New web library (http/https)

[fanfix.git] / src / be / nikiroo / utils / CookieUtils.java

diff --git a/src/be/nikiroo/utils/CookieUtils.java b/src/be/nikiroo/utils/CookieUtils.java
new file mode 100644 (file)
index 0000000..f082026
--- /dev/null
+++ b/src/be/nikiroo/utils/CookieUtils.java
@@ -0,0 +1,57 @@
+package be.nikiroo.utils;
+
+import java.util.Date;
+
+public class CookieUtils {
+       /**
+        * The number of seconds for the period (we accept the current or the
+        * previous period as valid for a cookie, via "offset").
+        */
+       static public int GRACE_PERIOD = 3600 * 1000; // between 1 and 2h
+
+       /**
+        * Generate a new cookie value from the user (email) and an offset.
+        * <p>
+        * You should use an offset of "0" when creating the cookie, and an offset
+        * of "0" or "-1" if required when checking for the value (the idea is to
+        * allow a cookie to persist across two timespans; if not, the cookie will
+        * be expired the very second we switch to a new timespan).
+        * 
+        * @param value
+        *            the value to generate a cookie for -- you must be able to
+        *            regenerate it in order to check it later
+        * @param offset
+        *            the offset (should be 0 for creating, 0 then -1 if needed for
+        *            checking)
+        * 
+        * @return the new cookie
+        */
+       static public String generateCookie(String value, int offset) {
+               long unixTime = (long) Math.floor(new Date().getTime() / GRACE_PERIOD)
+                               + offset;
+               return HashUtils.sha512(value + Long.toString(unixTime));
+       }
+
+       /**
+        * Check the given cookie.
+        * 
+        * @param value
+        *            the value to generate a cookie for -- you must be able to
+        *            regenerate it in order to check it later
+        * @param cookie
+        *            the cookie to validate
+        * 
+        * @return TRUE if it is correct
+        */
+       static public boolean validateCookie(String value, String cookie) {
+               if (cookie != null)
+                       cookie = cookie.trim();
+
+               String newCookie = generateCookie(value, 0);
+               if (!newCookie.equals(cookie)) {
+                       newCookie = generateCookie(value, -1);
+               }
+
+               return newCookie.equals(cookie);
+       }
+}