[FIX] Crash on some requests without header

[IMP] Only load the patch when the module is installed

log_forwarded_for_ip/__init__.py

@@ -2,14 +2,5 @@
 # © 2015 Aserti Global Solutions
 # License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html).
 
-from werkzeug.serving import WSGIRequestHandler
-
-
-def address_string(self):
-    forwarded_for = self.headers.get('X-Forwarded-For', '').split(',')
-    if forwarded_for and forwarded_for[0]:
-        return forwarded_for[0]
-    else:
-        return self.client_address[0]
-
-WSGIRequestHandler.address_string = address_string
+from . import models
+from .hooks import restore_address_string

log_forwarded_for_ip/__openerp__.py

@@ -14,4 +14,5 @@
     "depends": [
         "base",
     ],
+    "uninstall_hook": "restore_address_string"
 }

log_forwarded_for_ip/hooks.py

@@ -0,0 +1,12 @@
+# -*- coding: utf-8 -*-
+# © 2015 Aserti Global Solutions
+# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html).
+
+from werkzeug.serving import WSGIRequestHandler
+
+
+def restore_address_string(cr, reg):
+    if hasattr(WSGIRequestHandler, '_address_string_org'):
+        WSGIRequestHandler.address_string = \
+            WSGIRequestHandler._address_string_org
+        del WSGIRequestHandler._address_string_org

log_forwarded_for_ip/models/__init__.py

@@ -0,0 +1,5 @@
+# -*- coding: utf-8 -*-
+# © 2015 Aserti Global Solutions
+# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html).
+
+from . import log_forwarded_for_ip_installed

log_forwarded_for_ip/models/log_forwarded_for_ip_installed.py

@@ -0,0 +1,26 @@
+# -*- coding: utf-8 -*-
+# © 2015 Aserti Global Solutions
+# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html).
+
+from werkzeug.serving import WSGIRequestHandler
+from mimetools import Message
+from openerp import models
+
+
+def address_string(self):
+    if self.headers and isinstance(self.headers, Message):
+        forwarded_for = self.headers.get('X-Forwarded-For', '').split(',')
+        if forwarded_for and forwarded_for[0]:
+            return forwarded_for[0]
+    return self.client_address[0]
+
+
+class LogForwardedForIpInstalled(models.AbstractModel):
+    _name = 'log.forwarded.for.ip.installed'
+
+    def _register_hook(self, cr):
+        if not hasattr(WSGIRequestHandler, '_address_string_org'):
+            WSGIRequestHandler._address_string_org = \
+                WSGIRequestHandler.address_string
+            WSGIRequestHandler.address_string = address_string
+        return super(LogForwardedForIpInstalled, self)._register_hook(cr)