weblib: set custom covers
[fanfix.git] / src / be / nikiroo / utils / CookieUtils.java
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1package be.nikiroo.utils;
2
3import java.util.Date;
4
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5/**
6 * Some utilities for cookie management.
7 *
8 * @author niki
9 */
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10public 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}