Make it easier to subclass a remote ActiveSession

Author: shs96c

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

@@ -78,6 +78,7 @@ java_library(
     'NewSessionPipeline.java',
     'Passthrough.java',
     'ProtocolConverter.java',
+    'RemoteSession.java',
     'ServicedSession.java',
     'SessionCodec.java',
     'SessionFactory.java',

java/server/src/org/openqa/selenium/remote/server/RemoteSession.java

@@ -0,0 +1,197 @@
+package org.openqa.selenium.remote.server;
+
+import static org.openqa.selenium.remote.Dialect.OSS;
+
+import com.google.common.base.Preconditions;
+import com.google.common.base.StandardSystemProperty;
+import com.google.common.collect.ImmutableMap;
+
+import org.openqa.selenium.Capabilities;
+import org.openqa.selenium.ImmutableCapabilities;
+import org.openqa.selenium.WebDriver;
+import org.openqa.selenium.io.TemporaryFilesystem;
+import org.openqa.selenium.remote.Augmenter;
+import org.openqa.selenium.remote.Command;
+import org.openqa.selenium.remote.CommandCodec;
+import org.openqa.selenium.remote.CommandExecutor;
+import org.openqa.selenium.remote.Dialect;
+import org.openqa.selenium.remote.DriverCommand;
+import org.openqa.selenium.remote.ProtocolHandshake;
+import org.openqa.selenium.remote.RemoteWebDriver;
+import org.openqa.selenium.remote.Response;
+import org.openqa.selenium.remote.ResponseCodec;
+import org.openqa.selenium.remote.SessionId;
+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.http.W3CHttpCommandCodec;
+import org.openqa.selenium.remote.http.W3CHttpResponseCodec;
+import org.openqa.selenium.remote.internal.ApacheHttpClient;
+
+import java.io.File;
+import java.io.IOException;
+import java.net.URL;
+import java.util.Map;
+import java.util.Optional;
+import java.util.Set;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+/**
+ * Abstract class designed to do things like protocol conversion.
+ */
+public abstract class RemoteSession implements ActiveSession {
+
+  protected static Logger log = Logger.getLogger(ActiveSession.class.getName());
+
+  private final SessionId id;
+  private final Dialect downstream;
+  private final Dialect upstream;
+  private final SessionCodec codec;
+  private final Map<String, Object> capabilities;
+  private final TemporaryFilesystem filesystem;
+  private final WebDriver driver;
+
+  protected RemoteSession(
+      Dialect downstream,
+      Dialect upstream,
+      SessionCodec codec,
+      SessionId id,
+      Map<String, Object> capabilities) {
+    this.downstream = downstream;
+    this.upstream = upstream;
+    this.codec = codec;
+    this.id = id;
+    this.capabilities = capabilities;
+
+    File tempRoot = new File(StandardSystemProperty.JAVA_IO_TMPDIR.value(), id.toString());
+    Preconditions.checkState(tempRoot.mkdirs());
+    this.filesystem = TemporaryFilesystem.getTmpFsBasedOn(tempRoot);
+
+    CommandExecutor executor = new ActiveSessionCommandExecutor(this);
+    this.driver = new Augmenter().augment(new RemoteWebDriver(
+        executor,
+        new ImmutableCapabilities(getCapabilities())));
+  }
+
+  @Override
+  public SessionId getId() {
+    return id;
+  }
+
+  @Override
+  public Dialect getUpstreamDialect() {
+    return upstream;
+  }
+
+  @Override
+  public Dialect getDownstreamDialect() {
+    return downstream;
+  }
+
+  @Override
+  public Map<String, Object> getCapabilities() {
+    return capabilities;
+  }
+
+  @Override
+  public TemporaryFilesystem getFileSystem() {
+    return filesystem;
+  }
+
+  @Override
+  public WebDriver getWrappedDriver() {
+    return driver;
+  }
+
+  @Override
+  public void execute(HttpRequest req, HttpResponse resp) throws IOException {
+    codec.handle(req, resp);
+  }
+
+  public abstract static class Factory<X> implements SessionFactory {
+
+    protected Optional<ActiveSession> performHandshake(
+        X additionalData,
+        URL url,
+        Set<Dialect> downstreamDialects,
+        Capabilities capabilities) {
+      try {
+        HttpClient client = new ApacheHttpClient.Factory().createClient(url);
+
+        Command command = new Command(
+            null,
+            DriverCommand.NEW_SESSION,
+            ImmutableMap.of("desiredCapabilities", capabilities));
+
+        ProtocolHandshake.Result result = new ProtocolHandshake().createSession(client, command);
+
+        SessionCodec codec;
+        Dialect upstream = result.getDialect();
+        Dialect downstream;
+        if (downstreamDialects.contains(result.getDialect())) {
+          codec = new Passthrough(url);
+          downstream = upstream;
+        } else {
+          downstream = downstreamDialects.isEmpty() ? OSS : downstreamDialects.iterator().next();
+
+          codec = new ProtocolConverter(
+              url,
+              getCommandCodec(downstream),
+              getResponseCodec(downstream),
+              getCommandCodec(upstream),
+              getResponseCodec(upstream));
+        }
+
+        Response response = result.createResponse();
+        //noinspection unchecked
+        return Optional.of(newActiveSession(
+            additionalData,
+            downstream,
+            upstream,
+            codec,
+            new SessionId(response.getSessionId()),
+            (Map<String, Object>) response.getValue()));
+      } catch (IOException | IllegalStateException | NullPointerException e) {
+        log.log(Level.WARNING, e.getMessage(), e);
+        return Optional.empty();
+      }
+    }
+
+    protected abstract ActiveSession newActiveSession(
+        X additionalData,
+        Dialect downstream,
+        Dialect upstream,
+        SessionCodec codec,
+        SessionId id,
+        Map<String, Object> capabilities);
+
+    private CommandCodec<HttpRequest> getCommandCodec(Dialect dialect) {
+      switch (dialect) {
+        case OSS:
+          return new JsonHttpCommandCodec();
+
+        case W3C:
+          return new W3CHttpCommandCodec();
+
+        default:
+          throw new IllegalStateException("Unknown dialect: " + dialect);
+      }
+    }
+
+    private ResponseCodec<HttpResponse> getResponseCodec(Dialect dialect) {
+      switch (dialect) {
+        case OSS:
+          return new JsonHttpResponseCodec();
+
+        case W3C:
+          return new W3CHttpResponseCodec();
+
+        default:
+          throw new IllegalStateException("Unknown dialect: " + dialect);
+      }
+    }
+  }
+}