From 35ac61764499c272d2760de2b2a432be412ecede Mon Sep 17 00:00:00 2001
From: "Eric Wong (Contractor, The Linux Foundation)" <e@80x24.org>
Date: Tue, 6 Mar 2018 04:15:38 +0000
Subject: favor Received: date over Date: header globally

The first Received: header is believable since it typically
hits the user's mail server and can be treated as relatively
trustworthy.  We still show the Date: in per-message (permalink)
views, which may expose users for having incorrect Date:
headers, but all the ISO YYYY-MM-DD dates we display will
match what we see.
---
 lib/PublicInbox/MsgTime.pm | 51 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 51 insertions(+)
 create mode 100644 lib/PublicInbox/MsgTime.pm

(limited to 'lib/PublicInbox/MsgTime.pm')

diff --git a/lib/PublicInbox/MsgTime.pm b/lib/PublicInbox/MsgTime.pm
new file mode 100644
index 00000000..87664f4b
--- /dev/null
+++ b/lib/PublicInbox/MsgTime.pm
@@ -0,0 +1,51 @@
+# Copyright (C) 2018 all contributors <meta@public-inbox.org>
+# License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
+package PublicInbox::MsgTime;
+use strict;
+use warnings;
+use base qw(Exporter);
+our @EXPORT_OK = qw(msg_timestamp);
+use Date::Parse qw(str2time);
+use Time::Zone qw(tz_offset);
+
+sub msg_timestamp ($) {
+	my ($hdr) = @_; # Email::MIME::Header
+	my ($ts, $zone);
+	my $mid;
+	my @recvd = $hdr->header_raw('Received');
+	foreach my $r (@recvd) {
+		$zone = undef;
+		$r =~ /\s*(\d+\s+[[:alpha:]]+\s+\d{2,4}\s+
+			\d+\D\d+(?:\D\d+)\s+([\+\-]\d+))/sx or next;
+		$zone = $2;
+		$ts = eval { str2time($1) } and last;
+		$mid ||= $hdr->header_raw('Message-ID');
+		warn "no date in $mid Received: $r\n";
+	}
+	unless (defined $ts) {
+		my @date = $hdr->header_raw('Date');
+		foreach my $d (@date) {
+			$zone = undef;
+			$ts = eval { str2time($d) };
+			if ($@) {
+				$mid ||= $hdr->header_raw('Message-ID');
+				warn "bad Date: $d in $mid: $@\n";
+			} elsif ($d =~ /\s+([\+\-]\d+)\s*\z/) {
+				$zone = $1;
+			}
+		}
+	}
+	$ts = time unless defined $ts;
+	return $ts unless wantarray;
+
+	$zone ||= '+0000';
+	# "-1200" is the furthest westermost zone offset,
+	# but git fast-import is liberal so we use "-1400"
+	if ($zone >= 1400 || $zone <= -1400) {
+		warn "bogus TZ offset: $zone, ignoring and assuming +0000\n";
+		$zone = '+0000';
+	}
+	($ts, $zone);
+}
+
+1;
-- 
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