Allow disabling the usage of the default geolocation provider as fallback (#18634)

* Allow disabling the usage of the default geolocation provider as fallback

* Improve naming

* add changelog entry

* Introduce a disabled provider and setting to disable the default provider

* fix tests

* update changelog

18 files changed, 203 insertions, 23 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5845741e1d..f3a804c20e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,12 @@ This is the Developer Changelog for Matomo platform developers. All changes in o
 
 The Product Changelog at **[matomo.org/changelog](https://matomo.org/changelog)** lets you see more details about any Matomo release, such as the list of new guides and FAQs, security fixes, and links to all closed issues. 
 
+## Matomo 4.8.0
+
+### New config.ini.php settings
+
+* The config setting `enable_default_location_provider` in `Tracker` has been added. By setting this option to 0, you can disable the default location provider. This can be used to prevent the geolocator to guess the country based on the users language, if the configured provider doesn't provide any results.
+
 ## Matomo 4.7.0
 
 ### Deprecated APIs
diff --git a/config/global.ini.php b/config/global.ini.php
index aaf8fbd585..4da5694f47 100755
--- a/config/global.ini.php
+++ b/config/global.ini.php
@@ -928,6 +928,11 @@ default_time_one_page_visit = 0
 ; By default, Matomo will remove the most common parameters which are known to change often (eg. session ID parameters)
 url_query_parameter_to_exclude_from_url = "gclid,fbclid,fb_xd_fragment,fb_comment_id,phpsessid,jsessionid,sessionid,aspsessionid,doing_wp_cron,sid,pk_vid"
 
+; If set to 1, Matomo will use the default provider if no other provider is configured.
+; In addition the default provider will be used as a fallback when the configure provider does not return any results.
+; If set to 0, the default provider will be unavailable. Instead the "disabled" provider will be used as default and fallback instead.
+enable_default_location_provider = 1
+
 ; if set to 1, Matomo attempts a "best guess" at the visitor's country of
 ; origin when the preferred language tag omits region information.
 ; The mapping is defined in core/DataFiles/LanguageToCountry.php,
diff --git a/core/Common.php b/core/Common.php
index 08751d5cbe..9a8d45d6b7 100644
--- a/core/Common.php
+++ b/core/Common.php
@@ -1171,7 +1171,7 @@ class Common
     {
         $cache = TrackerCache::getCacheGeneral();
         return empty($cache['currentLocationProviderId'])
-            ? DefaultProvider::ID
+            ? Plugins\UserCountry\LocationProvider::getDefaultProviderId()
             : $cache['currentLocationProviderId'];
     }
 
diff --git a/lang/en.json b/lang/en.json
index 235e9b40b6..3bb323ed77 100644
--- a/lang/en.json
+++ b/lang/en.json
@@ -149,6 +149,7 @@
         "Description": "Description",
         "Desktop": "Desktop",
         "Details": "Details",
+        "Disabled": "Disabled",
         "Discount": "Discount",
         "DisplaySimpleTable": "Display simple table",
         "DisplayTableWithGoalMetrics": "Display a table with Goals metrics",
diff --git a/plugins/GeoIp2/GeoIp2.php b/plugins/GeoIp2/GeoIp2.php
index 03ccd58b1c..3f9363a3f2 100644
--- a/plugins/GeoIp2/GeoIp2.php
+++ b/plugins/GeoIp2/GeoIp2.php
@@ -40,7 +40,7 @@ class GeoIp2 extends \Piwik\Plugin
     {
         // switch to default provider if GeoIP2 provider was in use
         if (LocationProvider::getCurrentProvider() instanceof \Piwik\Plugins\GeoIp2\LocationProvider\GeoIp2) {
-            LocationProvider::setCurrentProvider(LocationProvider\DefaultProvider::ID);
+            LocationProvider::setCurrentProvider(LocationProvider::getDefaultProviderId());
         }
     }
 
diff --git a/plugins/GeoIp2/tests/Integration/LocationProviderTest.php b/plugins/GeoIp2/tests/Integration/LocationProviderTest.php
index 938325c5bd..ea1fc20927 100644
--- a/plugins/GeoIp2/tests/Integration/LocationProviderTest.php
+++ b/plugins/GeoIp2/tests/Integration/LocationProviderTest.php
@@ -8,7 +8,11 @@
  */
 namespace Piwik\Plugins\GeoIp2\tests\Integration;
 
+use Piwik\Config;
 use Piwik\Plugins\GeoIp2\LocationProvider\GeoIp2;
+use Piwik\Plugins\UserCountry\LocationProvider\DefaultProvider;
+use Piwik\Plugins\UserCountry\VisitorGeolocator;
+use Piwik\Tests\Framework\Fixture;
 
 /**
  * @group GeoIp2
@@ -109,4 +113,35 @@ class LocationProviderTest extends \PHPUnit\Framework\TestCase
             'org' => 'Innocraft'
         ], $result);
     }
+
+    public function testGeoIP2NoResultFallback()
+    {
+        Fixture::loadAllTranslations();
+        $locationProvider = new GeoIp2\Php(['loc' => ['GeoIP2-City.mmdb'], 'isp' => []]);
+        $geolocator = new VisitorGeolocator($locationProvider, new DefaultProvider());
+
+        $result = $geolocator->getLocation(['ip' => '221.0.0.9', 'lang' => 'de-ch'], false);
+
+        $this->assertEquals([
+            'country_code' => 'ch',
+            'country_name' => 'Switzerland',
+            'continent_code' => 'eur',
+            'continent_name' => 'Europe',
+        ], $result);
+    }
+
+    public function testGeoIP2NoResultFallbackDisabled()
+    {
+        Fixture::loadAllTranslations();
+        Config::getInstance()->Tracker['enable_default_location_provider'] = 0;
+
+        $locationProvider = new GeoIp2\Php(['loc' => ['GeoIP2-City.mmdb'], 'isp' => []]);
+        $geolocator = new VisitorGeolocator($locationProvider);
+
+        $result = $geolocator->getLocation(['ip' => '221.0.0.9', 'lang' => 'de-ch'], false);
+
+        $this->assertEquals([
+            'country_code' => 'xx',
+        ], $result);
+    }
 }
\ No newline at end of file
diff --git a/plugins/UserCountry/Controller.php b/plugins/UserCountry/Controller.php
index c3d84522aa..1001108a64 100644
--- a/plugins/UserCountry/Controller.php
+++ b/plugins/UserCountry/Controller.php
@@ -16,6 +16,7 @@ use Piwik\Piwik;
 use Piwik\Plugin\Manager;
 use Piwik\Plugins\GeoIp2\LocationProvider\GeoIp2;
 use Piwik\Plugins\UserCountry\LocationProvider\DefaultProvider;
+use Piwik\Plugins\UserCountry\LocationProvider\DisabledProvider;
 use Piwik\SettingsPiwik;
 use Piwik\View;
 
@@ -78,7 +79,7 @@ class Controller extends \Piwik\Plugin\ControllerAdmin
         // check if there is a working provider (that isn't the default one)
         $isThereWorkingProvider = false;
         foreach ($allProviderInfo as $id => $provider) {
-            if ($id != DefaultProvider::ID
+            if ($id != DefaultProvider::ID && $id != DisabledProvider::ID
                 && $provider['status'] == LocationProvider::INSTALLED
             ) {
                 $isThereWorkingProvider = true;
diff --git a/plugins/UserCountry/LocationProvider.php b/plugins/UserCountry/LocationProvider.php
index cbc2117b33..812f2bfc58 100644
--- a/plugins/UserCountry/LocationProvider.php
+++ b/plugins/UserCountry/LocationProvider.php
@@ -16,7 +16,9 @@ use Piwik\Piwik;
 use Piwik\Plugin;
 use Piwik\Plugins\UserCountry\LocationProvider\DefaultProvider;
 use Piwik\Plugin\Manager as PluginManager;
+use Piwik\Plugins\UserCountry\LocationProvider\DisabledProvider;
 use Piwik\Tracker\Cache;
+use Piwik\Tracker\TrackerConfig;
 
 /**
  * @see plugins/UserCountry/functions.php
@@ -340,7 +342,7 @@ abstract class LocationProvider
         } catch (\Exception $e) {
             $optionValue = false;
         }
-        return $optionValue === false ? DefaultProvider::ID : $optionValue;
+        return $optionValue === false ? self::getDefaultProviderId() : $optionValue;
     }
 
     /**
@@ -378,6 +380,20 @@ abstract class LocationProvider
     }
 
     /**
+     * Returns the default provider id to use
+     *
+     * @return string
+     */
+    public static function getDefaultProviderId()
+    {
+        if (!!TrackerConfig::getConfigValue('enable_default_location_provider')) {
+            return DefaultProvider::ID;
+        }
+
+        return DisabledProvider::ID;
+    }
+
+    /**
      * Returns a provider instance by ID or false if the ID is invalid or unavailable.
      *
      * @param string $providerId
diff --git a/plugins/UserCountry/LocationProvider/DefaultProvider.php b/plugins/UserCountry/LocationProvider/DefaultProvider.php
index 2abfe0098a..e5f311fed6 100644
--- a/plugins/UserCountry/LocationProvider/DefaultProvider.php
+++ b/plugins/UserCountry/LocationProvider/DefaultProvider.php
@@ -12,6 +12,7 @@ use Piwik\Common;
 use Piwik\Config;
 use Piwik\Piwik;
 use Piwik\Plugins\UserCountry\LocationProvider;
+use Piwik\Tracker\TrackerConfig;
 
 /**
  * The default LocationProvider, this LocationProvider guesses a visitor's country
@@ -47,13 +48,22 @@ class DefaultProvider extends LocationProvider
     /**
      * Returns whether this location provider is available.
      *
-     * This implementation is always available.
-     *
-     * @return bool  always true
+     * @return bool
      */
     public function isAvailable()
     {
-        return true;
+        return !!TrackerConfig::getConfigValue('enable_default_location_provider');
+    }
+
+
+    /**
+     * Returns whether this location provider is visible.
+     *
+     * @return bool
+     */
+    public function isVisible()
+    {
+        return !!TrackerConfig::getConfigValue('enable_default_location_provider');
     }
 
     /**
diff --git a/plugins/UserCountry/LocationProvider/DisabledProvider.php b/plugins/UserCountry/LocationProvider/DisabledProvider.php
new file mode 100644
index 0000000000..d5444a2c02
--- /dev/null
+++ b/plugins/UserCountry/LocationProvider/DisabledProvider.php
@@ -0,0 +1,98 @@
+<?php
+/**
+ * Matomo - free/libre analytics platform
+ *
+ * @link https://matomo.org
+ * @license http://www.gnu.org/licenses/gpl-3.0.html GPL v3 or later
+ *
+ */
+namespace Piwik\Plugins\UserCountry\LocationProvider;
+
+use Piwik\Common;
+use Piwik\Config;
+use Piwik\Piwik;
+use Piwik\Plugins\UserCountry\LocationProvider;
+
+/**
+ * The disabled LocationProvider, this LocationProvider always returns an empty result set.
+ *
+ */
+class DisabledProvider extends LocationProvider
+{
+    const ID = 'disabled';
+    const TITLE = 'General_Disabled';
+
+    /**
+     * Guesses a visitor's location using a visitor's browser language.
+     *
+     * @param array $info Contains 'ip' & 'lang' keys.
+     * @return false.
+     */
+    public function getLocation($info)
+    {
+        return false;
+    }
+
+    /**
+     * Returns whether this location provider is available.
+     *
+     * This implementation is always available.
+     *
+     * @return bool  always true
+     */
+    public function isAvailable()
+    {
+        return true;
+    }
+
+    /**
+     * Returns whether this location provider is working correctly.
+     *
+     * This implementation is always working correctly.
+     *
+     * @return bool  always true
+     */
+    public function isWorking()
+    {
+        return true;
+    }
+
+    /**
+     * Returns an array describing the types of location information this provider will
+     * return.
+     *
+     * @return array
+     */
+    public function getSupportedLocationInfo()
+    {
+        return [];
+    }
+
+    /**
+     * Returns information about this location provider. Contains an id, title & description:
+     *
+     * array(
+     *     'id' => 'default',
+     *     'title' => '...',
+     *     'description' => '...'
+     * );
+     *
+     * @return array
+     */
+    public function getInfo()
+    {
+        $desc = Piwik::translate('UserCountry_DisabledLocationProvider');
+        return array('id' => self::ID, 'title' => self::TITLE, 'description' => $desc, 'order' => 0);
+    }
+
+    public function getUsageWarning(): ?string
+    {
+        $comment = Piwik::translate('UserCountry_DefaultLocationProviderDesc1') . ' ';
+        $comment .= Piwik::translate('UserCountry_DefaultLocationProviderDesc2', array(
+            '<a href="https://matomo.org/docs/geo-locate/" rel="noreferrer noopener" target="_blank">', '', '', '</a>'
+        ));
+
+        return $comment;
+    }
+}
+
diff --git a/plugins/UserCountry/VisitorGeolocator.php b/plugins/UserCountry/VisitorGeolocator.php
index 23395dea17..b5725d5188 100644
--- a/plugins/UserCountry/VisitorGeolocator.php
+++ b/plugins/UserCountry/VisitorGeolocator.php
@@ -11,10 +11,13 @@ namespace Piwik\Plugins\UserCountry;
 use Matomo\Cache\Cache;
 use Matomo\Cache\Transient;
 use Piwik\Common;
+use Piwik\Config\GeneralConfig;
 use Piwik\Container\StaticContainer;
 use Piwik\DataAccess\RawLogDao;
 use Matomo\Network\IPUtils;
 use Piwik\Plugins\UserCountry\LocationProvider\DefaultProvider;
+use Piwik\Plugins\UserCountry\LocationProvider\DisabledProvider;
+use Piwik\Tracker\TrackerConfig;
 use Piwik\Tracker\Visit;
 use Psr\Log\LoggerInterface;
 
@@ -90,7 +93,7 @@ class VisitorGeolocator
             $provider = LocationProvider::getProviderById(Common::getCurrentLocationProviderId());
 
             if (empty($provider)) {
-                Common::printDebug("GEO: no current location provider sent, falling back to default '" . DefaultProvider::ID . "' one.");
+                Common::printDebug("GEO: no current location provider sent, falling back to '" . LocationProvider::getDefaultProviderId() . "' one.");
 
                 $provider = $this->getDefaultProvider();
             }
@@ -118,7 +121,8 @@ class VisitorGeolocator
             $providerId = $this->provider->getId();
             Common::printDebug("GEO: couldn't find a location with Geo Module '$providerId'");
 
-            if ($providerId != $this->backupProvider->getId()) {
+            // Only use the default provider as fallback if the configured one isn't "disabled"
+            if ($providerId != DisabledProvider::ID && $providerId != $this->backupProvider->getId()) {
                 Common::printDebug("Using default provider as fallback...");
 
                 $location = $this->getLocationObject($this->backupProvider, $userInfo);
@@ -299,7 +303,7 @@ class VisitorGeolocator
 
     private function getDefaultProvider()
     {
-        return LocationProvider::getProviderById(DefaultProvider::ID);
+        return LocationProvider::getProviderById(LocationProvider::getDefaultProviderId());
     }
 
     public static function getDefaultLocationCache()
diff --git a/plugins/UserCountry/lang/en.json b/plugins/UserCountry/lang/en.json
index 2c52d95574..deed27baf9 100644
--- a/plugins/UserCountry/lang/en.json
+++ b/plugins/UserCountry/lang/en.json
@@ -16,6 +16,7 @@
         "DefaultLocationProviderDesc1": "The default location provider guesses a visitor's country based on the language they use.",
         "DefaultLocationProviderDesc2": "This is not very accurate, so %1$swe recommend installing and using %2$sa geolocation database%3$s.%4$s",
         "DefaultLocationProviderExplanation": "You are using the default location provider, which means Matomo will guess the visitor's location based on the language they use. %1$sRead this%2$s to learn how to setup more accurate geolocation.",
+        "DisabledLocationProvider": "Disables the geolocation.",
         "DistinctCountries": "%s distinct countries",
         "FromDifferentCities": "different cities",
         "GeoIPDocumentationSuffix": "In order to see data for this report, you must setup GeoIP in the Geolocation admin tab. The commercial %1$sMaxmind%2$s GeoIP databases are more accurate than the free ones. To see how accurate they are, click %3$shere%4$s.",
diff --git a/plugins/UserCountry/templates/adminIndex.twig b/plugins/UserCountry/templates/adminIndex.twig
index b83aa07333..20cc6deede 100644
--- a/plugins/UserCountry/templates/adminIndex.twig
+++ b/plugins/UserCountry/templates/adminIndex.twig
@@ -89,7 +89,10 @@
     {% endfor %}
 
 
-    {% if locationProviders|length == 1 %}
+    {% if locationProviders|filter(provider => (
+        provider.id != constant("Piwik\\Plugins\\UserCountry\\LocationProvider\\DefaultProvider::ID") and
+        provider.id != constant("Piwik\\Plugins\\UserCountry\\LocationProvider\\DisabledProvider::ID")
+    ))|length == 0 %}
     <div piwik-notification
          noclear="true"
          context="warning">
diff --git a/plugins/UserCountry/tests/Integration/LocationProviderTest.php b/plugins/UserCountry/tests/Integration/LocationProviderTest.php
index 262317653f..ee9397cf16 100644
--- a/plugins/UserCountry/tests/Integration/LocationProviderTest.php
+++ b/plugins/UserCountry/tests/Integration/LocationProviderTest.php
@@ -23,9 +23,9 @@ class LocationProviderTest extends IntegrationTestCase
     {
         $allProviders = LocationProvider::getAllProviderInfo();
 
-        // We currently have 3 Providers shipped with core
-        $this->assertSame(3, count($allProviders));
-        $this->assertEquals(['default', 'geoip2php', 'geoip2server'], array_keys($allProviders));
+        // We currently have 4 Providers shipped with core
+        $this->assertSame(4, count($allProviders));
+        $this->assertEquals(['disabled', 'default', 'geoip2php', 'geoip2server'], array_keys($allProviders));
     }
 
     public function testGetAllProviderInfoWithDuplicateOrder()
diff --git a/plugins/UserCountry/tests/UI/expected-screenshots/UserCountry_admin_geoip2.png b/plugins/UserCountry/tests/UI/expected-screenshots/UserCountry_admin_geoip2.png
index b3626a974c..3efae3951b 100644
--- a/plugins/UserCountry/tests/UI/expected-screenshots/UserCountry_admin_geoip2.png
+++ b/plugins/UserCountry/tests/UI/expected-screenshots/UserCountry_admin_geoip2.png
@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:64cc7b555c783a0365eb8249701cabf6d1650fc0eeebac8f562dfcf9bd70fba9
-size 247298
+oid sha256:61efd451e6bd350c71beb3ea6da0e40e0f4ee9a1add39252ae39b0b1e530f976
+size 260278
diff --git a/plugins/UserCountry/tests/UI/expected-screenshots/UserCountry_admin_geoip2_no_provider.png b/plugins/UserCountry/tests/UI/expected-screenshots/UserCountry_admin_geoip2_no_provider.png
index 532e60ab82..a236cc76d8 100644
--- a/plugins/UserCountry/tests/UI/expected-screenshots/UserCountry_admin_geoip2_no_provider.png
+++ b/plugins/UserCountry/tests/UI/expected-screenshots/UserCountry_admin_geoip2_no_provider.png
@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:33c3b0f2924e79a33fcdca6f541b6c259d1255817d294643fd64513fe566668f
-size 256721
+oid sha256:1a15ce0840e134885bc87ec6fa97a2e15425d2412faf06b7f79279328e3708b8
+size 269720
diff --git a/plugins/UserCountry/tests/UI/expected-screenshots/UserCountry_admin_no_providers.png b/plugins/UserCountry/tests/UI/expected-screenshots/UserCountry_admin_no_providers.png
index 04e05d4a2b..86d911fa77 100644
--- a/plugins/UserCountry/tests/UI/expected-screenshots/UserCountry_admin_no_providers.png
+++ b/plugins/UserCountry/tests/UI/expected-screenshots/UserCountry_admin_no_providers.png
@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:b9bfdbf2b4fa503fefb46fffbe75d641dcff47d6597079f6fba34ba0f102a13a
-size 67371
+oid sha256:219dba7d0c5fabfa578cad517c226bd263111ddb72348a15ed022d9289ee1d3b
+size 80454
diff --git a/tests/UI/expected-screenshots/UIIntegrationTest_admin_diagnostics_configfile.png b/tests/UI/expected-screenshots/UIIntegrationTest_admin_diagnostics_configfile.png
index a1cff9db36..90b3b40a89 100644
--- a/tests/UI/expected-screenshots/UIIntegrationTest_admin_diagnostics_configfile.png
+++ b/tests/UI/expected-screenshots/UIIntegrationTest_admin_diagnostics_configfile.png
@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:137be8e7a24b7075052f0839e2e5c10816d28d418ed9afb0f348e53c8b906b14
-size 5308352
+oid sha256:44f0bb1657d44f4d272f1460ede23965e8ea3a87b60d8233cf5f6e6d7576fa52
+size 5335101