Send diff in notifications (#296)

changedetectionio/diff.py

@@ -0,0 +1,43 @@
+# used for the notifications, the front-end is using a JS library
+
+import difflib
+
+# like .compare but a little different output
+def customSequenceMatcher(before, after, include_equal=False):
+    cruncher = difflib.SequenceMatcher(isjunk=lambda x: x in " \\t", a=before, b=after)
+
+    for tag, alo, ahi, blo, bhi in cruncher.get_opcodes():
+        if include_equal and tag == 'equal':
+            g = before[alo:ahi]
+            yield g
+        elif tag == 'delete':
+            g = "(removed) {}".format(before[alo])
+            yield g
+        elif tag == 'replace':
+            g = ["(changed) {}".format(before[alo]), "(-> into) {}".format(after[blo])]
+            yield g
+        elif tag == 'insert':
+            g = "(added) {}".format(after[blo])
+            yield g
+
+# only_differences - only return info about the differences, no context
+# line_feed_sep could be "<br/>" or "<li>" or "\n" etc
+def render_diff(previous_file, newest_file, include_equal=False, line_feed_sep="\n"):
+    with open(newest_file, 'r') as f:
+        newest_version_file_contents = f.read()
+        newest_version_file_contents = [line.rstrip() for line in newest_version_file_contents.splitlines()]
+
+    if previous_file:
+        with open(previous_file, 'r') as f:
+            previous_version_file_contents = f.read()
+            previous_version_file_contents = [line.rstrip() for line in previous_version_file_contents.splitlines()]
+    else:
+        previous_version_file_contents = ""
+
+    rendered_diff = customSequenceMatcher(previous_version_file_contents,
+                                          newest_version_file_contents,
+                                          include_equal)
+
+    # Recursively join lists
+    f = lambda L: line_feed_sep.join([f(x) if type(x) is list else x for x in L])
+    return f(rendered_diff)