initial

.gitignore

+.idea
+.cache
+.eggs
+.coverage
+*.egg-info
+dist
+build

setup.py

+from setuptools import setup
+
+setup(
+    name='wsgiware',
+    py_modules=['wsgiware'],
+    use_scm_version=True,
+    setup_requires=['setuptools_scm'],
+    entry_points="""
+    [paste.filter_factory]
+    add_headers = wsgiware.add_headers:factory
+    """,
+)

wsgiware/add_headers.py

+import copy
+
+
+def factory(global_conf, **settings):
+    """
+    Factory for use by PasteDeploy INI configuration. To use::
+
+        # wrap our API app with the headers app configured below
+        [pipeline:main]
+        pipeline =
+            headers
+            app
+
+        # Add the following headers to all requests
+        [filter:headers]
+        use = egg:sipswebapi#headers
+        My-Header = MY_HEADER_VALUE
+
+    :param global_conf: Global INI config
+    :param settings: Settings from INI config section
+    :return: Factory that takes an app
+    """
+    headers = settings
+
+    def factory(app):
+        return AddHeadersMiddleware(app, headers)
+
+    return factory
+
+
+class AddHeadersMiddleware(object):
+    def __init__(self, app, headers):
+        self.app = app
+        self.headers = copy.deepcopy(headers)
+
+    def __call__(self, environ, start_response):
+        def x_start_response(status, headers, exc_info=None):
+            for name, val in self.headers.items():
+                headers.append((name, val))
+            return start_response(status, headers, exc_info)
+
+        return self.app(environ, x_start_response)