mediawiki: Fix problem with session cache failing logins

Set the session cache to use database. This will also have the added benefit of
sessions persisting across reboots (and PHP session cleanups). See bug report on
why this is needed. https://salsa.debian.org/freedombox-team/plinth/issues/1736

We are unfortunately modifying the MediaWiki settings that file that we are
shipping when preferences are modified in the FreedomBox UI. This means that if
a newer version of this settings file is shipped, then FreedomBox package will
show configuration file prompts. To solve this, introduce a new static settings
file that will have lower priority than the file modified by FreedomBox UI.

Closes: #1736.

Tests:

- Test that running FreedomBox daemon with changes runs the MediaWiki app's
  setup and introduces the new line into LocalSettings.php

- That LocalSettings.php will be populated with lines to include
  FreedomBoxStaticSettings.php and FreedomBoxSettings.php in that order when
  'actions/mediawiki setup' is run. This should work when no lines are present,
  one of the lines is already present and both the lines are already present.

- Test that running './setup.py install' installs FreedomBoxStaticSettings.php.

- Test that MediaWiki runs without FreedomBoxStaticSettings.php

- Test that private wiki and public registrations settings work with the new
  changes.

- Run functional tests for MediaWiki app with the changes.

Signed-off-by: Sunil Mohan Adapa <sunil@medhas.org>
Reviewed-by: James Valleroy <jvalleroy@mailbox.org>

actions/mediawiki

@@ -25,7 +25,7 @@ import subprocess
 import sys
 import tempfile
 
-from plinth.utils import generate_password, grep
+from plinth.utils import generate_password
 
 MAINTENANCE_SCRIPTS_DIR = "/usr/share/mediawiki/maintenance"
 CONF_FILE = '/etc/mediawiki/FreedomBoxSettings.php'
@@ -87,12 +87,30 @@ def subcommand_setup(_):
 
 
 def include_custom_config():
-    """Include FreedomBox specific configuration in LocalSettings.php
-    """
-    if not grep(r'FreedomBoxSettings', LOCAL_SETTINGS_CONF):
-        with open(LOCAL_SETTINGS_CONF, 'a') as conf_file:
-            conf_file.write(
-                'include dirname(__FILE__)."/FreedomBoxSettings.php";\n')
+    """Include FreedomBox specific configuration in LocalSettings.php."""
+    with open(LOCAL_SETTINGS_CONF, 'r') as conf_file:
+        lines = conf_file.readlines()
+
+    static_settings_index = None
+    settings_index = None
+    for line_number, line in enumerate(lines):
+        if 'FreedomBoxSettings.php' in line:
+            settings_index = line_number
+
+        if 'FreedomBoxStaticSettings.php' in line:
+            static_settings_index = line_number
+
+    if settings_index is None:
+        settings_index = len(lines)
+        lines.append('include dirname(__FILE__)."/FreedomBoxSettings.php";\n')
+
+    if static_settings_index is None:
+        lines.insert(
+            settings_index,
+            'include dirname(__FILE__)."/FreedomBoxStaticSettings.php";\n')
+
+    with open(LOCAL_SETTINGS_CONF, 'w') as conf_file:
+        conf_file.writelines(lines)
 
 
 def subcommand_change_password(arguments):

plinth/modules/mediawiki/__init__.py

@@ -29,7 +29,7 @@ from plinth.modules.firewall.components import Firewall
 
 from .manifest import backup, clients  # noqa, pylint: disable=unused-import
 
-version = 6
+version = 7
 
 managed_packages = ['mediawiki', 'imagemagick', 'php-sqlite3']
 

plinth/modules/mediawiki/data/etc/mediawiki/FreedomBoxStaticSettings.php

@@ -0,0 +1,37 @@
+<?php
+/*
+ This file is shipped by FreedomBox to manage static settings. Newer versions of
+ this file are shipped by FreedomBox and are expected to override this file
+ without any user prompts. It should not be modified by the system
+ administrator. Additional setting modified by FreedomBox at placed in
+ FreedomBoxSettings.php. No newer version of that file is ever shipped by
+ FreedomBox.
+*/
+
+# Default logo
+$wgLogo = "$wgResourceBasePath/resources/assets/mediawiki.png";
+
+# Enable file uploads
+$wgEnableUploads = true;
+
+# Public registrations
+$wgGroupPermissions['*']['createaccount'] = false;
+
+# Read/write permissions for anonymous users
+$wgGroupPermissions['*']['edit'] = false;
+$wgGroupPermissions['*']['read'] = true;
+
+# Short urls
+$wgArticlePath = "/mediawiki/$1";
+$wgUsePathInfo = true;
+
+# Instant Commons
+$wgUseInstantCommons = true;
+
+# SVG Enablement
+$wgFileExtensions[] = 'svg';
+$wgAllowTitlesInSVG = true;
+$wgSVGConverter = 'ImageMagick';
+
+# Fix issue with session cache preventing logins, #1736
+$wgSessionCacheType = CACHE_DB;