org.springframework.web.reactive.function.server

Class RouterFunctions

java.lang.Object

org.springframework.web.reactive.function.server.RouterFunctions

public abstract class RouterFunctions
extends Object

Central entry point to Spring's functional web framework. Exposes routing functionality, such as to create a RouterFunction using a discoverable builder-style API, to create a RouterFunction given a RequestPredicate and HandlerFunction, and to do further subrouting on an existing routing function.

Additionally, this class can transform a RouterFunction into an HttpHandler, which can be run in Servlet 3.1+, Reactor, or Undertow.

Since:

5.0

Author:

Arjen Poutsma

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	RouterFunctions.Builder Represents a discoverable builder for router functions.
static interface	RouterFunctions.Visitor Receives notifications from the logical structure of router functions.

Field Summary

Fields

Modifier and Type	Field and Description
static String	MATCHING_PATTERN_ATTRIBUTE Name of the attribute that contains the matching pattern, as a PathPattern.
static String	REQUEST_ATTRIBUTE Name of the ServerWebExchange attribute that contains the ServerRequest.
static String	URI_TEMPLATE_VARIABLES_ATTRIBUTE Name of the ServerWebExchange attribute that contains the URI templates map, mapping variable names to values.

Constructor Summary

Constructors

Constructor and Description
RouterFunctions()

Method Summary

Modifier and Type	Method and Description
static <T extends ServerResponse> RouterFunction<T>	nest(RequestPredicate predicate, RouterFunction<T> routerFunction) Route to the given router function if the given request predicate applies.
static Function<ServerRequest,reactor.core.publisher.Mono<Resource>>	resourceLookupFunction(String pattern, Resource location) Returns the resource lookup function used by resources(String, Resource).
static RouterFunction<ServerResponse>	resources(Function<ServerRequest,reactor.core.publisher.Mono<Resource>> lookupFunction) Route to resources using the provided lookup function.
static RouterFunction<ServerResponse>	resources(String pattern, Resource location) Route requests that match the given pattern to resources relative to the given root location.
static RouterFunctions.Builder	route() Offers a discoverable way to create router functions through a builder-style interface.
static <T extends ServerResponse> RouterFunction<T>	route(RequestPredicate predicate, HandlerFunction<T> handlerFunction) Route to the given handler function if the given request predicate applies.
static HttpHandler	toHttpHandler(RouterFunction<?> routerFunction) Convert the given router function into a HttpHandler.
static HttpHandler	toHttpHandler(RouterFunction<?> routerFunction, HandlerStrategies strategies) Convert the given router function into a HttpHandler, using the given strategies.
static WebHandler	toWebHandler(RouterFunction<?> routerFunction) Convert the given router function into a WebHandler.
static WebHandler	toWebHandler(RouterFunction<?> routerFunction, HandlerStrategies strategies) Convert the given router function into a WebHandler, using the given strategies.

Methods inherited from class java.lang.Object

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

Field Detail

REQUEST_ATTRIBUTE

public static final String REQUEST_ATTRIBUTE

Name of the ServerWebExchange attribute that contains the ServerRequest.

URI_TEMPLATE_VARIABLES_ATTRIBUTE

public static final String URI_TEMPLATE_VARIABLES_ATTRIBUTE

Name of the ServerWebExchange attribute that contains the URI templates map, mapping variable names to values.

MATCHING_PATTERN_ATTRIBUTE

public static final String MATCHING_PATTERN_ATTRIBUTE

Name of the attribute that contains the matching pattern, as a PathPattern.

Constructor Detail

RouterFunctions

public RouterFunctions()

Method Detail

route

public static RouterFunctions.Builder route()

Offers a discoverable way to create router functions through a builder-style interface.

Returns:

a router function builder

Since:

5.1

route

public static <T extends ServerResponse> RouterFunction<T> route(RequestPredicate predicate,
                                                                 HandlerFunction<T> handlerFunction)

Route to the given handler function if the given request predicate applies.

For instance, the following example routes GET requests for "/user" to the listUsers method in userController:

 RouterFunction<ServerResponse> route =
     RouterFunctions.route(RequestPredicates.GET("/user"), userController::listUsers);
 

Type Parameters:

T - the type of response returned by the handler function

Parameters:

predicate - the predicate to test

handlerFunction - the handler function to route to if the predicate applies

Returns:

a router function that routes to handlerFunction if predicate evaluates to true

See Also:

RequestPredicates

nest

public static <T extends ServerResponse> RouterFunction<T> nest(RequestPredicate predicate,
                                                                RouterFunction<T> routerFunction)

Route to the given router function if the given request predicate applies. This method can be used to create nested routes, where a group of routes share a common path (prefix), header, or other request predicate.

For instance, the following example first creates a composed route that resolves to listUsers for a GET, and createUser for a POST. This composed route then gets nested with a "/user" path predicate, so that GET requests for "/user" will list users, and POST request for "/user" will create a new user.

 RouterFunction<ServerResponse> userRoutes =
   RouterFunctions.route(RequestPredicates.method(HttpMethod.GET), this::listUsers)
     .andRoute(RequestPredicates.method(HttpMethod.POST), this::createUser);
 RouterFunction<ServerResponse> nestedRoute =
   RouterFunctions.nest(RequestPredicates.path("/user"), userRoutes);
 

Type Parameters:

T - the type of response returned by the handler function

Parameters:

predicate - the predicate to test

routerFunction - the nested router function to delegate to if the predicate applies

Returns:

a router function that routes to routerFunction if predicate evaluates to true

See Also:

RequestPredicates

resources

public static RouterFunction<ServerResponse> resources(String pattern,
                                                       Resource location)

Route requests that match the given pattern to resources relative to the given root location. For instance

 Resource location = new FileSystemResource("public-resources/");
 RouterFunction<ServerResponse> resources = RouterFunctions.resources("/resources/**", location);
 

Parameters:

pattern - the pattern to match

location - the location directory relative to which resources should be resolved

Returns:

a router function that routes to resources

See Also:

resourceLookupFunction(String, Resource)

resourceLookupFunction

public static Function<ServerRequest,reactor.core.publisher.Mono<Resource>> resourceLookupFunction(String pattern,
                                                                                                   Resource location)

Returns the resource lookup function used by resources(String, Resource). The returned function can be composed on, for instance to return a default resource when the lookup function does not match:

 Mono<Resource> defaultResource = Mono.just(new ClassPathResource("index.html"));
 Function<ServerRequest, Mono<Resource>> lookupFunction =
   RouterFunctions.resourceLookupFunction("/resources/**", new FileSystemResource("public-resources/"))
     .andThen(resourceMono -> resourceMono.switchIfEmpty(defaultResource));
 RouterFunction<ServerResponse> resources = RouterFunctions.resources(lookupFunction);
 

Parameters:

pattern - the pattern to match

location - the location directory relative to which resources should be resolved

Returns:

the default resource lookup function for the given parameters.

resources

public static RouterFunction<ServerResponse> resources(Function<ServerRequest,reactor.core.publisher.Mono<Resource>> lookupFunction)

Route to resources using the provided lookup function. If the lookup function provides a Resource for the given request, it will be it will be exposed using a HandlerFunction that handles GET, HEAD, and OPTIONS requests.

Parameters:

lookupFunction - the function to provide a Resource given the ServerRequest

Returns:

a router function that routes to resources

toHttpHandler

public static HttpHandler toHttpHandler(RouterFunction<?> routerFunction)

Convert the given router function into a HttpHandler. This conversion uses default strategies.

The returned handler can be adapted to run in

• Servlet 3.1+ using the ServletHttpHandlerAdapter,
• Reactor using the ReactorHttpHandlerAdapter,
• Undertow using the UndertowHttpHandlerAdapter.

Note that HttpWebHandlerAdapter also implements WebHandler, allowing for additional filter and exception handler registration through WebHttpHandlerBuilder.

Parameters:

routerFunction - the router function to convert

Returns:

an http handler that handles HTTP request using the given router function

toHttpHandler

public static HttpHandler toHttpHandler(RouterFunction<?> routerFunction,
                                        HandlerStrategies strategies)

Convert the given router function into a HttpHandler, using the given strategies.

The returned HttpHandler can be adapted to run in

• Servlet 3.1+ using the ServletHttpHandlerAdapter,
• Reactor using the ReactorHttpHandlerAdapter,
• Undertow using the UndertowHttpHandlerAdapter.

Parameters:

routerFunction - the router function to convert

strategies - the strategies to use

Returns:

an http handler that handles HTTP request using the given router function

toWebHandler

public static WebHandler toWebHandler(RouterFunction<?> routerFunction)

Convert the given router function into a WebHandler. This conversion uses default strategies.

Parameters:

routerFunction - the router function to convert

Returns:

a web handler that handles web request using the given router function

toWebHandler

public static WebHandler toWebHandler(RouterFunction<?> routerFunction,
                                      HandlerStrategies strategies)

Convert the given router function into a WebHandler, using the given strategies.

Parameters:

routerFunction - the router function to convert

strategies - the strategies to use

Returns:

a web handler that handles web request using the given router function