I have a situation in a Flex web app where we use a PHP webservice to lookup, read the contents and then send the Base64 encoded data back to the Flex app as part of an XML document.The Flex app must then extract, Base64 decode the byte stream and then send it DIRECTLY to the browser user (for download) without writing the file to disk.
This all must occur on the click of a "DOWNLOAD NOW" button for example.
I have been searching but all I have been finding are examples of either downloading from a URL or actually writing the byte stream to disk, which i don't want.
I need to get the stream pushed directly to the browser. This way i can keep the files on the server protected by being outside the webspace as opposed to publicly accessible.
Can anyone help?
You can pop a ByteArray into a Loader then use FileReference to initiate the download dialog.
var file:FileReference = new FileReference();
var loader:Loader = new Loader();
//put loader in binary mode
loader.dataFormat = URLLoaderDataFormat.BINARY;
loader.addEventListener(Event.COMPLETE, loader_completeHandler);
//I will assume you are getting an appropriate ByteArray from your stream
var data:ByteArray = new ByteArray();
loader.loadBytes(data);
private function loader_completeHandler(evt:Event):void {
//now pop a save window
file.save(loader.data,"default_file_name.png")
}
edit
I will also assume you are doing this to stream a file through a non standard protocol, such as AMF, otherwise you would simply output the file over HTTP and let the browser handle the rest.
Related
I m trying to use Google Image service and I m trying out the follwing example to resize an image.
import com.google.appengine.api.images.Image;
import com.google.appengine.api.images.ImagesService;
import com.google.appengine.api.images.ImagesServiceFactory;
import com.google.appengine.api.images.Transform;
// ...
byte[] oldImageData; // ...
ImagesService imagesService = ImagesServiceFactory.getImagesService();
Image oldImage = ImagesServiceFactory.makeImage(oldImageData);
Transform resize = ImagesServiceFactory.makeResize(200, 300);
Image newImage = imagesService.applyTransform(resize, oldImage);
byte[] newImageData = newImage.getImageData();
I m stuck at the point where I need to store the byte[] newImageData to a jpg file in google cloud storage. I know how to create a txt file but not a jpg.
Anybody could help me please?
As far as I know GAE operates with bytes. The source/destination of the image data (your jpg) can be: URL connection, DataStore BLOB or BlobStorage.
Don't forget you have to use pure Java.There can be several ways:
First try to use Jimi - it's pure Java library for working with images.Rather simple.
Also there exists an alpha version of the appengine-awt library:https://code.google.com/p/appengine-awt/source/checkout
It will allow you to use standard BufferedImage but there are a lot of bugs in it, so may be some problems.
But you still can use standard GAE Api for Images.There is an Image interface in which nested class Image.Format specified JPEG format.Method setImageData(byte[] data) will be useful for you.
Here is documentation on it: https://developers.google.com/appengine/docs/java/javadoc/com/google/appengine/api/images/Image#setImageData(byte[])
everyone!
I have a trouble. I tried to save excel file in jsf web application.
I generated file by my utils and trying to get "save" window, but I failed.
Here is my code:
<div>
<h:commandButton value="Apply" actionListener="#{hornPhonesBean.generateReport}"/>
</div>
and:
public void generateReport(ActionEvent event) {
System.out.println("GENERATE REPORT FROM = " + this.dateFrom + "; TO = " + this.dateTo);
try {
XSSFWorkbook workbook = (XSSFWorkbook) HornReportGenerator.getWorkbook(null, null);
String fileName = "1.xlsx";
FacesContext fc = FacesContext.getCurrentInstance();
ExternalContext ec = fc.getExternalContext();
// Some JSF component library or some Filter might have set some headers in the buffer beforehand. We want to get rid of them, else it may collide.
ec.responseReset();
// Check http://www.w3schools.com/media/media_mimeref.asp for all types. Use if necessary ExternalContext#getMimeType() for auto-detection based on filename.
ec.setResponseContentType("application/vnd.ms-excel");
// Set it with the file size. This header is optional. It will work if it's omitted, but the download progress will be unknown.
//ec.setResponseContentLength(contentLength);
// The Save As popup magic is done here. You can give it any file name you want, this only won't work in MSIE, it will use current request URL as file name instead.
ec.setResponseHeader("Content-Disposition", "attachment; filename=\"" + fileName + "\"");
OutputStream output = ec.getResponseOutputStream();
workbook.write(output);
output.flush();
output.close();
fc.responseComplete(); // Important! Otherwise JSF will attempt to render the response which obviously will fail since it's already written with a file and closed.
System.out.println("END");
} catch (Exception e) {
e.printStackTrace();
}
}
I read suggestions here and from another forums - everyone says I shouldnt use , but I didn't use it at all.
Then I thought that the problem could be in the
<ice:form>,
where I kept the
<h:commandButton>,
and I changed to
<h:form>,
but it didn't help.
Maybe the problem in the request - it has header Faces-Request partial/ajax. But I am not sure.
Please give me some ideas - I already spent 4 hours for this crazy jsf download issue)
Maybe the problem in the request - it has header Faces-Request partial/ajax. But I am not sure.
This suggests that the request is an ajax request. You can't download files by ajax. Ajax requests are processed by JavaScript which has for obvious security reasons no facilities to programmatically pop a Save As dialogue nor to access/manipulate client's disk file system.
Your code snippet does however not show that you're using ajax. Perhaps you oversimplified it too much or you're using ICEfaces which silently auto-enables ajax on all standard JSF command components.
In any case, you need to make sure that it's not sending an ajax request.
See also:
How to provide a file download from a JSF backing bean?
ICEfaces libary in classpath prevents Save As dialog from popping up on file download
I have the following requirement for a business application:
(All of this could be on local or server)
Allow user to select folder location
Show contents of folder
Print selected items from folder (*.pdf)
Display which files have been printed
Potentially move printed files to new location (sub-folder of printed)
How can I make this happen in Silverlight?
Kind regards,
ribald
First of all, all but the last item can be done (the way you expect). Due to security protocols, silverlight cannot access the user's drive and manipulate it. The closest you can get is accessing silverlight's application storage which will be of no help to you whatsoever in this case. I will highlight how to do the first 4 items.
Allow user to select folder location & Show contents of folder
public void OnSelectPDF(object sender)
{
//create the open file dialog
OpenFileDialog ofg = new OpenFileDialog();
//filter to show only pdf files
ofg.Filter = "PDF Files|*.pdf";
ofg.ShowDialog();
byte[] _import_file = new byte[0];
//once a file is selected proceed
if (!object.ReferenceEquals(ofg.File, null))
{
try
{
fs = ofg.File.OpenRead();
_import_file = new byte[fs.Length];
fs.Read(_import_file, 0, (int)fs.Length);
}
catch (Exception ex)
{
}
finally
{
if (!object.ReferenceEquals(fs, null))
fs.Close();
}
//do stuff with file - such as upload the file to the server
};
}
If you noticed, in my example, once the file is retrieved, i suggest uploading it to a webserver or somewhere with temporary public access. I would recommend doing this via a web service. E.g
//configure the system file (customn class)
TSystemFile objFile = new TNetworkFile().Initialize();
//get the file description from the Open File Dialog (ofg)
objFile.Description = ofg.File.Extension.Contains(".") ? ofg.File.Extension : "." + ofg.File.Extension;
objFile.FileData = _import_file;
objFile.FileName = ofg.File.Name;
//upload the file
MasterService.ToolingInterface.UploadTemporaryFileAsync(objFile);
Once this file is uploaded, on the async result, most likely returning the temporary file name and upload location, I would foward the call to some javascript method in the browser for it to use the generic "download.aspx?fileName=givenFileName" technique to force a download on the users system which would take care of both saving to a new location and printing. Which is what your are seeking.
Example of the javascript technique (remember to include System.Windows.Browser):
public void OnInvokeDownload(string _destination)
{
//call the browser method/jquery method
//(I use constants to centralize the names of the respective browser methods)
try
{
HtmlWindow window = HtmlPage.Window;
//where BM_INVOKE_DOWNLOAD is something like "invokeDownload"
window.Invoke(Constants.TBrowserMethods.BM_INVOKE_DOWNLOAD, new object[] { _destination});
}
catch (Exception ex) { System.Diagnostics.Debug.WriteLine(ex.ToString()); }
}
Ensure you have the javascript method existing either in an included javaScript file or in the same hosting page as your silverlight app. E.g:
function invokeDownload(_destination) {
//some fancy jquery or just the traditional document.location change here
//open a popup window to http://www.myurl.com/downloads/download.aspx? fileName=_destination
}
The code for download.aspx is outside the scope of my answer, as it varies per need and would just lengthen this post (A LOT MORE). But from what I've given, it will "work" for what you're looking for, but maybe not in exactly the way you expected. However, remember that this is primarily due to silverlight restrictions. What this approach does is rather than forcing you to need a pluging to view pdf files in your app, it allows the user computer to play it's part by using the existing adobe pdf reader. In silverlight, most printing, at least to my knowledge is done my using what you call and "ImageVisual" which is a UIElement. To print a pdf directly from silverlight, you need to either be viewing that PDF in a silverlight control, or ask a web service to render the PDF as an image and then place that image in a control. Only then could you print directly. I presented this approach as a lot more clean and direct approach.
One note - with the temp directory, i would recommend doing a clean up by some timespan of the files on the server side everytime a file is being added. Saves you the work of running some task periodically to check the folder and remove old files. ;)
I'm working with a ComponentOne (C1) silverlight PDF viewer control.
It has a "LoadDocument" method that accepts a "Stream".
I'm making an HTTP get call from my client app to get a PDF document.
This document, on the server side, has been streamed in through File.ReadAllBytes(), then converted to a base64 string using Convert.ToBase64String().
This string is sent across the wire back to my silverlight app where it's then reversely converted back into a byte array with Convert.FromBase64String(val).
Then I'm creating a MemoryStream with that byte array and passing "LoadDocument()" that memory stream.
The viewer is rendering nothing. It shows the toolbar and scrollbars, but the contents are blank and the save button is grayed out, suggesting that no document loaded.
I know for certain the file made it across because the byte array size on the client matches teh byte array pre-conversion on the server side.
Here's my code: (in the interest of time/space, i've truncated, removing validation, etc.)
SERVERSIDE
string sendingToClient = Convert.ToBase64String(File.ReadAllBytes(filePath))
CLIENTSIDE
byte[] image = null;
image = Convert.FromBase64String(stringFromServerCall);
MemoryStream stream = new MemoryStream(image);
docViewer.LoadDocument(stream);
edit As a potential workaround, I attempted to save the file into isolated storage with a ".pdf" extension. Then I use the IsolatedStorageFileStream to send to LoadDocument().
I've come to an actual error, it now says "PdfParserException was unhandled by user code: invalid file format (missing pdf header)"
Can anyone shed some light on this PDF header?
Here is an experiment I would conduct.
Add a button to your Xaml and on click use OpenFileDialog to get a FileInfo. From that FileInfo use its Open method to get a stream and pass that to docViewer.LoadDocument.
Now run it, click the button and select the same PDF document you are trying to send from the server.
If that succeeds you need to continue investigating your server streaming strategy. On the other hand if you still have the same problem, well it doesn't get more raw than that. Try other PDF files and start investigating the PDF component. Have you ever actually used it successfully, if so how does this current usage differ.
you should get the stream pointer back to 0 ,so this should do the trick
byte[] image = null;
image = Convert.FromBase64String(stringFromServerCall);
MemoryStream stream = new MemoryStream(image);
stream.Position = 0;
docViewer.LoadDocument(stream);
I have a Silverlight app where I want to do an export of some data. The file output format is most likely going to be PDF or Word. But let's assume I can generate the file contents appropriately. I want to be able to pop up a Save dialog for the user to save this data or open it directly in the program.
Now obviously I could just launch the user to a URL and do the export on the server, and change the MIME type of the response to be either Word or PDF. This would work just fine. However, the sticking point is that I already have the correct data on the client (including complex filters and the like) and recreating this data set on the server just to send it back to the client again seems silly if I can avoid it.
Is there any way to take an existing set of data in Silverlight and generate a Word or PDF file and get it onto the user's computer? I could also do it from JavaScript using browser interop from Silverlight. I don't want to use out-of-browser Silverlight.
You need to use the SaveFileDialog class. Note that due to Silverlight's security settings, the SaveFileDialog needs to be opened as the result of a user event (e.g., a button click).
The dialog can be configured (if you want) using properties such as DefaultExt or Filter before you display it using the ShowDialog() method.
The ShowDialog() method will return true if the user correctly specified a file and clicked OK. If this is the case, you can then call the SaveFileDialog.OpenFile() method to access this file and write your data to it.
Example:
private void Button_Click(object sender, EventArgs e)
{
SaveFileDialog saveDialog = new SaveFileDialog();
if (saveDialog.ShowDialog())
{
System.IO.Stream fileStream = textDialog.OpenFile();
System.IO.StreamWriter sw = new System.IO.StreamWriter(fileStream);
sw.Write("TODO: Generate the data you want to put in your file");
sw.Flush();
sw.Close();
}
}