BAEL-3863 Introduction to Finagle

finagle/README.md

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+## Finagle
+
+This module contains articles about Finagle and associated libraries.
+
+### Relevant articles
+
+- [Introduction to Finagle](https://www.baeldung.com/introduction-to-finagle)

finagle/pom.xml

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+<?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/maven-v4_0_0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>Finagle</artifactId>
+    <name>Finagle</name>
+    <packaging>jar</packaging>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
+    <dependencies>
+      <dependency>
+        <groupId>com.twitter</groupId>
+        <artifactId>finagle-core_2.13</artifactId>
+        <version>20.4.0</version>
+      </dependency>
+      <dependency>
+          <groupId>com.twitter</groupId>
+          <artifactId>finagle-http_2.13</artifactId>
+          <version>20.4.0</version>
+      </dependency>
+
+    </dependencies>
+
+
+</project>

finagle/src/main/java/com/baeldung/finagle/Client.java

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+package com.baeldung.finagle;
+
+import com.twitter.finagle.Http;
+import com.twitter.finagle.Service;
+import com.twitter.finagle.http.Method;
+import com.twitter.finagle.http.Request;
+import com.twitter.finagle.http.Response;
+import com.twitter.util.Await;
+import com.twitter.util.Future;
+import scala.runtime.BoxedUnit;
+
+public class Client {
+    public static void main(String[] args) throws Exception {
+        Service<Request, Response> service = new LogFilter().andThen(Http.newService(":8080"));
+        Request request = Request.apply(Method.Get(), "/?name=John");
+        request.host("localhost");
+        Future<Response> response = service.apply(request);
+        Await.result(response
+                .onSuccess(r -> {
+                    System.out.println(r.getContentString());
+                    return BoxedUnit.UNIT;
+                }));
+    }
+}

finagle/src/main/java/com/baeldung/finagle/GreetingService.java

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+package com.baeldung.finagle;
+
+import com.twitter.finagle.Service;
+import com.twitter.finagle.http.Request;
+import com.twitter.finagle.http.Response;
+import com.twitter.finagle.http.Status;
+import com.twitter.io.Buf;
+import com.twitter.io.Reader;
+import com.twitter.util.Future;
+
+public class GreetingService extends Service<Request, Response> {
+    @Override
+    public Future<Response> apply(Request request) {
+        String greeting = "Hello " + request.getParam("name");
+        Reader<Buf> reader = Reader.fromBuf(new Buf.ByteArray(greeting.getBytes(), 0, greeting.length()));
+        return Future.value(Response.apply(request.version(), Status.Ok(), reader));
+    }
+}

finagle/src/main/java/com/baeldung/finagle/LogFilter.java

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+package com.baeldung.finagle;
+
+import com.twitter.finagle.Service;
+import com.twitter.finagle.SimpleFilter;
+import com.twitter.finagle.http.Request;
+import com.twitter.finagle.http.Response;
+import com.twitter.util.Future;
+
+public class LogFilter extends SimpleFilter<Request, Response> {
+    @Override
+    public Future<Response> apply(Request request, Service<Request, Response> service) {
+        System.out.println("Request host:" + request.host().getOrElse(() -> ""));
+        System.out.println("Request params:");
+        request.getParams().forEach(entry -> System.out.println("\t" + entry.getKey() + " : " + entry.getValue()));
+        return service.apply(request);
+    }
+}

finagle/src/main/java/com/baeldung/finagle/Server.java

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+package com.baeldung.finagle;
+
+import com.twitter.finagle.Http;
+import com.twitter.finagle.ListeningServer;
+import com.twitter.finagle.Service;
+import com.twitter.util.Await;
+import com.twitter.util.TimeoutException;
+
+public class Server {
+    public static void main(String[] args) throws TimeoutException, InterruptedException {
+        Service service = new LogFilter().andThen(new GreetingService());
+        ListeningServer server = Http.serve(":8080", service);
+        Await.ready(server);
+    }
+}

finagle/src/main/resources/logback.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<configuration>
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n
+            </pattern>
+        </encoder>
+    </appender>
+
+    <root level="INFO">
+        <appender-ref ref="STDOUT" />
+    </root>
+</configuration>

finagle/src/main/resources/twitter4j.properties

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+oauth.consumerKey=//TODO
+oauth.consumerSecret=//TODO
+oauth.accessToken=//TODO
+oauth.accessTokenSecret=//TODO