import com.google.ipc.invalidation.ticl.android2.channel.AndroidChannelConstants.HttpConstants; //导入依赖的package包/类
/**
 * Returns a URL to use to send a message to the data center.
 *
 * @param gaiaServiceId Gaia service for which the request will be authenticated (when using a
 *      GoogleLogin token), or {@code null} when using an OAuth2 token.
 * @param networkEndpointId network id of the client
 */
private static URL buildUrl(String gaiaServiceId, NetworkEndpointId networkEndpointId)
    throws MalformedURLException {
  StringBuilder urlBuilder = new StringBuilder();

  // Build base URL that targets the inbound request service with the encoded network endpoint
  // id.
  urlBuilder.append((channelUrlForTest != null) ? channelUrlForTest : HttpConstants.CHANNEL_URL);
  urlBuilder.append(HttpConstants.REQUEST_URL);

  // TODO: We should be sending a ClientGatewayMessage in the request body
  // instead of appending the client's network endpoint id to the request URL. Once we do that, we
  // should use a UriBuilder to build up a structured Uri object instead of the brittle string
  // concatenation we're doing below.
  urlBuilder.append(base64Encode(networkEndpointId.toByteArray()));

  // Add query parameter indicating the service to authenticate against
  if (gaiaServiceId != null) {
    urlBuilder.append('?');
    urlBuilder.append(HttpConstants.SERVICE_PARAMETER);
    urlBuilder.append('=');
    urlBuilder.append(gaiaServiceId);
  }
  return new URL(urlBuilder.toString());
}
 

import com.google.ipc.invalidation.ticl.android2.channel.AndroidChannelConstants.HttpConstants; //导入依赖的package包/类
/**
 * Returns an {@link HttpURLConnection} to use to POST a message to the data center. Sets
 * the content-type and user-agent headers; also sets the echo token header if we have an
 * echo token.
 *
 * @param context Android context
 * @param url URL to which to post
 * @param authToken auth token to provide in the request header
 * @param isOAuth2Token whether the token is an OAuth2 token (vs. a GoogleLogin token)
 */

public static HttpURLConnection createUrlConnectionForPost(Context context, URL url,
    String authToken, boolean isOAuth2Token) throws IOException {
  HttpURLConnection connection = (HttpURLConnection) url.openConnection();
  try {
    connection.setRequestMethod("POST");
  } catch (ProtocolException exception) {
    throw new RuntimeException("Cannot set request method to POST: " + exception);
  }
  connection.setDoOutput(true);
  if (isOAuth2Token) {
    connection.setRequestProperty("Authorization", "Bearer " + authToken);
  } else {
    connection.setRequestProperty("Authorization", "GoogleLogin auth=" + authToken);
  }
  connection.setRequestProperty("Content-Type", HttpConstants.PROTO_CONTENT_TYPE);
  connection.setRequestProperty("User-Agent",
      context.getApplicationInfo().className + "(" + Build.VERSION.RELEASE + ")");
  String echoToken = AndroidChannelPreferences.getEchoToken(context);
  if (echoToken != null) {
    // If we have a token to echo to the server, echo it.
    connection.setRequestProperty(HttpConstants.ECHO_HEADER, echoToken);
  }
  return connection;
}
 

import com.google.ipc.invalidation.ticl.android2.channel.AndroidChannelConstants.HttpConstants; //导入依赖的package包/类
/**
 * Returns an {@link HttpURLConnection} to use to POST a message to the data center. Sets
 * the content-type and user-agent headers; also sets the echo token header if we have an
 * echo token.
 *
 * @param context Android context
 * @param url URL to which to post
 * @param authToken auth token to provide in the request header
 * @param isOAuth2Token whether the token is an OAuth2 token (vs. a GoogleLogin token)
 */

public static HttpURLConnection createUrlConnectionForPost(
    Context context, URL url, String authToken, boolean isOAuth2Token) throws IOException {
  HttpURLConnection connection = (HttpURLConnection) url.openConnection();
  try {
    connection.setRequestMethod("POST");
  } catch (ProtocolException exception) {
    throw new RuntimeException("Cannot set request method to POST", exception);
  }
  connection.setDoOutput(true);
  if (isOAuth2Token) {
    connection.setRequestProperty("Authorization", "Bearer " + authToken);
  } else {
    connection.setRequestProperty("Authorization", "GoogleLogin auth=" + authToken);
  }
  connection.setRequestProperty("Content-Type", HttpConstants.PROTO_CONTENT_TYPE);
  connection.setRequestProperty(
      "User-Agent", context.getApplicationInfo().className + "(" + Build.VERSION.RELEASE + ")");
  
  String echoToken = AndroidChannelPreferences.getEchoToken(context);
  if (echoToken != null) {
    // If we have a token to echo to the server, echo it.
    connection.setRequestProperty(HttpConstants.ECHO_HEADER, echoToken);
  }
  return connection;
}