wplingua / inc / browser-language.php

browser-language.php in Translate and Go multilingual – Automatic AI translation – wpLingua 2.10.0, at inc/browser-language.php

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1	<?php
2
3	// If this file is called directly, abort.
4	if ( ! defined( 'WPINC' ) ) {
5	die;
6	}
7
8
9	/**
10	* Outputs a JavaScript snippet to handle browser language-based redirection.
11	*
12	* This function is designed to inject a JavaScript script into the front-end
13	* for redirecting users based on their browser's language settings. It ensures
14	* that the script is only output under specific conditions:
15	* - The user is not logged in with editing permissions.
16	* - The user is not a bot.
17	* - The current page is the front page.
18	* - The current language matches the website's default language.
19	*
20	* If the JavaScript file is missing or empty, the function exits early.
21	*
22	* @return void
23	*/
24	function wplng_browser_language_redirect_js_only() {
25
26	if ( current_user_can( 'edit_posts' )
27	\|\| wplng_is_bot()
28	\|\| ! is_front_page()
29	\|\| ( wplng_get_language_website_id() !== wplng_get_language_current_id() )
30	) {
31	return;
32	}
33
34	$script = file_get_contents( WPLNG_PLUGIN_PATH . '/assets/js/browser-redirect.js' );
35
36	if ( empty( $script ) ) {
37	return;
38	}
39
40	$script = str_replace(
41	'//# sourceMappingURL=browser-redirect.js.map',
42	'',
43	$script
44	);
45
46	echo '<script id="wplingue-browser-redirect-js">' . rtrim( $script ) . '</script>';
47	}
48
49
50	/**
51	* Redirects the user to the translated version of the page based on browser language or a user-defined cookie.
52	*
53	* This function is designed to run on the 'template_redirect' hook. It handles the logic for
54	* redirecting users to the appropriate language version of a page. The redirection is based on
55	* a stored cookie (if available) or the browser's 'Accept-Language' header.
56	*
57	* It prevents redirection for specific user types (e.g., logged-in users with 'edit_posts' capability)
58	* and for known web crawlers and bots.
59	*
60	* @return void
61	*/
62	function wplng_browser_language_redirect_php_js() {
63
64	// Exit early for users with editing permissions or for bots to prevent redirection loops.
65	if ( current_user_can( 'edit_posts' )
66	\|\| wplng_is_bot()
67	) {
68	return;
69	}
70
71	$language_website_id = wplng_get_language_website_id();
72	$language_current_id = wplng_get_language_current_id();
73	$is_translated_page = $language_website_id !== $language_current_id;
74	$cookie = wplng_browser_language_cookie_get();
75
76	// If the user is on a translated page.
77	if ( $is_translated_page ) {
78	// Update the cookie with the selected language code.
79	// This is a voluntary choice by the user.
80	wplng_browser_language_cookie_set( $language_current_id );
81	return;
82	}
83
84	// The user is on the original language page (no language prefix).
85
86	// Determine the language to redirect to.
87	$redirect_language_id = false;
88
89	if ( $cookie !== false ) {
90	// If the cookie contains a valid language code, use it for redirection.
91	// This honors the user's last choice.
92	if ( wplng_is_valid_language_id( $cookie ) ) {
93
94	if ( $cookie === $language_website_id ) {
95	return;
96	} else {
97	$redirect_language_id = $cookie;
98	}
99	}
100	} else {
101	// This is the very first visit (no cookie). Use the browser's language.
102	if ( ! empty( $_SERVER['HTTP_ACCEPT_LANGUAGE'] ) ) {
103	$langs = explode( ',', sanitize_text_field( $_SERVER['HTTP_ACCEPT_LANGUAGE'] ) );
104	if ( ! empty( $langs ) ) {
105	$language_browser_id = strtolower( substr( trim( $langs[0] ), 0, 2 ) );
106	$redirect_language_id = $language_browser_id;
107	}
108	}
109	}
110
111	// Check if the determined language is a valid target language.
112	if ( empty( $redirect_language_id )
113	\|\| ( $redirect_language_id === $language_website_id )
114	\|\| ! in_array( $redirect_language_id, wplng_get_languages_target_ids(), true )
115	) {
116	// If not, set the cookie to 'original' to prevent future redirects on the original page.
117	wplng_browser_language_cookie_set( $language_website_id );
118	return;
119	}
120
121	// Check if the URL to redirect is translatable.
122	$url_to_redirect = wplng_get_url_current_for_language( $redirect_language_id );
123
124	if ( $url_to_redirect === wplng_get_url_original() ) {
125	wplng_browser_language_cookie_set( $language_website_id );
126	return;
127	}
128
129	// Perform the redirection.
130	wplng_browser_language_cookie_set( $redirect_language_id );
131	wp_safe_redirect(
132	$url_to_redirect,
133	302
134	);
135	exit;
136	}
137
138
139	/**
140	* Retrieves the language code from the 'wplingua-lang' cookie.
141	*
142	* This function safely retrieves the language code stored in the user's cookie,
143	* sanitizing the value to prevent security issues. It returns the language code
144	* if it's valid ('original' or a known language ID), otherwise it returns false.
145	*
146	* @return string\|false The language code from the cookie, or false if the cookie is not set or invalid.
147	*/
148	function wplng_browser_language_cookie_get() {
149	$cookie = false;
150	if ( ! empty( $_COOKIE['wplingua-lang'] ) ) {
151	$cookie = sanitize_text_field( $_COOKIE['wplingua-lang'] );
152	if ( ! wplng_is_valid_language_id( $cookie ) ) {
153	$cookie = false;
154	}
155	}
156
157	return $cookie;
158	}
159
160
161	/**
162	* Sets the 'wplingua-lang' cookie with a specified language ID.
163	*
164	* This function creates or updates a cookie to store the user's preferred language choice.
165	* The cookie is set to expire in 30 days and is accessible across the site's domain.
166	*
167	* @param string $language_id The language code to be stored (e.g., 'en', 'fr', 'es', or 'original').
168	* @return void
169	*/
170	function wplng_browser_language_cookie_set( $language_id ) {
171	setcookie(
172	'wplingua-lang',
173	$language_id,
174	time() + 30 * DAY_IN_SECONDS,
175	COOKIEPATH,
176	COOKIE_DOMAIN
177	);
178	}
179
180
181	/**
182	* Determines if the current user agent is a bot or a web crawler.
183	*
184	* This function checks the user agent string against a predefined list of known bots
185	* using a regular expression. The result is cached for the duration of the request
186	* to improve performance on multiple calls.
187	*
188	* @return bool True if the user agent is a bot, false otherwise.
189	*/
190	function wplng_is_bot() {
191	return (bool) preg_match(
192	'/googlebot\|bingbot\|slurp\|duckduckbot\|baiduspider\|yandex\|semrushbot\|ahrefsbot\|mj12bot\|dotbot\|exabot\|facebookexternalhit/i',
193	strtolower( $_SERVER['HTTP_USER_AGENT'] ?? '' )
194	);
195	}
196