Load WSGI middleware from configuration

issue8807
review270521002

CHANGELOG

@@ -1,3 +1,4 @@
+* Load WSGI middleware from configuration
 * Add help text to Dict keys
 * Update button_action with returned values
 * Use direct access to backend classes

doc/topics/configuration.rst

@@ -462,6 +462,21 @@ It can be overridden for specific models and fields using the names:
 
 Default: `''`
 
+wsgi middleware
+---------------
+
+The section lists the `WSGI middleware`_ class to load.
+Each middleware can be configured with a section named `wsgi <middleware>`
+containing `args` and `kwargs` options.
+
+Example::
+
+    [wsgi middleware]
+    ie = werkzeug.contrib.fixers.InternetExplorerFix
+
+    [wsgi ie]
+    kwargs={'fix_attach': False}
+
 
 .. _JSON-RPC: http://en.wikipedia.org/wiki/JSON-RPC
 .. _XML-RPC: http://en.wikipedia.org/wiki/XML-RPC
@@ -470,3 +485,4 @@ Default: `''`
 .. _SSL: http://en.wikipedia.org/wiki/Secure_Sockets_Layer
 .. _SSL-CERT: https://docs.python.org/library/ssl.html#ssl.wrap_socket
 .. _STARTTLS: http://en.wikipedia.org/wiki/STARTTLS
+.. _WSGI middleware: https://en.wikipedia.org/wiki/Web_Server_Gateway_Interface#Specification_overview

trytond/wsgi.py

@@ -35,6 +35,7 @@ from trytond.config import config
 from trytond.protocols.wrappers import Request
 from trytond.protocols.jsonrpc import JSONProtocol
 from trytond.protocols.xmlrpc import XMLProtocol
+from trytond.tools import resolve
 
 __all__ = ['TrytondWSGI', 'app']
 
@@ -213,5 +214,18 @@ if config.get('web', 'root'):
 num_proxies = config.getint('web', 'num_proxies')
 if num_proxies:
     app.wsgi_app = NumProxyFix(app.wsgi_app, num_proxies)
+
+if config.has_section('wsgi middleware'):
+    for middleware in config.options('wsgi middleware'):
+        Middleware = resolve(config.get('wsgi middleware', middleware))
+        args, kwargs = (), {}
+        section = 'wsgi %s' % middleware
+        if config.has_section(section):
+            if config.has_option(section, 'args'):
+                args = eval(config.get(section, 'args'))
+            if config.has_option(section, 'kwargs'):
+                kwargs = eval(config.get(section, 'kwargs'))
+        app.wsgi_app = Middleware(app.wsgi_app, *args, **kwargs)
+
 import trytond.protocols.dispatcher
 import trytond.bus