package org.example;

import java.io.IOException;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.nio.file.FileSystem;
import java.nio.file.Files;
import java.nio.file.Path;
import com.google.common.jimfs.Configuration;
import com.google.common.jimfs.Jimfs;
import com.sun.net.httpserver.SimpleFileServer;

import static com.sun.net.httpserver.SimpleFileServer.OutputLevel;

/*
 * A Simple Web Server as in-memory server, using Jimfs.
 */
public class SWSJimFS {
    private static final InetSocketAddress LOOPBACK_ADDR =
            new InetSocketAddress(InetAddress.getLoopbackAddress(), 8080);

    /* Creates an in-memory directory hierarchy and starts a Simple Web Server
     * to serve it.
     *
     * Upon receiving a GET request, the server sends a response with a status
     * of 200 if the relative URL matches /some/thing or /some/other/thing.
     * Query parameters are ignored. The body of the response will be a directory
     * listing in html and a Content-type header will be sent with a value of
     * "text/html; charset=UTF-8".
     */
    public static void main( String[] args ) throws Exception {
        Path root = createDirectoryHierarchy();
        var server = SimpleFileServer.createFileServer(LOOPBACK_ADDR, root, OutputLevel.VERBOSE);
        server.start();
    }

    private static Path createDirectoryHierarchy() throws IOException {
        FileSystem fs = Jimfs.newFileSystem(Configuration.unix());
        Path root = fs.getPath("/");

        /* Create directory hierarchy:
         *    |-- root
         *        |-- some
         *            |-- thing
         *            |-- other
         *                |-- thing
         */

        Files.createDirectories(root.resolve("some/thing"));
        Files.createDirectories(root.resolve("some/other/thing"));
        return root;
    }
}

package org.example;

import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.nio.file.FileSystems;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.Map;
import com.sun.net.httpserver.SimpleFileServer;

import static java.nio.file.StandardOpenOption.CREATE;

/*
 * A Simple Web Server that serves the contents of a zip file system.
 */
public class SWSZipFS {
    private static final InetSocketAddress LOOPBACK_ADDR =
            new InetSocketAddress(InetAddress.getLoopbackAddress(), 8080);
    static final Path CWD = Path.of(".").toAbsolutePath();

    /* Creates a zip file system and starts a Simple Web Server to serve its
     * contents.
     *
     * Upon receiving a GET request, the server sends a response with a status
     * of 200 if the relative URL matches /someFile.txt, otherwise a 404 response
     * is sent. Query parameters are ignored.
     * The body of the response will be the content of the file "Hello world!"
     * and a Content-type header will be sent with a value of "text/plain".
     */
    public static void main( String[] args ) throws Exception {
        Path root = createZipFileSystem();
        var server = SimpleFileServer.createFileServer(LOOPBACK_ADDR, root, SimpleFileServer.OutputLevel.VERBOSE);
        server.start();
    }

    private static Path createZipFileSystem() throws Exception {
        var path = CWD.resolve("zipFS.zip").toAbsolutePath().normalize();
        var fs = FileSystems.newFileSystem(path, Map.of("create", "true"));
        assert fs != FileSystems.getDefault();
        var root = fs.getPath("/");  // root entry

        /* Create zip file system:
         *    |-- root
         *        |-- aFile.txt
         */

        Files.writeString(root.resolve("someFile.txt"), "Hello world!", CREATE);
        return root;
    }
}

package org.example;

import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.URI;
import java.nio.file.FileSystems;
import com.sun.net.httpserver.SimpleFileServer;

import static com.sun.net.httpserver.SimpleFileServer.OutputLevel;

public class SWSJRT {
    private static final InetSocketAddress LOOPBACK_ADDR =
            new InetSocketAddress(InetAddress.getLoopbackAddress(), 8080);

    public static void main( String[] args ) {
        var fs = FileSystems.getFileSystem(URI.create("jrt:/"));
        var root = fs.getPath("modules").toAbsolutePath();
        var server = SimpleFileServer.createFileServer(LOOPBACK_ADDR, root, OutputLevel.VERBOSE);
        server.start();
    }
}

$ curl -OL http://<address>:<port>/java.base/java/lang/Object.class

package org.example;

import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.nio.file.Path;
import java.util.function.Predicate;
import com.sun.net.httpserver.Headers;
import com.sun.net.httpserver.HttpHandlers;
import com.sun.net.httpserver.HttpServer;
import com.sun.net.httpserver.Request;
import com.sun.net.httpserver.SimpleFileServer;

import static com.sun.net.httpserver.SimpleFileServer.OutputLevel;

/*
 * HttpServer with a handler that combines Simple Web Server's file handler with
 * a canned response handler for DELETE requests.
 */
public class SWSHandlerWithDeleteHandler {
    private static final InetSocketAddress LOOPBACK_ADDR =
            new InetSocketAddress(InetAddress.getLoopbackAddress(), 8080);
    static final Path CWD = Path.of(".").toAbsolutePath();


    /* Creates an HttpServer with a conditional handler that combines two
     * handlers: (1) A file handler for the current working directory and
     * (2) a canned response handler for DELETE requests.
     *
     * If a DELETE request is received, the server sends a 204 response.
     * The body of the response will be empty.
     * All other requests are handled by the file handler, equivalent to the
     * previous example.
     */
    public static void main( String[] args ) throws Exception {
        var fileHandler = SimpleFileServer.createFileHandler(CWD);
        var deleteHandler = HttpHandlers.of(204, Headers.of(), "");
        Predicate<Request> IS_DELETE = r -> r.getRequestMethod().equals("DELETE");
        var handler = HttpHandlers.handleOrElse(IS_DELETE, deleteHandler, fileHandler);
    
        var outputFilter = SimpleFileServer.createOutputFilter(System.out, OutputLevel.VERBOSE);
        var server = HttpServer.create(LOOPBACK_ADDR, 10, "/", handler, outputFilter);
        server.start();
    }
}