How to set the contentType for JSF Content Portlet.

Question

Hi,
When I tried to get the data from data base and construct a downloadable .csv appending the html at the end of the actual csv content. Please find the below given code for reference.
JSP Code :
<f:view>
<h:form id = "test">
          <h:commandButton immediate="true" value = "Download CSV" actionListener="#{myManagedBean.downloadCSV}">
          </h:commandButton>
</h:form>
</f:view>
Managed Bean method (Listener Method):
     public void downloadCSV(ActionEvent event) {
          FacesContext.getCurrentInstance().responseComplete();
          OutputStream os = null;
          try {
               HttpServletResponse response = (HttpServletResponse) FacesContext
                         .getCurrentInstance().getExternalContext().getResponse();
               response.setHeader("Content-Disposition","attachment;filename=report.csv");
               response.setContentType("application/download");
               os = response.getOutputStream();
               StringBuffer buffer = new StringBuffer();
               //following code has to be replaced by records retrieved from database.
               for (int i = 0; i < 1000; i++) {
                    for (int j = 0; j < 100; j++) {
                         if (j == 0) {
                              buffer.append("Test " + j);
                         } else {
                              buffer.append(",").append("Test " + j);
                    buffer.append("\n");
               System.out.println("Get Content Type :==>"+response.getContentType()); // always returning text/html;
               os.write(buffer.toString().getBytes());
          } catch (Exception e) {
               e.printStackTrace();
          } finally {
               if(os != null){
                    try {
                         os.close();
                    } catch (IOException e) {
                         // TODO Auto-generated catch block
                         e.printStackTrace();
The above given code is appending the html content at the end of the actual content. I noticed one thing, even though I am setting the content type to application/download (or) text/csv when i am printing the content type it is always returning "text/html".
Thanks.

Answer 1

Hello,
The portal will not allow you to change the content-type of a single portlet's response. Since each portlet is rendered onto a single HTML page along with other portlets, the content-type of the whole page (and therefore of each portlet) must be HTML-- you can't have a different content-type for just a portion of the page.
This means that you cannot render non-HTML content for a portlet within the portal framework. However, you can render non-HTML content as a separate "resource" outside of the portal context- for example, if you create a resource URL in your portlet that points at a servlet, the servlet can serve up any content-type you wish.
The JSR329 JSF portlet bridge (and the JSR286 portlet specification it is based on) even have a special "portlet-served resource" mechanism that allows you to serve non-HTML content while still having access to all of the portal context (all of your portlet state). From the code you posted, it looks like you are not using the JSR329 portlet bridge, but you might want to take a look at it.
Kevin