package io.happycoding;

import java.net.URL;
import org.eclipse.jetty.annotations.AnnotationConfiguration;
import org.eclipse.jetty.server.Handler;
import org.eclipse.jetty.server.handler.DefaultHandler;
import org.eclipse.jetty.server.Server;
import org.eclipse.jetty.servlet.DefaultServlet;
import org.eclipse.jetty.webapp.Configuration;
import org.eclipse.jetty.webapp.WebAppContext;
import org.eclipse.jetty.webapp.WebInfConfiguration;

/**
 * Starts up the server, including a DefaultServlet that handles static files,
 * and any servlet classes annotated with the @WebServlet annotation.
 */
public class ServerMain {

  public static void main(String[] args) throws Exception {

    // Create a server that listens on port 8080.
    Server server = new Server(8080);
    WebAppContext webAppContext = new WebAppContext();
    server.setHandler(webAppContext);

    // Load static content from inside the jar file.
    URL webAppDir =
        ServerMain.class.getClassLoader().getResource("META-INF/resources");
    webAppContext.setResourceBase(webAppDir.toURI().toString());

    // Enable annotations so the server sees classes annotated with @WebServlet.
    webAppContext.setConfigurations(new Configuration[]{
      new AnnotationConfiguration(),
      new WebInfConfiguration(),
    });

    // Look for annotations in the classes directory (dev server) and in the
    // jar file (live server)
    webAppContext.setAttribute(
        "org.eclipse.jetty.server.webapp.ContainerIncludeJarPattern",
        ".*/target/classes/|.*\\.jar");

    // Handle static resources, e.g. html files.
    webAppContext.addServlet(DefaultServlet.class, "/");

    // Start the server! 🚀
    server.start();
    System.out.println("Server started!");

    // Keep the main thread alive while the server is running.
    server.join();
  }
}

package io.happycoding.servlets;

import com.google.cloud.storage.Blob;
import com.google.cloud.storage.BlobId;
import com.google.cloud.storage.BlobInfo;
import com.google.cloud.storage.Storage;
import com.google.cloud.storage.StorageOptions;
import java.io.IOException;
import java.io.InputStream;
import javax.servlet.ServletException;
import javax.servlet.annotation.MultipartConfig;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.Part;

@MultipartConfig
@WebServlet("/upload")
public class UploadServlet extends HttpServlet {

  @Override
  public void doPost(HttpServletRequest request, HttpServletResponse response)
      throws ServletException, IOException {

    // Submissions can contain other types of data
    String message = request.getParameter("message");

    // Get the file chosen by the user
    Part filePart = request.getPart("image");
    String fileName = filePart.getSubmittedFileName();
    InputStream fileInputStream = filePart.getInputStream();

    // Upload the file and get its URL
    String uploadedFileUrl = uploadToCloudStorage(fileName, fileInputStream);

    // Use the URL to output some HTML
    response.setContentType("text/html;");
    response.getWriter().println("<p>Your message: " + message + "</p>");
    response.getWriter().println("<p>Your image:</p>");
    response.getWriter().println("<img src=\"" + uploadedFileUrl + "\"  />");
  }

  /** Uploads a file to Cloud Storage and returns the uploaded file's URL. */
  private static String uploadToCloudStorage(String fileName, InputStream fileInputStream) {
    String projectId = "happy-coding-gcloud";
    String bucketName = "happy-coding-gcloud.appspot.com";
    Storage storage =
        StorageOptions.newBuilder().setProjectId(projectId).build().getService();
    BlobId blobId = BlobId.of(bucketName, fileName);
    BlobInfo blobInfo = BlobInfo.newBuilder(blobId).build();
    Blob blob = storage.create(blobInfo, fileInputStream);
    return blob.getMediaLink();
  }
}