org.springframework.cloud.gateway.mvc

Class ProxyExchange<T>

java.lang.Object

org.springframework.cloud.gateway.mvc.ProxyExchange<T>

public class ProxyExchange<T>
extends Object

A @RequestMapping argument type that can proxy the request to a backend. Spring will inject one of these into your MVC handler method, and you get return a ResponseEntity that you get from one of the HTTP methods get(), post(), put(), patch(), delete() etc. Example:

 @GetMapping("/proxy/{id}")
 public ResponseEntity<?> proxy(@PathVariable Integer id, ProxyExchange<?> proxy)
                throws Exception {
        return proxy.uri("http://localhost:9000/foos/" + id).get();
 }
 

By default the incoming request body and headers are sent intact to the downstream service (with the exception of "sensitive" headers). To manipulate the downstream request there are "builder" style methods in ProxyExchange, but only the uri(String) is mandatory. You can change the sensitive headers by calling the sensitive(String...) method (Authorization and Cookie are sensitive by default).

The type parameter T in ProxyExchange<T> is the type of the response body, so it comes out in the ResponseEntity that you return from your @RequestMapping. If you don't care about the type of the request and response body (e.g. if it's just a passthru) then use a wildcard, or byte[] or Object. Use a concrete type if you want to transform or manipulate the response, or if you want to assert that it is convertible to the type you declare.

To manipulate the response use the overloaded HTTP methods with a Function argument and pass in code to transform the response. E.g.

 @PostMapping("/proxy")
 public ResponseEntity<Foo> proxy(ProxyExchange<Foo> proxy) throws Exception {
        return proxy.uri("http://localhost:9000/foos/") //
                        .post(response -> ResponseEntity.status(response.getStatusCode()) //
                                        .headers(response.getHeaders()) //
                                        .header("X-Custom", "MyCustomHeader") //
                                        .body(response.getBody()) //
                        );
 }

 

The full machinery of Spring message converters is applied to the incoming request and response and also to the backend request. If you need additional converters then they need to be added upstream in the MVC configuration and also to the RestTemplate that is used in the backend calls (see the constructor for details).

As well as the HTTP methods for a backend call you can also use forward(String) for a local in-container dispatch.

Author:

Dave Syer

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected static class	ProxyExchange.BodyGrabber
protected static class	ProxyExchange.BodySender

Field Summary

Fields

Modifier and Type	Field and Description
static Set<String>	DEFAULT_SENSITIVE Contains headers that are considered case-sensitive by default.

Constructor Summary

Constructors

Constructor and Description
ProxyExchange(org.springframework.web.client.RestTemplate rest, org.springframework.web.context.request.NativeWebRequest webRequest, org.springframework.web.method.support.ModelAndViewContainer mavContainer, org.springframework.web.bind.support.WebDataBinderFactory binderFactory, Type type)

Method Summary

Modifier and Type	Method and Description
ProxyExchange<T>	body(Object body) Sets the body for the downstream request (if using post(), put() or patch()).
org.springframework.http.ResponseEntity<T>	delete()
<S> org.springframework.http.ResponseEntity<S>	delete(Function<org.springframework.http.ResponseEntity<T>,org.springframework.http.ResponseEntity<S>> converter)
void	forward(String path)
org.springframework.http.ResponseEntity<T>	get()
<S> org.springframework.http.ResponseEntity<S>	get(Function<org.springframework.http.ResponseEntity<T>,org.springframework.http.ResponseEntity<S>> converter)
org.springframework.http.ResponseEntity<T>	head()
<S> org.springframework.http.ResponseEntity<S>	head(Function<org.springframework.http.ResponseEntity<T>,org.springframework.http.ResponseEntity<S>> converter)
ProxyExchange<T>	header(String name, String... value) Sets a header for the downstream call.
ProxyExchange<T>	headers(org.springframework.http.HttpHeaders headers) Additional headers, or overrides of the incoming ones, to be used in the downstream call.
org.springframework.http.ResponseEntity<T>	options()
<S> org.springframework.http.ResponseEntity<S>	options(Function<org.springframework.http.ResponseEntity<T>,org.springframework.http.ResponseEntity<S>> converter)
org.springframework.http.ResponseEntity<T>	patch()
<S> org.springframework.http.ResponseEntity<S>	patch(Function<org.springframework.http.ResponseEntity<T>,org.springframework.http.ResponseEntity<S>> converter)
String	path()
String	path(String prefix)
org.springframework.http.ResponseEntity<T>	post()
<S> org.springframework.http.ResponseEntity<S>	post(Function<org.springframework.http.ResponseEntity<T>,org.springframework.http.ResponseEntity<S>> converter)
org.springframework.http.ResponseEntity<T>	put()
<S> org.springframework.http.ResponseEntity<S>	put(Function<org.springframework.http.ResponseEntity<T>,org.springframework.http.ResponseEntity<S>> converter)
ProxyExchange<T>	sensitive(String... names) Sets the names of sensitive headers that are not passed downstream to the backend service.
ProxyExchange<T>	uri(String uri) Sets the uri for the backend call when triggered by the HTTP methods.
ProxyExchange<T>	uri(URI uri) Sets the uri for the backend call when triggered by the HTTP methods.

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_SENSITIVE

public static Set<String> DEFAULT_SENSITIVE

Contains headers that are considered case-sensitive by default.

Constructor Detail

ProxyExchange

public ProxyExchange(org.springframework.web.client.RestTemplate rest,
                     org.springframework.web.context.request.NativeWebRequest webRequest,
                     org.springframework.web.method.support.ModelAndViewContainer mavContainer,
                     org.springframework.web.bind.support.WebDataBinderFactory binderFactory,
                     Type type)

Method Detail

body

public ProxyExchange<T> body(Object body)

Sets the body for the downstream request (if using post(), put() or patch()). The body can be omitted if you just want to pass the incoming request downstream without changing it. If you want to transform the incoming request you can declare it as a @RequestBody in your @RequestMapping in the usual Spring MVC way.

Parameters:

body - the request body to send downstream

Returns:

this for convenience

header

public ProxyExchange<T> header(String name,
                               String... value)

Sets a header for the downstream call.

Parameters:

name - Header name

value - Header values

Returns:

this for convenience

headers

public ProxyExchange<T> headers(org.springframework.http.HttpHeaders headers)

Additional headers, or overrides of the incoming ones, to be used in the downstream call.

Parameters:

headers - the http headers to use in the downstream call

Returns:

this for convenience

sensitive

public ProxyExchange<T> sensitive(String... names)

Sets the names of sensitive headers that are not passed downstream to the backend service.

Parameters:

names - the names of sensitive headers

Returns:

this for convenience

uri

public ProxyExchange<T> uri(URI uri)

Sets the uri for the backend call when triggered by the HTTP methods.

Parameters:

uri - the backend uri to send the request to

Returns:

this for convenience

uri

public ProxyExchange<T> uri(String uri)

Sets the uri for the backend call when triggered by the HTTP methods.

Parameters:

uri - the backend uri to send the request to

Returns:

this for convenience

path

public String path()

path

public String path(String prefix)

forward

public void forward(String path)

get

public org.springframework.http.ResponseEntity<T> get()

get

public <S> org.springframework.http.ResponseEntity<S> get(Function<org.springframework.http.ResponseEntity<T>,org.springframework.http.ResponseEntity<S>> converter)

head

public org.springframework.http.ResponseEntity<T> head()

head

public <S> org.springframework.http.ResponseEntity<S> head(Function<org.springframework.http.ResponseEntity<T>,org.springframework.http.ResponseEntity<S>> converter)

options

public org.springframework.http.ResponseEntity<T> options()

options

public <S> org.springframework.http.ResponseEntity<S> options(Function<org.springframework.http.ResponseEntity<T>,org.springframework.http.ResponseEntity<S>> converter)

post

public org.springframework.http.ResponseEntity<T> post()

post

public <S> org.springframework.http.ResponseEntity<S> post(Function<org.springframework.http.ResponseEntity<T>,org.springframework.http.ResponseEntity<S>> converter)

delete

public org.springframework.http.ResponseEntity<T> delete()

delete

public <S> org.springframework.http.ResponseEntity<S> delete(Function<org.springframework.http.ResponseEntity<T>,org.springframework.http.ResponseEntity<S>> converter)

put

public org.springframework.http.ResponseEntity<T> put()

put

public <S> org.springframework.http.ResponseEntity<S> put(Function<org.springframework.http.ResponseEntity<T>,org.springframework.http.ResponseEntity<S>> converter)

patch

public org.springframework.http.ResponseEntity<T> patch()

patch

public <S> org.springframework.http.ResponseEntity<S> patch(Function<org.springframework.http.ResponseEntity<T>,org.springframework.http.ResponseEntity<S>> converter)