Sling Filter - Access an asset URL with the RequestDispatcher

[julianhs2024]

Hello!

I am working in a feature about Sling Filters in AEM. I have to intercept a specific URL in AEM, e.g /en-us/abc/folder1 and without modify that URL, forward an asset URL from the DAM folder. The asset exist in the DAM folder at this location: /content/dam/myApp/test.pdf.  So here is an approach of this implementation:

public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { if (!(request instanceof SlingHttpServletRequest) || !(response instanceof SlingHttpServletResponse)) { // Not a SlingHttpServletRequest/Response, so ignore. chain.doFilter(request, response); // This line would let you // proceed to the rest of the // filters. return; } final SlingHttpServletRequest slingRequest = (SlingHttpServletRequest) request; final SlingHttpServletResponse slingResponse = (SlingHttpServletResponse) response; String tempURI = ""; //some impl here if (matchFound) { tempURI = "/content/dam/app/test.pdf"; RequestDispatcher dispatch = slingRequest.getRequestDispatcher(tempURI); dispatch.forward(slingRequest, slingResponse); return; } chain.doFilter(request, response); }

But the problem is that I get an empty or blank pdf so the asset is not loaded correctly.  I tried instead of forwarding an DAM asset go to a URL page and is working good in that case.  So, I wonder if the forward method only works for pages (contentType="text/html") and how can I do this by retrieving the asset with that filter ?

Any help will be appreciated!

Thanks

[smacdonald2008]

We will look at getting an example of this on mon. 

[julianhs2024]

smacdonald2008 wrote...

We will look at getting an example of this on mon. 

Hello, have you found something about this ?

Thanks and regards!

[julianhs2024]

Hello, I tried another scenario to get an idea about the issue that I am facing.  And when I do a forward to a image or text URL e.g:  en-us/folder1/folder2/test.jpg . I get an "You don't have permission to access to this page. Please contact the Administrator" message, so I wonder if maybe there is something else that is executing before my custom filter. I tried putting a breakpoint and debugging but after the call to 

dispatch.forward(slingRequest, slingResponse);

I get always the same error.

[smacdonald2008 · Accepted solution]

I checked with some internal Adobe ppl - this was their response: 

There is some DAM Asset filter that prevents Forwards from occurring. You *might* be able to bump that up to a Felix Servlet Filter and do something up there (might need to wrap the Request and change the URI, not sure)

Check the ACS AEM Samples page for a Felix Servlet Filter if you want to try it out.

ACS AEM Samples -- http://adobe-consulting-services.github.io/acs-aem-samples/

[Premkarthic-7WP]

Can you try with order = -700, // The smaller the number, the earlier in the Filter chain (can go negative);

Its worked for me.

@SlingFilter(generateComponent = true, generateService = true, order = -700, scope = SlingFilterScope.REQUEST)
public class SampleFilter implements Filter {

    private Logger logger = LoggerFactory.getLogger(SampleFilter.class);

    public void init(FilterConfig filterConfig) throws ServletException {
    }

    public void doFilter(ServletRequest request, ServletResponse response,
            FilterChain chain) throws IOException, ServletException {
        if (!(request instanceof SlingHttpServletRequest)
                || !(response instanceof SlingHttpServletResponse)) {
            // Not a SlingHttpServletRequest/Response, so ignore.
            chain.doFilter(request, response); // This line would let you
                                                // proceed to the rest of the
                                                // filters.
            return;
        }

        final SlingHttpServletRequest slingRequest = (SlingHttpServletRequest) request;
        final SlingHttpServletResponse slingResponse = (SlingHttpServletResponse) response;
        String tempURI = "";
        // some impl here

        logger.info("Inside sample filter {}", slingRequest
                .getRequestPathInfo().getResourcePath());

        boolean matchFound = false;

        if (slingRequest.getRequestPathInfo().getResourcePath()
                .contains("/en-us/abc/folder1")) {

            matchFound = true;
        }

        if (matchFound) {

            tempURI = "/content/dam/geometrixx/documents/GeoPyramid_Datasheet.pdf";

            RequestDispatcher dispatch = slingRequest
                    .getRequestDispatcher(tempURI);
            dispatch.forward(slingRequest, slingResponse);
            return;
        }

        chain.doFilter(request, response);
    }

    public void destroy() {
    }

}

Thanks

Prem