neiam /feedpug

feedpub

An impossible feed date reads as nil, not a crashed fetch

cb32133 · Gabe Morell · 2026-11-04 21:36

8 files +28 -21

Message

{commit_body(@commit)}

modified lib/feed_pug/feeds/fetcher.ex

+13 −21

@@ -138,27 +138,19 @@ defmodule FeedPug.Feeds.Fetcher do

138	138
139	139	# Minimal RFC-822/1123 parser, e.g. "Wed, 02 Oct 2002 13:00:00 GMT".
140	140	defp parse_rfc822(str) do
141		− case Regex.run(~r/(\d{1,2})\s+(\w{3})\s+(\d{2,4})\s+(\d{2}):(\d{2})(?::(\d{2}))?/, str) do
142		− [_, d, mon, y, h, min \| rest] ->
143		− case month_number(mon) do
144		− {:ok, month} ->
145		− year = String.to_integer(y) \|> normalize_year()
146		− sec = rest \|> List.first() \|> to_int(0)
147		−
148		− case DateTime.new(
149		− Date.new!(year, month, String.to_integer(d)),
150		− Time.new!(String.to_integer(h), String.to_integer(min), sec)
151		− ) do
152		− {:ok, dt} -> dt
153		− _ -> nil
154		− end
155		−
156		− :error ->
157		− nil
158		− end
159		−
160		− _ ->
161		− nil
	141	+ # An impossible date or time ("31 Feb", hour 25) reads as nil like any
	142	+ # other unparseable string, rather than crashing the whole feed fetch.
	143	+ with [_, d, mon, y, h, min \| rest] <-
	144	+ Regex.run(~r/(\d{1,2})\s+(\w{3})\s+(\d{2,4})\s+(\d{2}):(\d{2})(?::(\d{2}))?/, str),
	145	+ {:ok, month} <- month_number(mon),
	146	+ year = String.to_integer(y) \|> normalize_year(),
	147	+ sec = rest \|> List.first() \|> to_int(0),
	148	+ {:ok, date} <- Date.new(year, month, String.to_integer(d)),
	149	+ {:ok, time} <- Time.new(String.to_integer(h), String.to_integer(min), sec),
	150	+ {:ok, dt} <- DateTime.new(date, time) do
	151	+ dt
	152	+ else
	153	+ _ -> nil
162	154	end
163	155	end
164	156

modified test/feed_pug/feeds/fetcher_test.exs

+15 −0

@@ -58,4 +58,19 @@ defmodule FeedPug.Feeds.FetcherTest do

58	58
59	59	assert Fetcher.parse_datetime(nil) == nil
60	60	end
	61	+
	62	+ test "parse_datetime reads an impossible RFC-822 date or time as nil" do
	63	+ assert Fetcher.parse_datetime("Sat, 31 Feb 2024 13:00:00 GMT") == nil
	64	+ assert Fetcher.parse_datetime("Wed, 02 Oct 2002 25:00:00 GMT") == nil
	65	+ assert Fetcher.parse_datetime("Wed, 02 Oct 2002 13:61:00 GMT") == nil
	66	+ assert Fetcher.parse_datetime("Wed, 02 Oct 2002 13:00:99 GMT") == nil
	67	+ end
	68	+
	69	+ test "an entry with an impossible date is still stored, not a crashed fetch" do
	70	+ {:ok, feed} = Feeds.upsert_feed_by_url("https://ex.com/feed.xml")
	71	+ rss = String.replace(@rss, "Wed, 02 Oct 2002", "Sat, 31 Feb 2024")
	72	+ Req.Test.stub(__MODULE__, fn conn -> Req.Test.text(conn, rss) end)
	73	+
	74	+ assert {:ok, [_item]} = Fetcher.refresh(feed, stub())
	75	+ end
61	76	end

Parents: fa42332