From d57e9170056480ca71267957325cf469b09fbdc3 Mon Sep 17 00:00:00 2001
From: bsorrentino <bartolomeo.sorrentino@gmail.com>
Date: Mon, 8 Jul 2024 23:23:04 +0200
Subject: [PATCH] feat: add http streaming support

---
 jetty/pom.xml                                 | 75 +++++++++++++++++++
 .../bsc/langgraph4j/JettyStreamingServer.java | 74 ++++++++++++++++++
 jetty/src/main/webapp/streaming.html          | 33 ++++++++
 pom.xml                                       |  1 +
 4 files changed, 183 insertions(+)
 create mode 100644 jetty/pom.xml
 create mode 100644 jetty/src/main/java/org/bsc/langgraph4j/JettyStreamingServer.java
 create mode 100644 jetty/src/main/webapp/streaming.html

diff --git a/jetty/pom.xml b/jetty/pom.xml
new file mode 100644
index 0000000..92513a8
--- /dev/null
+++ b/jetty/pom.xml
@@ -0,0 +1,75 @@
+<?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>
+    <parent>
+        <groupId>org.bsc.langgraph4j</groupId>
+        <artifactId>langgraph4j-parent</artifactId>
+        <version>1.0-SNAPSHOT</version>
+    </parent>
+
+    <artifactId>jetty</artifactId>
+
+    <packaging>war</packaging>
+    <name>Servlet 3 Webapp with Jetty Plugin</name>
+
+    <properties>
+        <maven.compiler.source>1.8</maven.compiler.source>
+        <maven.compiler.target>1.8</maven.compiler.target>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <jetty.version>12.0.11</jetty.version>
+    </properties>
+
+    <dependencyManagement>
+        <dependencies>
+        </dependencies>
+    </dependencyManagement>
+
+    <dependencies>
+
+<!--
+        <dependency>
+            <groupId>javax.servlet</groupId>
+            <artifactId>javax.servlet-api</artifactId>
+            <version>3.0.1</version>
+            <scope>provided</scope>
+        </dependency>
+-->
+
+        <dependency>
+            <groupId>org.eclipse.jetty</groupId>
+            <artifactId>jetty-server</artifactId>
+            <version>${jetty.version}</version>
+        </dependency>
+
+        <!-- https://mvnrepository.com/artifact/org.eclipse.jetty.ee10/jetty-ee10-servlet -->
+        <dependency>
+            <groupId>org.eclipse.jetty.ee10</groupId>
+            <artifactId>jetty-ee10-servlet</artifactId>
+            <version>${jetty.version}</version>
+        </dependency>
+
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter</artifactId>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.codehaus.mojo</groupId>
+                <artifactId>exec-maven-plugin</artifactId>
+                <version>3.3.0</version>
+                <executions>
+                    <execution><goals><goal>java</goal></goals></execution>
+                </executions>
+                <configuration>
+                    <mainClass>org.bsc.langgraph4j.JettyStreamingServer</mainClass>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+</project>
diff --git a/jetty/src/main/java/org/bsc/langgraph4j/JettyStreamingServer.java b/jetty/src/main/java/org/bsc/langgraph4j/JettyStreamingServer.java
new file mode 100644
index 0000000..fad0a78
--- /dev/null
+++ b/jetty/src/main/java/org/bsc/langgraph4j/JettyStreamingServer.java
@@ -0,0 +1,74 @@
+package org.bsc.langgraph4j;
+
+import jakarta.servlet.ServletException;
+import jakarta.servlet.http.HttpServlet;
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+import org.eclipse.jetty.ee10.servlet.ServletContextHandler;
+import org.eclipse.jetty.ee10.servlet.ServletHolder;
+import org.eclipse.jetty.server.Handler;
+import org.eclipse.jetty.server.Server;
+import org.eclipse.jetty.server.ServerConnector;
+import org.eclipse.jetty.server.handler.ResourceHandler;
+import org.eclipse.jetty.util.resource.ResourceFactory;
+
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.concurrent.TimeUnit;
+
+public class JettyStreamingServer {
+
+    public static void main(String[] args) throws Exception {
+        Server server = new Server();
+        ServerConnector connector = new ServerConnector(server);
+        connector.setPort(8080);
+        server.addConnector(connector);
+
+        ResourceHandler resourceHandler = new ResourceHandler();
+        Path publicResourcesPath = Paths.get( "jetty", "src", "main", "webapp" );
+        resourceHandler.setBaseResource(ResourceFactory.of(resourceHandler).newResource(publicResourcesPath));
+        resourceHandler.setDirAllowed(true);
+
+        ServletContextHandler context = new ServletContextHandler(ServletContextHandler.SESSIONS);
+        context.setContextPath("/");
+        // Add the streaming servlet
+        context.addServlet(new ServletHolder(new StreamingServlet()), "/stream");
+
+        Handler.Sequence handlerList = new Handler.Sequence(resourceHandler, context );
+
+        server.setHandler(handlerList);
+
+        server.start();
+        server.join();
+    }
+
+    public static class StreamingServlet extends HttpServlet {
+        @Override
+        protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+            response.setContentType("text/plain");
+            response.setCharacterEncoding("UTF-8");
+
+            final PrintWriter writer = response.getWriter();
+
+            // Start asynchronous processing
+            request.startAsync();
+
+            // Simulate a long-running process
+            new Thread(() -> {
+                try {
+                    for (int i = 0; i < 10; i++) {
+                        writer.println("Line " + i);
+                        writer.flush();
+                        TimeUnit.SECONDS.sleep(1);
+                    }
+                } catch (InterruptedException e) {
+                    Thread.currentThread().interrupt();
+                } finally {
+                    writer.close();
+                }
+            }).start();
+        }
+    }
+}
\ No newline at end of file
diff --git a/jetty/src/main/webapp/streaming.html b/jetty/src/main/webapp/streaming.html
new file mode 100644
index 0000000..e4a562b
--- /dev/null
+++ b/jetty/src/main/webapp/streaming.html
@@ -0,0 +1,33 @@
+<html>
+<title>streaming</title>
+<head>
+</head>
+
+<body>
+<script>
+async function* streamingFetch( fetchcall ) {
+
+    const response = await fetchcall();
+    // Attach Reader
+    const reader = response.body.getReader();
+    while (true) {
+        // wait for next encoded chunk
+        const { done, value } = await reader.read();
+         // check if stream is done
+        if (done) break;
+        // Decodes data chunk and yields it
+        yield (new TextDecoder().decode(value));
+    }
+}
+
+(async () => {
+
+    for await ( let chunk of streamingFetch( () => fetch('http://localhost:8080/stream') ) ) {
+        console.log( chunk )
+    }
+
+})();
+</script>
+
+</body>
+</html>
\ No newline at end of file
diff --git a/pom.xml b/pom.xml
index a13b829..6c659ea 100644
--- a/pom.xml
+++ b/pom.xml
@@ -33,6 +33,7 @@
     <module>agent-executor</module>
     <module>image-to-diagram</module>
     <module>adaptive-rag</module>
+    <module>jetty</module>
   </modules>
 
   <dependencyManagement>