Getting contents of system clipboard on headless linux server for automated testing

Question

I am trying to run some selenium cases on a headless linux system through docker in which the "user" clicks a button that copys text to the system clipboard. When I run this code, I get an error that says "No X11 DISPLAY variable was set, but this program performed an operation which requires it." I am now running the case using xvfb to account for the lack of X11 Display variable, but the code still does not work. Now, I am getting a nullpointer when trying to access the contents of the system clipboard.

Here is the code that I am running to get the copied text.

String copied = null;

    try {

        Clipboard clipboard = Toolkit.getDefaultToolkit().getSystemClipboard();
        Transferable transferable = clipboard.getContents(null);
        DataFlavor[] availableFlavors = clipboard.getAvailableDataFlavors();

        if ( transferable != null && transferable.isDataFlavorSupported(DataFlavor.stringFlavor) ) {
            copied = (String)transferable.getTransferData(DataFlavor.stringFlavor);
        } else {
            System.out.println("Could not find a suitable flavor.");
            if ( transferable.getTransferDataFlavors().length == 0 ) {
                System.out.println("no supported flavors");
            }
            for ( DataFlavor availableFlav : availableFlavors ) {
                System.out.println("availableFlav = " + availableFlav);
            }
            for ( DataFlavor flavaflav : transferable.getTransferDataFlavors() ) {
                System.out.println("transferDataFlavor = " + flavaflav);
            }
        }

    // I am not sure what could cause the below exceptions to happen, but we should just fail the case if they occur.
    } catch (IOException e) {
        e.printStackTrace();
        fail("IOException while fetching copied text.");
    } catch (UnsupportedFlavorException e) {
        e.printStackTrace();
        fail("UnsupportedFlavorException while fetching copied text.");
    }

    return copied;

Running this code with xvfb is resulting in the following output:

Could not find a suitable flavor.
no supported flavors

And then throws the NullPointerException.

Is there a way to fake a system clipboard that actually works in this headless linux server? What might be causing the system clipboard running in xvfb to have nothing copied?

Getting contents of system clipboard on headless linux server for automated testing

0 Answers0