- Fixed fallback implementation of manage_DAVget (fixes #799)

CHANGES.rst

@@ -28,6 +28,9 @@ Bug fixes
 - Fixed encoding issue of `displayname` WebDAV property
   (`#797 <https://github.com/zopefoundation/Zope/issues/797>`_)
 
+- Fixed fallback implementation of ``manage_DAVget``
+  (`#799 <https://github.com/zopefoundation/Zope/issues/799>`_)
+
 
 Other changes
 +++++++++++++

src/OFS/Image.py

@@ -23,6 +23,7 @@
 from AccessControl.Permissions import change_images_and_files  # NOQA
 from AccessControl.Permissions import view as View
 from AccessControl.Permissions import view_management_screens
+from AccessControl.Permissions import webdav_access
 from AccessControl.SecurityInfo import ClassSecurityInfo
 from Acquisition import Implicit
 from App.Common import rfc1123_date
@@ -694,6 +695,32 @@ def __len__(self):
         data = bytes(self.data)
         return len(data)
 
+    @security.protected(webdav_access)
+    def manage_DAVget(self):
+        """Return body for WebDAV."""
+        RESPONSE = self.REQUEST.RESPONSE
+
+        if self.ZCacheable_isCachingEnabled():
+            result = self.ZCacheable_get(default=None)
+            if result is not None:
+                # We will always get None from RAMCacheManager but we will
+                # get something implementing the IStreamIterator interface
+                # from FileCacheManager.
+                # the content-length is required here by HTTPResponse.
+                RESPONSE.setHeader('Content-Length', self.size)
+                return result
+
+        data = self.data
+        if isinstance(data, bytes):
+            RESPONSE.setBase(None)
+            return data
+
+        while data is not None:
+            RESPONSE.write(data.data)
+            data = data.next
+
+        return b''
+
 
 InitializeClass(File)
 

src/OFS/tests/testFileAndImage.py

@@ -299,6 +299,15 @@ def testPrincipiaSearchSource_text(self):
                                        b'come to the aid of the Party.')
         self.assertTrue(b'Party' in self.file.PrincipiaSearchSource())
 
+    def test_manage_DAVget_binary(self):
+        self.assertEqual(self.file.manage_DAVget(), self.data)
+
+    def test_manage_DAVget_text(self):
+        text = (b'Now is the time for all good men to '
+                b'come to the aid of the Party.')
+        self.file.manage_edit('foobar', 'text/plain', filedata=text)
+        self.assertEqual(self.file.manage_DAVget(), text)
+
     def test_interfaces(self):
         from zope.interface.verify import verifyClass
         from OFS.Image import File

src/webdav/Resource.py

@@ -675,9 +675,19 @@ def UNLOCK(self, REQUEST, RESPONSE):
 
     @security.protected(webdav_access)
     def manage_DAVget(self):
-        """Gets the document source"""
-        # The default implementation calls PrincipiaSearchSource
-        return self.PrincipiaSearchSource()
+        """Gets the document source or file data.
+
+        This implementation is a last resort fallback. The subclass should
+        override this method to provide a more appropriate implementation.
+
+        Using PrincipiaSearchSource, if it exists. It is one of the few shared
+        interfaces still around in common Zope content objects.
+        """
+        if getattr(aq_base(self), 'PrincipiaSearchSource', None) is not None:
+            return self.PrincipiaSearchSource()
+
+        # If it doesn't exist, give up.
+        return ''
 
     @security.protected(webdav_access)
     def listDAVObjects(self):

src/webdav/tests/testNullResource.py

@@ -84,3 +84,7 @@ def _verifyObjectPaste(self, *args, **kw):
             nonesuch.PUT(request, response)
         except Unauthorized as e:
             self.assertTrue(str(e).startswith('Unable to create object'))
+
+    def test_manage_DAVget(self):
+        nonesuch = self._makeOne()
+        self.assertFalse(nonesuch.manage_DAVget())