Change Flask.__init__ to accept two new keyword arguments, host_match…

…ing and static_host.

This enables host_matching to be set properly by the time the constructor adds
the static route, and enables the static route to be properly associated with
the required host.

Previously, you could only enable host_matching once your app was already
instantiated (e.g. app.url_map.host_matching = True), but at that point
the constructor would have already added the static route without host matching
and an associated host, leaving the static route in a broken state.

Fixes pallets#1559.

AUTHORS

@@ -21,6 +21,7 @@ Patches and Suggestions
 - Florent Xicluna
 - Georg Brandl
 - Jeff Widman @jeffwidman
+- Joshua Bronson @jab
 - Justin Quick
 - Kenneth Reitz
 - Keyan Pishdadian

CHANGES

@@ -14,6 +14,11 @@ Major release, unreleased
 - Change default configuration `JSONIFY_PRETTYPRINT_REGULAR=False`. jsonify()
   method returns compressed response by default, and pretty response in
   debug mode.
+- Change Flask.__init__ to accept two new keyword arguments, ``host_matching``
+  and ``static_host``. This enables ``host_matching`` to be set properly by the
+  time the constructor adds the static route, and enables the static route to
+  be properly associated with the required host. (``#1559``)
+
 
 Version 0.12.1
 --------------

flask/app.py

@@ -123,13 +123,23 @@ class Flask(_PackageBoundObject):
     .. versionadded:: 0.11
        The `root_path` parameter was added.
 
+    .. versionadded:: 0.13
+       The `host_matching` and `static_host` parameters were added.
+
     :param import_name: the name of the application package
     :param static_url_path: can be used to specify a different path for the
                             static files on the web.  Defaults to the name
                             of the `static_folder` folder.
     :param static_folder: the folder with static files that should be served
                           at `static_url_path`.  Defaults to the ``'static'``
                           folder in the root path of the application.
+                          folder in the root path of the application. Defaults
+                          to None.
+    :param host_matching: sets the app's ``url_map.host_matching`` to the given
+                          given value. Defaults to False.
+    :param static_host: the host to use when adding the static route. Defaults
+                        to None. Required when using ``host_matching=True``
+                        with a ``static_folder`` configured.
     :param template_folder: the folder that contains the templates that should
                             be used by the application.  Defaults to
                             ``'templates'`` folder in the root path of the
@@ -337,7 +347,8 @@ def _set_request_globals_class(self, value):
     session_interface = SecureCookieSessionInterface()
 
     def __init__(self, import_name, static_path=None, static_url_path=None,
-                 static_folder='static', template_folder='templates',
+                 static_folder='static', static_host=None,
+                 host_matching=False, template_folder='templates',
                  instance_path=None, instance_relative_config=False,
                  root_path=None):
         _PackageBoundObject.__init__(self, import_name,
@@ -525,19 +536,22 @@ def __init__(self, import_name, static_path=None, static_url_path=None,
         #:    app.url_map.converters['list'] = ListConverter
         self.url_map = Map()
 
+        self.url_map.host_matching = host_matching
+
         # tracks internally if the application already handled at least one
         # request.
         self._got_first_request = False
         self._before_request_lock = Lock()
 
-        # register the static folder for the application.  Do that even
-        # if the folder does not exist.  First of all it might be created
-        # while the server is running (usually happens during development)
-        # but also because google appengine stores static files somewhere
-        # else when mapped with the .yml file.
+        # Add a static route using the provided static_url_path, static_host,
+        # and static_folder iff there is a configured static_folder.
+        # Note we do this without checking if static_folder exists.
+        # For one, it might be created while the server is running (e.g. during
+        # development). Also, Google App Engine stores static files somewhere
         if self.has_static_folder:
+            assert bool(static_host) == host_matching, 'Invalid static_host/host_matching combination'
             self.add_url_rule(self.static_url_path + '/<path:filename>',
-                              endpoint='static',
+                              endpoint='static', host=static_host,
                               view_func=self.send_static_file)
 
         #: The click command line context for this application.  Commands

tests/test_basic.py

@@ -1171,6 +1171,23 @@ def test_static_url_path():
         assert flask.url_for('static', filename='index.html') == '/foo/index.html'
 
 
+def test_static_route_with_host_matching():
+    app = flask.Flask(__name__, host_matching=True, static_host='example.com')
+    c = app.test_client()
+    assert c.get('http://example.com/static/index.html').status_code == 200
+    with app.test_request_context():
+       rv = flask.url_for('static', filename='index.html', _external=True)
+       assert rv == 'http://example.com/static/index.html'
+    # Providing static_host without host_matching=True should error.
+    with pytest.raises(Exception):
+        flask.Flask(__name__, static_host='example.com')
+    # Providing host_matching=True with static_folder but without static_host should error.
+    with pytest.raises(Exception):
+        flask.Flask(__name__, host_matching=True)
+    # Providing host_matching=True without static_host but with static_folder=None should not error.
+    flask.Flask(__name__, host_matching=True, static_folder=None)
+
+
 def test_none_response():
     app = flask.Flask(__name__)
     app.testing = True