Adding cookie to make redirection once-only (have code)

I have a multisite with the root as the default english language and then /fr/ and /it/ subsites. So if the current redirect plugin is used then a visitor will always get sent to the /fr/ or /it/ subsites even if they wanted to stay on the english default.

The fix I have come up with is to set a cookie so if the user has visited then the redirect action is skipped.

The code is trivial …

In language-redirect.php I added in to language_redirect_register_settings()

register_setting('language_redirect_group', 'language_redirect_use_has_visited_cookie');

And in function language_redirect_plugins_loaded() about line 34,

if (get_option('language_redirect_use_has_visited_cookie') == "1") {
		if (isset($_COOKIE['languageredirect_hasvisted'])) {
			return;
		}
		if (!isset($_COOKIE['languageredirect_hasvisted'])) {
			setcookie('languageredirect_hasvisted', 1, time()+2419200, COOKIEPATH, COOKIE_DOMAIN, false);
		}
	}

And in options.php I added the extra setting,

<tr valign="top">
					<th scope="row">Set and use visit cookie</th>
					<td>
						<input id="language_redirect_use_has_visited_cookie" name="language_redirect_use_has_visited_cookie" class="checkbox" type="checkbox" value="1" <?= checked( get_option('language_redirect_use_has_visited_cookie'), 1, false );?>   />
						<p class="description">Used to stop redirect if user has already visited site</p>
					</td>
				</tr>

That’s a 4 week timer for the cookie.

The behaviour now is that the redirect will work once when the client hits the root site i.e. a French browser will go to e.g. /fr/ but if they go back to the root i.e. / then the redirect action will not then redirect them back to /fr/. After 28 days (the cookie timer I have used though it could be anything), the browser will redirect just once again if they visit the root site.

http://wordpress.org/plugins/language-redirect/