support dumping thread as an mbox

Some folks may not want to download and install Perl code like
ssoma, so allow downloading an mbox containing the entire
thread.

4 files changed, 115 insertions, 13 deletions

diff --git a/lib/PublicInbox/Mbox.pm b/lib/PublicInbox/Mbox.pm
new file mode 100644
index 00000000..2ec50656
--- /dev/null
+++ b/lib/PublicInbox/Mbox.pm
@@ -0,0 +1,55 @@
+# Copyright (C) 2015, all contributors <meta@public-inbox.org>
+# License: AGPLv3 or later (https://www.gnu.org/licenses/agpl-3.0.txt)
+# Streaming interface for formatting messages as an mbox
+package PublicInbox::Mbox;
+use strict;
+use warnings;
+use PublicInbox::MID qw/mid_clean mid_compressed mid2path/;
+use Fcntl qw(SEEK_SET);
+
+sub thread_mbox {
+        my ($ctx, $srch) = @_;
+        my $mid = mid_compressed($ctx->{mid});
+        my $res = $srch->get_thread($mid);
+        my $msgs = delete $res->{msgs};
+        require PublicInbox::GitCatFile;
+        require Email::Simple;
+        my $git = PublicInbox::GitCatFile->new($ctx->{git_dir});
+
+        sub {
+                my ($res) = @_; # Plack callback
+                my $w = $res->([200, [ 'Content-Type' => 'text/plain' ] ]);
+                while (defined(my $smsg = shift @$msgs)) {
+                        my $msg = eval {
+                                my $path = 'HEAD:' . mid2path($smsg->mid);
+                                Email::Simple->new($git->cat_file($path));
+                        };
+                        emit($w, $msg) if $msg;
+                }
+        }
+}
+
+sub emit {
+        my ($fh, $simple) = @_; # Email::Simple object
+
+        # drop potentially confusing headers, ssoma already should've dropped
+        # Lines and Content-Length
+        foreach my $d (qw(Lines Content-Length Status)) {
+                $simple->header_set($d);
+        }
+
+        my $buf = $simple->header_obj->as_string;
+        unless ($buf =~ /\AFrom /) {
+                $fh->write("From a\@a Thu Jan  1 00:00:00 1970\n");
+        }
+        $fh->write($buf .= $simple->crlf);
+
+        $buf = $simple->body;
+        $simple->body_set('');
+        $buf =~ s/^(From )/>$1/gm;
+        $buf .= "\n" unless $buf =~ /\n\z/s;
+
+        $fh->write($buf);
+}
+
+1;
diff --git a/lib/PublicInbox/WWW.pm b/lib/PublicInbox/WWW.pm
index b0c13486..cd8a5705 100644
--- a/lib/PublicInbox/WWW.pm
+++ b/lib/PublicInbox/WWW.pm
@@ -53,6 +53,9 @@ sub run {
         } elsif ($path_info =~ m!$LISTNAME_RE/t/(\S+)\.html\z!o) {
                 invalid_list_mid(\%ctx, $1, $2) || get_thread(\%ctx, $cgi);
 
+        } elsif ($path_info =~ m!$LISTNAME_RE/t/(\S+)\.mbox\z!o) {
+                invalid_list_mid(\%ctx, $1, $2) || get_thread_mbox(\%ctx, $cgi);
+
         } elsif ($path_info =~ m!$LISTNAME_RE/f/\S+\.txt\z!o) {
                 invalid_list_mid(\%ctx, $1, $2) ||
                         redirect_mid_txt(\%ctx, $cgi);
@@ -326,4 +329,12 @@ sub msg_pfx {
         "../f/$href.html";
 }
 
+# /$LISTNAME/t/$MESSAGE_ID.mbox                    -> search results as mbox
+sub get_thread_mbox {
+        my ($ctx, $cgi) = @_;
+        my $srch = searcher($ctx) or return need_search($ctx);
+        require PublicInbox::Mbox;
+        PublicInbox::Mbox::thread_mbox($ctx, $srch);
+}
+
 1;
diff --git a/public-inbox.cgi b/public-inbox.cgi
index ed0f12c8..5c6dfe8a 100755
--- a/public-inbox.cgi
+++ b/public-inbox.cgi
@@ -3,12 +3,22 @@
 # License: AGPLv3 or later (https://www.gnu.org/licenses/agpl-3.0.txt)
 use strict;
 use warnings;
+use IO::Handle;
 require PublicInbox::WWW;
 use CGI qw/-nosticky/;
 our $NO_SCRIPT_NAME;
+our %HTTP_CODES;
 BEGIN {
         $NO_SCRIPT_NAME = 1 if $ENV{NO_SCRIPT_NAME};
         CGI->compile if $ENV{MOD_PERL};
+
+        %HTTP_CODES = (
+                200 => 'OK',
+                301 => 'Moved Permanently',
+                404 => 'Not Found',
+                405 => 'Method Not Allowed',
+                501 => 'Not Implemented',
+        );
 }
 
 # some servers (Ruby webrick) include scheme://host[:port] here,
@@ -19,23 +29,30 @@ delete $ENV{REQUEST_URI};
 $ENV{SCRIPT_NAME} = '' if $NO_SCRIPT_NAME;
 my $req = CGI->new;
 my $ret = PublicInbox::WWW::run($req, $req->request_method);
-binmode STDOUT;
+
+my $out = select;
+$out->binmode;
 if (@ARGV && $ARGV[0] eq 'static') {
-        print $ret->[2]->[0]; # only show the body
+        $out->write($ret->[2]->[0]); # only show the body
 } else { # CGI
-        my ($status, $headers, $body) = @$ret;
-        my %codes = (
-                200 => 'OK',
-                301 => 'Moved Permanently',
-                404 => 'Not Found',
-                405 => 'Method Not Allowed',
-                501 => 'Not Implemented',
-        );
+        if (ref($ret) eq 'CODE') {
+                $ret->(*dump_header);
+        } else {
+                my ($status, $headers, $body) = @$ret;
+
+                dump_header([$status, $headers])->write($body->[0]);
+        }
+}
 
-        print "Status: $status $codes{$status}\r\n";
+sub dump_header {
+        my ($res) = @_;
+        my $fh = select;
+        my ($status, $headers) = @$res;
+        $fh->write("Status: $status $HTTP_CODES{$status}\r\n");
         my @tmp = @$headers;
         while (my ($k, $v) = splice(@tmp, 0, 2)) {
-                print "$k: $v\r\n";
+                $fh->write("$k: $v\r\n");
         }
-        print "\r\n", $body->[0];
+        $fh->write("\r\n");
+        $fh;
 }
diff --git a/t/cgi.t b/t/cgi.t
index a16ebd8d..2747a159 100644
--- a/t/cgi.t
+++ b/t/cgi.t
@@ -10,6 +10,7 @@ use IPC::Run qw/run/;
 
 use constant CGI => "blib/script/public-inbox.cgi";
 my $mda = "blib/script/public-inbox-mda";
+my $index = "blib/script/public-inbox-index";
 my $tmpdir = tempdir(CLEANUP => 1);
 my $home = "$tmpdir/pi-home";
 my $pi_home = "$home/.public-inbox";
@@ -178,6 +179,24 @@ EOF
                 "slashy URL generated correctly");
 }
 
+# retrieve thread as an mbox
+{
+        local $ENV{HOME} = $home;
+        local $ENV{PATH} = $main_path;
+        my $path = "/test/t/blahblah%40example.com.mbox";
+        my $res = cgi_run($path);
+        like($res->{head}, qr/^Status: 501 /, "search not-yet-enabled");
+        my $indexed = system($index, $maindir) == 0;
+        if ($indexed) {
+                $res = cgi_run($path);
+                # use Data::Dumper; print STDERR Dumper($res);
+                like($res->{head}, qr/^Status: 200 /, "search returned mbox");
+                like($res->{body}, qr/^From /m, "From lines in mbox");
+        } else {
+                like($res->{head}, qr/^Status: 501 /, "search not available");
+        }
+}
+
 # redirect list-name-only URLs
 {
         local $ENV{HOME} = $home;