commit 1045eb74978b0936743a76a3b690ccdd6e85450e
from: Oliver Lowe <o@olowe.co>
date: Sat Apr 19 06:47:32 2025 UTC

rss: handle more timestamp variants

I parsed every feed listed in opml/otl.opml and found a bunch of
variants of RFC 822 and RFC 1123 timestamps used.

commit - 5f9e6325936e158cd3c8afcbd5005b278dc9a855
commit + 1045eb74978b0936743a76a3b690ccdd6e85450e
blob - 4764ad87ee5f6482c61abe96e62f5e5ccb9c5bd7
blob + a5c140780646d227a942d7a707253af3797847c6
--- rss/rss.go
+++ rss/rss.go
@@ -2,6 +2,7 @@ package rss
 
 import (
 	"encoding/xml"
+	"fmt"
 	"io"
 	"time"
 )
@@ -44,16 +45,16 @@ func (ch *Channel) UnmarshalXML(d *xml.Decoder, start 
 	}
 
 	if aux.PubDate != "" {
-		t, err := time.Parse(time.RFC1123Z, aux.PubDate)
+		t, err := parseTime(aux.PubDate)
 		if err != nil {
-			return err
+			return fmt.Errorf("parse published date %q: %w", aux.PubDate, err)
 		}
 		ch.PubDate = t
 	}
 	if aux.LastBuildDate != "" {
-		t, err := time.Parse(time.RFC1123Z, aux.LastBuildDate)
+		t, err := parseTime(aux.LastBuildDate)
 		if err != nil {
-			return err
+			return fmt.Errorf("parse last build date %q: %w", aux.LastBuildDate, err)
 		}
 		ch.LastBuildDate = t
 	}
@@ -98,9 +99,9 @@ func (it *Item) UnmarshalXML(d *xml.Decoder, start xml
 		return err
 	}
 	if aux.PubDate != "" {
-		t, err := time.Parse(time.RFC1123Z, aux.PubDate)
+		t, err := parseTime(aux.PubDate)
 		if err != nil {
-			return err
+			return fmt.Errorf("parse published date %q: %w", aux.PubDate, err)
 		}
 		it.PubDate = t
 	}
@@ -118,3 +119,19 @@ func Decode(r io.Reader) (*RSS, error) {
 	}
 	return &rss, nil
 }
+
+func parseTime(s string) (time.Time, error) {
+	layouts := []string{
+		time.RFC1123Z, time.RFC1123,
+		time.RFC822Z, time.RFC822,
+		"Mon, _2 Jan 2006 15:04:05 -0700",     // rfc1123z with no trailing zero
+		"Mon, _2 January 2006 15:04:05 -0700", // long month name
+	}
+	for _, l := range layouts {
+		t, err := time.Parse(l, s)
+		if err == nil {
+			return t, nil
+		}
+	}
+	return time.Time{}, fmt.Errorf("unsupported layout")
+}
blob - f2cf2b7c74ea4e2ea0fe2d68bcaa70f6e51dfa26
blob + b194fe55a25f5e30dfa9aa05d351b3d5c843e5cc
--- rss/rss_test.go
+++ rss/rss_test.go
@@ -61,3 +61,20 @@ func TestEmpty(t *testing.T) {
 		t.Fatal(err)
 	}
 }
+
+func TestParseTime(t *testing.T) {
+	var tests = []struct {
+		name      string
+		timestamp string
+	}{
+		{"no leading zero", "Fri, 4 Feb 2022 09:30:00 +1300"}, // https://benhoyt.com/writings/rss.xml
+		{"long month", "Mon, 10 June 2024 12:20:00 +0000"},    // https://www.claws-mail.org/releases.rss
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if _, err := parseTime(tt.timestamp); err != nil {
+				t.Errorf("parse %q: %v", tt.timestamp, err)
+			}
+		})
+	}
+}