Question

I would like to add the lng parameter to all the links. How can I do that without using

<f:param name="lng" .... 

in every link? The value of lng is in a session scoped bean.

Maybe a Filter can do that, but in this case how can I access the value without injection?

Answer 1

So just looking to the URLRewrite filter i found the solution.

I code a filter that override the response, and the encodeURL method.

The doFilter method, that detect if there is a lng param on the request and if not it gets the default lng value from the bean in the getDefaultLng method:

public void doFilter(ServletRequest request, ServletResponse response,
        FilterChain chain) throws IOException, ServletException {
    final HttpServletRequest hsRequest = (HttpServletRequest) request;
    final HttpServletResponse hsResponse = (HttpServletResponse) response;
    if (hsRequest.getParameter("lng")!=null){
        lng = hsRequest.getParameter("lng");
    }  else {
        lng = getDefaultlng(hsRequest, hsResponse);
    }
    LngResponse lngResponse = new LngResponse(hsResponse,lng);
    chain.doFilter(hsRequest, lngResponse);
}

An the LngResponse#encodeURL that just adds the param.

public String encodeURL(String s) {
    s = parseUrl(s);
    return super.encodeURL(s);
}

private String parseUrl(String s){
    if (s.indexOf("lng=")==-1){
        if (s.indexOf("?")>-1){
            s = s+"&lng="+this.lng;
        } else {
            s = s+"?lng="+this.lng;
        }
    }
    return s;
}

Finally it works, so our SEO department has their unique URI’s.