configuration: Use augeas to edit Apache files

Move the file editing code to actions/config since it must be executed by a
super user.

Signed-off-by: Joseph Nuthalapati <njoseph@thoughtworks.com>
Reviewed-by: James Valleroy <jvalleroy@mailbox.org>

actions/config

@@ -0,0 +1,77 @@
+#!/usr/bin/python3
+# -*- mode: python -*-
+#
+# This file is part of FreedomBox.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+"""
+Configuration helper for FreedomBox general configuration.
+"""
+
+import argparse
+
+import augeas
+
+from plinth import action_utils
+
+APACHE_CONFIGURATION = '/etc/apache2/conf-available/freedombox.conf'
+
+
+def parse_arguments():
+    """Return parsed command line arguments as dictionary."""
+    parser = argparse.ArgumentParser()
+    subparsers = parser.add_subparsers(dest='subcommand', help='Sub command')
+    set_default_app = subparsers.add_parser(
+        'set-default-app',
+        help='Set the default app for this FreedomBox instance.')
+    set_default_app.add_argument('app', help='name of the default app')
+
+    subparsers.required = True
+    return parser.parse_args()
+
+
+def subcommand_set_default_app(arguments):
+    """Set the default app for this FreedomBox."""
+    app = arguments.app
+
+    aug = augeas.Augeas(flags=augeas.Augeas.NO_LOAD +
+                        augeas.Augeas.NO_MODL_AUTOLOAD)
+    aug.set('/augeas/load/Httpd/lens', 'Httpd.lns')
+    aug.set('/augeas/load/Httpd/incl[last() + 1]', APACHE_CONFIGURATION)
+    aug.load()
+
+    aug.defvar('conf', '/files' + APACHE_CONFIGURATION)
+
+    for match in aug.match('/files' + APACHE_CONFIGURATION +
+                           '/directive["RedirectMatch"]'):
+        if aug.get(match + "/arg[1]") == '''"^/$"''':
+            aug.set(match + "/arg[2]", '"/{}/"'.format(app))
+
+    aug.save()
+
+    action_utils.service_reload('apache2')
+
+
+def main():
+    """Parse arguments and perform all duties."""
+    arguments = parse_arguments()
+
+    subcommand = arguments.subcommand.replace('-', '_')
+    subcommand_method = globals()['subcommand_' + subcommand]
+    subcommand_method(arguments)
+
+
+if __name__ == '__main__':
+    main()

data/etc/apache2/conf-available/freedombox.conf

@@ -10,5 +10,4 @@ Header set Strict-Transport-Security "max-age=31536000; includeSubDomains" env=H
 ##
 RedirectMatch "^/$" "/plinth"
 RedirectMatch "^/freedombox" "/plinth"
-RedirectMatch "^/home" "/plinth"
 

plinth/modules/config/__init__.py

@@ -18,9 +18,9 @@
 FreedomBox app for basic system configuration.
 """
 
-import re
 import socket
 
+import augeas
 from django.utils.translation import ugettext_lazy
 
 from plinth import actions
@@ -51,11 +51,21 @@ def get_hostname():
 
 def get_default_app():
     """Get the default application for the domain."""
-    with open('/etc/apache2/conf-available/freedombox.conf') as conf_file:
-        for line in conf_file:
-            if re.findall(r'\^\/\$', line):
-                app_path = line.split()[-1].strip('"')
-                break
+    APACHE_CONFIGURATION = '/etc/apache2/conf-available/freedombox.conf'
+
+    aug = augeas.Augeas(flags=augeas.Augeas.NO_LOAD +
+                        augeas.Augeas.NO_MODL_AUTOLOAD)
+    aug.set('/augeas/load/Httpd/lens', 'Httpd.lns')
+    aug.set('/augeas/load/Httpd/incl[last() + 1]', APACHE_CONFIGURATION)
+    aug.load()
+
+    aug.defvar('conf', '/files' + APACHE_CONFIGURATION)
+
+    for match in aug.match('/files' + APACHE_CONFIGURATION +
+                           '/directive["RedirectMatch"]'):
+        if aug.get(match + "/arg[1]") == '''"^/$"''':
+            app_path = aug.get(match + "/arg[2]")
+
     return app_path.strip("/")
 
 

plinth/modules/config/views.py

@@ -114,16 +114,8 @@ def change_default_app(app_id):
             shortcut['url'] for shortcut in shortcuts
             if shortcut['id'] == app_id
         ][0]
-    lines = []
-    freedombox_apache_conf = '/etc/apache2/conf-available/freedombox.conf'
-    with open(freedombox_apache_conf, 'r') as conf_file:
-        for line in conf_file:
-            if re.findall(r'\^\/\$', line):
-                line = 'RedirectMatch "^/$" ' + '"{}"'.format(url)
-            lines.append(line)
-    with open(freedombox_apache_conf, 'w') as conf_file:
-        conf_file.write("\n".join(lines))
-    action_utils.service_reload('apache2')
+
+    actions.superuser_run('config', ['set-default-app', url.strip("/")])
 
 
 def set_hostname(hostname):