/* * Copyright 2018 Viritin. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.vaadin.firitin; import com.vaadin.flow.component.button.Button; import com.vaadin.flow.component.html.Anchor; import com.vaadin.flow.component.html.AttachmentType; import com.vaadin.flow.component.icon.VaadinIcon; import com.vaadin.flow.component.notification.Notification; import com.vaadin.flow.component.orderedlayout.VerticalLayout; import com.vaadin.flow.router.Route; import com.vaadin.flow.server.streams.DownloadEvent; import com.vaadin.flow.server.streams.DownloadHandler; import org.vaadin.firitin.components.button.VButton; import java.io.ByteArrayOutputStream; import java.io.ObjectOutputStream; import java.io.OutputStream; import java.net.URLEncoder; import java.nio.charset.StandardCharsets; import java.nio.file.Files; import java.nio.file.Path; import java.time.LocalDateTime; /** * Vaadin 24.8 and later should make DynamicFileDownloader obsolete. This class * contains examples of how to use new core features instead of DynamicFileDownloader. * @author mstahv */ @Route public class DynamicFileDownloadingDemoWithFlowAnchor extends VerticalLayout { private boolean cancelled = false; private Anchor actaulButtonLikeDownloadButton = null; private Anchor downloadThatNotifiesWhenReady; public DynamicFileDownloadingDemoWithFlowAnchor() { Anchor downloadButton = new Anchor((DownloadEvent event) -> { event.setFileName("foobar.txt"); try (OutputStream outputStream = event.getOutputStream()) { // Write data to the output stream outputStream.write("HelloWorld".getBytes()); } event.getUI().access(() -> { /* UI updates */}); }, "Download foobar.txt"); add(downloadButton); add(new Button("Toggle attached", e->{ if(downloadButton.isAttached()) { remove(downloadButton); } else { add(downloadButton); } })); add(new Button("Toggle enabled", e->{ downloadButton.setEnabled(!downloadButton.isEnabled()); })); // This generates download with VaadinIcons.DOWNLOAD icon // Doable, but a bit nasty without constructors and button-like behavior Anchor veryBasic = new Anchor(){{ setHref((DownloadEvent event) -> { event.getOutputStream().write("content".getBytes()); }, AttachmentType.DOWNLOAD); // This should be the default!! add(new VButton(VaadinIcon.DOWNLOAD).withTooltip("Download a file...")); }}; add(veryBasic); Anchor downloadFromIcon = new Anchor(){{ setHref((DownloadEvent event) -> { event.setFileName("foobaröä.txt"); event.getOutputStream().write("HelloWorld".getBytes()); }, AttachmentType.DOWNLOAD); add(VaadinIcon.DROP.create()); }}; add(downloadFromIcon); Anchor downloadButton2 = new Anchor((DownloadEvent event) -> { event.setFileName(LocalDateTime.now() + "foobaröä.txt"); event.getRequest().setAttribute("foo", "bar"); event.setContentType("text/plain"); event.getOutputStream().write("HelloWorld".getBytes()); }, "Download file with timestamp in name"); add(downloadButton2); add(new Button("Ping", e-> Notification.show("Pong"))); downloadThatNotifiesWhenReady = new Anchor((DownloadEvent event) -> { event.getUI().access(() -> { // Note, this is not executed without Push or Polling, on by default in Viritin test app Notification.show("Download is now started, but it might take time (artificial slowness for demo)."); }); event.setFileName("foobar.txt"); OutputStream outputStream = event.getOutputStream(); outputStream.write("HelloWorld".getBytes()); try { Thread.sleep(10*1000); } catch (InterruptedException e) { throw new RuntimeException(e); } outputStream.write("Remainings...".getBytes()); event.getUI().access(() -> { // Note, this is not executed without Push or Polling Notification.show("Download is now finished"); // you could do something else here as well, like removing the downloader remove(downloadThatNotifiesWhenReady); }); }, "Download that notifies the UI when finished"); /* * TODO, figure out if this can be down with Flow Anchor (without push) * TransferProgressListener is kind of for this, but don't know how to hook it to * dynamically generated download and does NOT work without push or polling. * It also complicates usage quite a bit. downloadThatNotifiesWhenRead.addDownloadStartedListener(e-> { Notification.show("Download is now started, but it might take time (artificial slowness for demo)."); }); downloadThatNotifiesWhenReady.addDownloadFinishedListener(e->{ Notification.show("Download is now finished"); // you could do something else here as well, like removing the downloader remove(downloadThatNotifiesWhenReady); }); */ add(downloadThatNotifiesWhenReady); // No support for "disableOnClick" in Flow Anchor, so this is a workaround // Note, this only works with Push or Polling enabled, otherwise the UI is not updated var disableOnClick = new Anchor((DownloadHandler) event -> { event.getUI().access(() -> { // eh..., well, not a problem if one creats a proper custom class... ((Anchor) event.getOwningComponent()).setEnabled(false); }); event.getOutputStream().write("HelloWorld".getBytes()); new Thread() { @Override public void run() { try { Thread.sleep(10000); } catch (InterruptedException ex) { ex.printStackTrace(); } event.getUI().access(() -> { // This is executed after 10 seconds, so the download button is enabled again ((Anchor) event.getOwningComponent()).setEnabled(true); }); } }.start(); }, "Allow just one download per 10 secs"); add(disableOnClick); actaulButtonLikeDownloadButton = new Anchor() {{ setHref((DownloadHandler) downloadEvent -> { OutputStream outputStream = downloadEvent.getOutputStream(); outputStream.write("HelloWorld".getBytes()); try { Thread.sleep(4000); } catch (InterruptedException e) { e.printStackTrace(); } outputStream.write("HelloWorld".getBytes()); if(true) throw new RuntimeException("Die"); // TODO figure out what happens here. With DynamicFileDownloader on Safari // one gets half of the file, but with Flow Anchor it seems to get an error pages outputStream.write("HelloWorld".getBytes()); }, AttachmentType.DOWNLOAD); add(new VButton(VaadinIcon.DOWNLOAD).withText("Download foobar.txt (should fail in Chrome)")); }}; // Not supported in Flow Anchor easily /* actaulButtonLikeDownloadButton.setDisableOnClick(true); actaulButtonLikeDownloadButton.addDownloadFinishedListener(e -> { actaulButtonLikeDownloadButton.setEnabled(true); }); */ add(actaulButtonLikeDownloadButton); var interruptable = new Anchor((DownloadHandler) downloadEvent -> { downloadEvent.setFileName("foobar.txt"); OutputStream outputStream = downloadEvent.getOutputStream(); for (int i = 0; i < 10; i++) { if (cancelled) { // TODO same as above, should return half generated content vs. error page !? // Is something buffering the output stream? If so, it might eat up a lot of memory? // Chrome handles this "correctly" just shows an error in the downloads dialog // both with Flow Anchor and DynamicFileDownloader throw new RuntimeException("Die"); } outputStream.write("HelloWorld".getBytes()); try { Thread.sleep(1000); } catch (InterruptedException e) { throw new RuntimeException(e); } } }, "Download foobar.txt (interrupt-able)"); Button b = new Button("Cancel file generation"); b.addClickListener( e -> { cancelled = true; }); add(interruptable, b); var withError = new Anchor((DownloadHandler) downloadEvent -> { downloadEvent.setFileName("foobar.txt"); // This will throw an exception and the file will not be generated throw new RuntimeException("Fail on purpose!"); }, "Download that fails"); // No failed listener in Flow Anchor, so only option is to use Push or Polling // and override error handler. /* withError.addDownloadFailedListener(e -> { Notification.show(e.getException().getMessage() +" Note, file may have been generated on some browsers. Chrome should not do it."); }); */ add(withError); var inNewWindow = new Anchor(){{ add(new Button("\"Download\" a txt file in a new window")); setHref((DownloadHandler) downloadEvent -> { downloadEvent.setContentType("text/plain"); // INLINE only works with Firefox, so this is a workaround to make Safari and Chrome // to show content in the browser window... // When looking at the implementation, not reflected to headers at all, but only affects anchor attributs !?? // And When looking at the implementation, it seems we don't use UTF-8 encoding for the filename, causes issues with soma non-ASCII characters in filename downloadEvent.getResponse().setHeader("Content-Disposition","filename*=UTF-8''" + URLEncoder.encode("generated.txt", StandardCharsets.UTF_8)); OutputStream outputStream = downloadEvent.getOutputStream(); // Override the content disposition header, only FF works with INLINE outputStream.write("HelloWorld".getBytes()); }, AttachmentType.INLINE); setTarget("_blank"); }}; add(inNewWindow); var pdfInNewWindow = new Anchor(){{ setText("\"Download\" a pdf file in a new window"); setHref((DownloadHandler) downloadEvent -> { downloadEvent.setContentType("application/pdf"); downloadEvent.getResponse().setHeader("Content-Disposition","filename*=UTF-8''" + // NOTE, should do like encodeRfc5987Filename() in DynamicFileDownloader URLEncoder.encode("inlöäöäineشريط.pdf", StandardCharsets.UTF_8)); OutputStream outputStream = downloadEvent.getOutputStream(); Files.copy(Path.of("src/test/resources/pdf.pdf"), outputStream); }, AttachmentType.INLINE); setTarget("_blank"); }}; add(pdfInNewWindow); if(true) { add(new Button("Test UI serialization", event -> { ByteArrayOutputStream bout = new ByteArrayOutputStream(); try { new ObjectOutputStream(bout).writeObject(DynamicFileDownloadingDemoWithFlowAnchor.this); // This seems to be broken in Vaadin 24.8 (maybe earlier), so not using it for now // Throws some UI not found exception 🤯 //Notification.show("UI successfully serialized"); } catch (Exception e) { throw new RuntimeException(e); } })); } } }