Monday 24 July 2023

Micronaut: Inject HttpRequest object

We can inject HttpRequest object in any Micronaut bean methods.

 

For example,

@Get(value = "/demo1", produces = MediaType.APPLICATION_JSON)
public HttpResponse<Map<String, String>> demo1(final HttpRequest<?> httpRequest) {

	final HttpParameters httpParameters = httpRequest.getParameters();
	final String city = httpParameters.get("city");
	final String country = httpParameters.get("country");

	final Map<String, String> data = new HashMap<>();
	data.put("city", city);
	data.put("country", country);

	return HttpResponse.ok(data);

}

 

Above snippet

 

a.   Define demo1 method that is mapped to the URI /demo1 and accepts a HttpRequest.

b.   The HttpRequest is used to obtain the value of a query parameter named city and conuntry.

 

Find the below working application.

 

Step 1: Create new maven project ‘micronaut-inject-http-request’.

 

Step 2: Update pom.xml with maven dependencies.

 

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<groupId>com.sample.app</groupId>
	<artifactId>micronaut-inject-http-request</artifactId>
	<version>0.1</version>
	<packaging>jar</packaging>

	<parent>
		<groupId>io.micronaut</groupId>
		<artifactId>micronaut-parent</artifactId>
		<version>3.7.4</version>
	</parent>

	<properties>
		<packaging>jar</packaging>
		<jdk.version>11</jdk.version>
		<release.version>11</release.version>
		<micronaut.version>3.7.3</micronaut.version>
		<micronaut.runtime>netty</micronaut.runtime>
		<exec.mainClass>com.sample.app.App</exec.mainClass>
	</properties>

	<repositories>
		<repository>
			<id>central</id>
			<url>https://repo.maven.apache.org/maven2</url>
		</repository>
	</repositories>

	<dependencies>
		<dependency>
			<groupId>io.micronaut</groupId>
			<artifactId>micronaut-inject</artifactId>
			<scope>compile</scope>
		</dependency>
		<dependency>
			<groupId>io.micronaut</groupId>
			<artifactId>micronaut-validation</artifactId>
			<scope>compile</scope>
		</dependency>
		<dependency>
			<groupId>io.micronaut</groupId>
			<artifactId>micronaut-http-client</artifactId>
			<scope>compile</scope>
		</dependency>
		<dependency>
			<groupId>io.micronaut</groupId>
			<artifactId>micronaut-http-server-netty</artifactId>
			<scope>compile</scope>
		</dependency>
		<dependency>
			<groupId>io.micronaut</groupId>
			<artifactId>micronaut-jackson-databind</artifactId>
			<scope>compile</scope>
		</dependency>
		<dependency>
			<groupId>jakarta.annotation</groupId>
			<artifactId>jakarta.annotation-api</artifactId>
			<scope>compile</scope>
		</dependency>
		<dependency>
			<groupId>ch.qos.logback</groupId>
			<artifactId>logback-classic</artifactId>
			<scope>runtime</scope>
		</dependency>
		<dependency>
			<groupId>io.micronaut.test</groupId>
			<artifactId>micronaut-test-junit5</artifactId>
			<scope>test</scope>
		</dependency>
		<dependency>
			<groupId>org.junit.jupiter</groupId>
			<artifactId>junit-jupiter-api</artifactId>
			<scope>test</scope>
		</dependency>
		<dependency>
			<groupId>org.junit.jupiter</groupId>
			<artifactId>junit-jupiter-engine</artifactId>
			<scope>test</scope>
		</dependency>
	</dependencies>

	<build>
		<plugins>
			<plugin>
				<groupId>io.micronaut.build</groupId>
				<artifactId>micronaut-maven-plugin</artifactId>
			</plugin>

			<plugin>
				<groupId>org.apache.maven.plugins</groupId>
				<artifactId>maven-compiler-plugin</artifactId>
				<configuration>
					<!-- Uncomment to enable incremental compilation -->
					<!-- <useIncrementalCompilation>false</useIncrementalCompilation> -->

					<annotationProcessorPaths
						combine.children="append">
						<path>
							<groupId>io.micronaut</groupId>
							<artifactId>micronaut-http-validation</artifactId>
							<version>${micronaut.version}</version>
						</path>
					</annotationProcessorPaths>

				</configuration>
			</plugin>
		</plugins>
	</build>

</project>

 

Step 3: Define HelloController class.

 

HelloController.java

 

package com.sample.app.controller;

import java.util.HashMap;
import java.util.Map;

import io.micronaut.http.HttpParameters;
import io.micronaut.http.HttpRequest;
import io.micronaut.http.HttpResponse;
import io.micronaut.http.MediaType;
import io.micronaut.http.annotation.Controller;
import io.micronaut.http.annotation.Get;

@Controller("/hello")
public class HelloController {

	@Get(value = "/demo1", produces = MediaType.APPLICATION_JSON)
	public HttpResponse<Map<String, String>> demo1(final HttpRequest<?> httpRequest) {

		final HttpParameters httpParameters = httpRequest.getParameters();
		final String city = httpParameters.get("city");
		final String country = httpParameters.get("country");

		final Map<String, String> data = new HashMap<>();
		data.put("city", city);
		data.put("country", country);

		return HttpResponse.ok(data);

	}

}

 

Step 4: Define main application class.

 

App.java

 

package com.sample.app;

import io.micronaut.runtime.Micronaut;

public class App {

	public static void main(String[] args) {

		Micronaut.run(App.class);

		// Use this if you want the beans to be initialized eagerly
		/*
		 * Micronaut.build(args) .eagerInitSingletons(true) .mainClass(App.class)
		 * .start();
		 */
	}
}

 

Total project structure looks like below.

 


Build the project using mvn package command.

Navigate to the folder where pom.xml is located and execute the command ‘mvn package’.

 

Upon command successful execution, you can see the jar file ‘micronaut-inject-http-request-0.1.jar’ in project target folder.

$ ls ./target/
classes
generated-sources
generated-test-sources
maven-archiver
maven-status
micronaut-inject-http-request-0.1.jar
original-micronaut-inject-http-request-0.1.jar
test-classes

Execute below command to run the application.

java -jar ./target/micronaut-inject-http-request-0.1.jar

Execute below command to test the api.

curl --location --request GET 'http://localhost:8080/hello/demo1?city=Bangalore&country=India'

$curl --location --request GET 'http://localhost:8080/hello/demo1?city=Bangalore&country=India'
{"country":"India","city":"Bangalore"}

You can download this application from this link.



 

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