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