From 3109483219d9d936f378de9e1eb5e0f8000c04b3 Mon Sep 17 00:00:00 2001
From: Thomas Segismont <tsegismont@gmail.com>
Date: Thu, 28 Nov 2024 17:18:14 +0100
Subject: [PATCH] HTTP Proxy examples

Signed-off-by: Thomas Segismont <tsegismont@gmail.com>
---
 http-proxy-examples/README.adoc               | 57 +++++++++++++++++++
 http-proxy-examples/pom.xml                   | 38 +++++++++++++
 .../example/proxy/interception/Backend.java   | 28 +++++++++
 .../example/proxy/interception/Proxy.java     | 43 ++++++++++++++
 .../vertx/example/proxy/simple/Backend.java   | 21 +++++++
 .../io/vertx/example/proxy/simple/Proxy.java  | 28 +++++++++
 .../example/proxy/websocket/Backend.java      | 27 +++++++++
 .../vertx/example/proxy/websocket/Client.java | 25 ++++++++
 .../vertx/example/proxy/websocket/Proxy.java  | 27 +++++++++
 pom.xml                                       |  1 +
 10 files changed, 295 insertions(+)
 create mode 100644 http-proxy-examples/README.adoc
 create mode 100644 http-proxy-examples/pom.xml
 create mode 100644 http-proxy-examples/src/main/java/io/vertx/example/proxy/interception/Backend.java
 create mode 100644 http-proxy-examples/src/main/java/io/vertx/example/proxy/interception/Proxy.java
 create mode 100644 http-proxy-examples/src/main/java/io/vertx/example/proxy/simple/Backend.java
 create mode 100644 http-proxy-examples/src/main/java/io/vertx/example/proxy/simple/Proxy.java
 create mode 100644 http-proxy-examples/src/main/java/io/vertx/example/proxy/websocket/Backend.java
 create mode 100644 http-proxy-examples/src/main/java/io/vertx/example/proxy/websocket/Client.java
 create mode 100644 http-proxy-examples/src/main/java/io/vertx/example/proxy/websocket/Proxy.java

diff --git a/http-proxy-examples/README.adoc b/http-proxy-examples/README.adoc
new file mode 100644
index 000000000..fbd21b7c7
--- /dev/null
+++ b/http-proxy-examples/README.adoc
@@ -0,0 +1,57 @@
+= Vert.x HTTP Proxy examples
+
+Here you will find examples demonstrating Vert.x HTTP Proxy.
+
+Vert.x HTTP Proxy is a reverse proxy based on Vert.x, it aims to implement reusable reverse proxy logic to focus on higher concerns.
+
+[#_simple_reverse_proxy]
+== Simple reverse proxy
+
+In this example, there are two verticles:
+
+* the backend verticle, which is a simple HTTP server replying to requests with a greeting, and
+* the proxy verticle, which configures a `ReverseProxy` that relays incoming traffic to the backend.
+
+After starting the backend and the proxy, browse to http://localhost:8080 or your use your favorite command-line tool, such as `curl` or `HTTPie`.
+
+link:src/main/java/io/vertx/example/proxy/simple/Backend.java[`Backend`]
+link:src/main/java/io/vertx/example/proxy/simple/Proxy.java[`Proxy`]
+
+== Proxy interceptors
+
+This example is a follow-up of the <<_simple_reverse_proxy,simple reverse proxy>> example.
+
+The backend replies with a success code (200) only to requests starting with the `/app` prefix.
+Besides, it puts an internal HTTP header value on responses.
+
+The proxy uses two types of interceptors: head and body interceptors.
+
+The head interceptor is configured to:
+
+- add the `/app` prefix to the path of HTTP requests
+- remove the internal HTTP header from HTTP responses
+
+The body interceptor is configured to replace `Hello` with `Hi in the response text.
+
+After starting the backend and the proxy, browse to http://localhost:8080 or your use your favorite command-line tool, such as `curl` or `HTTPie`.
+
+link:src/main/java/io/vertx/example/proxy/interception/Backend.java[`Backend`]
+link:src/main/java/io/vertx/example/proxy/interception/Proxy.java[`Proxy`]
+
+== WebSocket support
+
+In this example, there are three verticles:
+
+* the backend verticle, which is a simple WebSocket server sending messages periodically to clients, and
+* the proxy verticle, which configures a `ReverseProxy` for WebSocket support, and
+* the client verticle, which connects a WebSocket to the proxy
+
+After starting the different parts, the client should print this message every 3 seconds:
+
+----
+Received message: Hello World
+----
+
+link:src/main/java/io/vertx/example/proxy/websocket/Backend.java[`Backend`]
+link:src/main/java/io/vertx/example/proxy/websocket/Proxy.java[`Proxy`]
+link:src/main/java/io/vertx/example/proxy/websocket/Client.java[`Client`]
diff --git a/http-proxy-examples/pom.xml b/http-proxy-examples/pom.xml
new file mode 100644
index 000000000..e18a70824
--- /dev/null
+++ b/http-proxy-examples/pom.xml
@@ -0,0 +1,38 @@
+<?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>
+
+    <parent>
+        <groupId>io.vertx</groupId>
+        <artifactId>vertx-examples</artifactId>
+        <version>5.0.0.CR2</version>
+    </parent>
+
+    <artifactId>http-proxy-examples</artifactId>
+
+    <dependencies>
+        <dependency>
+            <groupId>io.vertx</groupId>
+            <artifactId>vertx-core</artifactId>
+            <version>${project.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>io.vertx</groupId>
+            <artifactId>vertx-launcher-application</artifactId>
+            <version>${project.version}</version>
+        </dependency>
+
+        <dependency>
+            <groupId>io.vertx</groupId>
+            <artifactId>vertx-http-proxy</artifactId>
+            <version>${project.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>io.vertx</groupId>
+            <artifactId>vertx-web</artifactId>
+            <version>${project.version}</version>
+        </dependency>
+    </dependencies>
+</project>
diff --git a/http-proxy-examples/src/main/java/io/vertx/example/proxy/interception/Backend.java b/http-proxy-examples/src/main/java/io/vertx/example/proxy/interception/Backend.java
new file mode 100644
index 000000000..29be2b653
--- /dev/null
+++ b/http-proxy-examples/src/main/java/io/vertx/example/proxy/interception/Backend.java
@@ -0,0 +1,28 @@
+package io.vertx.example.proxy.interception;
+
+import io.vertx.core.Future;
+import io.vertx.core.VerticleBase;
+import io.vertx.launcher.application.VertxApplication;
+
+public class Backend extends VerticleBase {
+
+  public static void main(String[] args) {
+    VertxApplication.main(new String[]{Backend.class.getName()});
+  }
+
+  @Override
+  public Future<?> start() {
+    return vertx
+      .createHttpServer()
+      .requestHandler(req -> {
+        if (req.path().equals("/app") || req.path().startsWith("/app")) {
+          req.response()
+            .putHeader("x-internal-header", "some-internal-header-value")
+            .putHeader("content-type", "text/html")
+            .end("<html><body><h1>Hello from Vert.x!</h1></body></html>");
+        } else {
+          req.response().setStatusCode(400).end();
+        }
+      }).listen(7070);
+  }
+}
diff --git a/http-proxy-examples/src/main/java/io/vertx/example/proxy/interception/Proxy.java b/http-proxy-examples/src/main/java/io/vertx/example/proxy/interception/Proxy.java
new file mode 100644
index 000000000..1da999ecc
--- /dev/null
+++ b/http-proxy-examples/src/main/java/io/vertx/example/proxy/interception/Proxy.java
@@ -0,0 +1,43 @@
+package io.vertx.example.proxy.interception;
+
+import io.vertx.core.Future;
+import io.vertx.core.VerticleBase;
+import io.vertx.core.http.HttpClient;
+import io.vertx.core.http.HttpServer;
+import io.vertx.httpproxy.HttpProxy;
+import io.vertx.httpproxy.interceptors.BodyInterceptor;
+import io.vertx.httpproxy.interceptors.BodyTransformer;
+import io.vertx.httpproxy.interceptors.HeadInterceptor;
+import io.vertx.launcher.application.VertxApplication;
+
+import java.util.Set;
+
+public class Proxy extends VerticleBase {
+
+  public static void main(String[] args) {
+    VertxApplication.main(new String[]{Proxy.class.getName()});
+  }
+
+  @Override
+  public Future<?> start() {
+    HttpClient proxyClient = vertx.createHttpClient();
+
+    HttpProxy proxy = HttpProxy.reverseProxy(proxyClient);
+    proxy.origin(7070, "localhost");
+
+    HeadInterceptor headInterceptor = HeadInterceptor.builder()
+      .addingPathPrefix("/app")
+      .filteringResponseHeaders(Set.of("x-internal-header"))
+      .build();
+    proxy.addInterceptor(headInterceptor);
+
+    BodyTransformer responseTransformer = BodyTransformer.transformText(txt -> {
+      return txt.replace("Hello", "Hi");
+    }, "ISO-8859-1");
+    proxy.addInterceptor(BodyInterceptor.modifyResponseBody(responseTransformer));
+
+    HttpServer proxyServer = vertx.createHttpServer();
+
+    return proxyServer.requestHandler(proxy).listen(8080);
+  }
+}
diff --git a/http-proxy-examples/src/main/java/io/vertx/example/proxy/simple/Backend.java b/http-proxy-examples/src/main/java/io/vertx/example/proxy/simple/Backend.java
new file mode 100644
index 000000000..cd3c86ed9
--- /dev/null
+++ b/http-proxy-examples/src/main/java/io/vertx/example/proxy/simple/Backend.java
@@ -0,0 +1,21 @@
+package io.vertx.example.proxy.simple;
+
+import io.vertx.core.Future;
+import io.vertx.core.VerticleBase;
+import io.vertx.launcher.application.VertxApplication;
+
+public class Backend extends VerticleBase {
+
+  public static void main(String[] args) {
+    VertxApplication.main(new String[]{Backend.class.getName()});
+  }
+
+  @Override
+  public Future<?> start() {
+    return vertx
+      .createHttpServer()
+      .requestHandler(req -> {
+        req.response().putHeader("content-type", "text/html").end("<html><body><h1>Hello from Vert.x!</h1></body></html>");
+      }).listen(7070);
+  }
+}
diff --git a/http-proxy-examples/src/main/java/io/vertx/example/proxy/simple/Proxy.java b/http-proxy-examples/src/main/java/io/vertx/example/proxy/simple/Proxy.java
new file mode 100644
index 000000000..b4de67a83
--- /dev/null
+++ b/http-proxy-examples/src/main/java/io/vertx/example/proxy/simple/Proxy.java
@@ -0,0 +1,28 @@
+package io.vertx.example.proxy.simple;
+
+import io.vertx.core.Future;
+import io.vertx.core.VerticleBase;
+import io.vertx.core.http.HttpClient;
+import io.vertx.core.http.HttpServer;
+import io.vertx.httpproxy.HttpProxy;
+import io.vertx.httpproxy.ProxyOptions;
+import io.vertx.launcher.application.VertxApplication;
+
+public class Proxy extends VerticleBase {
+
+  public static void main(String[] args) {
+    VertxApplication.main(new String[]{Proxy.class.getName()});
+  }
+
+  @Override
+  public Future<?> start() {
+    HttpClient proxyClient = vertx.createHttpClient();
+
+    HttpProxy proxy = HttpProxy.reverseProxy(new ProxyOptions().setSupportWebSocket(true), proxyClient);
+    proxy.origin(7070, "localhost");
+
+    HttpServer proxyServer = vertx.createHttpServer();
+
+    return proxyServer.requestHandler(proxy).listen(8080);
+  }
+}
diff --git a/http-proxy-examples/src/main/java/io/vertx/example/proxy/websocket/Backend.java b/http-proxy-examples/src/main/java/io/vertx/example/proxy/websocket/Backend.java
new file mode 100644
index 000000000..910aa6381
--- /dev/null
+++ b/http-proxy-examples/src/main/java/io/vertx/example/proxy/websocket/Backend.java
@@ -0,0 +1,27 @@
+package io.vertx.example.proxy.websocket;
+
+import io.vertx.core.Future;
+import io.vertx.core.VerticleBase;
+import io.vertx.launcher.application.VertxApplication;
+
+public class Backend extends VerticleBase {
+
+  public static void main(String[] args) {
+    VertxApplication.main(new String[]{Backend.class.getName()});
+  }
+
+  @Override
+  public Future<?> start() {
+    return vertx
+      .createHttpServer()
+      .webSocketHandler(ws -> {
+        vertx.setPeriodic(3000, tid -> {
+          if (ws.isClosed()) {
+            vertx.cancelTimer(tid);
+            return;
+          }
+          ws.writeTextMessage("Hello World");
+        });
+      }).listen(7070);
+  }
+}
diff --git a/http-proxy-examples/src/main/java/io/vertx/example/proxy/websocket/Client.java b/http-proxy-examples/src/main/java/io/vertx/example/proxy/websocket/Client.java
new file mode 100644
index 000000000..deae3107a
--- /dev/null
+++ b/http-proxy-examples/src/main/java/io/vertx/example/proxy/websocket/Client.java
@@ -0,0 +1,25 @@
+package io.vertx.example.proxy.websocket;
+
+import io.vertx.core.Future;
+import io.vertx.core.VerticleBase;
+import io.vertx.core.http.WebSocketClient;
+import io.vertx.core.http.WebSocketConnectOptions;
+import io.vertx.launcher.application.VertxApplication;
+
+public class Client extends VerticleBase {
+
+    public static void main(String[] args) {
+        VertxApplication.main(new String[]{Client.class.getName()});
+    }
+
+    private WebSocketClient client;
+
+    @Override
+    public Future<?> start() throws Exception {
+        client = vertx.createWebSocketClient();
+        return client.connect(new WebSocketConnectOptions().setHost("localhost").setPort(8080))
+                .onSuccess(ws -> ws.textMessageHandler(msg -> {
+                    System.out.println("Received message: " + msg);
+                }));
+    }
+}
diff --git a/http-proxy-examples/src/main/java/io/vertx/example/proxy/websocket/Proxy.java b/http-proxy-examples/src/main/java/io/vertx/example/proxy/websocket/Proxy.java
new file mode 100644
index 000000000..c9bd1b745
--- /dev/null
+++ b/http-proxy-examples/src/main/java/io/vertx/example/proxy/websocket/Proxy.java
@@ -0,0 +1,27 @@
+package io.vertx.example.proxy.websocket;
+
+import io.vertx.core.Future;
+import io.vertx.core.VerticleBase;
+import io.vertx.core.http.HttpClient;
+import io.vertx.core.http.HttpServer;
+import io.vertx.httpproxy.HttpProxy;
+import io.vertx.launcher.application.VertxApplication;
+
+public class Proxy extends VerticleBase {
+
+  public static void main(String[] args) {
+    VertxApplication.main(new String[]{Proxy.class.getName()});
+  }
+
+  @Override
+  public Future<?> start() {
+    HttpClient proxyClient = vertx.createHttpClient();
+
+    HttpProxy proxy = HttpProxy.reverseProxy(proxyClient);
+    proxy.origin(7070, "localhost");
+
+    HttpServer proxyServer = vertx.createHttpServer();
+
+    return proxyServer.requestHandler(proxy).listen(8080);
+  }
+}
diff --git a/pom.xml b/pom.xml
index 23492209c..76efff267 100644
--- a/pom.xml
+++ b/pom.xml
@@ -49,6 +49,7 @@
     <module>json-schema-examples</module>
     <module>config-examples</module>
     <module>health-check-examples</module>
+    <module>http-proxy-examples</module>
   </modules>
 
   <build>