Approach to 301 redirect the internal URL's to dynamic SEO friendly URL

This post will explain the approach to 301 redirect the internal URLs to the dynamic SEO friendly URL.

We had a scenario to display the SEO friendly URL to the user instead of displaying the internal URL for the PDP pages in eCommerce website - The SEO friendly URL is formed dynamically based on the product title and format from Hybris.

The internal product URL is - /en/test/pdp/book.html?id=123(Internal Publisher page that handles the request based on the product id)
New SEO friendly URL - /en/test/Sample_Book/book/pdp.html?id=123(Dynamic URL and should be rewritten to internal URL to process by publisher )

Whenever users access the SEO specific URL(/en/test/Sample_Book/book/pdp.html?id=123) in the browser the user should be redirected to the internal URL(/en/test/pdp/book.html?id=123) without changing the browser URL.

Also, the user should be 301 redirected to SEO friendly URL while accessing the internal URL directly from the browser.

Redirect the internal URL to the new Dynamic URL:
As the new URL is dynamic based on the product title and product format` from Hybris, the dispatcher rules cant be defined to handle the redirect from internal URL to new SEO friendly dynamic URL.

The alternative solution is to define a Request filter that will form the dynamic URL by fetching the product tile from Hybris and 301 redirect to the new URL.

import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletResponse;

import org.apache.felix.scr.annotations.sling.SlingFilter;
import org.apache.felix.scr.annotations.sling.SlingFilterScope;
import org.apache.sling.api.SlingHttpServletRequest;
import org.apache.sling.api.SlingHttpServletResponse;

@SlingFilter(label = "301 URL redirector", description = "301 URL redirector", metatype = true, generateComponent = true, // True if you want to leverage activate/deactivate
generateService = true, order = 0, scope = SlingFilterScope.REQUEST)
public class Redirect301HandlerFilter implements Filter {
@Override
public void init(FilterConfig filterConfig) throws ServletException {
}

@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
throws IOException, ServletException {

final SlingHttpServletRequest slingRequest = (SlingHttpServletRequest) request;

final SlingHttpServletResponse slingResponse = (SlingHttpServletResponse) response;
String requestPath= slingRequest.getRequestURI();
String pid = slingRequest.getParameter("pid");
if (!requestPath.contains("/pdp/") || slingRequest.getParameter("isInternalRedirect")!=null) {
chain.doFilter(request, response);
return;
}

String title = "";// Get the product title and product format from Hybris based on the pid
String format = "";//// Get the product title and product format from Hybris based on the pid

String newURL = slingRequest.getScheme() + "://" + slingRequest.getServerName() + ":"+ slingRequest.getServerPort() + "/en/test/" + title + "/" + format + "/pdp.html?pid=" + pid;

slingResponse.setStatus(HttpServletResponse.SC_MOVED_PERMANENTLY);
slingResponse.setHeader("Location", newURL);
}

@Override
public void destroy() {
// TODO Auto-generated method stub
}
}

Rewrite the SEO friendly URL to internal URL:
The SEO friendly URL is not recognized by the publisher so rewrite the SEO friendly URL to internal URL in dispatcher without changing browser URL.

Add an additional parameter isInternalRedirect while rewriting the SEO URL to internal URL from Dispatcher to avoid the redirect loop

RewriteCond %{QUERY_STRING} ^id=(.*) [NC]
RewriteRule ^/en/test/(.*)/(.*)/pdp.html$ /en/test/pdp/$2.html?isInternalRedirect=true&id=%1 [PT,L]