qspawn: learn to gzip streaming responses

This will allow us to gzip responses generated by cgit
and any other CGI programs or long-lived streaming
responses we may spawn.

1 files changed, 16 insertions, 0 deletions

diff --git a/lib/PublicInbox/GzipFilter.pm b/lib/PublicInbox/GzipFilter.pm
index 0fbb4476..0a6c56a5 100644
--- a/lib/PublicInbox/GzipFilter.pm
+++ b/lib/PublicInbox/GzipFilter.pm
@@ -32,6 +32,22 @@ sub gzf_maybe ($$) {
         bless { gz => $gz }, __PACKAGE__;
 }
 
+sub qsp_maybe ($$) {
+        my ($res_hdr, $env) = @_;
+        return if ($env->{HTTP_ACCEPT_ENCODING} // '') !~ /\bgzip\b/;
+        my $hdr = join("\n", @$res_hdr);
+        return if $hdr !~ m!^Content-Type\n
+                                (?:(?:text/(?:html|plain))|
+                                application/atom\+xml)\b!ixsm;
+        return if $hdr =~ m!^Content-Encoding\ngzip\n!smi;
+        return if $hdr =~ m!^Content-Length\n[0-9]+\n!smi;
+        return if $hdr =~ m!^Transfer-Encoding\n!smi;
+        # in case Plack::Middleware::Deflater is loaded:
+        return if $env->{'plack.skip-deflater'}++;
+        push @$res_hdr, @GZIP_HDRS;
+        bless {}, __PACKAGE__;
+}
+
 sub gzip_or_die () {
         my ($gz, $err) = Compress::Raw::Zlib::Deflate->new(%OPT);
         $err == Z_OK or die "Deflate->new failed: $err";