Add a max_registrations limit

- Allow user to create accounts (not implemented)
- Admin only can set this limit

See https://github.com/FreshRSS/FreshRSS/issues/679

app/Controllers/userController.php

@@ -211,4 +211,28 @@ class FreshRSS_user_Controller extends Minz_ActionController {
 
 		Minz_Request::forward(array('c' => 'user', 'a' => 'manage'), true);
 	}
+
+	/**
+	 * This action updates the max number of registrations.
+	 *
+	 * Request parameter is:
+	 *   - max-registrations (int >= 0)
+	 */
+	public function setRegistrationAction() {
+		if (Minz_Request::isPost() && FreshRSS_Auth::hasAccess('admin')) {
+			$limits = FreshRSS_Context::$system_conf->limits;
+			$limits['max_registrations'] = Minz_Request::param('max-registrations', 1);
+			FreshRSS_Context::$system_conf->limits = $limits;
+			FreshRSS_Context::$system_conf->save();
+
+			invalidateHttpCache();
+
+			Minz_Session::_param('notification', array(
+				'type' => 'good',
+				'content' => _t('feedback.user.set_registration')
+			));
+		}
+
+		Minz_Request::forward(array('c' => 'user', 'a' => 'manage'), true);
+	}
 }

app/Models/ConfigurationSetter.php

@@ -352,6 +352,9 @@ class FreshRSS_ConfigurationSetter {
 				'min' => 0,
 				'max' => $max_small_int,
 			),
+			'max_registrations' => array(
+				'min' => 0,
+			),
 		);
 
 		foreach ($values as $key => $value) {

app/views/user/manage.phtml

@@ -3,6 +3,25 @@
 <div class="post">
 	<a href="<?php echo _url('index', 'index'); ?>"><?php echo _t('gen.action.back_to_rss_feeds'); ?></a>
 
+	<form method="post" action="<?php echo _url('user', 'setRegistration'); ?>">
+		<legend><?php echo _t('admin.user.registration.allow'); ?></legend>
+
+		<div class="form-group">
+			<label class="group-name" for="max-registrations"><?php echo _t('admin.user.registration.number'); ?></label>
+			<div class="group-controls">
+				<input type="number" id="max-registrations" name="max-registrations" value="<?php echo FreshRSS_Context::$system_conf->limits['max_registrations']; ?>" min="0" data-leave-validation="<?php echo FreshRSS_Context::$system_conf->limits['max_registrations']; ?>"/>
+				<?php echo _i('help'); ?> <?php echo _t('admin.user.registration.help'); ?>
+			</div>
+		</div>
+
+		<div class="form-group form-actions">
+			<div class="group-controls">
+				<button type="submit" class="btn btn-important"><?php echo _t('gen.action.submit'); ?></button>
+				<button type="reset" class="btn"><?php echo _t('gen.action.cancel'); ?></button>
+			</div>
+		</div>
+	</form>
+
 	<form method="post" action="<?php echo _url('user', 'create'); ?>">
 		<legend><?php echo _t('admin.user.create'); ?></legend>
 

data/config.default.php

@@ -77,6 +77,10 @@ return array(
 		# Max number of categories for a user.
 		'max_categories' => 16384,
 
+		# Max number of accounts that anonymous users can create
+		#   0 for an unlimited number of accounts
+		#   1 is to not allow user registrations (1 is corresponding to the admin account)
+		'max_registrations' => 1,
 	),
 
 	# Options used by cURL when making HTTP requests, e.g. when the SimplePie library retrieves feeds.