[FIX] web: company logo file extension

The company logo file extension is always '.png', even if the logo is of
another type such as 'jpg' or 'gif'. This is not an issue for decent
browsers, but IE might not display the image under specific
circumstancies, e.g. in combination with nginx.

opw-676836

addons/web/controllers/main.py

@@ -4,6 +4,7 @@ import base64
 import csv
 import functools
 import glob
+import imghdr
 import itertools
 import jinja2
 import logging
@@ -1077,7 +1078,8 @@ class Binary(http.Controller):
         '/logo.png',
     ], type='http', auth="none", cors="*")
     def company_logo(self, dbname=None, **kw):
-        imgname = 'logo.png'
+        imgname = 'logo'
+        imgext = '.png'
         placeholder = functools.partial(get_resource_path, 'web', 'static', 'src', 'img')
         uid = None
         if request.session.db:
@@ -1090,7 +1092,7 @@ class Binary(http.Controller):
             uid = openerp.SUPERUSER_ID
 
         if not dbname:
-            response = http.send_file(placeholder(imgname))
+            response = http.send_file(placeholder(imgname + imgext))
         else:
             try:
                 # create an empty registry
@@ -1104,12 +1106,14 @@ class Binary(http.Controller):
                                """, (uid,))
                     row = cr.fetchone()
                     if row and row[0]:
-                        image_data = StringIO(str(row[0]).decode('base64'))
-                        response = http.send_file(image_data, filename=imgname, mtime=row[1])
+                        image_base64 = str(row[0]).decode('base64')
+                        image_data = StringIO(image_base64)
+                        imgext = '.' + (imghdr.what(None, h=image_base64) or 'png')
+                        response = http.send_file(image_data, filename=imgname + imgext, mtime=row[1])
                     else:
                         response = http.send_file(placeholder('nologo.png'))
             except Exception:
-                response = http.send_file(placeholder(imgname))
+                response = http.send_file(placeholder(imgname + imgext))
 
         return response