[PATCH] www: strip and redirect on `<' and `>' in MSGID of URL

[Eric Wong <e@80x24.org>]

Junio C Hamano <gitster@pobox.com> wrote:
> When I have a specific message on a mailing list, and I am
> interested in the discussion around the message, I often go to the
> URL of that message in public-inbox powered mailing list archive.
> For example, I go to
> 
>     https://public-inbox.org/meta/20240606074416.3900983-1-e@80x24.org/
> 
> when I find "Message-ID: <20240606074416.3900983-1-e@80x24.org>"
> 
> It would be immensely convenient if cutting and pasting including
> the surrounding <angle-brackets>, i.e.
> 
>     https://public-inbox.org/meta/<20240606074416.3900983-1-e@80x24.org>/
> 
> is silently accepted and redirected to
> 
>     https://public-inbox.org/meta/20240606074416.3900983-1-e@80x24.org/
> 
> instead of the "partial matches found" page.

Seems reasonable; especially since sr.ht uses <> in URLs nowadays
and some users may be conditioned to include them.
I don't see 404s in my logs from this, but I don't keep a lot of logs.

------8<------
Subject: [PATCH] www: strip and redirect on `<' and `>' in MSGID of URL

Some users may needlessly include `<' and `>' braces in URLs, so
account for this common mistake and redirect users to the
non-braced URL.  This common mistake could be learned behavior
from other sites (e.g. sr.ht) which include `<' and `>' in URLs.

Reported-by: Junio C Hamano <gitster@pobox.com>
Link: https://public-inbox.org/meta/xmqqtthvh4r6.fsf@gitster.g/
---
 lib/PublicInbox/View.pm | 10 +++++++---
 t/psgi_search.t         | 11 +++++++++++
 2 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/lib/PublicInbox/View.pm b/lib/PublicInbox/View.pm
index dcceb311..cc1ab79a 100644
--- a/lib/PublicInbox/View.pm
+++ b/lib/PublicInbox/View.pm
@@ -74,9 +74,13 @@ sub msg_page {
 	my ($id, $prev);
 	my $next_arg = $ctx->{next_arg} = [ $ctx->{mid}, \$id, \$prev ];
 
-	my $smsg = $ctx->{smsg} = $over->next_by_mid(@$next_arg) or
-		return; # undef == 404
-
+	my $smsg = $ctx->{smsg} = $over->next_by_mid(@$next_arg);
+	if (!$smsg && $ctx->{mid} =~ /\A\<(.+)\>\z/ and
+			($next_arg->[0] = $1) and
+			($over->next_by_mid(@$next_arg))) {
+		return PublicInbox::WWW::r301($ctx, undef, $next_arg->[0]);
+	}
+	$smsg or return; # undef=404
 	# allow user to easily browse the range around this message if
 	# they have ->over
 	$ctx->{-t_max} = $smsg->{ts};
diff --git a/t/psgi_search.t b/t/psgi_search.t
index 8c981c6c..759dab78 100644
--- a/t/psgi_search.t
+++ b/t/psgi_search.t
@@ -179,6 +179,17 @@ test_psgi(sub { $www->call(@_) }, sub {
 
 	$res = $cb->(GET(q{/test/?q=%22s'more%22&x=A}));
 	is $res->code, 200, 'single quote inside phrase';
+
+	$res = $cb->(GET("/test/<$mid>/"));
+	is $res->code, 301, "redirect for raw `<' and `>' in msgid";
+	like $res->header('location'), qr!/test/\Q$mid\E/\z!,
+		"redirected to URL without raw `<' and `>'";
+
+	$res = $cb->(GET("/test/%3c$mid%3e/"));
+	is $res->code, 301, "redirect for escaped `<' and `>' in msgid";
+	like $res->header('location'), qr!/test/\Q$mid\E/\z!,
+		"redirected to URL without escaped `<' and `>'";
+
 	# TODO: more tests and odd cases
 });