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-rw-r--r--lib/PublicInbox/WwwStatic.pm198
1 files changed, 194 insertions, 4 deletions
diff --git a/lib/PublicInbox/WwwStatic.pm b/lib/PublicInbox/WwwStatic.pm
index ce4bfe9b..bc42236e 100644
--- a/lib/PublicInbox/WwwStatic.pm
+++ b/lib/PublicInbox/WwwStatic.pm
@@ -1,19 +1,48 @@
 # Copyright (C) 2016-2019 all contributors <meta@public-inbox.org>
 # License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
 
+# This package can either be a PSGI response body for a static file
+# OR a standalone PSGI app which returns the above PSGI response body
+# (or an HTML directory listing).
+#
+# It encapsulates the "autoindex", "index", and "gzip_static"
+# functionality of nginx.
 package PublicInbox::WwwStatic;
 use strict;
 use parent qw(Exporter);
+use bytes ();
 use Fcntl qw(SEEK_SET O_RDONLY O_NONBLOCK);
+use POSIX qw(strftime lround);
 use HTTP::Date qw(time2str);
 use HTTP::Status qw(status_message);
 use Errno qw(EACCES ENOTDIR ENOENT);
-our @EXPORT_OK = qw(@NO_CACHE r);
+use URI::Escape qw(uri_escape_utf8);
+use PublicInbox::Hval qw(ascii_html);
+use Plack::MIME;
+our @EXPORT_OK = qw(@NO_CACHE r path_info_raw);
 
 our @NO_CACHE = ('Expires', 'Fri, 01 Jan 1980 00:00:00 GMT',
                 'Pragma', 'no-cache',
                 'Cache-Control', 'no-cache, max-age=0, must-revalidate');
 
+our $STYLE = <<'EOF';
+<style>
+@media screen {
+        *{background:#000;color:#ccc}
+        a{color:#69f;text-decoration:none}
+        a:visited{color:#96f}
+}
+@media screen AND (prefers-color-scheme:light) {
+        *{background:#fff;color:#333}
+        a{color:#00f;text-decoration:none}
+        a:visited{color:#808}
+}
+</style>
+EOF
+
+$STYLE =~ s/^\s*//gm;
+$STYLE =~ tr/\n//d;
+
 sub r ($;$) {
         my ($code, $msg) = @_;
         $msg ||= status_message($code);
@@ -69,8 +98,28 @@ sub prepare_range {
         ($code, $len);
 }
 
-sub response {
+# returns a PSGI arrayref response iff .gz and non-.gz mtimes match
+sub try_gzip_static ($$$$) {
         my ($env, $h, $path, $type) = @_;
+        return unless ($env->{HTTP_ACCEPT_ENCODING} // '') =~ /\bgzip\b/i;
+        my $mtime;
+        return unless -f $path && defined(($mtime = (stat(_))[9]));
+        my $gz = "$path.gz";
+        return unless -f $gz && (stat(_))[9] == $mtime;
+        my $res = response($env, $h, $gz, $type);
+        return if ($res->[0] > 300 || $res->[0] < 200);
+        push @{$res->[1]}, qw(Cache-Control no-transform Content-Encoding gzip);
+        $res;
+}
+
+sub response ($$$;$) {
+        my ($env, $h, $path, $type) = @_;
+        $type //= Plack::MIME->mime_type($path) // 'application/octet-stream';
+        if ($path !~ /\.gz\z/i) {
+                if (my $res = try_gzip_static($env, $h, $path, $type)) {
+                        return $res;
+                }
+        }
 
         my $in;
         if ($env->{REQUEST_METHOD} eq 'HEAD') {
@@ -108,7 +157,7 @@ sub response {
         [ $code, $h, $body ];
 }
 
-# called by PSGI servers:
+# called by PSGI servers on each response chunk:
 sub getline {
         my ($self) = @_;
         my $len = $self->{len} or return; # undef, tells server we're done
@@ -132,6 +181,147 @@ sub getline {
         undef;
 }
 
-sub close {} # noop, just let everything go out-of-scope
+sub close {} # noop, called by PSGI server, just let everything go out-of-scope
+
+# OO interface for use as a Plack app
+sub new {
+        my ($class, %opt) = @_;
+        my $index = $opt{'index'} // [ 'index.html' ];
+        $index = [ $index ] if defined($index) && ref($index) ne 'ARRAY';
+        $index = undef if scalar(@$index) == 0;
+        my $style = $opt{style};
+        if (defined $style) {
+                $style = \$style unless ref($style);
+        }
+        my $docroot = $opt{docroot};
+        die "`docroot' not set" unless defined($docroot) && $docroot ne '';
+        bless {
+                docroot => $docroot,
+                index => $index,
+                autoindex => $opt{autoindex},
+                style => $style // \$STYLE,
+        }, $class;
+}
+
+# PATH_INFO is decoded, and we want the undecoded original
+my %path_re_cache;
+sub path_info_raw ($) {
+        my ($env) = @_;
+        my $sn = $env->{SCRIPT_NAME};
+        my $re = $path_re_cache{$sn} ||= do {
+                $sn = '/'.$sn unless index($sn, '/') == 0;
+                $sn =~ s!/\z!!;
+                qr!\A(?:https?://[^/]+)?\Q$sn\E(/[^\?\#]+)!;
+        };
+        $env->{REQUEST_URI} =~ $re ? $1 : $env->{PATH_INFO};
+}
+
+sub redirect_slash ($) {
+        my ($env) = @_;
+        my $url = $env->{'psgi.url_scheme'} . '://';
+        my $host_port = $env->{HTTP_HOST} //
+                "$env->{SERVER_NAME}:$env->{SERVER_PORT}";
+        $url .= $host_port . path_info_raw($env) . '/';
+        my $body = "Redirecting to $url\n";
+        [ 302, [ qw(Content-Type text/plain), 'Location', $url,
+                'Content-Length', length($body) ], [ $body ] ]
+}
+
+sub human_size ($) {
+        my ($size) = @_;
+        my $suffix = '';
+        for my $s (qw(K M G T P)) {
+                last if $size < 1024;
+                $size /= 1024;
+                if ($size <= 1024) {
+                        $suffix = $s;
+                        last;
+                }
+        }
+        lround($size).$suffix;
+}
+
+# by default, this returns "index.html" if it exists for a given directory
+# It'll generate a directory listing, (autoindex).
+# May be disabled by setting autoindex => 0
+sub dir_response ($$$) {
+        my ($self, $env, $fs_path) = @_;
+        if (my $index = $self->{'index'}) { # serve index.html or similar
+                for my $html (@$index) {
+                        my $p = $fs_path . $html;
+                        my $res = response($env, [], $p);
+                        return $res if $res->[0] != 404;
+                }
+        }
+        return r(404) unless $self->{autoindex};
+        opendir(my $dh, $fs_path) or do {
+                return r(404) if ($! == ENOENT || $! == ENOTDIR);
+                return r(403) if $! == EACCES;
+                return r(500);
+        };
+        my @entries = grep(!/\A\./, readdir($dh));
+        $dh = undef;
+        my (%dirs, %other, %want_gz);
+        my $path_info = $env->{PATH_INFO};
+        push @entries, '..' if $path_info ne '/';
+        for my $base (@entries) {
+                my $href = ascii_html(uri_escape_utf8($base));
+                my $name = ascii_html($base);
+                my @st = stat($fs_path . $base) or next; # unlikely
+                my ($gzipped, $uncompressed, $hsize);
+                my $entry = '';
+                my $mtime = $st[9];
+                if (-d _) {
+                        $href .= '/';
+                        $name .= '/';
+                        $hsize = '-';
+                        $dirs{"$base\0$mtime"} = \$entry;
+                } elsif (-f _) {
+                        $other{"$base\0$mtime"} = \$entry;
+                        if ($base !~ /\.gz\z/i) {
+                                $want_gz{"$base.gz\0$mtime"} = undef;
+                        }
+                        $hsize = human_size($st[7]);
+                } else {
+                        next;
+                }
+                # 54 = 80 - (SP length(strftime(%Y-%m-%d %k:%M)) SP human_size)
+                $hsize = sprintf('% 8s', $hsize);
+                my $pad = 54 - length($name);
+                $pad = 1 if $pad <= 0;
+                $entry .= qq(<a\nhref="$href">$name</a>) . (' ' x $pad);
+                $mtime = strftime('%Y-%m-%d %k:%M', gmtime($mtime));
+                $entry .= $mtime . $hsize;
+        }
+
+        # filter out '.gz' files as long as the mtime matches the
+        # uncompressed version
+        delete(@other{keys %want_gz});
+        @entries = ((map { ${$dirs{$_}} } sort keys %dirs),
+                        (map { ${$other{$_}} } sort keys %other));
+
+        my $path_info_html = ascii_html($path_info);
+        my $body = "<html><head><title>Index of $path_info_html</title>" .
+                ${$self->{style}} .
+                "</head><body><pre>Index of $path_info_html</pre><hr><pre>\n";
+        $body .= join("\n", @entries) . "</pre><hr></body></html>\n";
+        [ 200, [ qw(Content-Type text/html
+                        Content-Length), bytes::length($body) ], [ $body ] ]
+}
+
+sub call { # PSGI app endpoint
+        my ($self, $env) = @_;
+        return r(405) if $env->{REQUEST_METHOD} !~ /\A(?:GET|HEAD)\z/;
+        my $path_info = $env->{PATH_INFO};
+        return r(403) if index($path_info, "\0") >= 0;
+        my (@parts) = split(m!/+!, $path_info, -1);
+        return r(403) if grep(/\A(?:\.\.)\z/, @parts) || $parts[0] ne '';
+
+        my $fs_path = join('/', $self->{docroot}, @parts);
+        return dir_response($self, $env, $fs_path) if $parts[-1] eq '';
+
+        my $res = response($env, [], $fs_path);
+        $res->[0] == 404 && -d $fs_path ? redirect_slash($env) : $res;
+}
 
 1;