Merge branch 'FreshRSS/dev' into FreshRSS/dev-1.14.0

18 files changed, 175 insertions, 63 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index a77c7b703..ff306cb7c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,21 @@
 
 * Bug fixing
 	* Fix missing HTTP `X-Forwarded-Prefix` in cookie path behind a reverse-proxy [#2201](https://github.com/FreshRSS/FreshRSS/pull/2201)
+* Deployment
+	* Docker improvements [#2202](https://github.com/FreshRSS/FreshRSS/pull/2202)
+		* Performance: Hard-include Apache .htaccess to avoid having to scan for changes in those files
+		* Performance: Disable unused Apache security check of symlinks
+		* Performance: Disable unused Apache modules
+		* Add option to mount custom `.htaccess` for HTTP authentication
+		* Docker logs gets PHP syslog messages (e.g. from cron job and when fetching external content)
+	* Send a copy of PHP syslog messages to STDERR [#2208](https://github.com/FreshRSS/FreshRSS/pull/2208)
+	* Run Docker cron job with Apache user instead of root [#2208](https://github.com/FreshRSS/FreshRSS/pull/2208)
+	* Accept HTTP header `X-WebAuth-User` for delegated HTTP Authentication [#2204](https://github.com/FreshRSS/FreshRSS/pull/2204)
+* API
+	* Automatic test of API configuration [#2207](https://github.com/FreshRSS/FreshRSS/pull/2207)
+	* Use Apache SetEnvIf module if available and fall-back to RewriteRule [#2202](https://github.com/FreshRSS/FreshRSS/pull/2202)
+* Security
+	* Fixes when HTTP user does not exist in FreshRSS [#2204](https://github.com/FreshRSS/FreshRSS/pull/2204)
 
 
 ## 2018-12-22 FreshRSS 1.13.0
diff --git a/Docker/Dockerfile b/Docker/Dockerfile
index 2a25e567d..52ac5f2fc 100644
--- a/Docker/Dockerfile
+++ b/Docker/Dockerfile
@@ -2,15 +2,14 @@ FROM alpine:3.8
 
 RUN apk add --no-cache \
 	apache2 php7-apache2 \
-	php7 php7-curl php7-intl php7-mbstring php7-xml php7-zip \
+	php7 php7-curl php7-gmp php7-intl php7-mbstring php7-xml php7-zip \
 	php7-ctype php7-dom php7-fileinfo php7-iconv php7-json php7-session php7-simplexml php7-xmlreader php7-zlib \
 	php7-pdo_sqlite php7-pdo_mysql php7-pdo_pgsql
 
-ENV FRESHRSS_ROOT /var/www/FreshRSS
-RUN mkdir -p ${FRESHRSS_ROOT} /run/apache2/
-WORKDIR ${FRESHRSS_ROOT}
+RUN mkdir -p /var/www/FreshRSS /run/apache2/
+WORKDIR /var/www/FreshRSS
 
-COPY . ${FRESHRSS_ROOT}
+COPY . /var/www/FreshRSS
 COPY ./Docker/*.Apache.conf /etc/apache2/conf.d/
 
 RUN rm -f /etc/apache2/conf.d/languages.conf /etc/apache2/conf.d/info.conf \
@@ -21,8 +20,8 @@ RUN rm -f /etc/apache2/conf.d/languages.conf /etc/apache2/conf.d/info.conf \
 		/etc/apache2/httpd.conf && \
 	sed -r -i "/^\s*(CustomLog|ErrorLog|Listen) /s/^/#/" \
 		/etc/apache2/httpd.conf && \
-	echo "17,37 * * * * php ${FRESHRSS_ROOT}/app/actualize_script.php 2>&1 | tee /tmp/FreshRSS.log" >> \
-		/var/spool/cron/crontabs/www-data
+	echo "17,37 * * * * su apache -s /bin/sh -c 'php /var/www/FreshRSS/app/actualize_script.php' 2>> /proc/1/fd/2 > /tmp/FreshRSS.log" >> \
+		/var/spool/cron/crontabs/root
 
 ENV CRON_MIN ''
 ENTRYPOINT ["./Docker/entrypoint.sh"]
diff --git a/Docker/README.md b/Docker/README.md
index 6b3871c6b..1a915f326 100644
--- a/Docker/README.md
+++ b/Docker/README.md
@@ -205,6 +205,27 @@ sudo docker run -d --restart unless-stopped --log-opt max-size=10m \
 
 ## More deployment options
 
+### Custom Apache configuration (advanced users)
+
+Changes in Apache `.htaccess` files are applied when restarting the container.
+In particular, if you want FreshRSS to use HTTP-based login (instead of the easier Web form login), you can mount your own `./FreshRSS/p/i/.htaccess`:
+
+```
+sudo docker run ...
+  -v /your/.htaccess:/var/www/FreshRSS/p/i/.htaccess \
+  -v /your/.htpasswd:/var/www/FreshRSS/data/.htpasswd \
+  ...
+  --name freshrss freshrss/freshrss
+```
+
+Example of `/your/.htaccess` referring to `/your/.htpasswd`:
+```
+AuthUserFile /var/www/FreshRSS/data/.htpasswd
+AuthName "FreshRSS"
+AuthType Basic
+Require valid-user
+```
+
 ### Example with [docker-compose](https://docs.docker.com/compose/)
 
 A [docker-compose.yml](docker-compose.yml) file is given as an example, using PostgreSQL. In order to use it, you have to adapt:
diff --git a/Docker/entrypoint.sh b/Docker/entrypoint.sh
index ba5d12bf2..d4e1808bc 100755
--- a/Docker/entrypoint.sh
+++ b/Docker/entrypoint.sh
@@ -6,7 +6,7 @@ chown -R :www-data .
 chmod -R g+r . && chmod -R g+w ./data/
 
 if [ -n "$CRON_MIN" ]; then
-	sed -r -i "\#FreshRSS#s#^[^ ]+ #$CRON_MIN #" /var/spool/cron/crontabs/www-data
+	sed -r -i "\#FreshRSS#s#^[^ ]+ #$CRON_MIN #" /var/spool/cron/crontabs/root
 fi
 
 exec "$@"
diff --git a/app/Controllers/authController.php b/app/Controllers/authController.php
index 5ad1a51d9..3b2d78b19 100644
--- a/app/Controllers/authController.php
+++ b/app/Controllers/authController.php
@@ -79,8 +79,12 @@ class FreshRSS_auth_Controller extends Minz_ActionController {
 			Minz_Request::forward(array('c' => 'auth', 'a' => 'formLogin'));
 			break;
 		case 'http_auth':
+			Minz_Error::error(403, array('error' => array(_t('feedback.access.denied'),
+					' [HTTP Remote-User=' . htmlspecialchars(httpAuthUser(), ENT_NOQUOTES, 'UTF-8') . ']'
+				)), false);
+			break;
 		case 'none':
-			// It should not happened!
+			// It should not happen!
 			Minz_Error::error(404);
 		default:
 			// TODO load plugin instead
diff --git a/app/Models/Auth.php b/app/Models/Auth.php
index 9c3e31952..513a9cb2f 100644
--- a/app/Models/Auth.php
+++ b/app/Models/Auth.php
@@ -28,13 +28,13 @@ class FreshRSS_Auth {
 
 		if (self::$login_ok) {
 			self::giveAccess();
-		} elseif (self::accessControl()) {
-			self::giveAccess();
+		} elseif (self::accessControl() && self::giveAccess()) {
 			FreshRSS_UserDAO::touch();
 		} else {
 			// Be sure all accesses are removed!
 			self::removeAccess();
 		}
+		return self::$login_ok;
 	}
 
 	/**
@@ -60,7 +60,7 @@ class FreshRSS_Auth {
 			return $current_user != '';
 		case 'http_auth':
 			$current_user = httpAuthUser();
-			$login_ok = $current_user != '';
+			$login_ok = $current_user != '' && FreshRSS_UserDAO::exists($current_user);
 			if ($login_ok) {
 				Minz_Session::_param('currentUser', $current_user);
 			}
@@ -81,7 +81,7 @@ class FreshRSS_Auth {
 		$user_conf = get_user_configuration($current_user);
 		if ($user_conf == null) {
 			self::$login_ok = false;
-			return;
+			return false;
 		}
 		$system_conf = Minz_Configuration::get('system');
 
@@ -102,6 +102,7 @@ class FreshRSS_Auth {
 
 		Minz_Session::_param('loginOk', self::$login_ok);
 		Minz_Session::_param('REMOTE_USER', httpAuthUser());
+		return self::$login_ok;
 	}
 
 	/**
diff --git a/app/Models/Entry.php b/app/Models/Entry.php
index 985276734..f2f3d08fe 100644
--- a/app/Models/Entry.php
+++ b/app/Models/Entry.php
@@ -209,6 +209,7 @@ class FreshRSS_Entry extends Minz_Model {
 		$feed_timeout = empty($attributes['timeout']) ? 0 : intval($attributes['timeout']);
 
 		if ($system_conf->simplepie_syslog_enabled) {
+			prepareSyslog();
 			syslog(LOG_INFO, 'FreshRSS GET ' . SimplePie_Misc::url_remove_credentials($url));
 		}
 
diff --git a/app/Models/UserDAO.php b/app/Models/UserDAO.php
index 5fb46c947..e9d3a7329 100644
--- a/app/Models/UserDAO.php
+++ b/app/Models/UserDAO.php
@@ -65,7 +65,7 @@ class FreshRSS_UserDAO extends Minz_ModelPdo {
 		require_once(APP_PATH . '/SQL/install.sql.' . $db['type'] . '.php');
 
 		if ($db['type'] === 'sqlite') {
-			return unlink(join_path(DATA_PATH, 'users', $username, 'db.sqlite'));
+			return unlink(USERS_PATH . '/' . $username . '/db.sqlite');
 		} else {
 			$userPDO = new Minz_ModelPdo($username);
 
@@ -81,18 +81,18 @@ class FreshRSS_UserDAO extends Minz_ModelPdo {
 		}
 	}
 
-	public static function exist($username) {
-		return is_dir(join_path(DATA_PATH, 'users', $username));
+	public static function exists($username) {
+		return is_dir(USERS_PATH . '/' . $username);
 	}
 
 	public static function touch($username = '') {
 		if (!FreshRSS_user_Controller::checkUsername($username)) {
 			$username = Minz_Session::param('currentUser', '_');
 		}
-		return touch(join_path(DATA_PATH, 'users', $username, 'config.php'));
+		return touch(USERS_PATH . '/' . $username . '/config.php');
 	}
 
 	public static function mtime($username) {
-		return @filemtime(join_path(DATA_PATH, 'users', $username, 'config.php'));
+		return @filemtime(USERS_PATH . '/' . $username . '/config.php');
 	}
 }
diff --git a/app/actualize_script.php b/app/actualize_script.php
index ba9660a14..f1dec5640 100755
--- a/app/actualize_script.php
+++ b/app/actualize_script.php
@@ -12,6 +12,9 @@ if (defined('STDOUT')) {
 	fwrite(STDOUT, 'Starting feed actualization at ' . $begin_date->format('c') . "\n");	//Unbuffered
 }
 
+prepareSyslog();
+syslog(LOG_INFO, 'FreshRSS Start feeds actualization...');
+
 // Set the header params ($_GET) to call the FRSS application.
 $_GET['c'] = 'feed';
 $_GET['a'] = 'actualize';
@@ -64,7 +67,7 @@ foreach ($users as $user) {
 	if (!invalidateHttpCache()) {
 		Minz_Log::warning('FreshRSS write access problem in ' . join_path(USERS_PATH, $user, 'log.txt'), ADMIN_LOG);
 		if (defined('STDERR')) {
-			fwrite(STDERR, 'Write access problem in ' . join_path(USERS_PATH, $user, 'log.txt') . "\n");
+			fwrite(STDERR, 'FreshRSS write access problem in ' . join_path(USERS_PATH, $user, 'log.txt') . "\n");
 		}
 	}
 }
@@ -75,7 +78,8 @@ if (defined('STDOUT')) {
 	$end_date = date_create('now');
 	$duration = date_diff($end_date, $begin_date);
 	fwrite(STDOUT, 'Ending feed actualization at ' . $end_date->format('c') . "\n");	//Unbuffered
-	fwrite(STDOUT, 'Feed actualizations took ' . $duration->format('%a day(s), %h hour(s),  %i minute(s) and %s seconds') . ' for ' . count($users) . " users\n");	//Unbuffered
+	fwrite(STDOUT, 'Feed actualizations took ' . $duration->format('%a day(s), %h hour(s), %i minute(s) and %s seconds') . ' for ' . count($users) . " users\n");	//Unbuffered
 }
 echo 'End.', "\n";
 ob_end_flush();
+syslog(LOG_INFO, 'FreshRSS feeds actualization done.');
diff --git a/cli/_cli.php b/cli/_cli.php
index 72629171c..e8fb6ae42 100644
--- a/cli/_cli.php
+++ b/cli/_cli.php
@@ -4,7 +4,7 @@ if (php_sapi_name() !== 'cli') {
 }
 
 require(__DIR__ . '/../constants.php');
-require(LIB_PATH . '/lib_rss.php');
+require(LIB_PATH . '/lib_rss.php');	//Includes class autoloader
 require(LIB_PATH . '/lib_install.php');
 
 Minz_Configuration::register('system',
diff --git a/lib/Minz/Configuration.php b/lib/Minz/Configuration.php
index 3e486d68e..aae3accc6 100644
--- a/lib/Minz/Configuration.php
+++ b/lib/Minz/Configuration.php
@@ -27,23 +27,16 @@ class Minz_Configuration {
 	/**
 	 * Parse a file and return its data.
 	 *
-	 * If the file does not contain a valid PHP code returning an array, an
-	 * empty array is returned anyway.
-	 *
 	 * @param $filename the name of the file to parse.
 	 * @return an array of values
-	 * @throws Minz_FileNotExistException if the file does not exist.
+	 * @throws Minz_FileNotExistException if the file does not exist or is invalid.
 	 */
 	public static function load($filename) {
-		if (!file_exists($filename)) {
-			throw new Minz_FileNotExistException($filename);
-		}
-
-		$data = include($filename);
+		$data = @include($filename);
 		if (is_array($data)) {
 			return $data;
 		} else {
-			return array();
+			throw new Minz_FileNotExistException($filename);
 		}
 	}
 
@@ -117,7 +110,7 @@ class Minz_Configuration {
 		$this->default_filename = $default_filename;
 		$this->_configurationSetter($configuration_setter);
 
-		if (!is_null($this->default_filename)) {
+		if ($this->default_filename != null) {
 			$this->data = self::load($this->default_filename);
 		}
 
@@ -126,7 +119,7 @@ class Minz_Configuration {
 				$this->data, self::load($this->config_filename)
 			);
 		} catch (Minz_FileNotExistException $e) {
-			if (is_null($this->default_filename)) {
+			if ($this->default_filename == null) {
 				throw $e;
 			}
 		}
diff --git a/lib/favicons.php b/lib/favicons.php
index fe2e65f1f..7a2d1187e 100644
--- a/lib/favicons.php
+++ b/lib/favicons.php
@@ -22,6 +22,7 @@ function isImgMime($content) {
 }
 
 function downloadHttp(&$url, $curlOptions = array()) {
+	prepareSyslog();
 	syslog(LOG_INFO, 'FreshRSS Favicon GET ' . $url);
 	if (substr($url, 0, 2) === '//') {
 		$url = 'https:' . $url;
diff --git a/lib/lib_install.php b/lib/lib_install.php
index d51a37e58..6e4df4e9c 100644
--- a/lib/lib_install.php
+++ b/lib/lib_install.php
@@ -81,6 +81,7 @@ function generateSalt() {
 function checkDb(&$dbOptions) {
 	$dsn = '';
 	$driver_options = null;
+	prepareSyslog();
 	try {
 		switch ($dbOptions['type']) {
 		case 'mysql':
diff --git a/lib/lib_rss.php b/lib/lib_rss.php
index 333920c8c..738ccf641 100644
--- a/lib/lib_rss.php
+++ b/lib/lib_rss.php
@@ -202,12 +202,19 @@ function html_only_entity_decode($text) {
 	return strtr($text, $htmlEntitiesOnly);
 }
 
+function prepareSyslog() {
+	return openlog("FreshRSS", LOG_PERROR | LOG_PID, LOG_USER);
+}
+
 function customSimplePie($attributes = array()) {
 	$system_conf = Minz_Configuration::get('system');
 	$limits = $system_conf->limits;
 	$simplePie = new SimplePie();
 	$simplePie->set_useragent(FRESHRSS_USERAGENT);
 	$simplePie->set_syslog($system_conf->simplepie_syslog_enabled);
+	if ($system_conf->simplepie_syslog_enabled) {
+		prepareSyslog();
+	}
 	$simplePie->set_cache_location(CACHE_PATH);
 	$simplePie->set_cache_duration($limits['cache_duration']);
 
@@ -364,9 +371,9 @@ function get_user_configuration($username) {
 		                             join_path(FRESHRSS_PATH, 'config-user.default.php'));
 	} catch (Minz_ConfigurationNamespaceException $e) {
 		// namespace already exists, do nothing.
-		Minz_Log::warning($e->getMessage());
+		Minz_Log::warning($e->getMessage(), USERS_PATH . '/_/log.txt');
 	} catch (Minz_FileNotExistException $e) {
-		Minz_Log::warning($e->getMessage());
+		Minz_Log::warning($e->getMessage(), USERS_PATH . '/_/log.txt');
 		return null;
 	}
 
@@ -375,14 +382,13 @@ function get_user_configuration($username) {
 
 
 function httpAuthUser() {
-	if (isset($_SERVER['REMOTE_USER'])) {
+	if (!empty($_SERVER['REMOTE_USER'])) {
 		return $_SERVER['REMOTE_USER'];
-	}
-
-	if (isset($_SERVER['REDIRECT_REMOTE_USER'])) {
+	} elseif (!empty($_SERVER['REDIRECT_REMOTE_USER'])) {
 		return $_SERVER['REDIRECT_REMOTE_USER'];
+	} elseif (!empty($_SERVER['HTTP_X_WEBAUTH_USER'])) {
+		return $_SERVER['HTTP_X_WEBAUTH_USER'];
 	}
-
 	return '';
 }
 
diff --git a/p/api/greader.php b/p/api/greader.php
index 7cd312f2c..d41430d3c 100644
--- a/p/api/greader.php
+++ b/p/api/greader.php
@@ -143,14 +143,11 @@ function checkCompatibility() {
 	Minz_Log::warning('checkCompatibility() ' . debugInfo(), API_LOG);
 	header('Content-Type: text/plain; charset=UTF-8');
 	if (PHP_INT_SIZE < 8 && !function_exists('gmp_init')) {
-		die('FAIL 64-bit or GMP extension!');
+		die('FAIL 64-bit or GMP extension! Wrong PHP configuration.');
 	}
-	if ((!array_key_exists('HTTP_AUTHORIZATION', $_SERVER)) &&	//Apache mod_rewrite trick should be fine
-		(!array_key_exists('REDIRECT_HTTP_AUTHORIZATION', $_SERVER)) &&	//Apache mod_rewrite with FCGI
-		(empty($_SERVER['SERVER_SOFTWARE']) || (stripos($_SERVER['SERVER_SOFTWARE'], 'nginx') === false)) &&	//nginx should be fine
-		(empty($_SERVER['SERVER_SOFTWARE']) || (stripos($_SERVER['SERVER_SOFTWARE'], 'lighttpd') === false)) &&	//lighttpd should be fine
-		((!function_exists('getallheaders')) || (stripos(php_sapi_name(), 'cgi') !== false))) {	//Main problem is Apache/CGI mode
-		die('FAIL getallheaders! (probably)');
+	$headerAuth = headerVariable('Authorization', 'GoogleLogin_auth');
+	if ($headerAuth == '') {
+		die('FAIL get HTTP Authorization header! Wrong Web server configuration.');
 	}
 	echo 'PASS';
 	exit();
@@ -913,6 +910,10 @@ FreshRSS_Context::$system_conf = Minz_Configuration::get('system');
 
 if (!FreshRSS_Context::$system_conf->api_enabled) {
 	serviceUnavailable();
+} elseif (count($pathInfos) < 3) {
+	badRequest();
+} elseif ($pathInfos[1] === 'check' && $pathInfos[2] === 'compatibility') {
+	checkCompatibility();
 }
 
 ini_set('session.use_cookies', '0');
@@ -927,9 +928,7 @@ if ($user !== '') {
 
 Minz_Session::_param('currentUser', $user);
 
-if (count($pathInfos) < 3) {
-	badRequest();
-} elseif ($pathInfos[1] === 'accounts') {
+if ($pathInfos[1] === 'accounts') {
 	if (($pathInfos[2] === 'ClientLogin') && isset($_REQUEST['Email']) && isset($_REQUEST['Passwd'])) {
 		clientLogin($_REQUEST['Email'], $_REQUEST['Passwd']);
 	}
@@ -1088,8 +1087,6 @@ if (count($pathInfos) < 3) {
 			userInfo();
 			break;
 	}
-} elseif ($pathInfos[1] === 'check' && $pathInfos[2] === 'compatibility') {
-	checkCompatibility();
 }
 
 badRequest();
diff --git a/p/api/index.php b/p/api/index.php
index ee37b794b..d441099d7 100644
--- a/p/api/index.php
+++ b/p/api/index.php
@@ -5,6 +5,18 @@
 <title>FreshRSS API endpoints</title>
 <meta name="robots" content="noindex" />
 <link rel="start" href="../i/" />
+<script src="../scripts/api.js" defer="defer"></script>
+<script id="jsonVars" type="application/json">
+<?php
+require(__DIR__ . '/../../constants.php');
+require(LIB_PATH . '/lib_rss.php');	//Includes class autoloader
+Minz_Configuration::register('system', DATA_PATH . '/config.php', FRESHRSS_PATH . '/config.default.php');
+echo json_encode(array(
+		'greader' => Minz_Url::display('/api/greader.php', 'php', true),
+		'fever' => Minz_Url::display('/api/fever.php', 'php', true),
+	));
+?>
+</script>
 </head>
 
 <body>
@@ -14,17 +26,11 @@
 <dl>
 <dt>Your API address:</dt>
 <dd><?php
-require(__DIR__ . '/../../constants.php');
-require(LIB_PATH . '/lib_rss.php');	//Includes class autoloader
-Minz_Configuration::register('system', DATA_PATH . '/config.php', FRESHRSS_PATH . '/config.default.php');
 echo Minz_Url::display('/api/greader.php', 'html', true);
 ?></dd>
+<dt>Google Reader API configuration test:</dt>
+<dd id="greaderOutput">?</dd>
 </dl>
-<ul>
-<li><a href="greader.php/check%2Fcompatibility" rel="nofollow">Check full server configuration</a></li>
-<li><a href="greader.php/check/compatibility" rel="nofollow">Check partial server
-configuration (without <code>%2F</code> support)</a></li>
-</ul>
 
 <h2>Fever compatible API</h2>
 <dl>
@@ -32,10 +38,9 @@ configuration (without <code>%2F</code> support)</a></li>
 <dd><?php
 echo Minz_Url::display('/api/fever.php', 'html', true);
 ?></dd>
+<dt>Fever API configuration test:</dt>
+<dd id="feverOutput">?</dd>
 </dl>
-<ul>
-<li><a href="fever.php?api" rel="nofollow">Test</a></li>
-</ul>
 
 </body>
 </html>
diff --git a/p/i/index.php b/p/i/index.php
index 5bc9c0d76..8a4f529d4 100755
--- a/p/i/index.php
+++ b/p/i/index.php
@@ -50,5 +50,7 @@ if (file_exists(DATA_PATH . '/do-install.txt')) {
 		echo '### Fatal error! ###<br />', "\n";
 		Minz_Log::error($e->getMessage());
 		echo 'See logs files.';
+		prepareSyslog();
+		syslog(LOG_INFO, 'FreshRSS Fatal error! ' . $e->getMessage());
 	}
 }
diff --git a/p/scripts/api.js b/p/scripts/api.js
new file mode 100644
index 000000000..841b16a6a
--- /dev/null
+++ b/p/scripts/api.js
@@ -0,0 +1,62 @@
+"use strict";
+/* jshint esversion:6, strict:global */
+
+function check(url, next) {
+	if (!url || !next) {
+		return;
+	}
+	const req = new XMLHttpRequest();
+	req.open('GET', url, true);
+	req.setRequestHeader('Authorization', 'GoogleLogin auth=test/1');
+	req.onerror = function (e) {
+			next('FAIL: HTTP ' + e);
+		};
+	req.onload = function () {
+		if (this.status == 200) {
+			next(this.response);
+		} else {
+			next('FAIL: HTTP error ' + this.status + ' ' + this.statusText);
+		}
+	};
+	req.send();
+}
+
+const jsonVars = JSON.parse(document.getElementById('jsonVars').innerHTML);
+
+check(jsonVars.greader + '/check/compatibility', function next(result1) {
+		const greaderOutput = document.getElementById('greaderOutput');
+		if (result1 === 'PASS') {
+			greaderOutput.innerHTML = '✔️ ' + result1;
+		} else {
+			check(jsonVars.greader + '/check%2Fcompatibility', function next(result2) {
+				if (result2 === 'PASS') {
+					greaderOutput.innerHTML = '⚠️ WARN: no <code>%2F</code> support, so some clients will not work!';
+				} else {
+					check('./greader.php/check/compatibility', function next(result3) {
+						if (result3 === 'PASS') {
+							greaderOutput.innerHTML = '⚠️ WARN: Probable invalid base URL in ./data/config.php';
+						} else {
+							greaderOutput.innerHTML = '❌ ' + result1;
+						}
+					});
+				}
+			});
+		}
+	});
+
+check(jsonVars.fever + '?api', function next(result1) {
+		const feverOutput = document.getElementById('feverOutput');
+		try {
+			JSON.parse(result1);
+			feverOutput.innerHTML = '✔️ PASS';
+		} catch (ex) {
+			check('./fever.php?api', function next(result2) {
+					try {
+						JSON.parse(result2);
+						feverOutput.innerHTML = '⚠️ WARN: Probable invalid base URL in ./data/config.php';
+					} catch (ex) {
+						feverOutput.innerHTML = '❌ ' + result1;
+					}
+				});
+		}
+	});