X-Git-Url: http://git.nikiroo.be/?p=fanfix.git;a=blobdiff_plain;f=src%2Fbe%2Fnikiroo%2Futils%2FCookieUtils.java;fp=src%2Fbe%2Fnikiroo%2Futils%2FCookieUtils.java;h=f0820260ffd7365facd6ebedf61d7069efd46bae;hp=0000000000000000000000000000000000000000;hb=f433d15308b70e23280a65cef8c54002a7a971ce;hpb=5ddc36eacad78641be59db473f9bae9bad47eb20

diff --git a/src/be/nikiroo/utils/CookieUtils.java b/src/be/nikiroo/utils/CookieUtils.java
new file mode 100644
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);
+	}
+}