support timedelta for SEND_FILE_MAX_AGE_DEFAULT config variable

docs/config.rst

@@ -130,7 +130,8 @@ The following configuration values are used internally by Flask:
 ``SEND_FILE_MAX_AGE_DEFAULT``     Default cache control max age to use with
                                   :meth:`~flask.Flask.send_static_file` (the
                                   default static file handler) and
-                                  :func:`~flask.send_file`, in
+                                  :func:`~flask.send_file`, as
+                                  :class:`datetime.timedelta` or as seconds.
                                   seconds. Override this value on a per-file
                                   basis using the
                                   :meth:`~flask.Flask.get_send_file_max_age`

flask/app.py

@@ -246,6 +246,16 @@ class Flask(_PackageBoundObject):
     permanent_session_lifetime = ConfigAttribute('PERMANENT_SESSION_LIFETIME',
         get_converter=_make_timedelta)
 
+    #: A :class:`~datetime.timedelta` which is used as default cache_timeout
+    #: for the :func:`send_file` functions. The default is 12 hours.
+    #:
+    #: This attribute can also be configured from the config with the
+    #: ``SEND_FILE_MAX_AGE_DEFAULT`` configuration key. This configuration
+    #: variable can also be set with an integer value used as seconds.
+    #: Defaults to ``timedelta(hours=12)``
+    send_file_max_age_default = ConfigAttribute('SEND_FILE_MAX_AGE_DEFAULT',
+        get_converter=_make_timedelta)
+
     #: Enable this if you want to use the X-Sendfile feature.  Keep in
     #: mind that the server has to support this.  This only affects files
     #: sent with the :func:`send_file` method.
@@ -297,7 +307,7 @@ class Flask(_PackageBoundObject):
         'SESSION_COOKIE_SECURE':                False,
         'SESSION_REFRESH_EACH_REQUEST':         True,
         'MAX_CONTENT_LENGTH':                   None,
-        'SEND_FILE_MAX_AGE_DEFAULT':            12 * 60 * 60,  # 12 hours
+        'SEND_FILE_MAX_AGE_DEFAULT':            timedelta(hours=12),
         'TRAP_BAD_REQUEST_ERRORS':              False,
         'TRAP_HTTP_EXCEPTIONS':                 False,
         'EXPLAIN_TEMPLATE_LOADING':             False,

flask/helpers.py

@@ -14,6 +14,7 @@ import sys
 import pkgutil
 import posixpath
 import mimetypes
+from datetime import timedelta
 from time import time
 from zlib import adler32
 from threading import RLock
@@ -856,7 +857,7 @@ class _PackageBoundObject(object):
 
         .. versionadded:: 0.9
         """
-        return current_app.config['SEND_FILE_MAX_AGE_DEFAULT']
+        return total_seconds(current_app.send_file_max_age_default)
 
     def send_static_file(self, filename):
         """Function used internally to send static files from the static
@@ -898,3 +899,14 @@ class _PackageBoundObject(object):
         if mode not in ('r', 'rb'):
             raise ValueError('Resources can only be opened for reading')
         return open(os.path.join(self.root_path, resource), mode)
+
+
+def total_seconds(td):
+    """Returns the total seconds from a timedelta object.
+
+    :param timedelta td: the timedelta to be converted in seconds
+
+    :returns: number of seconds
+    :rtype: int
+    """
+    return td.days * 60 * 60 * 24 + td.seconds

flask/sessions.py

@@ -17,14 +17,11 @@ from werkzeug.http import http_date, parse_date
 from werkzeug.datastructures import CallbackDict
 from . import Markup, json
 from ._compat import iteritems, text_type
+from .helpers import total_seconds
 
 from itsdangerous import URLSafeTimedSerializer, BadSignature
 
 
-def total_seconds(td):
-    return td.days * 60 * 60 * 24 + td.seconds
-
-
 class SessionMixin(object):
     """Expands a basic dictionary with an accessors that are expected
     by Flask extensions and users for the session.

tests/test_config.py

@@ -10,6 +10,7 @@
 import pytest
 
 import os
+from datetime import timedelta
 import flask
 
 
@@ -168,6 +169,14 @@ def test_session_lifetime():
     assert app.permanent_session_lifetime.seconds == 42
 
 
+def test_send_file_max_age():
+    app = flask.Flask(__name__)
+    app.config['SEND_FILE_MAX_AGE_DEFAULT'] = 3600
+    assert app.send_file_max_age_default.seconds == 3600
+    app.config['SEND_FILE_MAX_AGE_DEFAULT'] = timedelta(hours=2)
+    assert app.send_file_max_age_default.seconds == 7200
+
+
 def test_get_namespace():
     app = flask.Flask(__name__)
     app.config['FOO_OPTION_1'] = 'foo option 1'