want to observe the upload percentage of a file upload from GWT.
In JavaScript you can use a XMLHttpRequest and add an event listener like this:
var oReq = new XMLHttpRequest();
oReq.upload.addEventListener("progress", updateProgress, false);
// progress on transfers from the server to the client (downloads)
function updateProgress (oEvent) {
if (oEvent.lengthComputable) {
var percentComplete = oEvent.loaded / oEvent.total;
// ...
} else {
// Unable to compute progress information since the total size is unknown
}
}
(The above code is from here.)
This is also done very easily in jQuery as:
var $request = $.ajax({
xhr: function() {
xhrNativeObject = new window.XMLHttpRequest();
//Upload progress
xhrNativeObject.upload.addEventListener("progress", function(event) { ... }
}
});
I want to do the same with GWT. I could use a RequestBuilder to send a request, but this is only a high level wrapper around the XMLHttpRequest JavaScriot object. Another possibility would be to use the GWT XMLHttpRequest class which is a JSNI wrapper of the JavaScript XMLHttpRequest.
My problem:
How can I add a progress listener to the XMLHttpRequest or the RequestBuilder?
--
You received this message because you are subscribed to the Google Groups "Google Web Toolkit" group.
To unsubscribe from this group and stop receiving emails from it, send an email to google-web-tool...@googlegroups.com.
To post to this group, send email to google-we...@googlegroups.com.
Visit this group at http://groups.google.com/group/google-web-toolkit.
For more options, visit https://groups.google.com/groups/opt_out.
To unsubscribe from this group and stop receiving emails from it, send an email to google-web-toolkit+unsub...@googlegroups.com.
private static final int PROGRESS_DELAY_MSEC = 1000;
private static final int PROGRESS_UPDATE_MSEC = 1000;
private Timer m_progressUpdateTimer;
m_progressUpdateTimer = new Timer()
{
@Override
public void run()
{
requestProgressUpdate();
}
};
m_progressUpdateTimer.schedule(PROGRESS_DELAY_MSEC);
private void requestProgressUpdate()
{
if (DEBUG)
{
Log.log(Duration.currentTimeMillis()/1000 + " requestProgressUpdate");
}
RequestBuilder builder = new RequestBuilder(GET, FILE_UPLOAD_SERVLET);
try
{
builder.sendRequest(null, new RequestCallback()
{
@Override
public void onResponseReceived(Request p_request,
Response p_response)
{
m_progress.setVisible(true);
if (p_response.getStatusCode() == Response.SC_OK)
{
String text = p_response.getText();
if (DEBUG)
m_status.setHTML(text);
if (m_progressUpdateTimer != null && text.length() > 0)
updateProgress(text);
if (DEBUG)
{
Log.log(Duration.currentTimeMillis()/1000
+ " onResponseReceived " + text + " (OK)");
}
}
else
{
String text = p_response.getStatusText();
m_status.setHTML(text);
if (DEBUG)
{
Log.log(Duration.currentTimeMillis()/1000
+ " onResponseReceived " + text + " ("+p_response.getStatusCode()+")");
}
}
if (m_progressUpdateTimer != null && isAttached())
m_progressUpdateTimer.schedule(PROGRESS_UPDATE_MSEC);
}
@Override
public void onError(Request p_request, Throwable p_e)
{
m_progress.setVisible(true);
m_status.setText(p_e.getMessage());
if (m_progressUpdateTimer != null && isAttached())
m_progressUpdateTimer.schedule(PROGRESS_UPDATE_MSEC);
if (DEBUG)
{
Log.log(Duration.currentTimeMillis()/1000
+ " onError " + p_e.getMessage());
}
}
});
}
catch (RequestException e)
{
m_progress.setVisible(true);
m_status.setText(e.getMessage());
if (DEBUG)
{
Log.log(Duration.currentTimeMillis()/1000
+ " RequestException " + e.getMessage());
}
}
}
private void updateProgress(String p_text)
{
try
{
Document xml = XMLParser.parse(p_text);
Integer item = intValue(xml, "item");
if (item == null)
{
m_progress.setItem(null);
}
else
{
// form item 1 is the id, items 2+ are the files.
String filename = null;
if (item > 1 && item - 2 < m_uploadFilelist.size())
filename = m_uploadFilelist.get(item - 2);
m_progress.setItem(filename);
}
Integer percent_complete = intValue(xml, "percent_complete");
if (percent_complete != null)
{
m_progress.setProgress(percent_complete.doubleValue());
}
if (DEBUG)
{
Integer bytes_read = intValue(xml, "bytes_read");
Integer content_length = intValue(xml, "content_length");
String progress = "Uploaded " + bytes_read + " of "
+ content_length + ": " + percent_complete + "%";
m_status.setText(progress);
}
}
catch (Exception e)
{
m_status.setText(e.getMessage());
if (DEBUG)
{
Log.log(Duration.currentTimeMillis()/1000
+ " updateProgress " + e.getMessage());
}
}
}
private Integer intValue(Document p_xml, String p_tagname)
{
try
{
NodeList list = p_xml.getElementsByTagName(p_tagname);
if (list.getLength() > 0)
{
Node node = list.item(0);
list = node.getChildNodes();
node = list.item(0);
String value = node.getNodeValue();
if (value != null)
return Integer.valueOf(value);
}
}
catch (Exception e)
{
m_status.setText(e.getMessage());
}
return null;
}
private static class UploadProgressBar extends ProgressBar
{
private String m_item;
public UploadProgressBar()
{
super();
}
public void setItem(String p_item)
{
m_item = p_item;
}
@Override
protected String generateText(double curProgress)
{
if (m_item == null)
return (int)(100 * getPercent()) + "%";
else
return m_item + " " + (int)(100 * getPercent()) + "%";
}
}
@Override
protected void doGet(HttpServletRequest p_request,
HttpServletResponse p_response)
throws ServletException, IOException
{
if (DEBUG)
System.err.println("\n" + System.nanoTime() + " doGet request "
+ p_request.getContentType() + " " + p_request.getServletPath());
HttpSession session = p_request.getSession();
if (session == null)
return;
FileUploadProgress progress =
(FileUploadProgress)session.getAttribute("progress");
if (progress == null)
return;
long bytesRead = progress.getBytesRead();
long contentLength = progress.getContentLength();
int item = progress.getItem();
p_response.setContentType("text/xml");
StringBuffer buffer = new StringBuffer();
buffer.append("<?xml version=\"1.0\"?>\n");
buffer.append("<response>\n");
buffer.append("\t<item>").append(item)
.append("</item>\n");
buffer.append("\t<bytes_read>").append(bytesRead)
.append("</bytes_read>\n");
buffer.append("\t<content_length>").append(contentLength)
.append("</content_length>\n");
long percentComplete;
if (bytesRead < contentLength && contentLength != 0)
{
percentComplete = ((100 * bytesRead) / contentLength);
}
else
{
percentComplete = 100;
session.setAttribute("progress", null);
}
buffer.append("\t<percent_complete>").append(percentComplete)
.append("</percent_complete>\n");
buffer.append("</response>\n");
PrintWriter out = p_response.getWriter();
out.println(buffer.toString());
out.flush();
out.close();
}
import org.apache.commons.fileupload.ProgressListener;
public class FileUploadProgress implements ProgressListener
{
private volatile long m_bytesRead;
private volatile long m_contentLength;
private volatile int m_item;
public FileUploadProgress()
{
super();
}
@Override
public void update(long p_bytesRead, long p_contentLength, int p_item)
{
m_bytesRead = p_bytesRead;
m_contentLength = p_contentLength;
m_item = p_item;
}
public long getBytesRead()
{
return m_bytesRead;
}
public long getContentLength()
{
return m_contentLength;
}
public int getItem()
{
return m_item;
}
}