Package com.azure.core.http.policy

Class DefaultRedirectStrategy

java.lang.Object

com.azure.core.http.policy.DefaultRedirectStrategy

All Implemented Interfaces:

RedirectStrategy

public final class DefaultRedirectStrategy
extends Object
implements RedirectStrategy

The DefaultRedirectStrategy class is an implementation of the RedirectStrategy interface. This strategy uses the provided maximum retry attempts, header name to look up redirect URL value for, HTTP methods and a known set of redirect status response codes (301, 302, 307, 308) to determine if a request should be redirected.

This class is useful when you need to handle HTTP redirects. It ensures that the requests are redirected correctly based on the response status code and the maximum number of redirect attempts.

Code sample:

In this example, a DefaultRedirectStrategy is created with a maximum of 3 redirect attempts, "Location" as the header name to locate the redirect URL, and GET and HEAD as the allowed methods for performing the redirect. The strategy is then used in a RedirectPolicy which can be added to the pipeline. For a request sent by the pipeline, if the server responds with a redirect status code and provides a "Location" header, the request will be redirected up to 3 times as needed.

 DefaultRedirectStrategy redirectStrategy = new DefaultRedirectStrategy(3, "Location",
     EnumSet.of(HttpMethod.GET, HttpMethod.HEAD));
 RedirectPolicy redirectPolicy = new RedirectPolicy(redirectStrategy);
 

See Also:

• com.azure.core.http.policy
• RedirectStrategy
• RedirectPolicy
• HttpPipeline
• HttpRequest
• HttpResponse

Constructor Summary

Constructors

Constructor	Description
DefaultRedirectStrategy()	Creates an instance of DefaultRedirectStrategy with a maximum number of redirect attempts 3, header name "Location" to locate the redirect url in the response headers and HttpMethod.GET and HttpMethod.HEAD as allowed methods for performing the redirect.
DefaultRedirectStrategy(int maxAttempts)	Creates an instance of DefaultRedirectStrategy with the provided number of redirect attempts and default header name "Location" to locate the redirect url in the response headers and HttpMethod.GET and HttpMethod.HEAD as allowed methods for performing the redirect.
DefaultRedirectStrategy(int maxAttempts, String locationHeader, Set<HttpMethod> allowedMethods)	Creates an instance of DefaultRedirectStrategy.

Method Summary

Modifier and Type	Method	Description
HttpRequest	createRedirectRequest(HttpResponse httpResponse)	Creates an request for the redirect attempt.
int	getMaxAttempts()	Max number of redirect attempts to be made.
boolean	shouldAttemptRedirect(HttpPipelineCallContext context, HttpResponse httpResponse, int tryCount, Set<String> attemptedRedirectUrls)	Determines if the url should be redirected between each try.

Methods inherited from class java.lang.Object

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

Constructor Details

DefaultRedirectStrategy

public DefaultRedirectStrategy()

Creates an instance of DefaultRedirectStrategy with a maximum number of redirect attempts 3, header name "Location" to locate the redirect url in the response headers and HttpMethod.GET and HttpMethod.HEAD as allowed methods for performing the redirect.

DefaultRedirectStrategy

public DefaultRedirectStrategy(int maxAttempts)

Creates an instance of DefaultRedirectStrategy with the provided number of redirect attempts and default header name "Location" to locate the redirect url in the response headers and HttpMethod.GET and HttpMethod.HEAD as allowed methods for performing the redirect.

Parameters:

maxAttempts - The max number of redirect attempts that can be made.

Throws:

IllegalArgumentException - if maxAttempts is less than 0.

DefaultRedirectStrategy

public DefaultRedirectStrategy(int maxAttempts,
 String locationHeader,
 Set<HttpMethod> allowedMethods)

Creates an instance of DefaultRedirectStrategy.

Parameters:

maxAttempts - The max number of redirect attempts that can be made.

locationHeader - The header name containing the redirect URL.

allowedMethods - The set of HttpMethod that are allowed to be redirected.

Throws:

IllegalArgumentException - if maxAttempts is less than 0.

Method Details

shouldAttemptRedirect

public boolean shouldAttemptRedirect(HttpPipelineCallContext context,
 HttpResponse httpResponse,
 int tryCount,
 Set<String> attemptedRedirectUrls)

Description copied from interface: RedirectStrategy

Determines if the url should be redirected between each try.

Specified by:

shouldAttemptRedirect in interface RedirectStrategy

Parameters:

context - the HTTP pipeline context.

httpResponse - the HttpRequest containing the redirect url present in the response headers

tryCount - redirect attempts so far

attemptedRedirectUrls - attempted redirect locations used so far.

Returns:

true if the request should be redirected, false otherwise

createRedirectRequest

public HttpRequest createRedirectRequest(HttpResponse httpResponse)

Description copied from interface: RedirectStrategy

Creates an request for the redirect attempt.

Specified by:

createRedirectRequest in interface RedirectStrategy

Parameters:

httpResponse - the HttpResponse containing the redirect url present in the response headers

Returns:

the modified HttpRequest to redirect the incoming request.

getMaxAttempts

public int getMaxAttempts()

Description copied from interface: RedirectStrategy

Max number of redirect attempts to be made.

Specified by:

getMaxAttempts in interface RedirectStrategy

Returns:

The max number of redirect attempts.