remove XML::Atom::SimpleFeed dependency

We will attempt to generate Atom feeds "by hand" as the
XML::Atom::SimpleFeed API does not support streaming output.
Since email is large and servers are small, this should prevent
wasting memory when we generate larger feeds.

Of course, we hope clients use SAX parsers capable of handling
large streams without slurping.

2 files changed, 51 insertions, 43 deletions

diff --git a/lib/PublicInbox/Feed.pm b/lib/PublicInbox/Feed.pm
index 5d122ac6..8dd6d036 100644
--- a/lib/PublicInbox/Feed.pm
+++ b/lib/PublicInbox/Feed.pm
@@ -1,4 +1,4 @@
-# Copyright (C) 2013, Eric Wong <normalperson@yhbt.net> and all contributors
+# Copyright (C) 2013-2015, all contributors <meta@public-inbox.org>
 # License: AGPLv3 or later (https://www.gnu.org/licenses/agpl-3.0.txt)
 package PublicInbox::Feed;
 use strict;
@@ -20,43 +20,50 @@ my $enc_utf8 = find_encoding('UTF-8');
 
 # main function
 sub generate {
-        my ($class, $ctx) = @_;
-        require XML::Atom::SimpleFeed;
+        my ($ctx) = @_;
+        sub { emit_atom($_[0], $ctx) };
+}
+
+sub generate_html_index {
+        my ($ctx) = @_;
+        sub { emit_html_index($_[0], $ctx) };
+}
+
+# private subs
+
+sub emit_atom {
+        my ($cb, $ctx) = @_;
         require POSIX;
+        my $fh = $cb->([ 200, ['Content-Type' => 'application/xml']]);
         my $max = $ctx->{max} || MAX_PER_PAGE;
-
         my $feed_opts = get_feedopts($ctx);
         my $addr = $feed_opts->{address};
         $addr = $addr->[0] if ref($addr);
-        my $feed = XML::Atom::SimpleFeed->new(
-                title => $feed_opts->{description} || "unnamed feed",
-                link => $feed_opts->{url} || "http://example.com/",
-                link => {
-                        rel => 'self',
-                        href => $feed_opts->{atomurl} ||
-                                "http://example.com/atom.xml",
-                },
-                id => 'mailto:' . ($addr || 'public-inbox@example.com'),
-                updated => POSIX::strftime(DATEFMT, gmtime),
-        );
-        $feed->no_generator;
+        $addr ||= 'public-inbox@example.com';
+        my $title = $feed_opts->{description} || "unnamed feed";
+        $title = PublicInbox::Hval->new_oneline($title)->as_html;
+        my $type = index($title, '&') >= 0 ? "\ntype=\"html\"" : '';
+        my $url = $feed_opts->{url} || "http://example.com/";
+        my $atomurl = $feed_opts->{atomurl};
+        $fh->write(qq(<?xml version="1.0" encoding="us-ascii"?>\n) .
+                qq{<feed\nxmlns="http://www.w3.org/2005/Atom">} .
+                qq{<title$type>$title</title>} .
+                qq{<link\nhref="$url"/>} .
+                qq{<link\nrel="self"\nhref="$atomurl"/>} .
+                qq{<id>mailto:$addr</id>} .
+                '<updated>' . POSIX::strftime(DATEFMT, gmtime) . '</updated>');
 
         my $git = PublicInbox::GitCatFile->new($ctx->{git_dir});
         each_recent_blob($ctx, sub {
                 my ($add, undef) = @_;
-                add_to_feed($feed_opts, $feed, $add, $git);
+                add_to_feed($feed_opts, $fh, $add, $git);
         });
         $git = undef; # destroy pipes
         Email::Address->purge_cache;
-        $feed->as_string;
-}
-
-sub generate_html_index {
-        my ($ctx) = @_;
-        sub { emit_html_index($_[0], $ctx) };
+        $fh->write("</feed>");
+        $fh->close;
 }
 
-# private subs
 
 sub emit_html_index {
         my ($cb, $ctx) = @_;
@@ -253,10 +260,9 @@ sub feed_date {
 
 # returns 0 (skipped) or 1 (added)
 sub add_to_feed {
-        my ($feed_opts, $feed, $add, $git) = @_;
+        my ($feed_opts, $fh, $add, $git) = @_;
 
         my $mime = do_cat_mail($git, $add) or return 0;
-        my $midurl = $feed_opts->{midurl} || 'http://example.com/m/';
         my $fullurl = $feed_opts->{fullurl} || 'http://example.com/f/';
 
         my $header_obj = $mime->header_obj;
@@ -268,30 +274,34 @@ sub add_to_feed {
         defined($content) or return 0;
         $mime = undef;
 
-        my $subject = mime_header($header_obj, 'Subject') or return 0;
+        my $title = mime_header($header_obj, 'Subject') or return 0;
+        $title = PublicInbox::Hval->new_oneline($title)->as_html;
+        my $type = index($title, '&') >= 0 ? "\ntype=\"html\"" : '';
 
         my $from = mime_header($header_obj, 'From') or return 0;
         my @from = Email::Address->parse($from);
-        my $name = $from[0]->name;
-        defined $name or $name = "";
+        my $name = PublicInbox::Hval->new_oneline($from[0]->name)->as_html;
         my $email = $from[0]->address;
-        defined $email or $email = "";
+        $email = PublicInbox::Hval->new_oneline($email)->as_html;
 
         my $date = $header_obj->header('Date');
         $date = PublicInbox::Hval->new_oneline($date);
         $date = feed_date($date->raw) or return 0;
+
+        $fh->write("<entry><author><name>$name</name><email>$email</email>" .
+                   "</author><title$type>$title</title>" .
+                   "<updated>$date</updated>" .
+                   qq{<content\ntype="xhtml">} .
+                   qq{<div\nxmlns="http://www.w3.org/1999/xhtml">});
+        $fh->write($content);
+
         $add =~ tr!/!!d;
         my $h = '[a-f0-9]';
         my (@uuid5) = ($add =~ m!\A($h{8})($h{4})($h{4})($h{4})($h{12})!o);
-
-        $feed->add_entry(
-                author => { name => $name, email => $email },
-                title => $subject,
-                updated => $date,
-                content => { type => 'xhtml', content => $content },
-                link => $midurl . $href,
-                id => 'urn:uuid:' . join('-', @uuid5),
-        );
+        my $id = 'urn:uuid:' . join('-', @uuid5);
+        my $midurl = $feed_opts->{midurl} || 'http://example.com/m/';
+        $fh->write(qq{</div></content><link\nhref="$midurl$href"/>}.
+                   "<id>$id</id></entry>");
         1;
 }
 
diff --git a/lib/PublicInbox/WWW.pm b/lib/PublicInbox/WWW.pm
index 54f63991..30a7a436 100644
--- a/lib/PublicInbox/WWW.pm
+++ b/lib/PublicInbox/WWW.pm
@@ -81,7 +81,6 @@ sub preload {
         require Email::MIME;
         require Digest::SHA;
         require POSIX;
-        require XML::Atom::SimpleFeed;
 
         eval {
                 require PublicInbox::Search;
@@ -120,11 +119,10 @@ sub invalid_list_mid {
 # /$LISTNAME/atom.xml                       -> Atom feed, includes replies
 sub get_atom {
         my ($ctx, $cgi) = @_;
-        require PublicInbox::Feed;
         $ctx->{pi_config} = $pi_config;
         $ctx->{cgi} = $cgi;
-        [ 200, [ 'Content-Type' => 'application/xml' ],
-          [ PublicInbox::Feed->generate($ctx) ] ]
+        require PublicInbox::Feed;
+        PublicInbox::Feed::generate($ctx);
 }
 
 # /$LISTNAME/?r=$GIT_COMMIT                 -> HTML only