org.directwebremoting.convert.FileConverter Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of dwr Show documentation
DWR is easy Ajax for Java. It makes it simple to call Java code directly from Javascript. It gets rid of almost all the boilerplate code between the web browser and your Java code. This version 4.0.2 works with Jakarta Servlet 4.0.2.
The newest version!
package org.directwebremoting.convert;

import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;

import javax.imageio.ImageIO;
import jakarta.servlet.http.HttpServletRequest;

import org.directwebremoting.Container;
import org.directwebremoting.ConversionException;
import org.directwebremoting.WebContextFactory;
import org.directwebremoting.extend.AbstractConverter;
import org.directwebremoting.extend.ContainerUtil;
import org.directwebremoting.extend.DataUrlDownloadManager;
import org.directwebremoting.extend.DownloadManager;
import org.directwebremoting.extend.FormField;
import org.directwebremoting.extend.InboundVariable;
import org.directwebremoting.extend.NonNestedOutboundVariable;
import org.directwebremoting.extend.OutboundContext;
import org.directwebremoting.extend.OutboundVariable;
import org.directwebremoting.io.FileTransfer;
import org.directwebremoting.io.InputStreamFactory;
import org.directwebremoting.util.BrowserDetect;
import org.directwebremoting.util.CopyUtils;
import org.directwebremoting.util.UserAgent;

/**
 * The FileConverter can only convert inbound files, convertOutbound is not
 * supported.
 * Files come from an <input type="file"/> on the client.
 * @author Lance Semmens [uklance at gmail dot com]
 * @author Joe Walker [joe at getahead dot org]
 * @author Niklas Johansson [niklas dot json at gmail dot com]
 */
public class FileConverter extends AbstractConverter {

    public Object convertInbound(Class paramType, InboundVariable data) throws ConversionException {
        if (data.isNull()) {
            return null;
        }

        try {
            final FormField formField = data.getFormField();
            if (paramType == FileTransfer.class) {
                InputStreamFactory inFactory = new InputStreamFactory() {
                    public InputStream getInputStream() throws IOException {
                        return formField.getInputStream();
                    }

                    public void close() throws IOException {
                        formField.getInputStream().close();
                    }
                };
                return new FileTransfer(formField.getName(), formField.getMimeType(), formField.getFileSize(), inFactory);
            } else if (paramType == InputStream.class) {
                return formField.getInputStream();
            } else if (paramType == BufferedImage.class) {
                return ImageIO.read(formField.getInputStream());
            } else if (paramType.isArray() && paramType.getComponentType() == Byte.TYPE) {
                InputStream in = formField.getInputStream();
                ByteArrayOutputStream out = new ByteArrayOutputStream();
                CopyUtils.copy(in, out);
                return out.toByteArray();
            }
        } catch (IOException ex) {
            throw new ConversionException(paramType, ex);
        }

        throw new ConversionException(paramType, "File conversion is not possible for a " + paramType);
    }

    public OutboundVariable convertOutbound(final Object object, OutboundContext outboundContext) throws ConversionException {
        if (object == null) {
            return new NonNestedOutboundVariable("null");
        }

        try {
            FileTransfer transfer;

            if (object instanceof BufferedImage) {
                transfer = new FileTransfer((BufferedImage) object, "png");
            } else if (object instanceof InputStream) {
                final InputStream in = (InputStream) object;
                transfer = new FileTransfer("download.dat", "binary/octet-stream", -1, new InputStreamFactory() {
                    public InputStream getInputStream() throws IOException {
                        return in;
                    }

                    public void close() throws IOException {
                        in.close();
                    }
                });
            } else if (object instanceof FileTransfer) {
                transfer = (FileTransfer) object;
            } else if (object.getClass().isArray() && object.getClass().getComponentType() == Byte.TYPE) {
                transfer = new FileTransfer("download.dat", "binary/octet-stream", (byte[]) object);
            } else {
                throw new ConversionException(object.getClass());
            }

            Container container = WebContextFactory.get().getContainer();
            boolean preferDataUrlSchema = ContainerUtil.getBooleanSetting(container, "preferDataUrlSchema", false);

            DownloadManager downloadManager;
            if (preferDataUrlSchema && isDataUrlAvailable()) {
                downloadManager = new DataUrlDownloadManager();
            } else {
                downloadManager = container.getBean(DownloadManager.class);
            }

            String url = downloadManager.addFileTransfer(transfer);
            return new NonNestedOutboundVariable(url);
        } catch (IOException ex) {
            throw new ConversionException(getClass(), ex);
        }
    }

    /**
     * Is the data: URL allowed by the current browser.
     * @return true if data: is allowed
     */
    protected boolean isDataUrlAvailable() {
        HttpServletRequest request = WebContextFactory.get().getHttpServletRequest();

        return BrowserDetect.atLeast(request, UserAgent.IE, 8) ||
               BrowserDetect.atLeast(request, UserAgent.Gecko, 20041107) ||
               BrowserDetect.atLeast(request, UserAgent.AppleWebKit, 2) ||
               BrowserDetect.atLeast(request, UserAgent.Opera, 8);
    }
}