Fixes to date & timezone parsing, add ignore_errors flag

lib/icalendar.ex

@@ -5,7 +5,7 @@ defmodule ICalendar do
 
   defstruct events: []
   defdelegate to_ics(events, options \\ []), to: ICalendar.Serialize
-  defdelegate from_ics(events), to: ICalendar.Deserialize
+  defdelegate from_ics(events, options \\ []), to: ICalendar.Deserialize
 
   @doc """
   To create a Phoenix/Plug controller and view that output ics format:

lib/icalendar/deserialize.ex

@@ -1,40 +1,51 @@
 defprotocol ICalendar.Deserialize do
-  def from_ics(ics)
+  def from_ics(ics, opts \\ [])
 end
 
 alias ICalendar.Deserialize
 
 defimpl ICalendar.Deserialize, for: BitString do
   alias ICalendar.Util.Deserialize
+  require Logger
 
-  def from_ics(ics) do
+  def from_ics(ics, opts \\ []) do
     ics
     |> String.trim()
     |> String.split("\n")
     |> Enum.map(&String.trim_trailing/1)
-    |> get_events()
+    |> get_events([], [], opts)
   end
 
-  defp get_events(calendar_data, event_collector \\ [], temp_collector \\ [])
+  defp get_events(calendar_data, event_collector, temp_collector, opts)
 
-  defp get_events([head | calendar_data], event_collector, temp_collector) do
+  defp get_events([head | calendar_data], event_collector, temp_collector, opts) do
     case head do
       "BEGIN:VEVENT" ->
         # start collecting event
-        get_events(calendar_data, event_collector, [head])
+        get_events(calendar_data, event_collector, [head], opts)
 
       "END:VEVENT" ->
         # finish collecting event
-        event = Deserialize.build_event(temp_collector ++ [head])
-        get_events(calendar_data, [event] ++ event_collector, [])
+        try do
+          event = Deserialize.build_event(temp_collector ++ [head])
+          get_events(calendar_data, [event] ++ event_collector, [], opts)
+        rescue
+          e ->
+            if Keyword.get(opts, :ignore_errors) do
+              Logger.info("Error parsing: #{inspect(e)}")
+              get_events(calendar_data, event_collector, [], opts)
+            else
+              Kernel.reraise(e, __STACKTRACE__)
+            end
+        end
 
       event_property when temp_collector != [] ->
-        get_events(calendar_data, event_collector, temp_collector ++ [event_property])
+        get_events(calendar_data, event_collector, temp_collector ++ [event_property], opts)
 
       _unimportant_stuff ->
-        get_events(calendar_data, event_collector, temp_collector)
+        get_events(calendar_data, event_collector, temp_collector, opts)
     end
   end
 
-  defp get_events([], event_collector, _temp_collector), do: event_collector
+  defp get_events([], event_collector, _temp_collector, _opts), do: event_collector
 end

lib/icalendar/util/deserialize.ex

@@ -102,12 +102,19 @@ defmodule ICalendar.Util.Deserialize do
   end
 
   def parse_attr(
-        %Property{key: "EXDATE", value: exdate, params: params},
+        %Property{key: "EXDATE", value: new_exdates, params: params},
         acc
       ) do
     exdates = Map.get(acc, :exdates, [])
-    {:ok, timestamp} = to_date(exdate, params)
-    %{acc | exdates: [timestamp | exdates]}
+
+    new_dates =
+      String.split(new_exdates, ",")
+      |> Enum.map(fn exdate ->
+        {:ok, timestamp} = to_date(exdate, params)
+        timestamp
+      end)
+
+    %{acc | exdates: Enum.concat(new_dates, exdates)}
   end
 
   def parse_attr(
@@ -238,8 +245,13 @@ defmodule ICalendar.Util.Deserialize do
       if Regex.match?(~r/\//, timezone) do
         timezone
       else
-        Timex.Timezone.Utils.to_olson(timezone)
-      end
+        try do
+          Timex.Timezone.Utils.to_olson(timezone)
+        rescue
+          # probably a custom timezone defined in this file
+          _e -> nil
+        end
+      end || "UTC"
 
     date_string =
       case String.last(date_string) do

test/icalendar/deserialize_test.exs

@@ -49,6 +49,41 @@ defmodule ICalendar.DeserializeTest do
       assert event.dtend.time_zone == "America/Chicago"
     end
 
+    test "with custom Timezone won't crash" do
+      ics = """
+      BEGIN:VTIMEZONE
+      TZID:Eastern Standard Time 1
+      BEGIN:STANDARD
+      DTSTART:16010101T000000
+      TZOFFSETFROM:-0500
+      TZOFFSETTO:-0500
+      END:STANDARD
+      END:VTIMEZONE
+      BEGIN:VEVENT
+      DTEND;TZID=Eastern Standard Time 1:22221224T084500
+      DTSTART;TZID=Eastern Standard Time 1:22221224T083000
+      END:VEVENT
+      """
+
+      [event] = ICalendar.from_ics(ics)
+      assert event.dtstart.time_zone == "Etc/UTC"
+      assert event.dtend.time_zone == "Etc/UTC"
+    end
+
+    test "with rrule exceptions" do
+      ics = """
+      BEGIN:VEVENT
+      RRULE:FREQ=WEEKLY
+      EXDATE;TZID=Eastern Standard Time:20201126T091500,20201127T091500
+      DTSTART;TZID=Eastern Standard Time:20201023T091500
+      DTEND;TZID=Eastern Standard Time:20201023T093000
+      END:VEVENT
+      """
+
+      [event] = ICalendar.from_ics(ics)
+      assert length(event.exdates) == 2
+    end
+
     test "with CR+LF line endings" do
       ics = """
       BEGIN:VEVENT