6 The HTTP Server - 6.9 The HttpRequest and HttpResponse - 《Micronaut v2.3.1 Documentation》

6.9 The HttpRequest and HttpResponse

6.9 The HttpRequest and HttpResponse

If you need more control over request processing then you can instead write a method that receives the complete HttpRequest.

In fact, there are several higher level interfaces that can be bound to method parameters of controllers. These include:

Table 1. Bindable Micronaut Interfaces
Interface	Description	Example
HttpRequest	The full `HttpRequest`	`String hello(HttpRequest request)`
HttpHeaders	All HTTP headers present in the request	`String hello(HttpHeaders headers)`
HttpParameters	All HTTP parameters (either from URI variables or request parameters) present in the request	`String hello(HttpParameters params)`
Cookies	All the Cookies present in the request	`String hello(Cookies cookies)`

The HttpRequest should be declared parametrized with a concrete generic type if the request body is needed, e.g. HttpRequest<MyClass> request. The body may not be available from the request otherwise.

In addition, for full control over the emitted HTTP response you can use the static factory methods of the HttpResponse class which return a MutableHttpResponse.

The following example implements the previous MessageController example using the HttpRequest and HttpResponse objects:

Request and Response Example

import io.micronaut.http.HttpRequest;
import io.micronaut.http.HttpResponse;
import io.micronaut.http.annotation.Controller;
import io.micronaut.http.annotation.Get;
@Controller("/request")
public class MessageController {
    @Get("/hello") (1)
    public HttpResponse<String> hello(HttpRequest<?> request) {
        String name = request.getParameters()
                             .getFirst("name")
                             .orElse("Nobody"); (2)
        return HttpResponse.ok("Hello " + name + "!!")
                 .header("X-My-Header", "Foo"); (3)
    }
}

Request and Response Example

import io.micronaut.http.HttpRequest
import io.micronaut.http.HttpResponse
import io.micronaut.http.annotation.Controller
import io.micronaut.http.annotation.Get
@Controller("/request")
class MessageController {
    @Get("/hello") (1)
    HttpResponse<String> hello(HttpRequest<?> request) {
        String name = request.getParameters()
                             .getFirst("name")
                             .orElse("Nobody") (2)
        HttpResponse.ok("Hello " + name + "!!")
                 .header("X-My-Header", "Foo") (3)
    }
}

Request and Response Example

import io.micronaut.http.HttpRequest
import io.micronaut.http.HttpResponse
import io.micronaut.http.annotation.Controller
import io.micronaut.http.annotation.Get
@Controller("/request")
class MessageController {
    @Get("/hello") (1)
    fun hello(request: HttpRequest<*>): HttpResponse<String> {
        val name = request.parameters
                .getFirst("name")
                .orElse("Nobody") (2)
        return HttpResponse.ok("Hello $name!!")
                .header("X-My-Header", "Foo") (3)
    }
}

1	The method is mapped to the URI `/hello` and accepts a HttpRequest
2	The HttpRequest is used to obtain the value of a query parameter called `name`.
3	The HttpResponse.ok(T) method is used to return a MutableHttpResponse with a text body. A header called `X-My-Header` is also added to the response object.

HttpRequest is also available from static context via ServerRequestContext.

Generally ServerRequestContext is available within reactive flow, but the recommended approach is to propagate the necessary state through lambdas.