Enable ZMI History tab for OFS.Image.File

Modernize a bit the condition to display online text editor: support
editing json inline and tolerate larger file content.

Author: perrinjerome

CHANGES.rst

@@ -10,6 +10,9 @@ https://github.com/zopefoundation/Zope/blob/4.x/CHANGES.rst
 5.11.2 (unreleased)
 -------------------
 
+- Enable ZMI History tab for ``OFS.Image.File``.
+  (`#396 <https://github.com/zopefoundation/Zope/pull/396>`_)
+
 - Fix error messages from spam/pen test requests.
 
 - Fix a ``ResourceWarning`` emitted when uploading large files.

src/OFS/Image.py

@@ -33,6 +33,8 @@
 from App.special_dtml import DTMLFile
 from DateTime.DateTime import DateTime
 from OFS.Cache import Cacheable
+from OFS.History import Historical
+from OFS.History import html_diff
 from OFS.interfaces import IWriteLock
 from OFS.PropertyManager import PropertyManager
 from OFS.role import RoleManager
@@ -167,6 +169,7 @@ class File(
     PropertyManager,
     RoleManager,
     Item_w__name__,
+    Historical,
     Cacheable
 ):
     """A File object is a content object for arbitrary files."""
@@ -201,7 +204,9 @@ class File(
                       + PropertyManager.manage_options
                       + RoleManager.manage_options
                       + Item_w__name__.manage_options
-                      + Cacheable.manage_options)
+                      + Cacheable.manage_options
+                      + Historical.manage_options
+                      )
 
     _properties = (
         {'id': 'title', 'type': 'string'},
@@ -657,6 +662,31 @@ def manage_upload(self, file='', REQUEST=None):
             return self.manage_main(
                 self, REQUEST, manage_tabs_message=msg)
 
+    @security.protected(change_images_and_files)
+    def manage_is_editable_inline(self):
+        return (
+            self.content_type
+            and (
+                self.content_type.startswith('text')
+                or self.content_type.endswith('javascript')
+                or self.content_type == 'application/json'
+            )
+            and self.get_size() < 2**17
+        )
+
+    def manage_historyCompare(self, rev1, rev2, REQUEST,
+                              historyComparisonResults=''):
+        if self.manage_is_editable_inline():
+            return File.inheritedAttribute('manage_historyCompare')(
+                self, rev1, rev2, REQUEST,
+                historyComparisonResults=html_diff(
+                    str(rev1.data),
+                    str(rev2.data)))
+        return File.inheritedAttribute('manage_historyCompare')(
+            self, rev1, rev2, REQUEST,
+            historyComparisonResults=historyComparisonResults
+        )
+
     def _get_content_type(self, file, body, id, content_type=None):
         headers = getattr(file, 'headers', None)
         if headers and 'content-type' in headers:

src/OFS/dtml/fileEdit.dtml

@@ -38,28 +38,26 @@
 			</div>
 		</div>
 
-		<dtml-let ct=getContentType>
-			<dtml-if "(ct.startswith('text') or ct.endswith('javascript')) and this().get_size() < 65536">
-				<div class="form-group">
-					<dtml-try>
-						<textarea id="content" <dtml-if content_type>data-contenttype="&dtml-content_type;"</dtml-if>
-							class="form-control zmi-file zmi-code col-sm-12"
-							name="filedata:text" wrap="off" rows="20"><dtml-var __str__ html_quote></textarea>
-					<dtml-except UnicodeDecodeError>
-						<div class="alert alert-warning" role="alert">
-							The file could not be decoded with '<dtml-var "error_value.encoding">'.
-						</div>
-					</dtml-try>
-				</div>
-			<dtml-else>
-				<div class="form-group row">
-					<label for="size" class="form-label	col-sm-3 col-md-2">File Size</label>
-					<div class="form-text col-sm-9 col-md-10">
-						<dtml-var size thousands_commas> bytes
+		<dtml-if manage_is_editable_inline>
+			<div class="form-group">
+				<dtml-try>
+					<textarea id="content" <dtml-if content_type>data-contenttype="&dtml-content_type;"</dtml-if>
+						class="form-control zmi-file zmi-code col-sm-12"
+						name="filedata:text" wrap="off" rows="20"><dtml-var __str__ html_quote></textarea>
+				<dtml-except UnicodeDecodeError>
+					<div class="alert alert-warning" role="alert">
+						The file could not be decoded with '<dtml-var "error_value.encoding">'.
 					</div>
+				</dtml-try>
+			</div>
+		<dtml-else>
+			<div class="form-group row">
+				<label for="size" class="form-label	col-sm-3 col-md-2">File Size</label>
+				<div class="form-text col-sm-9 col-md-10">
+					<dtml-var size thousands_commas> bytes
 				</div>
-			</dtml-if>
-		</dtml-let>
+			</div>
+		</dtml-if>
 
 		<div class="zmi-controls">
 			<dtml-if wl_isLocked>

src/OFS/tests/testFileAndImage.py

@@ -391,6 +391,24 @@ def test_text_representation_is_tag(self):
                          '<img src="http://nohost/file"'
                          ' alt="" title="" height="16" width="16" />')
 
+    def test_history_compare(self):
+        self.file.manage_edit(
+            'a',
+            'text/plain',
+            filedata=b'content_of_a')
+        getattr(
+            self.app,
+            self.factory)(
+            'b',
+            file=b'content_of_b',
+            content_type='text/plain')
+        page = self.file.manage_historyCompare(
+            self.file,
+            self.app.b,
+            self.app.REQUEST)
+        self.assertIn('content_of_a', page)
+        self.assertIn('content_of_b', page)
+
 
 class SVGTests(ImageTests):
     content_type = 'image/svg+xml'