add tests for issue #355

src/icalendar/parser.py

@@ -259,25 +259,6 @@ def from_ical(cls, st, strict=False):
                                  % (param, exc))
         return result
 
-
-def escape_string(val):
-    # '%{:02X}'.format(i)
-    return val.replace(r'\,', '%2C').replace(r'\:', '%3A')\
-              .replace(r'\;', '%3B').replace(r'\\', '%5C')
-
-
-def unescape_string(val):
-    return val.replace('%2C', ',').replace('%3A', ':')\
-              .replace('%3B', ';').replace('%5C', '\\')
-
-
-def unescape_list_or_string(val):
-    if isinstance(val, list):
-        return [unescape_string(s) for s in val]
-    else:
-        return unescape_string(val)
-
-
 #########################################
 # parsing and generation of content lines
 
@@ -315,34 +296,68 @@ def from_parts(cls, name, params, values, sorted=True):
         return cls(f'{name}:{values}')
 
     def parts(self):
-        """Split the content line up into (name, parameters, values) parts.
+        """
+        Split the content line up into (name, parameters, values) parts.
+
+        Example with parameter:
+        DESCRIPTION;ALTREP="cid:part1.0001@example.org":The Fall'98 Wild
+
+        Example without parameters:
+        DESCRIPTION:The Fall'98 Wild
+
+        https://icalendar.org/iCalendar-RFC-5545/3-2-property-parameters.html
         """
         try:
-            st = escape_string(self)
+            st = self
             name_split = None
             value_split = None
             in_quotes = False
+            # Any character can be escaped using a backslash, e.g.: "test\:test"
+            quote_character = False
             for i, ch in enumerate(st):
-                if not in_quotes:
-                    if ch in ':;' and not name_split:
-                        name_split = i
-                    if ch == ':' and not value_split:
-                        value_split = i
+                # We can also quote using quotation marks. This ignores any output, until another quote appears.
                 if ch == '"':
                     in_quotes = not in_quotes
-            name = unescape_string(st[:name_split])
+                    continue
+
+                # Ignore input, as we are currently in quotation mark quotes
+                if in_quotes:
+                    continue
+
+                # Skip quoted character
+                if quote_character:
+                    quote_character = False
+                    continue
+
+                # The next character should be ignored
+                if ch == '\\':
+                    quote_character = True
+                    continue
+
+                # The name ends either after the parameter or value delimiter
+                if ch in ':;' and not name_split:
+                    name_split = i
+
+                # The value starts after the value delimiter
+                if ch == ':' and not value_split:
+                    value_split = i
+
+            # Get name
+            name = st[:name_split]
             if not name:
                 raise ValueError('Key name is required')
             validate_token(name)
+
+            # Check if parameters are empty
             if not name_split or name_split + 1 == value_split:
                 raise ValueError('Invalid content line')
+
+            # Get parameters (text between ; and :)
             params = Parameters.from_ical(st[name_split + 1: value_split],
                                           strict=self.strict)
-            params = Parameters(
-                (unescape_string(key), unescape_list_or_string(value))
-                for key, value in iter(params.items())
-            )
-            values = unescape_string(st[value_split + 1:])
+
+            # Get the value after the :
+            values = st[value_split + 1:]
             return (name, params, values)
         except ValueError as exc:
             raise ValueError(

src/icalendar/tests/events/issue_355_url_escaping.ics

@@ -0,0 +1,8 @@
+BEGIN:VEVENT
+DTSTAMP:20220822T164528Z
+UID:1661186704812-62650@ical.marudot.com
+DTSTART;TZID=Europe/Berlin:20220822T120000
+DTEND;TZID=Europe/Berlin:20220822T120000
+SUMMARY:test
+DESCRIPTION:https://www.facebook.com/events/756119502186737/?acontext=%7B%22source%22%3A5%2C%22action_history%22%3A[%7B%22surface%22%3A%22page%22%2C%22mechanism%22%3A%22main_list%22%2C%22extra_data%22%3A%22%5C%22[]%5C%22%22%7D]%2C%22has_source%22%3Atrue%7D
+END:VEVENT

src/icalendar/tests/events/issue_355_url_escaping_2.ics

@@ -0,0 +1,8 @@
+BEGIN:VEVENT
+DTSTAMP:20220822T164528Z
+UID:1661186704812-62650@ical.marudot.com
+DTSTART;TZID=Europe/Berlin:20220822T120000
+DTEND;TZID=Europe/Berlin:20220822T120000
+SUMMARY:test
+DESCRIPTION:https://www.facebook.com/events/756119502186737/?acontext=%7B%22source%22%3A5%2C%22action_history%22%3A[%7B%22surface%22%3A%22page%22%2C%22mechanism%22%3A%22main_list%22%2C%22extra_data%22%3A%22%5C%22[]%5C%22%22%7D]%2C%22has_source%22%3Atrue%7D
+END:VEVENT

src/icalendar/tests/events/issue_355_url_escaping_empty_param.ics

@@ -0,0 +1,3 @@
+BEGIN:VEVENT
+ORGANIZER;CN="":that
+END:VEVENT

src/icalendar/tests/test_issue_355_url_escaping.py

@@ -0,0 +1,23 @@
+"""Tests for Issue 355.
+
+see https://github.com/collective/icalendar/issues/355
+"""
+
+def test_facebook_link_is_correctly_parsed(events):
+    """The facebook link must not be damaged.
+
+    see https://github.com/collective/icalendar/pull/356#issuecomment-1222626128
+    """
+    assert events.issue_355_url_escaping["DESCRIPTION"] == "https://www.facebook.com/events/756119502186737/?acontext=%7B%22source%22%3A5%2C%22action_history%22%3A[%7B%22surface%22%3A%22page%22%2C%22mechanism%22%3A%22main_list%22%2C%22extra_data%22%3A%22%5C%22[]%5C%22%22%7D]%2C%22has_source%22%3Atrue%7D"
+
+def test_other_facebook_link_is_correctly_parsed(events):
+    """The facebook link must not be damaged.
+
+    see https://github.com/collective/icalendar/pull/356#issuecomment-1265872696
+    """
+    expected_result = 'https://www.facebook.com/events/756119502186737/?acontext=%7B%22source%22%3A5%2C%22action_history%22%3A[%7B%22surface%22%3A%22page%22%2C%22mechanism%22%3A%22main_list%22%2C%22extra_data%22%3A%22%5C%22[]%5C%22%22%7D]%2C%22has_source%22%3Atrue%7D'
+    assert events.issue_355_url_escaping_2["DESCRIPTION"] == expected_result
+
+def test_empty_quotes(events):
+    """Make sure that empty quoted parameter values are supported."""
+    assert events.issue_355_url_escaping_empty_param['ORGANIZER'].params['CN'] == ""