Using client side cookies in Java or javscript code in Enterprise Portal

Hi,

In this short blog post, you can find sample code on how to read/save cookies in portal component java code or using javascript.

First we build a portal component that demonstrates both.

The main doContent method, calling both techniques:

package com.sap.portal.examples;
import javax.servlet.http.Cookie;
import com.sapportals.portal.prt.component.*;
import com.sapportals.portal.prt.resource.IResource;
public class WebCookie extends AbstractPortalComponent
{
     public void doContent(IPortalComponentRequest request, IPortalComponentResponse response)
     {
       handleCookiesByJS(request,response);
       handleCookiesInJava(request,response);
     }
....

1. First method, writing cookies in Javascript and then reading them:

private void handleCookiesByJS(IPortalComponentRequest request, IPortalComponentResponse response)
  {
     //include the javascript source that holds the js method to store/read cookie
     IResource resource = request.getResource(IResource.SCRIPT,"scripts/cookiescript.js");
     response.include(request, resource);
     //launch a js method to write cookie
     response.write("<script>write_cookie();</script>");
     //launch a js method to read cookie and print on screen
     response.write("Cookie reads = " + "<script>document.write(gettimes());</script>");
  }

Above you can see javascript “cookiescript.js” is included in the response of the portal component. This js contains two methods write_cookie() and gettimes()

After which write_cookie() is called and eventually gettimes()  is called.

javascript code cookiescript.js:

The write_cookie() method  searches for a cookie named “Basic_Cookie” and adds 1 to the value of the cookie

Eventually the cookie actually stores the number of times this method was called:

var cookie_name = "Basic_Cookie"
function write_cookie() {
   var index =document.cookie? document.cookie.indexOf(cookie_name) : -1;
    if (index == -1){
     //creating new cookie which will expire in 2040
    document.cookie=cookie_name+"=1; expires=Wednesday, 01-Aug-2040 08:00:00 GMT";
  }
  else{
     //cookie exists, read its value
    var countbegin = (document.cookie.indexOf("=", index) + 1);
    var countend = document.cookie.indexOf(";", index);
    if (countend == -1) {
      countend = document.cookie.length;
    }
    var count = eval(document.cookie.substring(countbegin, countend)) + 1;
     //update the cookie
    document.cookie=cookie_name+"="+count+"; expires=Wednesday, 01-Aug-2040 08:00:00 GMT";
  }
}

The gettimes()  method read value of the “Basic_Cookie” and returns number stored in it:

//this method reads the value of the cookie and return number stored in it.
function gettimes() {
     var count = 0;
     if(document.cookie) {
          var index = document.cookie.indexOf(cookie_name);
         if (index != -1){
           var countbegin = (document.cookie.indexOf("=", index) + 1);
           var countend = document.cookie.indexOf(";", index);
           if (countend == -1){
             countend = document.cookie.length;
           }
           count = document.cookie.substring(countbegin, countend);
        }
      }
     return (count + " times");
}

2. Second method, accessing cookie in portal component java code:

private void handleCookiesInJava(IPortalComponentRequest request, IPortalComponentResponse response)
{
    response.write("<br>");
    saveToCookie(request,response,"MyCookie","MyCookieValue");
    String val = getCookieValue(request,"MyCookie");
    response.write("Got cookie MyCookie with its value="+val); //first time it will be null, since the response is not written yet
}

Here the component calls a java method saveToCookie with key and value.

Then it reads the cookie value by calling getCookieValue method and prints it.

saveToCookie method:

cookie is searched in all cookie that came with request, then its deleted and a new cookie is created:

private void saveToCookie(IPortalComponentRequest request , IPortalComponentResponse response , String cookieName, String cookieValue)
{
     //getting all cookies from request
     Cookie [] cookies = request.getServletRequest().getCookies();
     if(cookies != null)
     {
        for(int i = 0 ; i < cookies.length ; i++)
        {
             Cookie cookie = cookies[i];
            //find the specific cookie and deletes it
             if(cookie != null && cookie.getName().equals(cookieName))
             {
                  cookie.setMaxAge(0);
                  break;
             }
        }
   }
   //create a new cookie with new value and save it
   Cookie  cookie = new Cookie(cookieName , cookieValue);
   cookie.setPath("/");
   response.addCookie(cookie);
}

getCookieValue method:

Cookie is searched and its value (or null if not found) is returned:

private String getCookieValue(IPortalComponentRequest request, String cookieName)
{
     //get all cookies from request
     Cookie [] cookies = request.getServletRequest().getCookies();
     if(cookies != null)
     {
          for(int i = 0 ; i < cookies.length ; i++)
          {
               Cookie cookie = cookies[i];
               //search for the cookie and get its value
               if(cookie != null && cookie.getName().equals(cookieName))
               {
                    return cookie.getValue();
               }
            }
       }
       return null;
}

After deploying this portal component, If we execute it  3 times, we will get the following output , from both techniques:

Cookie reads = 3 times

Got cookie MyCookie with its value=MyCookieValue

Related Links:

Important –  Security consideration using cookies

http://www.allaboutcookies.org/cookies/

http://en.wikipedia.org/wiki/HTTP_cookie

Enjoy,

Tal

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