[locale] Make the style of GeoIP retrieval selectable

- Unchanged config files will continue to use the weird addition
   of /json, and interpret JSON data.
 - Allow to specify full URL with data format through one of
     geoipStyle: json
     geoipStyle: xml
 - XML support is optional

src/modules/locale/CMakeLists.txt

@@ -7,6 +7,7 @@ find_package(Qt5 COMPONENTS Xml)
 if( Qt5Xml_FOUND )
     list( APPEND geoip_src GeoIPXML.cpp )
     list( APPEND geoip_libs Qt5::Xml )
+    add_definitions( -DHAVE_XML )
 endif()
 
 calamares_add_plugin( locale

src/modules/locale/LocaleViewStep.cpp

@@ -21,6 +21,9 @@
 
 #include "GeoIP.h"
 #include "GeoIPFreeGeoIP.h"
+#ifdef HAVE_XML
+#include "GeoIPXML.h"
+#endif
 #include "GlobalStorage.h"
 #include "JobQueue.h"
 #include "LocalePage.h"
@@ -114,9 +117,32 @@ LocaleViewStep::setUpPage()
 void
 LocaleViewStep::fetchGeoIpTimezone()
 {
-    QNetworkAccessManager *manager = new QNetworkAccessManager( this );
-    GeoIP *handler = new FreeGeoIP;
+    QString actualUrl( m_geoipUrl );
+    GeoIP *handler = nullptr;
 
+    if ( m_geoipStyle.isEmpty() || m_geoipStyle == "legacy" )
+    {
+        actualUrl.append( "/json" );
+        handler = new FreeGeoIP;
+    }
+    else if ( m_geoipStyle == "json" )
+    {
+        handler = new FreeGeoIP;
+    }
+#if defined(HAVE_XML)
+    else if ( m_geoipStyle == "xml" )
+    {
+        handler = new XMLGeoIP;
+    }
+#endif
+    else
+    {
+        cDebug() << "WARNING: GeoIP Style" << m_geoipStyle << "is not recognized.";
+        setUpPage();
+        return;
+    }
+
+    QNetworkAccessManager *manager = new QNetworkAccessManager( this );
     connect( manager, &QNetworkAccessManager::finished,
             [=]( QNetworkReply* reply )
     {
@@ -269,4 +295,10 @@ LocaleViewStep::setConfigurationMap( const QVariantMap& configurationMap )
     {
         m_geoipUrl = configurationMap.value( "geoipUrl" ).toString();
     }
+    if ( configurationMap.contains( "geoipStyle" ) &&
+         configurationMap.value( "geoipStyle" ).type() == QVariant::String &&
+         !configurationMap.value( "geoipStyle" ).toString().isEmpty() )
+    {
+        m_geoipStyle = configurationMap.value( "geoipStyle" ).toString();
+    }
 }

src/modules/locale/LocaleViewStep.h

@@ -76,6 +76,7 @@ private:
     QPair< QString, QString > m_startingTimezone;
     QString m_localeGenPath;
     QString m_geoipUrl;
+    QString m_geoipStyle;
 
     QList< Calamares::job_ptr > m_jobs;
 };

src/modules/locale/locale.conf

@@ -19,8 +19,8 @@ zone:                       "New_York"
 
 # GeoIP settings. Leave commented out to disable GeoIP.
 #
-# An HTTP request is made to *geoipUrl* -- prior to Calamares 3.1.13,
-# an implicit "/json" was added at the end.. The request must return
+# An HTTP request is made to *geoipUrl* -- depending on the geoipStyle,
+# the URL may be modified before use. The request must return
 # valid JSON data in the FreeGeoIP format; there should
 # be an attribute *time_zone*, with a string value set to the
 # timezone, in <region>/<zone> format.
@@ -34,3 +34,19 @@ zone:                       "New_York"
 # ```
 #
 #geoipUrl:                  "freegeoip.net/json"
+
+# GeoIP style. Leave commented out for the "legacy" interpretation.
+# This setting only makes sense if geoipUrl is set, enabliing geoIP.
+#
+# Possible values are:
+#   unset       same as "legacy"
+#   blank       same as "legacy"
+#   "legacy"    appends "/json" to geoipUrl, above, and uses JSON format
+#               (which is what freegeoip.net provides there).
+#   "json"      URL is not modified, uses JSON format.
+#   "xml"       URL is not modified, uses XML format.
+#
+# The JSON format is provided by freegeoip.net, but that service is
+# shutting down in June 2018. There are other providers with the same
+# format. XML format is provided for Ubiquity.
+#geoipStyle:    "legacy"