == null) throw new NullPointerException("uriHost == null");
     if (uriPort <= 0) throw new IllegalArgumentException("uriPort <= 0: " + uriPort);
     if (authenticator == null) throw new IllegalArgumentException("authenticator == null");
-    if (transports == null) throw new IllegalArgumentException("transports == null");
+    if (protocols == null) throw new IllegalArgumentException("protocols == null");
     this.proxy = proxy;
     this.uriHost = uriHost;
     this.uriPort = uriPort;
     this.sslSocketFactory = sslSocketFactory;
     this.hostnameVerifier = hostnameVerifier;
     this.authenticator = authenticator;
-    this.transports = Util.immutableList(transports);
+    this.protocols = Util.immutableList(protocols);
   }
 
   /** Returns the hostname of the origin server. */
@@ -97,11 +97,12 @@ public final class Address {
   }
 
   /**
-   * Returns the client's transports. This method always returns a non-null list
-   * that contains "http/1.1", possibly among other transports.
+   * Returns the protocols the client supports. This method always returns a
+   * non-null list that contains minimally
+   * {@link Protocol#HTTP_11}.
    */
-  public List<String> getTransports() {
-    return transports;
+  public List<Protocol> getProtocols() {
+    return protocols;
   }
 
   /**
@@ -121,7 +122,7 @@ public final class Address {
           && equal(this.sslSocketFactory, that.sslSocketFactory)
           && equal(this.hostnameVerifier, that.hostnameVerifier)
           && equal(this.authenticator, that.authenticator)
-          && equal(this.transports, that.transports);
+          && equal(this.protocols, that.protocols);
     }
     return false;
   }
@@ -134,7 +135,7 @@ public final class Address {
     result = 31 * result + (hostnameVerifier != null ? hostnameVerifier.hashCode() : 0);
     result = 31 * result + (authenticator != null ? authenticator.hashCode() : 0);
     result = 31 * result + (proxy != null ? proxy.hashCode() : 0);
-    result = 31 * result + transports.hashCode();
+    result = 31 * result + protocols.hashCode();
     return result;
   }
 }

okhttp/src/main/java/com/squareup/okhttp/Connection.java

@@ -16,6 +16,7 @@
  */
 package com.squareup.okhttp;
 
+import com.squareup.okhttp.internal.ByteString;
 import com.squareup.okhttp.internal.Platform;
 import com.squareup.okhttp.internal.http.HttpAuthenticator;
 import com.squareup.okhttp.internal.http.HttpEngine;
@@ -31,7 +32,6 @@ import java.io.OutputStream;
 import java.net.Proxy;
 import java.net.Socket;
 import java.net.SocketTimeoutException;
-import java.util.Arrays;
 import javax.net.ssl.SSLSocket;
 
 import static java.net.HttpURLConnection.HTTP_OK;
@@ -56,7 +56,7 @@ import static java.net.HttpURLConnection.HTTP_PROXY_AUTH;
  *   <li>Server Name Indication (SNI) enables one IP address to negotiate secure
  *       connections for multiple domain names.
  *   <li>Next Protocol Negotiation (NPN) enables the HTTPS port (443) to be used
- *       for both HTTP and SPDY transports.
+ *       for both HTTP and SPDY protocols.
  * </ul>
  * Unfortunately, older HTTPS servers refuse to connect when such options are
  * presented. Rather than avoiding these options entirely, this class allows a
@@ -64,31 +64,6 @@ import static java.net.HttpURLConnection.HTTP_PROXY_AUTH;
  * should the attempt fail.
  */
 public final class Connection implements Closeable {
-  private static final byte[] ALL_PROTOCOLS = new byte[] {
-      17, 'H', 'T', 'T', 'P', '-', 'd', 'r', 'a', 'f', 't', '-', '0', '9', '/', '2', '.', '0',
-      6, 's', 'p', 'd', 'y', '/', '3',
-      8, 'h', 't', 't', 'p', '/', '1', '.', '1'
-  };
-
-  private static final byte[] SPDY3_AND_HTTP11 = new byte[] {
-      6, 's', 'p', 'd', 'y', '/', '3',
-      8, 'h', 't', 't', 'p', '/', '1', '.', '1'
-  };
-
-  private static final byte[] HTTP2_AND_HTTP = new byte[] {
-      17, 'H', 'T', 'T', 'P', '-', 'd', 'r', 'a', 'f', 't', '-', '0', '9', '/', '2', '.', '0',
-      8, 'h', 't', 't', 'p', '/', '1', '.', '1'
-  };
-
-  private static final byte[] HTTP_20_DRAFT_09 = new byte[] {
-      'H', 'T', 'T', 'P', '-', 'd', 'r', 'a', 'f', 't', '-', '0', '9', '/', '2', '.', '0'
-  };
-  private static final byte[] SPDY3 = new byte[] {
-      's', 'p', 'd', 'y', '/', '3'
-  };
-  private static final byte[] HTTP_11 = new byte[] {
-      'h', 't', 't', 'p', '/', '1', '.', '1'
-  };
 
   private final Route route;
 
@@ -145,19 +120,19 @@ public final class Connection implements Closeable {
       platform.supportTlsIntolerantServer(sslSocket);
     }
 
-    boolean useNpn = route.modernTls && (
-        route.address.transports.contains("HTTP-draft-09/2.0")
-     || route.address.transports.contains("spdy/3")
+    boolean useNpn = route.modernTls && (// Contains a spdy variant.
+        route.address.protocols.contains(Protocol.HTTP_2)
+     || route.address.protocols.contains(Protocol.SPDY_3)
     );
 
     if (useNpn) {
-      if (route.address.transports.contains("HTTP-draft-09/2.0")
-       && route.address.transports.contains("spdy/3")) {
-        platform.setNpnProtocols(sslSocket, ALL_PROTOCOLS);
-      } else if (route.address.transports.contains("HTTP-draft-09/2.0")) {
-        platform.setNpnProtocols(sslSocket, HTTP2_AND_HTTP);
+      if (route.address.protocols.contains(Protocol.HTTP_2) // Contains both spdy variants.
+          && route.address.protocols.contains(Protocol.SPDY_3)) {
+        platform.setNpnProtocols(sslSocket, Protocol.HTTP2_SPDY3_AND_HTTP);
+      } else if (route.address.protocols.contains(Protocol.HTTP_2)) {
+        platform.setNpnProtocols(sslSocket, Protocol.HTTP2_AND_HTTP_11);
       } else {
-        platform.setNpnProtocols(sslSocket, SPDY3_AND_HTTP11);
+        platform.setNpnProtocols(sslSocket, Protocol.SPDY3_AND_HTTP11);
       }
     }
 
@@ -174,19 +149,14 @@ public final class Connection implements Closeable {
     handshake = Handshake.get(sslSocket.getSession());
     streamWrapper();
 
-    byte[] selectedProtocol;
-    if (useNpn && (selectedProtocol = platform.getNpnSelectedProtocol(sslSocket)) != null) {
-      if (Arrays.equals(selectedProtocol, HTTP_20_DRAFT_09)
-       || Arrays.equals(selectedProtocol, SPDY3)) {
-        SpdyConnection.Builder builder =
-            new SpdyConnection.Builder(route.address.getUriHost(), true, in, out);
-        if (Arrays.equals(selectedProtocol, HTTP_20_DRAFT_09)) builder.http20Draft09();
+    ByteString maybeProtocol;
+    if (useNpn && (maybeProtocol = platform.getNpnSelectedProtocol(sslSocket)) != null) {
+      Protocol selectedProtocol = Protocol.find(maybeProtocol); // Throws IOE on unknown.
+      if (selectedProtocol.spdyVariant) {
         sslSocket.setSoTimeout(0); // SPDY timeouts are set per-stream.
-        spdyConnection = builder.build();
+        spdyConnection = new SpdyConnection.Builder(route.address.getUriHost(), true, in, out)
+            .protocol(selectedProtocol).build();
         spdyConnection.sendConnectionHeader();
-      } else if (!Arrays.equals(selectedProtocol, HTTP_11)) {
-        throw new IOException(
-            "Unexpected NPN transport " + new String(selectedProtocol, "ISO-8859-1"));
       }
     }
   }

okhttp/src/main/java/com/squareup/okhttp/OkHttpClient.java

@@ -15,11 +15,13 @@
  */
 package com.squareup.okhttp;
 
+import com.squareup.okhttp.internal.ByteString;
 import com.squareup.okhttp.internal.Util;
 import com.squareup.okhttp.internal.http.HttpAuthenticator;
 import com.squareup.okhttp.internal.http.HttpURLConnectionImpl;
 import com.squareup.okhttp.internal.http.HttpsURLConnectionImpl;
 import com.squareup.okhttp.internal.tls.OkHostnameVerifier;
+import java.io.IOException;
 import java.net.CookieHandler;
 import java.net.HttpURLConnection;
 import java.net.Proxy;
@@ -29,7 +31,7 @@ import java.net.URL;
 import java.net.URLConnection;
 import java.net.URLStreamHandler;
 import java.net.URLStreamHandlerFactory;
-import java.util.Arrays;
+import java.util.ArrayList;
 import java.util.List;
 import java.util.concurrent.TimeUnit;
 import javax.net.ssl.HostnameVerifier;
@@ -38,13 +40,11 @@ import javax.net.ssl.SSLSocketFactory;
 
 /** Configures and creates HTTP connections. */
 public final class OkHttpClient implements URLStreamHandlerFactory, Cloneable {
-  private static final List<String> DEFAULT_TRANSPORTS
-      = Util.immutableList(Arrays.asList("HTTP-draft-09/2.0", "spdy/3", "http/1.1"));
 
   private final RouteDatabase routeDatabase;
   private Dispatcher dispatcher;
   private Proxy proxy;
-  private List<String> transports;
+  private List<Protocol> protocols;
   private ProxySelector proxySelector;
   private CookieHandler cookieHandler;
   private OkResponseCache responseCache;
@@ -296,20 +296,39 @@ public final class OkHttpClient implements URLStreamHandlerFactory, Cloneable {
   }
 
   /**
-   * Configure the transports used by this client to communicate with remote
+   * @deprecated OkHttp 2 enforces an enumeration of {@link Protocol protocols}
+   * that can be selected. Please switch to {@link #setProtocols(java.util.List)}.
+   */
+  @Deprecated
+  public OkHttpClient setTransports(List<String> transports) {
+    List<Protocol> protocols = new ArrayList<Protocol>(transports.size());
+    for (int i = 0, size = transports.size(); i < size; i++) {
+      try {
+        Protocol protocol = Protocol.find(ByteString.encodeUtf8(transports.get(i)));
+        protocols.add(protocol);
+      } catch (IOException e) {
+        throw new IllegalArgumentException(e);
+      }
+    }
+    return setProtocols(protocols);
+  }
+
+  /**
+   * Configure the protocols used by this client to communicate with remote
    * servers. By default this client will prefer the most efficient transport
-   * available, falling back to more ubiquitous transports. Applications should
+   * available, falling back to more ubiquitous protocols. Applications should
    * only call this method to avoid specific compatibility problems, such as web
    * servers that behave incorrectly when SPDY is enabled.
    *
-   * <p>The following transports are currently supported:
+   * <p>The following protocols are currently supported:
    * <ul>
    *   <li><a href="http://www.w3.org/Protocols/rfc2616/rfc2616.html">http/1.1</a>
    *   <li><a href="http://www.chromium.org/spdy/spdy-protocol/spdy-protocol-draft3">spdy/3</a>
+   *   <li><a href="http://tools.ietf.org/html/draft-ietf-httpbis-http2-09">HTTP-draft-09/2.0</a>
    * </ul>
    *
    * <p><strong>This is an evolving set.</strong> Future releases may drop
-   * support for transitional transports (like spdy/3), in favor of their
+   * support for transitional protocols (like spdy/3), in favor of their
    * successors (spdy/4 or http/2.0). The http/1.1 transport will never be
    * dropped.
    *
@@ -319,28 +338,41 @@ public final class OkHttpClient implements URLStreamHandlerFactory, Cloneable {
    * (such as <a href="http://tools.ietf.org/html/draft-friedl-tls-applayerprotoneg-02">ALPN</a>)
    * to negotiate a transport.
    *
-   * @param transports the transports to use, in order of preference. The list
+   * @param protocols the protocols to use, in order of preference. The list
    *     must contain "http/1.1". It must not contain null.
    */
-  public OkHttpClient setTransports(List<String> transports) {
-    transports = Util.immutableList(transports);
-    if (!transports.contains("http/1.1")) {
-      throw new IllegalArgumentException("transports doesn't contain http/1.1: " + transports);
+  public OkHttpClient setProtocols(List<Protocol> protocols) {
+    protocols = Util.immutableList(protocols);
+    if (!protocols.contains(Protocol.HTTP_11)) {
+      throw new IllegalArgumentException("protocols doesn't contain http/1.1: " + protocols);
     }
-    if (transports.contains(null)) {
-      throw new IllegalArgumentException("transports must not contain null");
+    if (protocols.contains(null)) {
+      throw new IllegalArgumentException("protocols must not contain null");
     }
-    if (transports.contains("")) {
-      throw new IllegalArgumentException("transports contains an empty string");
+    if (protocols.contains(ByteString.EMPTY)) {
+      throw new IllegalArgumentException("protocols contains an empty string");
     }
-    this.transports = transports;
+    this.protocols = Util.immutableList(protocols);
     return this;
   }
 
+  /**
+   * @deprecated OkHttp 2 enforces an enumeration of {@link Protocol protocols}
+   * that can be selected. Please switch to {@link #getProtocols()}.
+   */
+  @Deprecated
   public List<String> getTransports() {
+    List<String> transports = new ArrayList<String>(protocols.size());
+    for (int i = 0, size = protocols.size(); i < size; i++) {
+      transports.add(protocols.get(i).name.utf8());
+    }
     return transports;
   }
 
+  public List<Protocol> getProtocols() {
+    return protocols;
+  }
+
   /**
    * Schedules {@code request} to be executed at some point in the future. The
    * {@link #getDispatcher dispatcher} defines when the request will run:
@@ -404,8 +436,8 @@ public final class OkHttpClient implements URLStreamHandlerFactory, Cloneable {
     if (result.connectionPool == null) {
       result.connectionPool = ConnectionPool.getDefault();
     }
-    if (result.transports == null) {
-      result.transports = DEFAULT_TRANSPORTS;
+    if (result.protocols == null) {
+      result.protocols = Protocol.HTTP2_SPDY3_AND_HTTP;
     }
     return result;
   }

okhttp/src/main/java/com/squareup/okhttp/Response.java

@@ -218,7 +218,7 @@ public final class Response {
 
     /**
      * Returns true if further data from this response body should be read at
-     * this time. For asynchronous transports like SPDY and HTTP/2.0, this will
+     * this time. For asynchronous protocols like SPDY and HTTP/2.0, this will
      * return false once all locally-available body bytes have been read.
      *
      * <p>Clients with many concurrent downloads can use this method to reduce

okhttp/src/main/java/com/squareup/okhttp/internal/http/HttpEngine.java

@@ -234,7 +234,7 @@ public class HttpEngine {
         hostnameVerifier = client.getHostnameVerifier();
       }
       Address address = new Address(uriHost, getEffectivePort(request.url()), sslSocketFactory,
-          hostnameVerifier, client.getAuthenticator(), client.getProxy(), client.getTransports());
+          hostnameVerifier, client.getAuthenticator(), client.getProxy(), client.getProtocols());
       routeSelector = new RouteSelector(address, request.uri(), client.getProxySelector(),
           client.getConnectionPool(), Dns.DEFAULT, client.getRoutesDatabase());
     }

okhttp/src/main/java/com/squareup/okhttp/internal/http/HttpTransport.java

@@ -21,6 +21,7 @@ import com.squareup.okhttp.Headers;
 import com.squareup.okhttp.Request;
 import com.squareup.okhttp.Response;
 import com.squareup.okhttp.internal.AbstractOutputStream;
+import com.squareup.okhttp.Protocol;
 import com.squareup.okhttp.internal.Util;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
@@ -155,7 +156,8 @@ public final class HttpTransport implements Transport {
 
       Response.Builder responseBuilder = new Response.Builder()
           .statusLine(statusLine)
-          .header(OkHeaders.SELECTED_TRANSPORT, "http/1.1");
+          .header(OkHeaders.SELECTED_TRANSPORT, Protocol.HTTP_11.name.utf8())
+          .header(OkHeaders.SELECTED_PROTOCOL, Protocol.HTTP_11.name.utf8());
 
       Headers.Builder headersBuilder = new Headers.Builder();
       OkHeaders.readHeaders(headersBuilder, in);

okhttp/src/main/java/com/squareup/okhttp/internal/http/HttpURLConnectionImpl.java

@@ -23,7 +23,9 @@ import com.squareup.okhttp.OkHttpClient;
 import com.squareup.okhttp.Request;
 import com.squareup.okhttp.Response;
 import com.squareup.okhttp.Route;
+import com.squareup.okhttp.internal.ByteString;
 import com.squareup.okhttp.internal.Platform;
+import com.squareup.okhttp.Protocol;
 import com.squareup.okhttp.internal.Util;
 import java.io.FileNotFoundException;
 import java.io.IOException;
@@ -502,8 +504,9 @@ public class HttpURLConnectionImpl extends HttpURLConnection {
       return;
     }
 
-    if ("X-Android-Transports".equals(field)) {
-      setTransports(newValue, false /* append */);
+    // TODO: Deprecate use of X-Android-Transports header?
+    if ("X-Android-Transports".equals(field) || "X-Android-Protocols".equals(field)) {
+      setProtocols(newValue, false /* append */);
     } else {
       requestHeaders.set(field, newValue);
     }
@@ -535,26 +538,33 @@ public class HttpURLConnectionImpl extends HttpURLConnection {
       return;
     }
 
-    if ("X-Android-Transports".equals(field)) {
-      setTransports(value, true /* append */);
+    // TODO: Deprecate use of X-Android-Transports header?
+    if ("X-Android-Transports".equals(field) || "X-Android-Protocols".equals(field)) {
+      setProtocols(value, true /* append */);
     } else {
       requestHeaders.add(field, value);
     }
   }
 
   /*
-   * Splits and validates a comma-separated string of transports.
+   * Splits and validates a comma-separated string of protocols.
    * When append == false, we require that the transport list contains "http/1.1".
+   * Throws {@link IllegalStateException} when one of the protocols isn't
+   * defined in {@link Protocol OkHttp's protocol enumeration}.
    */
-  private void setTransports(String transportsString, boolean append) {
-    List<String> transportsList = new ArrayList<String>();
+  private void setProtocols(String protocolsString, boolean append) {
+    List<Protocol> protocolsList = new ArrayList<Protocol>();
     if (append) {
-      transportsList.addAll(client.getTransports());
+      protocolsList.addAll(client.getProtocols());
     }
-    for (String transport : transportsString.split(",", -1)) {
-      transportsList.add(transport);
+    for (ByteString protocol : Util.byteStringList(protocolsString.split(",", -1))) {
+      try {
+        protocolsList.add(Protocol.find(protocol));
+      } catch (IOException e) {
+        throw new IllegalStateException(e);
+      }
     }
-    client.setTransports(transportsList);
+    client.setProtocols(protocolsList);
   }
 
   @Override public void setFixedLengthStreamingMode(int contentLength) {

okhttp/src/main/java/com/squareup/okhttp/internal/http/OkHeaders.java

@@ -50,10 +50,18 @@ public final class OkHeaders {
   public static final String RESPONSE_SOURCE = PREFIX + "-Response-Source";
 
   /**
-   * Synthetic response header: the selected transport ("spdy/3", "http/1.1", etc).
+   * @deprecated OkHttp 2 enforces an enumeration of {@link com.squareup.okhttp.Protocol protocols}
+   * that can be selected. Please use #SELECTED_PROTOCOL
    */
+  @Deprecated
   public static final String SELECTED_TRANSPORT = PREFIX + "-Selected-Transport";
 
+  /**
+   * Synthetic response header: the selected
+   * {@link com.squareup.okhttp.Protocol protocol} ("spdy/3", "http/1.1", etc).
+   */
+  public static final String SELECTED_PROTOCOL = PREFIX + "-Selected-Protocol";
+
   private OkHeaders() {
   }
 

okhttp/src/main/java/com/squareup/okhttp/internal/http/SpdyTransport.java

@@ -20,6 +20,7 @@ import com.squareup.okhttp.Headers;
 import com.squareup.okhttp.Request;
 import com.squareup.okhttp.Response;
 import com.squareup.okhttp.internal.ByteString;
+import com.squareup.okhttp.Protocol;
 import com.squareup.okhttp.internal.spdy.ErrorCode;
 import com.squareup.okhttp.internal.spdy.SpdyConnection;
 import com.squareup.okhttp.internal.spdy.SpdyStream;
@@ -41,7 +42,6 @@ public final class SpdyTransport implements Transport {
   private static final ByteString HEADER_HOST = ByteString.encodeUtf8(":host");
   private static final ByteString HEADER_AUTHORITY = ByteString.encodeUtf8(":authority");
   private static final ByteString HEADER_SCHEME = ByteString.encodeUtf8(":scheme");
-  private static final ByteString NULL = ByteString.of((byte) 0x00);
 
   private final HttpEngine httpEngine;
   private final SpdyConnection spdyConnection;
@@ -88,7 +88,7 @@ public final class SpdyTransport implements Transport {
    * Names are all lower case. No names are repeated. If any name has multiple
    * values, they are concatenated using "\0" as a delimiter.
    */
-  public static List<ByteString> writeNameValueBlock(Request request, String protocol,
+  public static List<ByteString> writeNameValueBlock(Request request, Protocol protocol,
       String version) {
     Headers headers = request.headers();
     // TODO: make the known header names constants.
@@ -99,9 +99,9 @@ public final class SpdyTransport implements Transport {
     result.add(ByteString.encodeUtf8(RequestLine.requestPath(request.url())));
     result.add(HEADER_VERSION);
     result.add(ByteString.encodeUtf8(version));
-    if (protocol.equals("spdy/3")) {
+    if (Protocol.SPDY_3 == protocol) {
       result.add(HEADER_HOST);
-    } else if (protocol.equals("HTTP-draft-09/2.0")) {
+    } else if (Protocol.HTTP_2 == protocol) {
       result.add(HEADER_AUTHORITY);
     } else {
       throw new AssertionError();
@@ -127,19 +127,19 @@ public final class SpdyTransport implements Transport {
           || name.equals(":scheme")) {
         continue;
       }
-      ByteString valueBytes = ByteString.encodeUtf8(value);
 
       // If we haven't seen this name before, add the pair to the end of the list...
       if (names.add(ByteString.encodeUtf8(name))) {
         result.add(ByteString.encodeUtf8(name));
-        result.add(valueBytes);
+        result.add(ByteString.encodeUtf8(value));
         continue;
       }
 
       // ...otherwise concatenate the existing values and this value.
       for (int j = 0; j < result.size(); j += 2) {
         if (result.get(j).utf8Equals(name)) {
-          result.set(j + 1, ByteString.concat(result.get(j + 1), NULL, valueBytes));
+          String concatenated = joinOnNull(result.get(j + 1).utf8(), value);
+          result.set(j + 1, ByteString.encodeUtf8(concatenated));
           break;
         }
       }
@@ -147,9 +147,13 @@ public final class SpdyTransport implements Transport {
     return result;
   }
 
+  private static String joinOnNull(String first, String second) {
+    return new StringBuilder(first).append('\0').append(second).toString();
+  }
+
   /** Returns headers for a name value block containing a SPDY response. */
   public static Response.Builder readNameValueBlock(List<ByteString> nameValueBlock,
-      String protocol) throws IOException {
+      Protocol protocol) throws IOException {
     if (nameValueBlock.size() % 2 != 0) {
       throw new IllegalArgumentException("Unexpected name value block: " + nameValueBlock);
     }
@@ -157,7 +161,8 @@ public final class SpdyTransport implements Transport {
     String version = "HTTP/1.1"; // TODO: why are we expecting :version?
 
     Headers.Builder headersBuilder = new Headers.Builder();
-    headersBuilder.set(OkHeaders.SELECTED_TRANSPORT, protocol);
+    headersBuilder.set(OkHeaders.SELECTED_TRANSPORT, protocol.name.utf8());
+    headersBuilder.set(OkHeaders.SELECTED_PROTOCOL, protocol.name.utf8());
     for (int i = 0; i < nameValueBlock.size(); i += 2) {
       String name = nameValueBlock.get(i).utf8();
       String values = nameValueBlock.get(i + 1).utf8();
@@ -206,9 +211,9 @@ public final class SpdyTransport implements Transport {
   }
 
   /** When true, this header should not be emitted or consumed. */
-  private static boolean isProhibitedHeader(String protocol, String name) {
+  private static boolean isProhibitedHeader(Protocol protocol, String name) {
     boolean prohibited = false;
-    if (protocol.equals("spdy/3")) {
+    if (protocol == Protocol.SPDY_3) {
       // http://www.chromium.org/spdy/spdy-protocol/spdy-protocol-draft3#TOC-3.2.1-Request
       if (name.equals("connection")
           || name.equals("host")
@@ -217,7 +222,7 @@ public final class SpdyTransport implements Transport {
           || name.equals("transfer-encoding")) {
         prohibited = true;
       }
-    } else if (protocol.equals("HTTP-draft-09/2.0")) {
+    } else if (protocol == Protocol.HTTP_2) {
       // http://tools.ietf.org/html/draft-ietf-httpbis-http2-09#section-8.1.3
       if (name.equals("connection")
           || name.equals("host")
@@ -230,7 +235,7 @@ public final class SpdyTransport implements Transport {
         prohibited = true;
       }
     } else {
-      throw new AssertionError();
+      throw new AssertionError(protocol);
     }
     return prohibited;
   }

okhttp/src/test/java/com/squareup/okhttp/ConnectionPoolTest.java

@@ -61,14 +61,14 @@ public final class ConnectionPoolTest {
 
     httpServer.play();
     httpAddress = new Address(httpServer.getHostName(), httpServer.getPort(), null, null,
-        HttpAuthenticator.SYSTEM_DEFAULT, null, Arrays.asList("spdy/3", "http/1.1"));
+        HttpAuthenticator.SYSTEM_DEFAULT, null, Protocol.SPDY3_AND_HTTP11);
     httpSocketAddress = new InetSocketAddress(InetAddress.getByName(httpServer.getHostName()),
         httpServer.getPort());
 
     spdyServer.play();
     spdyAddress = new Address(spdyServer.getHostName(), spdyServer.getPort(),
         sslContext.getSocketFactory(), new RecordingHostnameVerifier(),
-        HttpAuthenticator.SYSTEM_DEFAULT, null, Arrays.asList("spdy/3", "http/1.1"));
+        HttpAuthenticator.SYSTEM_DEFAULT, null,Protocol.SPDY3_AND_HTTP11);
     spdySocketAddress = new InetSocketAddress(InetAddress.getByName(spdyServer.getHostName()),
         spdyServer.getPort());
 

okhttp/src/test/java/com/squareup/okhttp/internal/http/HeadersTest.java

@@ -19,6 +19,7 @@ import com.squareup.okhttp.Headers;
 import com.squareup.okhttp.Request;
 import com.squareup.okhttp.Response;
 import com.squareup.okhttp.internal.ByteString;
+import com.squareup.okhttp.Protocol;
 import java.io.IOException;
 import java.util.List;
 import org.junit.Test;
@@ -36,21 +37,23 @@ public final class HeadersTest {
         ":version", "HTTP/1.1");
     Request request = new Request.Builder().url("http://square.com/").build();
     Response response =
-        SpdyTransport.readNameValueBlock(nameValueBlock, "spdy/3").request(request).build();
+        SpdyTransport.readNameValueBlock(nameValueBlock, Protocol.SPDY_3).request(request).build();
     Headers headers = response.headers();
-    assertEquals(4, headers.size());
+    assertEquals(5, headers.size());
     assertEquals("HTTP/1.1 200 OK", response.statusLine());
     assertEquals("no-cache, no-store", headers.get("cache-control"));
     assertEquals("Cookie2", headers.get("set-cookie"));
-    assertEquals("spdy/3", headers.get(OkHeaders.SELECTED_TRANSPORT));
+    assertEquals(Protocol.SPDY_3.name.utf8(), headers.get(OkHeaders.SELECTED_TRANSPORT));
     assertEquals(OkHeaders.SELECTED_TRANSPORT, headers.name(0));
-    assertEquals("spdy/3", headers.value(0));
-    assertEquals("cache-control", headers.name(1));
-    assertEquals("no-cache, no-store", headers.value(1));
-    assertEquals("set-cookie", headers.name(2));
-    assertEquals("Cookie1", headers.value(2));
+    assertEquals(Protocol.SPDY_3.name.utf8(), headers.get(OkHeaders.SELECTED_PROTOCOL));
+    assertEquals(OkHeaders.SELECTED_PROTOCOL, headers.name(1));
+    assertEquals(Protocol.SPDY_3.name.utf8(), headers.value(1));
+    assertEquals("cache-control", headers.name(2));
+    assertEquals("no-cache, no-store", headers.value(2));
     assertEquals("set-cookie", headers.name(3));
-    assertEquals("Cookie2", headers.value(3));
+    assertEquals("Cookie1", headers.value(3));
+    assertEquals("set-cookie", headers.name(4));
+    assertEquals("Cookie2", headers.value(4));
     assertNull(headers.get(":status"));
     assertNull(headers.get(":version"));
   }
@@ -62,11 +65,13 @@ public final class HeadersTest {
         "connection", "close");
     Request request = new Request.Builder().url("http://square.com/").build();
     Response response =
-        SpdyTransport.readNameValueBlock(nameValueBlock, "spdy/3").request(request).build();
+        SpdyTransport.readNameValueBlock(nameValueBlock, Protocol.SPDY_3).request(request).build();
     Headers headers = response.headers();
-    assertEquals(1, headers.size());
+    assertEquals(2, headers.size());
     assertEquals(OkHeaders.SELECTED_TRANSPORT, headers.name(0));
-    assertEquals("spdy/3", headers.value(0));;
+    assertEquals(Protocol.SPDY_3.name.utf8(), headers.value(0));
+    assertEquals(OkHeaders.SELECTED_PROTOCOL, headers.name(1));
+    assertEquals(Protocol.SPDY_3.name.utf8(), headers.value(1));;
   }
 
   @Test public void readNameValueBlockDropsForbiddenHeadersHttp2() throws IOException {
@@ -75,12 +80,14 @@ public final class HeadersTest {
         ":version", "HTTP/1.1",
         "connection", "close");
     Request request = new Request.Builder().url("http://square.com/").build();
-    Response response =
-        SpdyTransport.readNameValueBlock(nameValueBlock, "HTTP-draft-09/2.0").request(request).build();
+    Response response = SpdyTransport.readNameValueBlock(nameValueBlock, Protocol.HTTP_2)
+        .request(request).build();
     Headers headers = response.headers();
-    assertEquals(1, headers.size());
+    assertEquals(2, headers.size());
     assertEquals(OkHeaders.SELECTED_TRANSPORT, headers.name(0));
-    assertEquals("HTTP-draft-09/2.0", headers.value(0));;
+    assertEquals(Protocol.HTTP_2.name.utf8(), headers.value(0));
+    assertEquals(OkHeaders.SELECTED_PROTOCOL, headers.name(1));
+    assertEquals(Protocol.HTTP_2.name.utf8(), headers.value(1));
   }
 
   @Test public void toNameValueBlock() {
@@ -91,7 +98,8 @@ public final class HeadersTest {
         .addHeader("set-cookie", "Cookie2")
         .header(":status", "200 OK")
         .build();
-    List<ByteString> nameValueBlock = SpdyTransport.writeNameValueBlock(request, "spdy/3", "HTTP/1.1");
+    List<ByteString> nameValueBlock =
+        SpdyTransport.writeNameValueBlock(request, Protocol.SPDY_3, "HTTP/1.1");
     List<ByteString> expected = byteStringList(
         ":method", "GET",
         ":path", "/",
@@ -116,7 +124,7 @@ public final class HeadersTest {
         ":version", "HTTP/1.1",
         ":host", "square.com",
         ":scheme", "http");
-    assertEquals(expected, SpdyTransport.writeNameValueBlock(request, "spdy/3", "HTTP/1.1"));
+    assertEquals(expected, SpdyTransport.writeNameValueBlock(request, Protocol.SPDY_3, "HTTP/1.1"));
   }
 
   @Test public void toNameValueBlockDropsForbiddenHeadersHttp2() {
@@ -132,6 +140,6 @@ public final class HeadersTest {
         ":authority", "square.com",
         ":scheme", "http");
     assertEquals(expected,
-        SpdyTransport.writeNameValueBlock(request, "HTTP-draft-09/2.0", "HTTP/1.1"));
+        SpdyTransport.writeNameValueBlock(request, Protocol.HTTP_2, "HTTP/1.1"));
   }
 }

okhttp/src/test/java/com/squareup/okhttp/internal/http/HttpOverHttp20Draft09Test.java

@@ -15,12 +15,12 @@
  */
 package com.squareup.okhttp.internal.http;
 
+import com.squareup.okhttp.Protocol;
+
 public class HttpOverHttp20Draft09Test extends HttpOverSpdyTest {
 
   public HttpOverHttp20Draft09Test() {
-    super("HTTP-draft-09/2.0");
-    // TODO: is this really the whole authority, or just the host/port?
-    // https://github.com/http2/http2-spec/issues/334
+    super(Protocol.HTTP_2);
     this.hostHeader = ":authority";
   }
 }

okhttp/src/test/java/com/squareup/okhttp/internal/http/HttpOverSpdy3Test.java

@@ -15,9 +15,11 @@
  */
 package com.squareup.okhttp.internal.http;
 
+import com.squareup.okhttp.Protocol;
+
 public class HttpOverSpdy3Test extends HttpOverSpdyTest {
 
   public HttpOverSpdy3Test() {
-    super("spdy/3");
+    super(Protocol.SPDY_3);
   }
 }

okhttp/src/test/java/com/squareup/okhttp/internal/http/HttpOverSpdyTest.java

@@ -17,6 +17,7 @@ package com.squareup.okhttp.internal.http;
 
 import com.squareup.okhttp.HttpResponseCache;
 import com.squareup.okhttp.OkHttpClient;
+import com.squareup.okhttp.Protocol;
 import com.squareup.okhttp.internal.RecordingAuthenticator;
 import com.squareup.okhttp.internal.SslContextBuilder;
 import com.squareup.okhttp.internal.Util;
@@ -61,12 +62,12 @@ import static org.junit.Assert.fail;
 /** Test how SPDY interacts with HTTP features. */
 public abstract class HttpOverSpdyTest {
 
-  /** Transport to test, for example {@code spdy/3} */
-  private final String transport;
+  /** Protocol to test, for example {@link com.squareup.okhttp.Protocol#SPDY_3} */
+  private final Protocol protocol;
   protected String hostHeader = ":host";
 
-  protected HttpOverSpdyTest(String transport){
-    this.transport = transport;
+  protected HttpOverSpdyTest(Protocol protocol){
+    this.protocol = protocol;
   }
 
   private static final HostnameVerifier NULL_HOSTNAME_VERIFIER = new HostnameVerifier() {
@@ -83,11 +84,11 @@ public abstract class HttpOverSpdyTest {
 
   @Before public void setUp() throws Exception {
     server.useHttps(sslContext.getSocketFactory(), false);
-    client.setTransports(Arrays.asList(transport, "http/1.1"));
+    client.setProtocols(Arrays.asList(protocol, Protocol.HTTP_11));
     client.setSslSocketFactory(sslContext.getSocketFactory());
     client.setHostnameVerifier(NULL_HOSTNAME_VERIFIER);
     String systemTmpDir = System.getProperty("java.io.tmpdir");
-    File cacheDir = new File(systemTmpDir, "HttpCache-" + transport + "-" + UUID.randomUUID());
+    File cacheDir = new File(systemTmpDir, "HttpCache-" + protocol + "-" + UUID.randomUUID());
     cache = new HttpResponseCache(cacheDir, Integer.MAX_VALUE);
   }
 
@@ -386,8 +387,7 @@ public abstract class HttpOverSpdyTest {
 
     @Override public void run() {
       try {
-        HttpURLConnection conn = null;
-        conn = (HttpURLConnection) client.open(server.getUrl(path));
+        HttpURLConnection conn = client.open(server.getUrl(path));
         assertEquals("A", readAscii(conn.getInputStream(), 1));
         countDownLatch.countDown();
       } catch (Exception e) {

okhttp/src/test/java/com/squareup/okhttp/internal/http/RouteSelectorTest.java

@@ -21,6 +21,7 @@ import com.squareup.okhttp.ConnectionPool;
 import com.squareup.okhttp.OkAuthenticator;
 import com.squareup.okhttp.RouteDatabase;
 import com.squareup.okhttp.internal.Dns;
+import com.squareup.okhttp.Protocol;
 import com.squareup.okhttp.internal.SslContextBuilder;
 import java.io.IOException;
 import java.net.InetAddress;
@@ -75,12 +76,12 @@ public final class RouteSelectorTest {
   }
 
   private final OkAuthenticator authenticator = HttpAuthenticator.SYSTEM_DEFAULT;
-  private final List<String> transports = Arrays.asList("http/1.1");
+  private final List<Protocol> protocols = Arrays.asList(Protocol.HTTP_11);
   private final FakeDns dns = new FakeDns();
   private final FakeProxySelector proxySelector = new FakeProxySelector();
 
   @Test public void singleRoute() throws Exception {
-    Address address = new Address(uriHost, uriPort, null, null, authenticator, null, transports);
+    Address address = new Address(uriHost, uriPort, null, null, authenticator, null, protocols);
     RouteSelector routeSelector = new RouteSelector(address, uri, proxySelector, pool, dns,
         new RouteDatabase());
 
@@ -99,7 +100,7 @@ public final class RouteSelectorTest {
   }
 
   @Test public void singleRouteReturnsFailedRoute() throws Exception {
-    Address address = new Address(uriHost, uriPort, null, null, authenticator, null, transports);
+    Address address = new Address(uriHost, uriPort, null, null, authenticator, null, protocols);
     RouteSelector routeSelector = new RouteSelector(address, uri, proxySelector, pool, dns,
         new RouteDatabase());
 
@@ -120,7 +121,7 @@ public final class RouteSelectorTest {
   }
 
   @Test public void explicitProxyTriesThatProxiesAddressesOnly() throws Exception {
-    Address address = new Address(uriHost, uriPort, null, null, authenticator, proxyA, transports);
+    Address address = new Address(uriHost, uriPort, null, null, authenticator, proxyA, protocols);
     RouteSelector routeSelector = new RouteSelector(address, uri, proxySelector, pool, dns,
         new RouteDatabase());
 
@@ -138,7 +139,7 @@ public final class RouteSelectorTest {
 
   @Test public void explicitDirectProxy() throws Exception {
     Address address = new Address(uriHost, uriPort, null, null, authenticator, NO_PROXY,
-        transports);
+        protocols);
     RouteSelector routeSelector = new RouteSelector(address, uri, proxySelector, pool, dns,
         new RouteDatabase());
 
@@ -155,7 +156,7 @@ public final class RouteSelectorTest {
   }
 
   @Test public void proxySelectorReturnsNull() throws Exception {
-    Address address = new Address(uriHost, uriPort, null, null, authenticator, null, transports);
+    Address address = new Address(uriHost, uriPort, null, null, authenticator, null, protocols);
 
     proxySelector.proxies = null;
     RouteSelector routeSelector = new RouteSelector(address, uri, proxySelector, pool, dns,
@@ -172,7 +173,7 @@ public final class RouteSelectorTest {
   }
 
   @Test public void proxySelectorReturnsNoProxies() throws Exception {
-    Address address = new Address(uriHost, uriPort, null, null, authenticator, null, transports);
+    Address address = new Address(uriHost, uriPort, null, null, authenticator, null, protocols);
     RouteSelector routeSelector = new RouteSelector(address, uri, proxySelector, pool, dns,
         new RouteDatabase());
 
@@ -189,7 +190,7 @@ public final class RouteSelectorTest {
   }
 
   @Test public void proxySelectorReturnsMultipleProxies() throws Exception {
-    Address address = new Address(uriHost, uriPort, null, null, authenticator, null, transports);
+    Address address = new Address(uriHost, uriPort, null, null, authenticator, null, protocols);
 
     proxySelector.proxies.add(proxyA);
     proxySelector.proxies.add(proxyB);
@@ -224,7 +225,7 @@ public final class RouteSelectorTest {
   }
 
   @Test public void proxySelectorDirectConnectionsAreSkipped() throws Exception {
-    Address address = new Address(uriHost, uriPort, null, null, authenticator, null, transports);
+    Address address = new Address(uriHost, uriPort, null, null, authenticator, null, protocols);
 
     proxySelector.proxies.add(NO_PROXY);
     RouteSelector routeSelector = new RouteSelector(address, uri, proxySelector, pool, dns,
@@ -242,7 +243,7 @@ public final class RouteSelectorTest {
   }
 
   @Test public void proxyDnsFailureContinuesToNextProxy() throws Exception {
-    Address address = new Address(uriHost, uriPort, null, null, authenticator, null, transports);
+    Address address = new Address(uriHost, uriPort, null, null, authenticator, null, protocols);
 
     proxySelector.proxies.add(proxyA);
     proxySelector.proxies.add(proxyB);
@@ -284,7 +285,7 @@ public final class RouteSelectorTest {
   // https://github.com/square/okhttp/issues/442
   @Test public void nonSslErrorAddsAllTlsModesToFailedRoute() throws Exception {
     Address address = new Address(uriHost, uriPort, socketFactory, hostnameVerifier, authenticator,
-        Proxy.NO_PROXY, transports);
+        Proxy.NO_PROXY, protocols);
     RouteDatabase routeDatabase = new RouteDatabase();
     RouteSelector routeSelector = new RouteSelector(address, uri, proxySelector, pool, dns,
         routeDatabase);
@@ -298,7 +299,7 @@ public final class RouteSelectorTest {
 
   @Test public void sslErrorAddsOnlyFailedTlsModeToFailedRoute() throws Exception {
     Address address = new Address(uriHost, uriPort, socketFactory, hostnameVerifier, authenticator,
-        Proxy.NO_PROXY, transports);
+        Proxy.NO_PROXY, protocols);
     RouteDatabase routeDatabase = new RouteDatabase();
     RouteSelector routeSelector = new RouteSelector(address, uri, proxySelector, pool, dns,
         routeDatabase);
@@ -312,7 +313,7 @@ public final class RouteSelectorTest {
 
   @Test public void multipleProxiesMultipleInetAddressesMultipleTlsModes() throws Exception {
     Address address = new Address(uriHost, uriPort, socketFactory, hostnameVerifier, authenticator,
-        null, transports);
+        null, protocols);
     proxySelector.proxies.add(proxyA);
     proxySelector.proxies.add(proxyB);
     RouteSelector routeSelector = new RouteSelector(address, uri, proxySelector, pool, dns,
@@ -359,7 +360,7 @@ public final class RouteSelectorTest {
 
   @Test public void failedRoutesAreLast() throws Exception {
     Address address = new Address(uriHost, uriPort, socketFactory, hostnameVerifier, authenticator,
-        Proxy.NO_PROXY, transports);
+        Proxy.NO_PROXY, protocols);
 
     RouteDatabase routeDatabase = new RouteDatabase();
     RouteSelector routeSelector = new RouteSelector(address, uri, proxySelector, pool, dns,

okhttp/src/test/java/com/squareup/okhttp/internal/http/URLConnectionTest.java

@@ -18,6 +18,7 @@ package com.squareup.okhttp.internal.http;
 
 import com.squareup.okhttp.HttpResponseCache;
 import com.squareup.okhttp.OkHttpClient;
+import com.squareup.okhttp.Protocol;
 import com.squareup.okhttp.internal.RecordingAuthenticator;
 import com.squareup.okhttp.internal.RecordingHostnameVerifier;
 import com.squareup.okhttp.internal.RecordingOkAuthenticator;
@@ -2500,24 +2501,24 @@ public final class URLConnectionTest {
     assertTrue(call, call.contains("challenges=[Basic realm=\"protected area\"]"));
   }
 
-  @Test public void setTransports() throws Exception {
+  @Test public void setProtocols() throws Exception {
     server.enqueue(new MockResponse().setBody("A"));
     server.play();
-    client.setTransports(Arrays.asList("http/1.1"));
+    client.setProtocols(Arrays.asList(Protocol.HTTP_11));
     assertContent("A", client.open(server.getUrl("/")));
   }
 
-  @Test public void setTransportsWithoutHttp11() throws Exception {
+  @Test public void setProtocolsWithoutHttp11() throws Exception {
     try {
-      client.setTransports(Arrays.asList("spdy/3"));
+      client.setProtocols(Arrays.asList(Protocol.SPDY_3));
       fail();
     } catch (IllegalArgumentException expected) {
     }
   }
 
-  @Test public void setTransportsWithNull() throws Exception {
+  @Test public void setProtocolsWithNull() throws Exception {
     try {
-      client.setTransports(Arrays.asList("http/1.1", null));
+      client.setProtocols(Arrays.asList(Protocol.HTTP_11, null));
       fail();
     } catch (IllegalArgumentException expected) {
     }