com.google.api.client.http

Class HttpTransport

java.lang.Object

com.google.api.client.http.HttpTransport

Direct Known Subclasses:

ApacheHttpTransport, MockHttpTransport, NetHttpTransport, UrlFetchTransport

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.googleapis.javanet.GoogleNetHttpTransport is included in google-api-cient 1.22.0, so easy to include.
  • com.google.api.client.javanet.NetHttpTransport is based on the HttpURLConnection built into the Java SDK, so it used to be 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

Author:

Yaniv Inbar

Constructor Summary

Constructors

Constructor and Description
HttpTransport()

Method Summary

Modifier and Type	Method and Description
protected abstract LowLevelHttpRequest	buildRequest(String method, String url) Builds a low level HTTP request for the given HTTP method.
HttpRequestFactory	createRequestFactory() Returns a new instance of an HTTP request factory based on this HTTP transport.
HttpRequestFactory	createRequestFactory(HttpRequestInitializer initializer) Returns a new instance of an HTTP request factory based on this HTTP transport with the given HTTP request initializer.
void	shutdown() Default implementation does nothing, but subclasses may override to possibly release allocated system resources or close connections.
boolean	supportsMethod(String method) Returns whether a specified HTTP method is supported by this transport.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

HttpTransport

public HttpTransport()

Method Detail

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

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