highlight: initial wrapper and PSGI service

I'll probably expose the PSGI service for cgit;
but it could be useful to others as well.

1 files changed, 73 insertions, 0 deletions

diff --git a/lib/PublicInbox/WwwHighlight.pm b/lib/PublicInbox/WwwHighlight.pm
new file mode 100644
index 00000000..3d6ca03b
--- /dev/null
+++ b/lib/PublicInbox/WwwHighlight.pm
@@ -0,0 +1,73 @@
+# Copyright (C) 2019 all contributors <meta@public-inbox.org>
+# License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
+
+# Standalone PSGI app to provide syntax highlighting as-a-service
+# via "highlight" Perl module ("libhighlight-perl" in Debian).
+#
+# This allows exposing highlight as a persistent HTTP service for
+# other scripts via HTTP PUT requests.  PATH_INFO will be used
+# as a hint for detecting the language for highlight.
+#
+# The following example using curl(1) will do the right thing
+# regarding the file extension:
+#
+#   curl -HExpect: -T /path/to/file http://example.com/
+#
+# You can also force a file extension by giving a path
+# (in this case, "c") via:
+#
+#   curl -HExpect: -T /path/to/file http://example.com/x.c
+
+package PublicInbox::WwwHighlight;
+use strict;
+use warnings;
+use HTTP::Status qw(status_message);
+use parent qw(PublicInbox::HlMod);
+
+# TODO: support highlight(1) for distros which don't package the
+# SWIG extension.  Also, there may be admins who don't want to
+# have ugly SWIG-generated code in a long-lived Perl process.
+
+sub r ($) {
+        my ($code) = @_;
+        my $msg = status_message($code);
+        my $len = length($msg);
+        [ $code, [qw(Content-Type text/plain Content-Length), $len], [$msg] ]
+}
+
+# another slurp API hogging up all my memory :<
+# This is capped by whatever the PSGI server allows,
+# $ENV{GIT_HTTP_MAX_REQUEST_BUFFER} for PublicInbox::HTTP (10 MB)
+sub read_in_full ($) {
+        my ($env) = @_;
+
+        my $in = $env->{'psgi.input'};
+        my $off = 0;
+        my $buf = '';
+        my $len = $env->{CONTENT_LENGTH} || 8192;
+        while (1) {
+                my $r = $in->read($buf, $len, $off);
+                last unless defined $r;
+                return \$buf if $r == 0;
+                $off += $r;
+        }
+        $env->{'psgi.errors'}->print("input read error: $!\n");
+}
+
+# entry point for PSGI
+sub call {
+        my ($self, $env) = @_;
+        my $req_method = $env->{REQUEST_METHOD};
+
+        return r(405) if $req_method ne 'PUT';
+
+        my $bref = read_in_full($env) or return r(500);
+        $bref = $self->do_hl($bref, $env->{PATH_INFO});
+
+        my $h = [ 'Content-Type', 'text/html; charset=UTF-8' ];
+        push @$h, 'Content-Length', bytes::length($$bref);
+
+        [ 200, $h, [ $$bref ] ]
+}
+
+1;