Class HttpTransport

java.lang.Object
com.google.api.client.http.HttpTransport
Direct Known Subclasses:
ApacheHttpTransport, MockHttpTransport, NetHttpTransport

public abstract class HttpTransport extends Object
Thread-safe abstract HTTP transport.

Implementation is thread-safe, and sub-classes must be thread-safe. For maximum efficiency, applications should use a single globally-shared instance of the HTTP transport.

The recommended concrete implementation HTTP transport library to use depends on what environment you are running in:

  • Google App Engine: use com.google.api.client.extensions.appengine.http.UrlFetchTransport.
    • com.google.api.client.apache.ApacheHttpTransport doesn't work on App Engine because the Apache HTTP Client opens its own sockets (though in theory there are ways to hack it to work on App Engine that might work).
    • com.google.api.client.javanet.NetHttpTransport is discouraged due to a bug in the App Engine SDK itself in how it parses HTTP headers in the response.
  • Android:
    • For maximum backwards compatibility with older SDK's use newCompatibleTransport from com.google.api.client.extensions.android.http.AndroidHttp (read its JavaDoc for details).
    • If your application is targeting Gingerbread (SDK 2.3) or higher, simply use com.google.api.client.javanet.NetHttpTransport.
  • Other Java environments
    • com.google.api.client.javanet.NetHttpTransport is based on the HttpURLConnection built into the Java SDK, so it is normally the preferred choice.
    • com.google.api.client.apache.ApacheHttpTransport is a good choice for users of the Apache HTTP Client, especially if you need some of the configuration options available in that library.

Some HTTP transports do not support all HTTP methods. Use supportsMethod(String) to check if a certain HTTP method is supported. Calling buildRequest() on a method that is not supported will result in an IllegalArgumentException.

Subclasses should override supportsMethod(String) and buildRequest(String, String) to build requests and specify which HTTP methods are supported.

Since:
1.0
  • Field Details

    • LOGGER

      static final Logger LOGGER
    • SUPPORTED_METHODS

      private static final String[] SUPPORTED_METHODS
      All valid request methods as specified in supportsMethod(String), sorted in ascending alphabetical order.
  • Constructor Details

    • HttpTransport

      public HttpTransport()
  • Method Details

    • createRequestFactory

      public final HttpRequestFactory createRequestFactory()
      Returns a new instance of an HTTP request factory based on this HTTP transport.
      Returns:
      new instance of an HTTP request factory
      Since:
      1.4
    • createRequestFactory

      public final HttpRequestFactory createRequestFactory(HttpRequestInitializer initializer)
      Returns a new instance of an HTTP request factory based on this HTTP transport with the given HTTP request initializer.
      Parameters:
      initializer - HTTP request initializer or null for none
      Returns:
      new instance of an HTTP request factory
      Since:
      1.4
    • buildRequest

      HttpRequest buildRequest()
      Builds a request without specifying the HTTP method.
      Returns:
      new HTTP request
    • supportsMethod

      public boolean supportsMethod(String method) throws IOException
      Returns whether a specified HTTP method is supported by this transport.

      Default implementation returns true if and only if the request method is "DELETE", "GET", "POST", or "PUT". Subclasses should override.

      Parameters:
      method - HTTP method
      Throws:
      IOException - I/O exception
      Since:
      1.12
    • buildRequest

      protected abstract LowLevelHttpRequest buildRequest(String method, String url) throws IOException
      Builds a low level HTTP request for the given HTTP method.
      Parameters:
      method - HTTP method
      url - URL
      Returns:
      new low level HTTP request
      Throws:
      IllegalArgumentException - if HTTP method is not supported
      IOException
      Since:
      1.12
    • shutdown

      public void shutdown() throws IOException
      Default implementation does nothing, but subclasses may override to possibly release allocated system resources or close connections.
      Throws:
      IOException - I/O exception
      Since:
      1.4