/**Servlet generating it's environment variables and sends them to browsers making requests as plain text.
* Internet Programming 2 - Course
* @author Martin Carlsson
*/
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;

public class EnvironmentVariablesText extends HttpServlet {

    private final static String CONTENT_TYPE = "text/plain";
    
    public void doPost(HttpServletRequest req, HttpServletResponse res) throws IOException, ServletException {
    doGet(req, res);
    }
    
    public void doGet(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException {
    
        ServletContext sc = getServletContext();
        Enumeration e = null;
        res.setContentType(CONTENT_TYPE);
        PrintWriter pw = res.getWriter();
        print("*********SERVER-SIDE INFORMATION:**********\n", pw);
        print("Servlet Information:", pw);
        print("Servlet name", getServletName(), pw);
        print("Servlet Init Parameters:", pw);
        e = getInitParameterNames();
        while (e.hasMoreElements()) {
            String key = (String)e.nextElement();
            String value = getInitParameter(key);
            print(key, value, pw); 
        }
        
        print("Context Init Parameters:", pw);
        e = sc.getInitParameterNames();
        while (e.hasMoreElements()) {
            String key = (String)e.nextElement();
            String value = sc.getInitParameter(key);
            print(key, value, pw);
        }
    
        print("Server Information:", pw);
        print("Server name", req.getServerName(), pw);
        print("Server port", Integer.toString(req.getServerPort()), pw);
        print("Server info", sc.getServerInfo(), pw);
        
        print("Server Attributes:", pw);
        e = sc.getAttributeNames();
        while (e.hasMoreElements()) {
            String key = (String)e.nextElement();
            Object value = sc.getAttribute(key);
            print(key, value.toString(), pw);
        }
        
        print("Server and Java Versions:", pw);
        print("Major webserver version", Integer.toString(sc.getMajorVersion()), pw);
        print("Minor webserver version", Integer.toString(sc.getMinorVersion()), pw);
        print("JDK version", System.getProperty("java.version"), pw);
        
        print("*********CLIENT-SIDE INFORMATION:*************\n", pw);
        
        print("Client Information:", pw);
        print("Remote address", req.getRemoteAddr(), pw);
        print("Remote host", req.getRemoteHost(), pw);
        print("Remote user", req.getRemoteUser(), pw);
        print("Authentication type", req.getAuthType(), pw);
        
        print("Headers:", pw);
        e = req.getHeaderNames();
        while (e.hasMoreElements()) {
            String key = (String)e.nextElement();
            String value = req.getHeader(key);
            print(key, value, pw);
        }
        
        print("Request Information:", pw);
        print("Query string", req.getQueryString(), pw);
        print("Character encoding", req.getCharacterEncoding(), pw); // Test
        print("Content length", Integer.toString(req.getContentLength()), pw); // Test
        print("Content type", req.getContentType(), pw); // Test
        
        print("Request Parameters:", pw);
        e = req.getParameterNames();
        while (e.hasMoreElements()) {
            String key = (String)e.nextElement();
            String[] values = req.getParameterValues(key);
            for(int i = 0; i < values.length; i++) {
                print(key, values[i], pw);
            }
        }
        
        print("Cookies:", pw);
        Cookie[] cookies = req.getCookies();
        if(cookies != null) {
            for (int i = 0; i < cookies.length; i++) {
                Cookie cookie = cookies[i];
                print(cookie.getName(), cookie.getValue(), pw);
            }
        }
        
        print("Path and connection information:", pw);
        print("Path info", req.getPathInfo(), pw);
        print("Translated path", req.getPathTranslated(), pw);
        print("Request URI", req.getRequestURI(), pw);
        print("Request URL", req.getRequestURL().toString(), pw);
        print("Request scheme", req.getScheme(), pw);
        print("Context path", req.getContextPath(), pw);
        print("Servlet path", req.getServletPath(), pw);
        print("Request protocol", req.getProtocol(), pw);
        print("Request method", req.getMethod(), pw);
        
        print("Request Attributes:", pw);
        e = req.getAttributeNames();
        while (e.hasMoreElements()) {
            String key = (String)e.nextElement();
            Object value = req.getAttribute(key);
            print(key, value.toString(), pw);
        }
        
        print("Session Information:", pw);
        print("Requested session id", req.getRequestedSessionId(), pw);
        HttpSession session = req.getSession(true);
        print("Session is new", Boolean.toString(session.isNew()), pw);
        print("Session creation time", new Date(session.getCreationTime()).toString(), pw);
        print("Session id", session.getId(), pw);
        print("Session last accessed", new Date(session.getLastAccessedTime()).toString(), pw);
        print("Session max inactive interval", Integer.toString(session.getMaxInactiveInterval()), pw);
        
        print("Session Values:", pw);
        e = session.getAttributeNames();
        if(!e.hasMoreElements())
            print("key", null, pw);
        else
            while (e.hasMoreElements()) {
                String key = (String)e.nextElement();
                Object value = session.getAttribute(key);
                print(key, value.toString(), pw);
            }
    }
    
    private void print(String string, PrintWriter pw) {
        pw.println();
        pw.println(string);
    }
    
    private void print(String name, String value, PrintWriter pw) {
        if(value == null)
        value = "null";
        pw.println("  " + name + ": " + value);
    }
} //End class EnvironmentVariablesText