Use the ProtocolHandshake to determine remote end protocol version

At the moment, all protocols are modelled using the Json*Codecs.
A follow up diff will clean this up.

Author: shs96c

java/client/src/org/openqa/selenium/remote/BUCK

@@ -103,6 +103,8 @@ java_library(name = 'remote-lib',
     'http/HttpResponse.java',
     'http/JsonHttpCommandCodec.java',
     'http/JsonHttpResponseCodec.java',
+    'http/W3CHttpCommandCodec.java',
+    'http/W3CHttpResponseCodec.java',
     'internal/ApacheHttpClient.java',
     'internal/HttpClientFactory.java',
     'internal/JsonToWebElementConverter.java',

java/client/src/org/openqa/selenium/remote/CommandCodec.java

@@ -19,6 +19,7 @@
 
 import org.openqa.selenium.UnsupportedCommandException;
 import org.openqa.selenium.remote.Command;
+import org.openqa.selenium.remote.http.HttpMethod;
 
 /**
  * Converts {@link Command} objects to and from another representation.
@@ -44,4 +45,9 @@ public interface CommandCodec<T> {
    * @throws UnsupportedCommandException If the command is not supported by this codec.
    */
   Command decode(T encodedCommand);
+
+  /**
+   * Enhance this command codec with additional commands.
+   */
+  void defineCommand(String name, HttpMethod method, String pathPattern);
 }

java/client/src/org/openqa/selenium/remote/Dialect.java

@@ -17,7 +17,37 @@
 
 package org.openqa.selenium.remote;
 
+import org.openqa.selenium.remote.http.HttpRequest;
+import org.openqa.selenium.remote.http.HttpResponse;
+import org.openqa.selenium.remote.http.JsonHttpCommandCodec;
+import org.openqa.selenium.remote.http.JsonHttpResponseCodec;
+import org.openqa.selenium.remote.http.W3CHttpCommandCodec;
+import org.openqa.selenium.remote.http.W3CHttpResponseCodec;
+
 public enum Dialect {
-  OSS,
-  W3C;
+  OSS {
+    @Override
+    public CommandCodec<HttpRequest> getCommandCodec() {
+      return new JsonHttpCommandCodec();
+    }
+
+    @Override
+    public ResponseCodec<HttpResponse> getResponseCodec() {
+      return new JsonHttpResponseCodec();
+    }
+  },
+  W3C {
+    @Override
+    public CommandCodec<HttpRequest> getCommandCodec() {
+      return new W3CHttpCommandCodec();
+    }
+
+    @Override
+    public ResponseCodec<HttpResponse> getResponseCodec() {
+      return new W3CHttpResponseCodec();
+    }
+  };
+
+  public abstract CommandCodec<HttpRequest> getCommandCodec();
+  public abstract ResponseCodec<HttpResponse> getResponseCodec();
 }

java/client/src/org/openqa/selenium/remote/HttpCommandExecutor.java

@@ -25,6 +25,7 @@
 import com.google.common.collect.ImmutableMap;
 
 import org.openqa.selenium.NoSuchSessionException;
+import org.openqa.selenium.SessionNotCreatedException;
 import org.openqa.selenium.UnsupportedCommandException;
 import org.openqa.selenium.WebDriverException;
 import org.openqa.selenium.logging.LocalLogs;
@@ -35,8 +36,6 @@
 import org.openqa.selenium.remote.http.HttpClient;
 import org.openqa.selenium.remote.http.HttpRequest;
 import org.openqa.selenium.remote.http.HttpResponse;
-import org.openqa.selenium.remote.http.JsonHttpCommandCodec;
-import org.openqa.selenium.remote.http.JsonHttpResponseCodec;
 import org.openqa.selenium.remote.internal.ApacheHttpClient;
 
 import java.io.IOException;
@@ -50,8 +49,9 @@ public class HttpCommandExecutor implements CommandExecutor, NeedsLocalLogs {
 
   private final URL remoteServer;
   private final HttpClient client;
-  private final JsonHttpCommandCodec commandCodec;
-  private final JsonHttpResponseCodec responseCodec;
+  private final Map<String, CommandInfo> additionalCommands;
+  private CommandCodec<HttpRequest> commandCodec;
+  private ResponseCodec<HttpResponse> responseCodec;
 
   private LocalLogs logs = LocalLogs.getNullLogger();
 
@@ -83,13 +83,8 @@ public HttpCommandExecutor(
       throw new WebDriverException(e);
     }
 
-    commandCodec = new JsonHttpCommandCodec();
-    responseCodec = new JsonHttpResponseCodec();
-    client = httpClientFactory.createClient(remoteServer);
-
-    for (Map.Entry<String, CommandInfo> entry : additionalCommands.entrySet()) {
-      defineCommand(entry.getKey(), entry.getValue());
-    }
+    this.additionalCommands = additionalCommands;
+    this.client = httpClientFactory.createClient(remoteServer);
   }
 
   private static synchronized HttpClient.Factory getDefaultClientFactory() {
@@ -137,6 +132,28 @@ public Response execute(Command command) throws IOException {
       }
     }
 
+    if (NEW_SESSION.equals(command.getName())) {
+      if (commandCodec != null) {
+        throw new SessionNotCreatedException("Session already exists");
+      }
+      ProtocolHandshake handshake = new ProtocolHandshake();
+      log(LogType.PROFILER, new HttpProfilerLogEntry(command.getName(), true));
+      ProtocolHandshake.Result result = handshake.createSession(client, command);
+      Dialect dialect = result.getDialect();
+      commandCodec = dialect.getCommandCodec();
+      for (Map.Entry<String, CommandInfo> entry : additionalCommands.entrySet()) {
+        defineCommand(entry.getKey(), entry.getValue());
+      }
+      responseCodec = dialect.getResponseCodec();
+      log(LogType.PROFILER, new HttpProfilerLogEntry(command.getName(), false));
+      return result.createResponse();
+    }
+
+    if (commandCodec == null || responseCodec == null) {
+      throw new WebDriverException(
+        "No command or response codec has been defined. Unable to proceed");
+    }
+
     HttpRequest httpRequest = commandCodec.encode(command);
     try {
       log(LogType.PROFILER, new HttpProfilerLogEntry(command.getName(), true));