Added LAZY_FILE_LOADING constant to PageTemplateFile. When set to True Page...

Added LAZY_FILE_LOADING constant to PageTemplateFile. When set to True Page Template files aren't lo
aded and parsed on Zope startup anymore, but on first access instead. When complex add-ons like Plon
e are installed this can safe up to 30% of the Zope startup time. This gets a ZConfig switch ones I 
figured out how to write one ;)

doc/CHANGES.txt

@@ -71,6 +71,10 @@ Zope Changes
 
     Features added
 
+      - Added LAZY_FILE_LOADING constant to PageTemplateFile. When set to True
+        Page Template files aren't lo aded and parsed on Zope startup anymore,
+        but on first access instead.
+
       - Testing.ZopeTestCase: Introduced a "ZopeLite" test layer, making it
         possible to mix ZTC and non-ZTC tests much more freely.
 

lib/python/Products/PageTemplates/PageTemplateFile.py

@@ -31,6 +31,8 @@ from zope.pagetemplate.pagetemplatefile import sniff_type
 
 LOG = getLogger('PageTemplateFile')
 
+LAZY_FILE_LOADING = False
+
 def guess_type(filename, text):
 
     # check for XML ourself since guess_content_type can't
@@ -86,8 +88,9 @@ class PageTemplateFile(SimpleItem, Script, PageTemplate, Traversable):
 
         self.filename = filename
 
-        content = open(filename).read()
-        self.pt_edit( content, guess_type(filename, content))
+        if not LAZY_FILE_LOADING:
+            content = open(filename).read()
+            self.pt_edit( content, guess_type(filename, content))
 
     def pt_getContext(self):
         root = self.getPhysicalRoot()

lib/python/Products/PageTemplates/tests/test_ptfile.py

@@ -8,6 +8,7 @@ import transaction
 
 from Testing.makerequest import makerequest
 
+from Products.PageTemplates import PageTemplateFile as PTF
 from Products.PageTemplates.PageTemplateFile import PageTemplateFile
 
 
@@ -192,10 +193,42 @@ class LineEndingsTestCase(unittest.TestCase):
     def test_mac(self):
         self.assertEqual(self.runPTWithLineEndings('\r'), self.OUTPUT)
 
+
+class LazyLoadingTestCase(unittest.TestCase):
+
+    TEMPFILENAME = tempfile.mktemp(".zpt")
+    OLD_LAZY = None
+
+    def setUp(self):
+        self.OLD_LAZY = PTF.LAZY_FILE_LOADING
+
+    def tearDown(self):
+        if os.path.exists(self.TEMPFILENAME):
+            os.unlink(self.TEMPFILENAME)
+        PTF.LAZY_FILE_LOADING = self.OLD_LAZY
+
+    def test_not_lazy(self):
+        f = open(self.TEMPFILENAME, 'w')
+        print >> f, 'Lazyness'
+        f.close()
+        pt = PageTemplateFile(self.TEMPFILENAME)
+        self.failUnless(pt._text.startswith('Lazyness'))
+        self.failUnless(pt._v_program)
+
+    def test_lazy(self):
+        f = open(self.TEMPFILENAME, 'w')
+        print >> f, 'Lazyness'
+        f.close()
+        PTF.LAZY_FILE_LOADING = True
+        pt = PageTemplateFile(self.TEMPFILENAME)
+        self.failUnless(not pt._text and not pt._v_program)
+
+
 def test_suite():
     return unittest.TestSuite((
         unittest.makeSuite(TypeSniffingTestCase),
         unittest.makeSuite(LineEndingsTestCase),
+        unittest.makeSuite(LazyLoadingTestCase),
     ))
 
 if __name__ == "__main__":