package com.redneck.scriptedfilter.servlet;

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


import bsh.Interpreter;

public class BeanShellServletFilter implements javax.servlet.Filter {

    private javax.servlet.FilterConfig filterConfig;
    private Interpreter bshEngine;

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

        filterConfig.getServletContext().log("BeanShellServletFilter:: doFilter()");

        String preChainBshScript = "BSHServletFilter_PRE.bsh";
        String postChainBshScript = "BSHServletFilter_POST.bsh";

        try {
            bshEngine.set("request", request);
            bshEngine.source(preChainBshScript);
            request = (ServletRequest) bshEngine.get("request");
        } catch (bsh.EvalError e) {
            //for now just print it and move on
            // Don't want this filter to stop flow of chain or 
            // keep the target Servlet from running
            filterConfig.getServletContext().log(preChainBshScript + " BSH script failed to execute properly: " + e.toString());
            e.printStackTrace();
        } catch (Throwable t) {
            //for same reason as above, catch everythign else (e.g. file not found)
            filterConfig.getServletContext().log("BeanShellServletFilter failed to execute properly, passing through: " + t.toString());
            t.printStackTrace();
        }

        chain.doFilter(request, response);

        try {
            bshEngine.set("response", response);
            bshEngine.source(postChainBshScript);
            response = (ServletResponse) bshEngine.get("response");
        } catch (bsh.EvalError e) {
            //for now just print it and move on
            // Don't want this filter to stop flow of chain or 
            // keep the target Servlet from running
            filterConfig.getServletContext().log(postChainBshScript + " BSH script failed to execute properly: " + e.toString());
            e.printStackTrace();
        } catch (Throwable t) {
            //for same reason as above, catch everythign else (e.g. file not found)
            filterConfig.getServletContext().log("BeanShellServletFilter failed to execute properly, passing through: " + t.toString());
            t.printStackTrace();
        }

    }

    public void init(FilterConfig cfg) throws ServletException {
        this.filterConfig = cfg;
        filterConfig.getServletContext().log("BeanShellServletFilter:: init(): Creating BSH Interpreter.");
        bshEngine = new Interpreter();//instantiate script engine
        filterConfig.getServletContext().log("BeanShellServletFilter:: init(): Created BSH Interpreter.");
    }

    public void destroy() {
        bshEngine = null;
    }
}