Changeset 1202

Timestamp:

07/17/06 10:21:56

Author:

dowski

Message:

1. New "expires" tool for setting the "Expires" header.

2. Tests for the expires tool.

Files:

• trunk/cherrypy/_cptools.py (modified) (1 diff)
• trunk/cherrypy/lib/caching.py (modified) (2 diffs)
• trunk/cherrypy/test/test_caching.py (modified) (4 diffs)

trunk/cherrypy/_cptools.py

@@ -307 +307 @@
-default_toolbox.wsgiapp = WSGIAppTool(_wsgiapp.run)
-default_toolbox.caching = CachingTool()
+default_toolbox.expires = Tool('before_finalize', _caching.expires)
-default_toolbox.tidy = Tool('before_finalize', tidy.tidy)
-default_toolbox.nsgmls = Tool('before_finalize', tidy.nsgmls)

trunk/cherrypy/lib/caching.py

@@ +1 @@
+import datetime
-import threading
-import time
-
-import cherrypy
-
+, http
-
-
@@ -166 +167 @@
-    cherrypy.request.hooks.attach('before_main', _wrapper)
-
+def expires(e_time=0, ignore_indicators=False, force=True):
+    """Tool for influencing cache mechanisms using the 'Expires' header.
+
+    e_time can either be a datetime.datetime instance or number zero.
+
+    If a datetime.datetime instance is supplied, the 'Expires' header will be
+    set to that value.
+
+    If a number zero is supplied, the following "cache prevention" headers
+    are set:
+       'Expires': '0'
+       'Pragma': 'no-cache'
+       'Cache-Control: 'no-cache'
+
+    By default, if e_time is set to zero, the tool checks to see if the
+    response already includes some common "cacheability indicator" headers.
+    If they are present, the "cache prevention" headers are not set.  This
+    behavior can be overridden by setting the ignore_indicators parameter
+    to True.
+
+    Setting force to False will keep the tool from overwriting any headers
+    that are already present in the response.
+    """
+
+    if e_time and isinstance(e_time, datetime.datetime):
+        e_time = http.HTTPDate(time.mktime(e_time.timetuple()))
+        cptools.response_headers([("Expires", e_time)], force)
+        return
+
+    try:
+        if not(int(e_time)):
+            # some header names that indicate that the response can be cached
+            indicators = set(('Etag', 'Last-Modified', 'Age', 'Expires'))
+            cacheable = indicators.intersection(set(cherrypy.response.headers))
+            if not e_time and (ignore_indicators or not cacheable):
+                cptools.response_headers([("Pragma", "no-cache"),
+                                          ("Expires", "0")], force)
+                if cherrypy.request.version >= (1, 1):
+                    cptools.response_headers([("Cache-Control", "no-cache")], force)
+
+        else:
+            raise ValueError("e_time value must be number zero or a datetime."
+                             "datetime instance")
+
+    except TypeError, e:
+        e.args = ["e_time value must be datetime.datetime instance or number"
+                  "zero."]
+        raise

trunk/cherrypy/test/test_caching.py

@@ -2 +2 @@
-test.prefer_parent_path()
-
+import os
+curdir = os.path.join(os.getcwd(), os.path.dirname(__file__))
+
-import cherrypy
+import datetime
-import time
-
@@ -19 +23 @@
-            return msg
-        index.exposed = True
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-    cherrypy.tree.mount(Root())
+    cherrypy.tree.mount(UnCached(), "/expires")
-    cherrypy.config.update({
-        'log_to_screen': False,
-        'environment': 'production',
+        'show_tracebacks': True,
-    })
-
@@ -30 +83 @@
-
-class CacheTest(helper.CPWebCase):
-
+
-    def testCaching(self):
-        elapsed = 0.0
@@ -51 +104 @@
-        self.assertBody('visit #3')
-
+    def testExpiresTool(self):
+
+        # test setting a specific expires header
+        self.getPage("/expires/specific")
+        self.assertStatus("200 OK")
+        self.assertHeader("Expires", "Mon, 17 Jul 2006 12:55:59 GMT")
+
+        # test exceptions for bad e_time values
+        self.getPage("/expires/wrongtype")
+        self.assertStatus("500 Internal error")
+        self.assertInBody("TypeError")
+
+        self.getPage("/expires/wrongvalue")
+        self.assertStatus("500 Internal error")
+        self.assertInBody("ValueError")
+
+        self.getPage('/expires/dynamic')
+        self.assertBody("D-d-d-dynamic!")
+        # dynamic sets Cache-Control to private but it should  be
+        # overwritten here ...
+        self.assertHeader("Cache-Control", "no-cache")
+        self.assertHeader("Expires", "0")
+        self.assertHeader("Pragma", "no-cache")
+
+        # configure the tool to keep existing headers
+        self.getPage("/expires/gentle")
+        self.assertStatus("200 OK")
+
+        self.getPage('/expires/dynamic')
+        self.assertBody("D-d-d-dynamic!")
+        # the Cache-Control header should now be untouched
+        self.assertHeader("Cache-Control", "private")
+
+        # static content should not have "cache prevention" headers
+        self.getPage("/expires/index.html")
+        self.assertStatus("200 OK")
+        self.assertNoHeader("Pragma")
+        self.assertNoHeader("Cache-Control")
+        self.assertNoHeader("Expires")
+
+        # dynamic content that sets indicators should not have
+        # "cache prevention" headers
+        self.getPage("/expires/cacheable")
+        self.assertStatus("200 OK")
+        self.assertNoHeader("Pragma")
+        self.assertNoHeader("Cache-Control")
+        self.assertNoHeader("Expires")
+
+        # configure the tool to ignore indicators
+        self.getPage("/expires/ignorant")
+        self.assertStatus("200 OK")
+
+        # static content should now have "cache prevention" headers
+        self.getPage("/expires/index.html")
+        self.assertStatus("200 OK")
+        self.assertHeader("Pragma", "no-cache")
+        self.assertHeader("Cache-Control", "no-cache")
+        self.assertHeader("Expires", "0")
+
+        # the cacheable handler should now have "cache prevention" headers
+        self.getPage("/expires/cacheable")
+        self.assertStatus("200 OK")
+        self.assertHeader("Pragma", "no-cache")
+        self.assertHeader("Cache-Control", "no-cache")
+        self.assertHeader("Expires", "0")
-
-if __name__ == '__main__':