Introducing must_revalidate decorator, Closes #30

nanohttp/__init__.py

@@ -4,7 +4,7 @@
     HttpMethodNotAllowed, HttpConflict, HttpGone, HttpRedirect, HttpMovedPermanently, HttpFound, \
     HttpInternalServerError
 from .controllers import Controller, RestController, Static
-from .decorators import action, html, json, xml, binary, text
+from .decorators import action, html, json, xml, binary, text, must_revalidate
 from .helpers import quickstart, LazyAttribute
 from .cli import main
 from .contexts import context, ContextIsNotInitializedError

nanohttp/contexts.py

@@ -141,6 +141,16 @@ def encode_response(self, buffer):
         except AttributeError:  # pragma: no cover
             raise TypeError('The returned response should has the `encode` attribute, such as `str`.')
 
+    def expired(self, etag, force=False):
+        none_match = self.environ.get('HTTP_IF_NONE_MATCH')
+        match = self.environ.get('HTTP_IF_MATCH')
+        expired = etag not in (none_match, match)
+
+        if force and not expired:
+            raise exceptions.HttpNotModified()
+
+        return expired
+
 
 class ContextProxy(Context):
 

nanohttp/decorators.py

@@ -2,6 +2,7 @@
 import functools
 
 from .configuration import settings
+from .contexts import context
 
 
 def action(*args, verbs='any', encoding='utf-8', content_type=None, inner_decorator=None, **kwargs):
@@ -48,3 +49,16 @@ def wrapper(*args, **kwargs):
 json = functools.partial(action, content_type='application/json', inner_decorator=jsonify)
 xml = functools.partial(action, content_type='application/xml')
 binary = functools.partial(action, content_type='application/octet-stream', encoding=None)
+
+
+def must_revalidate(etag):
+    def decorator(func):
+        @functools.wraps(func)
+        def wrapper(*args, **kwargs):
+            etag_ = etag() if callable(etag) else etag
+            context.expired(etag_, force=True)
+            context.response_headers.add_header('Cache-Control', 'must-revalidate')
+            context.response_headers.add_header('ETag', etag_)
+            return func(*args, **kwargs)
+        return wrapper
+    return decorator

nanohttp/exceptions.py

@@ -71,11 +71,15 @@ def __init__(self, location, *args, **kw):
 
 
 class HttpMovedPermanently(HttpRedirect):
-    status_code, status_text, info = 301, 'Moved Permanently', 'Object moved permanently -- see URI list'
+    status_code, status_text, info = 301, 'Moved Permanently', 'Object moved permanently'
 
 
 class HttpFound(HttpRedirect):
-    status_code, status_text, info = 302, 'Found', 'Object moved temporarily -- see URI list'
+    status_code, status_text, info = 302, 'Found', 'Object moved temporarily'
+
+
+class HttpNotModified(HttpStatus):
+    status_code, status_text, info = 304, 'Not Modified', 'Resource is not modified'
 
 
 class HttpInternalServerError(HttpStatus):

nanohttp/tests/test_caching.py

@@ -0,0 +1,44 @@
+import unittest
+
+from nanohttp import Controller, text, must_revalidate
+from nanohttp.tests.helpers import WsgiAppTestCase
+
+
+_etag = '1'
+
+
+class CachingTestCase(WsgiAppTestCase):
+
+    class Root(Controller):
+
+        @text()
+        @must_revalidate(etag=lambda: _etag)
+        def index(self):
+            yield 'Something'
+
+        @text()
+        def about(self):
+            yield 'about'
+
+    def test_caching_header(self):
+        global _etag
+        self.assert_get('/', expected_headers={'Cache-Control': 'must-revalidate', 'ETag': _etag})
+
+        # Fetching again with etag header
+        ___, body = self.assert_get('/', headers={'If-None-Match': _etag}, status=304)
+        self.assertEqual(len(body), 0)
+
+        _old_etag = _etag
+        _etag = '2'
+        # Fetching again with etag header
+        ___, body = self.assert_get(
+            '/',
+            headers={'If-None-Match': _old_etag},
+            status=200,
+            expected_headers={'Cache-Control': 'must-revalidate', 'ETag': _etag}
+        )
+        self.assertEqual(body, b'Something')
+
+
+if __name__ == '__main__':  # pragma: no cover
+    unittest.main()

nanohttp/tests/test_redirect.py

@@ -1,3 +1,5 @@
+import unittest
+
 from nanohttp import Controller, action, text, HttpMovedPermanently, HttpFound
 from nanohttp.tests.helpers import WsgiAppTestCase
 
@@ -18,3 +20,6 @@ def test_redirect_response_header(self):
         self.assert_get('/', status=301, expected_headers={'Location': '/new/address'})
         self.assert_get('/about', status=302, expected_headers={'Location': '/new/address'})
 
+
+if __name__ == '__main__':  # pragma: no cover
+    unittest.main()