Download

Since 1.1.0

We usually perform file downloading through Filedownload when some events are triggered . Following is a typical example of downloading a file:

download.zul

<zk>
	<div apply="DownloadComposer">
		<button id="btn" label="download" />
	</div>
</zk>

DownloadComposer.java

public class DownloadComposer extends GenericForwardComposer {
	@Listen("onClick=#btn")
	public void download() throws IOException {
		Filedownload.save("/hello.txt", "application/octet-stream");
	}
}

The download mechanism is a process containing two steps. When you invoke save(), the Filedownload simply notifies ZK client engine of the download URL. Then, ZK client engine downloads such file according to the referred URL.

Notes

Download files in a ZATS Mimic test case

In order to simulate the behaviour of ZK client engine, ZATS Mimic introduces the Resource interface which represents a downloadable resource file saved at the server. Typical steps for testing whether a ZUL containing download features are as follows:

1. perform some operations through operation agents
2. check presence of a downloadable resource through desktop agent
3. fetch and verify the information or content of the resource

@Test
public void test() throws Exception {
	DesktopAgent desktop = Zats.newClient().connect("/download.zul");
	Assert.assertNull(desktop.getDownloadable());
	desktop.query("#btn").click();
	Resource resource = desktop.getDownloadable();
	Assert.assertNotNull(resource);
	Assert.assertEquals("hello.txt", resource.getName());
	String content = fetchContent(resource.getInputStream());
	Assert.assertEquals("Hello world!", content);
}

• Line 14-16: Since ZATS Mimic handles the response from ZK application automatically, we can retrieve current downloadable resource files from DesktopAgent.getDownloadable(). If the method returns a null when attempting to retrieve downloadable resources, it indicates that there are no downloadable resources after the previous operation.
• Line 17-19: We can get more information from Resource, or fetch the content of resource files in binary through the input stream.