feat(admin): document windows compatible filenames

Signed-off-by: Ferdinand Thiessen <opensource@fthiessen.de>

admin_manual/configuration_files/index.rst

@@ -21,3 +21,4 @@ File sharing and management
     file_versioning
     trashbin_configuration
     file_conversion
+    windows_compatible_filenames

admin_manual/configuration_files/windows_compatible_filenames.rst

@@ -0,0 +1,56 @@
+.. _windows_compatible_filenames:
+
+============================
+Windows compatible filenames
+============================
+
+.. note::
+
+    This feature was introduced in Nextcloud 31.
+
+By default Nextcloud supports all filenames which are valid on the underlying server.
+As Nextcloud runs only on POSIX compatible operating systems (Linux),
+this means that Nextcloud supports also filenames not valid on Microsoft Windows systems.
+
+If your users use Windows and use the Nextcloud Desktop clients to synchronize their work
+to their computer they might encounter files created in the web interface, or on a Linux
+machine, which cannot be synchronized as the filename is not valid.
+
+To solve this issue it is possible to enforce filenames only valid on Windows,
+this for example forbids characters like ``*`` from filenames
+or filenames like ``AUX.txt`` (on Windows ``AUX`` is a reserved name and cannot be used).
+
+.. note::
+
+	Enabling this setting will not enforce case-insensitivity
+	as modern Windows systems support case-sensitive filenames.
+
+Enabling Windows compatible filenames
+-------------------------------------
+
+.. note::
+
+	This feature works by setting a predefined set of system configuration settings.
+	So after enabling this the ``config.php`` will be adjusted, which also means enabling
+	this feature requires a writable configuration.
+
+Using the web interface
+^^^^^^^^^^^^^^^^^^^^^^^
+
+The setting is provided in the **Administration settings** under **Basic settings**.
+Within the **Files compatibility** section the Windows compatibility can be enabled.
+
+.. figure:: images/files-windows-compatibility.png
+   :alt: Enforce windows compatibility checkbox on the Administration - Basic settings - Files compatibility page.
+
+Consequences
+------------
+
+After enabling Windows compatible filenames users cannot create or modify files
+with invalid filenames. But they can still delete or rename those files (to valid names).
+
+This works by setting a pre-defined set of configuration settings:
+
+- ``forbidden_filename_basenames`` will be set to names reserved on Windows.
+- ``forbidden_filename_characters`` will be set to characters not valid for filenames on Windows.
+- ``forbidden_filename_extensions`` will be set to strings not allowed as trailing parts, like a trailing dot or spaces.

go.php

@@ -52,6 +52,7 @@ $mapping = array(
     'admin-trusted-domains'   => '/admin_manual/installation/installation_wizard.html#trusted-domains',
     'admin-update'            => '/admin_manual/maintenance/update.html',
     'admin-warnings'          => '/admin_manual/configuration_server/security_setup_warnings.html',
+    'admin-windows-compatible-filenames' => '/admin_manual/configuration_files/windows_compatible_filenames.html',
     'admin-workflowengine'    => '/admin_manual/file_workflows/index.html',
 
     'developer-manual'        => '/developer_manual',