From 7319f5d318a960eeb32a207d226eea7fd9ce2543 Mon Sep 17 00:00:00 2001
From: Eric Wong <e@80x24.org>
Date: Mon, 25 Oct 2021 02:45:53 +0000
Subject: www: $MSGID/raw: set charset in HTTP response
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

By using the charset specified in the message, web browsers are
more likely to display the raw text properly for human readers.

Inspired by a patch by Thomas Weißschuh:
  https://public-inbox.org/meta/20211024214337.161779-3-thomas@t-8ch.de/

Cc: Thomas Weißschuh <thomas@t-8ch.de>
---
 lib/PublicInbox/GzipFilter.pm | 19 +++++++++++++------
 lib/PublicInbox/Mbox.pm       | 24 +++++++++++++-----------
 2 files changed, 26 insertions(+), 17 deletions(-)

(limited to 'lib')

diff --git a/lib/PublicInbox/GzipFilter.pm b/lib/PublicInbox/GzipFilter.pm
index c4858a97..e37f1f76 100644
--- a/lib/PublicInbox/GzipFilter.pm
+++ b/lib/PublicInbox/GzipFilter.pm
@@ -46,11 +46,10 @@ sub gz_or_noop {
 sub gzf_maybe ($$) { bless { gz => gz_or_noop(@_) }, __PACKAGE__ }
 
 sub psgi_response {
+	# $code may be an HTTP response code (e.g. 200) or a CODE ref (mbox_hdr)
 	my ($self, $code, $res_hdr) = @_;
-	my $env = $self->{env};
-	$self->{gz} //= gz_or_noop($res_hdr, $env);
-	if ($env->{'pi-httpd.async'}) {
-		my $http = $env->{'psgix.io'}; # PublicInbox::HTTP
+	if ($self->{env}->{'pi-httpd.async'}) {
+		my $http = $self->{env}->{'psgix.io'}; # PublicInbox::HTTP
 		$http->{forward} = $self;
 		sub {
 			my ($wcb) = @_; # -httpd provided write callback
@@ -58,6 +57,9 @@ sub psgi_response {
 			$self->can('async_next')->($http); # start stepping
 		};
 	} else { # generic PSGI code path
+		ref($code) eq 'CODE' and
+			($code, $res_hdr) = @{$code->($self)};
+		$self->{gz} //= gz_or_noop($res_hdr, $self->{env});
 		[ $code, $res_hdr, $self ];
 	}
 }
@@ -116,9 +118,13 @@ sub translate ($$) {
 
 sub http_out ($) {
 	my ($self) = @_;
-	$self->{http_out} //= do {
+	$self->{http_out} // do {
 		my $args = delete $self->{wcb_args} // return undef;
-		pop(@$args)->($args); # $wcb->([$code, $hdr_ary])
+		my $wcb = pop @$args; # from PublicInbox:HTTP async
+		# $args->[0] may be \&mbox_hdr or similar
+		$args = $args->[0]->($self) if ref($args->[0]) eq 'CODE';
+		$self->{gz} //= gz_or_noop($args->[1], $self->{env});
+		$self->{http_out} = $wcb->($args); # $wcb->([$code, $hdr_ary])
 	};
 }
 
@@ -131,6 +137,7 @@ sub write {
 # more data to buffer after this
 sub zmore {
 	my $self = $_[0]; # $_[1] => input
+	http_out($self);
 	my $err = $self->{gz}->deflate($_[1], $self->{zbuf});
 	die "gzip->deflate: $err" if $err != Z_OK;
 	undef;
diff --git a/lib/PublicInbox/Mbox.pm b/lib/PublicInbox/Mbox.pm
index 4f84eea6..b977308d 100644
--- a/lib/PublicInbox/Mbox.pm
+++ b/lib/PublicInbox/Mbox.pm
@@ -18,7 +18,7 @@ sub getline {
 	my ($ctx) = @_; # ctx
 	my $smsg = $ctx->{smsg} or return;
 	my $ibx = $ctx->{ibx};
-	my $eml = $ibx->smsg_eml($smsg) or return;
+	my $eml = delete($ctx->{eml}) // $ibx->smsg_eml($smsg) // return;
 	my $n = $ctx->{smsg} = $ibx->over->next_by_mid(@{$ctx->{next_arg}});
 	$ctx->zmore(msg_hdr($ctx, $eml));
 	if ($n) {
@@ -45,14 +45,15 @@ sub async_eml { # for async_blob_cb
 	my $smsg = delete $ctx->{smsg};
 	# next message
 	$ctx->{smsg} = $ctx->{ibx}->over->next_by_mid(@{$ctx->{next_arg}});
-
+	local $ctx->{eml} = $eml; # for mbox_hdr
 	$ctx->zmore(msg_hdr($ctx, $eml));
 	$ctx->write(msg_body($eml));
 }
 
-sub res_hdr ($$) {
-	my ($ctx, $subject) = @_;
-	my $fn = $subject // '';
+sub mbox_hdr ($) {
+	my ($ctx) = @_;
+	my $eml = $ctx->{eml} //= $ctx->{ibx}->smsg_eml($ctx->{smsg});
+	my $fn = $eml->header_str('Subject') // '';
 	$fn =~ s/^re:\s+//i;
 	$fn = to_filename($fn) // 'no-subject';
 	my @hdr = ('Content-Type');
@@ -64,17 +65,19 @@ sub res_hdr ($$) {
 		push @hdr, 'text/plain';
 		$fn .= '.txt';
 	}
+	my $cs = $ctx->{eml}->ct->{attributes}->{charset} // 'UTF-8';
+	$cs = 'UTF-8' if $cs =~ /[^a-zA-Z0-9\-\_]/; # avoid header injection
+	$hdr[-1] .= "; charset=$cs";
 	push @hdr, 'Content-Disposition', "inline; filename=$fn";
-	\@hdr;
+	[ 200, \@hdr ];
 }
 
 # for rare cases where v1 inboxes aren't indexed w/ ->over at all
 sub no_over_raw ($) {
 	my ($ctx) = @_;
 	my $mref = $ctx->{ibx}->msg_by_mid($ctx->{mid}) or return;
-	my $eml = PublicInbox::Eml->new($mref);
-	[ 200, res_hdr($ctx, $eml->header_str('Subject')),
-		[ msg_hdr($ctx, $eml) . msg_body($eml) ] ]
+	my $eml = $ctx->{eml} = PublicInbox::Eml->new($mref);
+	[ @{mbox_hdr($ctx)}, [ msg_hdr($ctx, $eml) . msg_body($eml) ] ]
 }
 
 # /$INBOX/$MESSAGE_ID/raw
@@ -85,9 +88,8 @@ sub emit_raw {
 	my ($id, $prev);
 	my $mip = $ctx->{next_arg} = [ $ctx->{mid}, \$id, \$prev ];
 	my $smsg = $ctx->{smsg} = $over->next_by_mid(@$mip) or return;
-	my $res_hdr = res_hdr($ctx, $smsg->{subject});
 	bless $ctx, __PACKAGE__;
-	$ctx->psgi_response(200, $res_hdr);
+	$ctx->psgi_response(\&mbox_hdr);
 }
 
 sub msg_hdr ($$) {
-- 
cgit v1.2.3-24-ge0c7