Stop p:commandLink from scrolling to top of page when clicked

Question

I have a JSF2 commandlink with an image. When the image is clicked, the server will download a PDF file. While the file is downloaded after the image link is clicked, it also causes the entire page to scroll to the top of the page. the code snippet for the link is as follows:

<p:commandLink ajax="false"
        action="#{refereeAssessmentSummaryBean.stateLatestFormInPAVer(project.appId)}">
<p:graphicImage name="images/pdf.png"
            title="#{msg['label.downloadpdf']}" />
</p:commandLink>

How can I use the commandlink to download the PDF file, without the webpage scrolling to the top of the page every time I click on it?

Edit: FWIW, added PDF download code. This code is called as a shared method from the backing bean. As you can see, the code will set the content type before streaming the PDF data to the client.

public void downloadEformPdf(Integer appId, Integer revNo, Integer meetingId, 
            String password, boolean showSaveDialog, boolean getEditedIfAvailable, boolean showVersionInfo) {

    User user = WebUtils.getCurrentUser();

    PermissionResult permissionResult = ServiceProxy.getPermissionService().checkViewOnlineProposalPermission(user, appId, meetingId);

    if (permissionResult != PermissionResult.GRANTED) {

        if (!(permissionResult == PermissionResult.REJECTED_GRBE_COI_NOT_APPROVED
            || permissionResult == PermissionResult.REJECTED_GRBE_COI_NOT_DECLARED)) {
            throw new PermissionDeniedException("Permission Denied");
        } 
    }

    Application appl = ServiceProxy.getAppService().getApplication(appId);
    String scheme = appl.getScheme();

    boolean withNomination = false;
    boolean isEditedVersion = false;

    byte[] pdfData;

    if (getEditedIfAvailable) {

        if (revNo == null) {
            Appmatching appMatching = ServiceProxy.getAppFormService().getLatestAppMatching(appId,false);
            revNo = appMatching.getMainRevno();
        }

        Appattacheditedeform editedEntry = ServiceProxy.getAppService().getEditedProposalForApplication(appId, revNo, true);

        // give GRB, ER the edited version if it exists
        if (editedEntry != null) {

            Filestorage storage = editedEntry.getFilestorage();
            pdfData = storage.getContent();

            isEditedVersion = true;

        } else {

            pdfData = ServiceProxy.getReportService().getHMRFReportContentByRevNo(
                    appId.intValue(), revNo, withNomination);

        }

    } else { //Get the unedited version

        //Get latest rev no.
        if (revNo == null) {
            Appmatching appMatching = ServiceProxy.getAppFormService().getLatestAppMatching(appId,false);
            revNo = appMatching.getMainRevno();
        }

        pdfData = ServiceProxy.getReportService().getHMRFReportContentByRevNo(
                appId.intValue(), revNo, withNomination);

    }

    FacesContext context = FacesContext.getCurrentInstance();
    ExternalContext extContext = context.getExternalContext();

    extContext.responseReset();

    PDDocument doc = null;
    try {

        if (pdfData != null) {

            PDFParser parser = new PDFParser(new ByteArrayInputStream(pdfData));
            parser.parse();
            doc = parser.getPDDocument();

            AccessPermission ap = new AccessPermission();
            ap.setReadOnly();

            if (password != null) {
                StandardProtectionPolicy spp = new StandardProtectionPolicy(password, password, ap);
                spp.setEncryptionKeyLength(128);
                doc.protect(spp);
            }

            ByteArrayOutputStream bos = new ByteArrayOutputStream();
            doc.save(bos);
            doc.close();

            byte[] docbuff = bos.toByteArray();

            String refNo = appl.getRefNo();

            String filename = null;

            if (showVersionInfo) {

                if (isEditedVersion) {
                    filename = scheme.toLowerCase() + "_eform_" + refNo + "_(v" + revNo + ")_(Edited).pdf";
                } else {
                    filename = scheme.toLowerCase() + "_eform_" + refNo + "_(v" + revNo + ")_(PA).pdf";
                }
            } else {
                filename = scheme.toLowerCase() + "_eform_" + refNo + ".pdf";
            }

            extContext.setResponseContentType("application/pdf");
            extContext.setResponseContentLength(docbuff.length);
            extContext.setResponseHeader("Content-Disposition", (!showSaveDialog) ? "inline"
                    : "attachment" + "; filename=\"" + filename + "\"");

            OutputStream os = extContext.getResponseOutputStream();

            os.write(docbuff);
            os.close();

            context.responseComplete();

        } else {

            extContext.setResponseContentType("text/html");

            Writer writer = extContext.getResponseOutputWriter();
            writer.write("Cannot retrieve PDF form for this proposal.");
            writer.close();

            context.responseComplete();
        }

    } catch (IOException e) {
        logger.log(Level.ERROR, e.getMessage(), e);
    } catch (COSVisitorException e) {
        logger.log(Level.ERROR, e.getMessage(), e);
    } catch (BadSecurityHandlerException e) {
        logger.log(Level.ERROR, e.getMessage(), e);
    } finally {

    }

}

Could you provide your bean code that generates the pdf file? — MoYapro, Jun 04 '14 at 09:31
Added the download code. I can download the PDF no probs, so I don't think it's the issue. The issue is whenever I click the link, the page jumps to the top. — futureelite7, Jun 05 '14 at 02:50
Did you see my answer below futureelite7 ? i think it could help you — David H., Jun 05 '14 at 11:09

LarsBauer · Answer 1 · 2014-06-03T14:24:07.283

0

I think it's because you are using ajax=false. If you are not using ajax the whole page will be reloaded. Either remove it or change to ajax=true and give it a try.

Edit:

I was wrong. ajax=false is required when downloading files.

edited Jun 03 '14 at 14:24

answered Jun 03 '14 at 08:44

LarsBauer

1,539
18
23

The link is used to download a PDF file as attachment. As far as I know ajax needs to be false when downloading files. – futureelite7 Jun 03 '14 at 08:48
I read the documentation. You are right. So have you tried using `` instead of ``? – LarsBauer Jun 03 '14 at 14:23

score 0 · Answer 2 · answered Jun 03 '14 at 09:26

0

How do you generate the PDF? Did you set a mimetype so that the brower will recognize that you respond with a pdf? Did you also prevent primefaces from continuing the response after you have written your PDF file to it? (use facesContext.responseComplete(); for that)

answered Jun 03 '14 at 09:26

MoYapro

119
1
8

Yes, I have set the content-type and mimetype to PDF, and set response to complete after the PDF is output. – futureelite7 Jun 03 '14 at 11:58

score 0 · Answer 3 · answered Jun 03 '14 at 12:36

When you use the default HTML link tag <a />, you have to set href='javascript:void(0)' to avoid the current page to scroll to the top.

Maybe there is a way with a p:commandLink to do the same thing

<p:commandLink url="javascript:void(0)" ... /> ??

Hope this will help you to resolve your problem

Stop p:commandLink from scrolling to top of page when clicked

3 Answers3