Package com.google.api.client.http (1.44.2)

Subset of HTTP 1.1 needed from the specification in RFC 2616: Hypertext Transfer Protocol -- HTTP/1.1.

Classes

AbstractHttpContent

Abstract implementation of an HTTP content with typical options.

Implementation is not thread-safe.

AbstractInputStreamContent

Serializes HTTP request content from an input stream into an output stream.

The #type field is required. Subclasses should implement the #getLength(), #getInputStream(), and #retrySupported() for their specific type of input stream. By default, all content is read from the input stream. If instead you want to limit the maximum amount of content read from the input stream, you may use ByteStreams#limit(InputStream, long).

Implementations don't need to be thread-safe.

BasicAuthentication

Basic authentication HTTP request initializer as specified in Basic Authentication Scheme

Implementation is immutable and thread-safe. It can be used as either an HTTP request initializer or an HTTP request execute interceptor. #initialize(HttpRequest) only sets itself as the interceptor. Authentication is actually done in #intercept(HttpRequest), which is implemented using HttpHeaders#setBasicAuthentication(String, String).

ByteArrayContent

Concrete implementation of AbstractInputStreamContent that generates repeatable input streams based on the contents of byte array.

Sample use:

 
 static void setJsonContent(HttpRequest request, byte[] json) {
 request.setContent(new ByteArrayContent("application/json", json));
 }

Implementation is not thread-safe.

EmptyContent

Empty HTTP content of length zero just to force HttpRequest#execute() to add the header Content-Length: 0.

Note that there is no Content-Length header if the HTTP request content is null . However, when making a request like PUT or POST without a Content-Length header, some servers may respond with a 411 Length Required error. Specifying the Content-Length: 0 header may work around that problem.

ExponentialBackOffPolicy (deprecated)

Deprecated. (scheduled to be removed in 1.18). Use HttpBackOffUnsuccessfulResponseHandler with ExponentialBackOff instead.

Beta
Implementation of BackOffPolicy that increases the back off period for each retry attempt using a randomization function that grows exponentially.

#getNextBackOffMillis() is calculated using the following formula:

randomized_interval = retry_interval * (random value in range [1 - randomization_factor, 1 + randomization_factor])

In other words #getNextBackOffMillis() will range between the randomization factor percentage below and above the retry interval. For example, using 2 seconds as the base retry interval and 0.5 as the randomization factor, the actual back off period used in the next retry attempt will be between 1 and 3 seconds.

Note: max_interval caps the retry_interval and not the randomized_interval.

If the time elapsed since an ExponentialBackOffPolicy instance is created goes past the max_elapsed_time then the method #getNextBackOffMillis() starts returning BackOffPolicy#STOP. The elapsed time can be reset by calling #reset().

Example: The default retry_interval is .5 seconds, default randomization_factor is 0.5, default multiplier is 1.5 and the default max_interval is 1 minute. For 10 requests the sequence will be (values in seconds) and assuming we go over the max_elapsed_time on the 10th request:

 request#     retry_interval     randomized_interval

 1             0.5                [0.25,   0.75]
 2             0.75               [0.375,  1.125]
 3             1.125              [0.562,  1.687]
 4             1.687              [0.8435, 2.53]
 5             2.53               [1.265,  3.795]
 6             3.795              [1.897,  5.692]
 7             5.692              [2.846,  8.538]
 8             8.538              [4.269, 12.807]
 9            12.807              [6.403, 19.210]
 10           19.210              BackOffPolicy#STOP

Implementation is not thread-safe.

ExponentialBackOffPolicy.Builder

Beta
Builder for ExponentialBackOffPolicy.

Implementation is not thread-safe.

FileContent

Concrete implementation of AbstractInputStreamContent that generates repeatable input streams based on the contents of a file.

Sample use:

 
 private static void setRequestJpegContent(HttpRequest request, File jpegFile) {
 request.setContent(new FileContent("image/jpeg", jpegFile));
 }

Implementation is not thread-safe.

GZipEncoding

GZip HTTP content encoding.

GenericUrl

URL builder in which the query parameters are specified as generic data key/value pairs, based on the specification RFC 3986: Uniform Resource Identifier (URI).

The query parameters are specified with the data key name as the parameter name, and the data value as the parameter value. Subclasses can declare fields for known query parameters using the Key annotation. null parameter names are not allowed, but null query values are allowed.

Query parameter values are parsed using UrlEncodedParser#parse(String, Object).

Implementation is not thread-safe.

HttpBackOffIOExceptionHandler

Beta
HttpIOExceptionHandler implementation with BackOff.

It is designed to work with only one HttpRequest at a time. As a result you MUST create a new instance of HttpBackOffIOExceptionHandler with a new instance of BackOff for each instance of HttpRequest.

Sample usage:

request.setIOExceptionHandler(new HttpBackOffIOExceptionHandler(new ExponentialBackOff());

Note: Implementation doesn't call BackOff#reset at all, since it expects a new BackOff instance.

Implementation is not thread-safe

HttpBackOffUnsuccessfulResponseHandler

Beta
Back-off handler which handles an abnormal HTTP response with BackOff.

It is designed to work with only one HttpRequest at a time. As a result you MUST create a new instance of HttpBackOffUnsuccessfulResponseHandler with a new instance of BackOff for each instance of HttpRequest.

Sample usage:

request.setUnsuccessfulResponseHandler( new HttpBackOffUnsuccessfulResponseHandler(new ExponentialBackOff()));

Note: Implementation doesn't call BackOff#reset at all, since it expects a new BackOff instance.

Implementation is not thread-safe

HttpEncodingStreamingContent

Streaming content based on an HTTP encoding.

Implementation is thread-safe only if the streaming content and HTTP encoding are thread-safe.

HttpHeaders

Stores HTTP headers used in an HTTP request or response, as defined in Header Field Definitions.

null is not allowed as a name or value of a header. Names are case-insensitive.

Implementation is not thread-safe.

HttpMediaType

HTTP Media-type as specified in the HTTP RFC.

Implementation is not thread-safe.

HttpMethods

HTTP request method constants specified in RFC 2616 Section 5.1.1.

HttpRequest

HTTP request.

Implementation is not thread-safe.

HttpRequestFactory

Thread-safe light-weight HTTP request factory layer on top of the HTTP transport that has an optional HTTP request initializer for initializing requests.

For example, to use a particular authorization header across all requests, use:

public static HttpRequestFactory createRequestFactory(HttpTransport transport) { return transport.createRequestFactory(new HttpRequestInitializer() { public void initialize(HttpRequest request) throws IOException { request.getHeaders().setAuthorization("..."); } }); }

HttpResponse

HTTP response.

Callers should call #disconnect when the HTTP response object is no longer needed. However, #disconnect does not have to be called if the response stream is properly closed. Example usage:

HttpResponse response = request.execute(); try { // process the HTTP response object } finally { response.disconnect(); }

Implementation is not thread-safe.

HttpResponseException.Builder

Builder.

Implementation is not thread safe.

HttpStatusCodes

Constants enumerating the HTTP status codes. Includes status codes specified in RFC2616 (HTTP/1.1).

HttpTransport

Thread-safe abstract HTTP transport.

Implementation is thread-safe, and subclasses 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.

InputStreamContent

Concrete implementation of AbstractInputStreamContent that simply handles the transfer of data from an input stream to an output stream. This should only be used for streams that can not be re-opened and retried. If you have a stream that it is possible to recreate please create a new subclass of AbstractInputStreamContent.

The input stream is guaranteed to be closed at the end of #writeTo(OutputStream).

Sample use with a URL:

 
 private static void setRequestJpegContent(HttpRequest request, URL jpegUrl) throws IOException {
 request.setContent(new InputStreamContent("image/jpeg", jpegUrl.openStream()));
 }

Implementation is not thread-safe.

LowLevelHttpRequest

Low-level HTTP request.

This allows providing a different implementation of the HTTP request that is more compatible with the Java environment used.

Implementation has no fields and therefore thread-safe, but sub-classes are not necessarily thread-safe.

LowLevelHttpResponse

Low-level HTTP response.

This allows providing a different implementation of the HTTP response that is more compatible with the Java environment used.

Implementation has no fields and therefore thread-safe, but sub-classes are not necessarily thread-safe.

MultipartContent

Serializes MIME multipart content as specified by RFC 2387: The MIME Multipart/Related Content-type and RFC 2046: Multipurpose Internet Mail Extensions: The Multipart/mixed (primary) subtype.

By default the media type is "multipart/related; boundary=END_OF_PART, but this may be customized by calling #setMediaType(HttpMediaType), #getMediaType(), or #setBoundary(String).

Implementation is not thread-safe.

MultipartContent.Part

Single part of a multi-part request.

Implementation is not thread-safe.

OpenCensusUtils

Beta
Utilities for Census monitoring and tracing.

UriTemplate

Expands URI Templates.

This Class supports Level 1 templates and all Level 4 composite templates as described in: RFC 6570.

Specifically, for the variables: var := "value" list := ["red", "green", "blue"] keys := [("semi", ";"),("dot", "."),("comma", ",")]

The following templates results in the following expansions: {var} -> value {list} -> red,green,blue {list} -> red,green,blue {keys} -> semi,%3B,dot,.,comma,%2C {keys} -> semi=%3B,dot=.,comma=%2C {+list} -> red,green,blue {+list} -> red,green,blue {+keys} -> semi,;,dot,.,comma,, {+keys} -> semi=;,dot=.,comma=, {#list} -> #red,green,blue {#list*} ->

red,green,blue {#keys} -> #semi,;,dot,.,comma,, {#keys*} -> #semi=;,dot=.,comma=, X{.list} ->

X.red,green,blue X{.list} -> X.red.green.blue X{.keys} -> X.semi,%3B,dot,.,comma,%2C X{.keys} -> X.semi=%3B.dot=..comma=%2C {/list} -> /red,green,blue {/list} -> /red/green/blue {/keys} -> /semi,%3B,dot,.,comma,%2C {/keys} -> /semi=%3B/dot=./comma=%2C {;list} -> ;list=red,green,blue {;list} -> ;list=red;list=green;list=blue {;keys} -> ;keys=semi,%3B,dot,.,comma,%2C {;keys} -> ;semi=%3B;dot=.;comma=%2C {?list} -> ?list=red,green,blue {?list} -> ?list=red&list=green&list=blue {?keys} -> ?keys=semi,%3B,dot,.,comma,%2C {?keys} -> ?semi=%3B&dot=.&comma=%2C {&list} -> &list=red,green,blue {&list} -> &list=red&list=green&list=blue {&keys} -> &keys=semi,%3B,dot,.,comma,%2C {&keys} -> &semi=%3B&dot=.&comma=%2C {?var,list} -> ?var=value&list=red,green,blue

UrlEncodedContent

Implements support for HTTP form content encoding serialization of type application/x-www-form-urlencoded as specified in the HTML 4.0 Specification.

Sample usage:

static void setContent(HttpRequest request, Object item) { request.setContent(new UrlEncodedContent(item)); }

Implementation is not thread-safe.

UrlEncodedParser

Implements support for HTTP form content encoding parsing of type application/x-www-form-urlencoded as specified in the HTML 4.0 Specification.

Implementation is thread-safe.

The data is parsed using #parse(String, Object).

Sample usage:

static void setParser(HttpTransport transport) { transport.addParser(new UrlEncodedParser()); }

Interfaces

BackOffPolicy (deprecated)

Deprecated. (scheduled to be removed in 1.18) Use HttpBackOffUnsuccessfulResponseHandler instead.

Beta
Strategy interface to control back off between retry attempts.

HttpBackOffUnsuccessfulResponseHandler.BackOffRequired

Beta
Interface which defines if back-off is required based on an abnormal HttpResponse.

HttpContent

Serializes HTTP request content into an output stream.

Implementations don't need to be thread-safe.

HttpEncoding

HTTP content encoding.

Implementations don't need to be thread-safe.

HttpExecuteInterceptor

HTTP request execute interceptor to intercept the start of HttpRequest#execute() before executing the HTTP request.

For example, this might be used to sign a request for OAuth:

public class OAuthSigner implements HttpExecuteInterceptor { public void intercept(HttpRequest request) throws IOException { // sign request... } }

Sample usage with a request factory:

public static HttpRequestFactory createRequestFactory(HttpTransport transport) { final OAuthSigner signer = new OAuthSigner(...); return transport.createRequestFactory(new HttpRequestInitializer() { public void initialize(HttpRequest request) { request.setInterceptor(signer); } }); }

More complex usage example:

public static HttpRequestFactory createRequestFactory2(HttpTransport transport) { final OAuthSigner signer = new OAuthSigner(...); return transport.createRequestFactory(new HttpRequestInitializer() { public void initialize(HttpRequest request) { request.setInterceptor(new HttpExecuteInterceptor() { public void intercept(HttpRequest request) throws IOException { signer.intercept(request); } }); } }); }

Implementations should normally be thread-safe.

HttpIOExceptionHandler

Beta
Handles an IOException in an HTTP request.

For example, this might be used to handle an IOException with BackOff policy.

public static class HttpBackOffIOExceptionHandler implements HttpIOExceptionHandler { BackOff backOff; Sleeper sleeper; public boolean handle(HttpRequest request, boolean supportsRetry) throws IOException { if (!supportsRetry) { return false; } try { return BackOffUtils.next(sleeper, backOff); } catch (InterruptedException exception) { Thread.currentThread().interrupt(); return false; } } }

HttpRequestInitializer

HTTP request initializer.

For example, this might be used to disable request timeouts:

public class DisableTimeout implements HttpRequestInitializer { public void initialize(HttpRequest request) { request.setConnectTimeout(0); request.setReadTimeout(0); } }

Sample usage with a request factory:

public static HttpRequestFactory createRequestFactory(HttpTransport transport) { return transport.createRequestFactory(new DisableTimeout()); }

More complex usage example:

public static HttpRequestFactory createRequestFactory2(HttpTransport transport) { final DisableTimeout disableTimeout = new DisableTimeout(); return transport.createRequestFactory(new HttpRequestInitializer() { public void initialize(HttpRequest request) { disableTimeout.initialize(request); } }); }

Implementations should normally be thread-safe.

HttpResponseInterceptor

HTTP response interceptor to intercept the end of HttpRequest#execute() before returning a successful response or throwing an exception for an unsuccessful response.

For example, this might be used to add a simple timer on requests:

public static class TimerResponseInterceptor implements HttpResponseInterceptor {

private final long startTime = System.nanoTime();

public void interceptResponse(HttpResponse response) { long elapsedNanos = System.nanoTime() - startTime; System.out.println("elapsed seconds: " + TimeUnit.NANOSECONDS.toSeconds(elapsedNanos) + "s"); } }

Sample usage with a request factory:

public static HttpRequestFactory createRequestFactory(HttpTransport transport) { return transport.createRequestFactory(new HttpRequestInitializer() {

@Override public void initialize(HttpRequest request) { request.setResponseInterceptor(new TimerResponseInterceptor()); } }); }

More complex usage example:

public static HttpRequestFactory createRequestFactory2(HttpTransport transport) { final HttpResponseInterceptor responseInterceptor = new TimerResponseInterceptor(); return transport.createRequestFactory(new HttpRequestInitializer() {

public void initialize(HttpRequest request) { request.setResponseInterceptor(new HttpResponseInterceptor() {

public void interceptResponse(HttpResponse response) throws IOException { responseInterceptor.interceptResponse(response); } }); } }); }

Implementations should normally be thread-safe.

HttpUnsuccessfulResponseHandler

Interface which handles abnormal HTTP responses (in other words not 2XX).

For example, this might be used to refresh an OAuth 2 token:

public static class RefreshTokenHandler implements HttpUnsuccessfulResponseHandler { public boolean handleResponse( HttpRequest request, HttpResponse response, boolean retrySupported) throws IOException { if (response.getStatusCode() == HttpStatusCodes.STATUS_CODE_UNAUTHORIZED) { refreshToken(); } return false; } }

Sample usage with a request factory:

public static HttpRequestFactory createRequestFactory(HttpTransport transport) { final RefreshTokenHandler handler = new RefreshTokenHandler(); return transport.createRequestFactory(new HttpRequestInitializer() { public void initialize(HttpRequest request) { request.setUnsuccessfulResponseHandler(handler); } }); }

More complex usage example:

public static HttpRequestFactory createRequestFactory2(HttpTransport transport) { final RefreshTokenHandler handler = new RefreshTokenHandler(); return transport.createRequestFactory(new HttpRequestInitializer() { public void initialize(HttpRequest request) { request.setUnsuccessfulResponseHandler(new HttpUnsuccessfulResponseHandler() { public boolean handleResponse( HttpRequest request, HttpResponse response, boolean retrySupported) throws IOException { return handler.handleResponse(request, response, retrySupported); } }); } }); }

Exceptions

HttpResponseException

Exception thrown when an error status code is detected in an HTTP response.

Implementation is not thread safe.