nntp: support COMPRESS DEFLATE per RFC 8054

This is only tested so far with my patches to Net::NNTP at:
https://rt.cpan.org/Ticket/Display.html?id=129967

Memory use in C10K situations is disappointing, but that's
the nature of compression.

gzip compression over HTTPS does have the advantage of not
keeping zlib streams open when clients are idle, at the
cost of worse compression.

1 files changed, 7 insertions, 0 deletions

diff --git a/t/nntpd.t b/t/nntpd.t
index fdb4bee4..e264fa6b 100644
--- a/t/nntpd.t
+++ b/t/nntpd.t
@@ -151,6 +151,13 @@ EOF
         $buf = read_til_dot($s);
         like($buf, qr/\r\nVERSION 2\r\n/s, 'CAPABILITIES works');
         unlike($buf, qr/STARTTLS/s, 'STARTTLS not advertised');
+        my $deflate_capa = qr/\r\nCOMPRESS DEFLATE\r\n/;
+        if (eval { require Compress::Raw::Zlib }) {
+                like($buf, $deflate_capa, 'DEFLATE advertised');
+        } else {
+                unlike($buf, $deflate_capa,
+                        'DEFLATE not advertised (Compress::Raw::Zlib missing)');
+        }
 
         syswrite($s, "NEWGROUPS 19990424 000000 GMT\r\n");
         $buf = read_til_dot($s);