Downloading Files

[swd847]

At the moment to create a file download in SEAM it looks like you have to implement a custom servlet / filter. I was thinking it would be neat if you could just annotate an action method with an @ContentType("mimetype") annotation and return a byte array, and have seam take care of the rest?

[shane.bryzak]

Actually you can do something similar, you can just create a Seam component that extends org.jboss.seam.web.AbstractResource and implement the getResource() and getResourcePath() methods. Take a look at org.jboss.seam.captcha.CaptchaImage for an example.

[goku2]

Put this action in some Seam component.

<s:link action="{someSeamComponent.download}" value="Download"/>

And the action in SomeSeamComponent

public void download() {
 //Here you get the entity that has a byte array with the data
 SomeEntity entity = getEntityFromEntityManager();


 FacesContext facesContext = FacesContext.getCurrentInstance();
 HttpServletResponse response = (HttpServletResponse) facesContext
 .getExternalContext().getResponse();
 response.setContentType(entity.getContentType());
//Asume a data property inside entity
 byte[] data = entity.getData();
 response.setContentLength(data.length);
 response.setHeader("Content-disposition", "inline; filename=\""
 + entity.getFileName() + "\"");

 try {

 OutputStream out = response.getOutputStream();

 out.write(data);

 out.flush();
 out.close();

 facesContext.responseComplete();
 } catch (IOException ex) {
 FacesMessages.instance().add(
 "Error while downloading the file: " + entity.getFileName());
 }

 }

Cheers