CODEWITHSUNDEEP
javaajaxfilewicket
developer1
developer1

Reputation: 557

Download doesn't start on button click

Can file be downloaded using 

AjaxLink<Void> downloadButton = new AjaxLink<Void>("downloadButton") { 

        @Override
        public void onClick(AjaxRequestTarget ajaxRequestTarget) {
}

? Or it can only happen with onSubmit() action? Because I have a working code of downloading a file with a button click, but that method uses onSubmit. Now I am trying to do the same action with this kind of button, it prepares the file the same way, it even creates a temporary file in my local files, but when it comes to the popup in browser it just doesn't do anything. What could be the problem?

Edit:

Here is the working code, but if I use the same code in my AjaxLink it doesn't work properly as stated before:

 @Override
        protected void onSubmit() {
            super.onSubmit();

                        File file = null;

                        try {
                            file = File.createTempFile("temp-file-name", ".csv");
                            String data = getData();
                            if (data == null) {
                                FileUtils.writeByteArrayToFile(file, ("").getBytes());
                            } else {
                                FileUtils.writeByteArrayToFile(file, data.getBytes());
                            }
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                        if (file == null) {
                            throw new IllegalStateException(getClass().getName() +
                                    " failed to retrieve a File object from model");
                        }

                        final File preparedFile = file;


                        IResourceStream resourceStream = new FileResourceStream(
                                new org.apache.wicket.util.file.File(file));
                        getRequestCycle().scheduleRequestHandlerAfterCurrent(
                                new ResourceStreamRequestHandler(resourceStream) {
                                    @Override
                                    public void respond(IRequestCycle requestCycle) {
                                        super.respond(requestCycle);
                                        Files.remove(preparedFile);
                                    }
                                }.setFileName("Report.csv")
                                        .setContentDisposition(ContentDisposition.ATTACHMENT));
                    } 
            }
        }

Upvotes: 0

Views: 621

Answers (1)

martin-g
martin-g

Reputation: 17513

You cannot just stream a file in Ajax response.

You need to use Wicket's AjaxDownloadBehavior. It provides logic to overcome this restriction.

See https://github.com/apache/wicket/blob/0ba3ce015ae9f258246b92ac599a00481a26c37f/wicket-extensions/src/main/java/org/apache/wicket/extensions/ajax/AjaxDownloadBehavior.java

Demo code: https://github.com/apache/wicket/blob/0ba3ce015ae9f258246b92ac599a00481a26c37f/wicket-examples/src/main/java/org/apache/wicket/examples/ajax/builtin/AjaxDownloadPage.java Demo in action: http://examples8x.wicket.apache.org/ajax/download

Upvotes: 2

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