| 1 | package be.nikiroo.utils; |
| 2 | |
| 3 | import java.util.Date; |
| 4 | |
| 5 | /** |
| 6 | * Some utilities for cookie management. |
| 7 | * |
| 8 | * @author niki |
| 9 | */ |
| 10 | public class CookieUtils { |
| 11 | /** |
| 12 | * The number of seconds for the period (we accept the current or the |
| 13 | * previous period as valid for a cookie, via "offset"). |
| 14 | */ |
| 15 | static public int GRACE_PERIOD = 3600 * 1000; // between 1 and 2h |
| 16 | |
| 17 | /** |
| 18 | * Generate a new cookie value from the user (email) and an offset. |
| 19 | * <p> |
| 20 | * You should use an offset of "0" when creating the cookie, and an offset |
| 21 | * of "0" or "-1" if required when checking for the value (the idea is to |
| 22 | * allow a cookie to persist across two timespans; if not, the cookie will |
| 23 | * be expired the very second we switch to a new timespan). |
| 24 | * |
| 25 | * @param value |
| 26 | * the value to generate a cookie for -- you must be able to |
| 27 | * regenerate it in order to check it later |
| 28 | * @param offset |
| 29 | * the offset (should be 0 for creating, 0 then -1 if needed for |
| 30 | * checking) |
| 31 | * |
| 32 | * @return the new cookie |
| 33 | */ |
| 34 | static public String generateCookie(String value, int offset) { |
| 35 | long unixTime = (long) Math.floor(new Date().getTime() / GRACE_PERIOD) |
| 36 | + offset; |
| 37 | return HashUtils.sha512(value + Long.toString(unixTime)); |
| 38 | } |
| 39 | |
| 40 | /** |
| 41 | * Check the given cookie. |
| 42 | * |
| 43 | * @param value |
| 44 | * the value to generate a cookie for -- you must be able to |
| 45 | * regenerate it in order to check it later |
| 46 | * @param cookie |
| 47 | * the cookie to validate |
| 48 | * |
| 49 | * @return TRUE if it is correct |
| 50 | */ |
| 51 | static public boolean validateCookie(String value, String cookie) { |
| 52 | if (cookie != null) |
| 53 | cookie = cookie.trim(); |
| 54 | |
| 55 | String newCookie = generateCookie(value, 0); |
| 56 | if (!newCookie.equals(cookie)) { |
| 57 | newCookie = generateCookie(value, -1); |
| 58 | } |
| 59 | |
| 60 | return newCookie.equals(cookie); |
| 61 | } |
| 62 | } |