1 files changed, 97 insertions, 38 deletions

diff --git a/lib/JWebmail/Plugin/ServerSideSessionData.pm b/lib/JWebmail/Plugin/ServerSideSessionData.pm
index 9890358..e86a248 100644
--- a/lib/JWebmail/Plugin/ServerSideSessionData.pm
+++ b/lib/JWebmail/Plugin/ServerSideSessionData.pm
@@ -1,99 +1,151 @@
-package JWebmail::Plugin::ServerSideSessionData;
+package JWebmail::Plugin::ServerSideSessionData v1.1.0;
 
 use Mojo::Base 'Mojolicious::Plugin';
 
 use Mojo::JSON qw(decode_json encode_json);
 use Mojo::File;
 
-use constant {
-    S_KEY => 's3d.key',
-};
+use Fcntl ':DEFAULT', ':seek';
+use Time::HiRes 'sleep';
 
 
-has '_session_directory';
-sub session_directory { my $self = shift; @_ ? $self->_session_directory(Mojo::File->new(@_)) : $self->_session_directory }
+use constant S_KEY => 's3d.key';
+use constant CLEANUP_FILE_NAME => 'cleanup';
+use constant LOCK_ITER => 5;
+use constant ADVANCE_ON_FAILURE => 10; # seconds to retry to acquire the lock
 
+has 'session_directory';
 has 'expiration';
 has 'cleanup_interval';
 
-has '_cleanup';
-sub cleanup {
+has 'next_cleanup' => 0;
+
+
+# read und potentially update file return bool
+# needs atomic lock file
+# the file contains a single timestamp
+sub _rw_cleanup_file {
     my $self = shift;
-    if (@_) {
-        return $self->_cleanup(@_);
+    my $time = shift;
+
+    my $lock_name = $self->session_directory->child(CLEANUP_FILE_NAME . ".lock");
+    my $info_name = $self->session_directory->child(CLEANUP_FILE_NAME . ".info");
+
+    my ($lock, $ctr, $rmlock);
+    until (sysopen($lock, $lock_name, O_WRONLY | O_CREAT | O_EXCL)) {
+        die "unexpected error '$!'" unless $! eq 'File exists';
+        if ($ctr > LOCK_ITER) {
+            open($lock, '<', $lock_name) or die "unexpected error '$!'";
+            my $pid = <$lock>;
+            close $lock;
+            chomp $pid;
+            if (!$rmlock && (!$pid || !-e "/proc/$pid")) {
+                $lock_name->remove;
+                $rmlock = 1;
+                next;
+            }
+            $self->next_cleanup($time + ADVANCE_ON_FAILURE);
+            return 0;
+        }
+        sleep(0.01); # TODO: better spin locking
+    } continue {
+        $ctr++;
     }
-    else {
-        if ($self->_cleanup < time) {
+    $lock->say($$);
+    $lock->close;
+
+    my $ret = eval {
+        use autodie;
+
+        open(my $info, -e $info_name ? '+<' : '+>', $info_name);
+        my $next_time = $info->getline;
+        $next_time = 0 unless ($next_time//'') =~ /^\d+$/;
+        chomp $next_time;
+        if ($next_time > $time) {
+            $info->close;
+            $self->next_cleanup($next_time);
             return 0;
         }
         else {
-            $self->_cleanup(time + $self->cleanup_interval);
+            $info->truncate(0);
+            $info->seek(0, SEEK_SET);
+            $info->say($time + $self->cleanup_interval);
+            $info->close;
+            $self->next_cleanup($time + $self->cleanup_interval);
             return 1;
         }
-    }
+    };
+    $lock_name->remove;
+    return $ret;
 }
 
 
-sub s3d {
+sub cleanup_files {
     my $self = shift;
-    my $c = shift;
 
-    # cleanup old sessions
-    if ($self->cleanup) {
-        my $t = time;
+    my $t = time;
+    if ($self->next_cleanup < $t && $self->_rw_cleanup_file($t)) {
         for ($self->session_directory->list->each) {
             if ( $_->stat->mtime + $self->expiration < $t ) {
                 $_->remove;
             }
         }
     }
+}
+
+
+sub s3d {
+    my $self = shift;
+    my $c = shift;
+    my ($key, $val) = @_;
+
+    # cleanup old sessions
+    $self->cleanup_files;
 
     my $file = $self->session_directory->child($c->session(S_KEY) || $c->req->request_id . $$);
 
     if (-e $file) {
         if ($file->stat->mtime + $self->expiration < time) {
-            $file->remove;
+            truncate $file, 0;
         }
         else {
             $file->touch;
         }
     }
-    my $data = decode_json($file->slurp) if (-s $file);
+    elsif (defined $val) {
+        $file->touch;
+        $file->chmod(0600);
+        $c->session(S_KEY, $file->basename);
+    }
 
-    my ($key, $val) = @_;
+    my $data = decode_json($file->slurp) if (-s $file);
 
     if (defined $val) { # set
-        unless (-e $file) {
-            $c->session(S_KEY, $file->basename);
-        }
         $data = ref $data ? $data : {};
         $data->{$key} = $val;
 
-        #$file->spurt(encode_json $data);
-        open(my $f, '>', $file) or die "$!";
-        chmod 0600, $f;
-        $f->say(encode_json $data);
-        close($f);
+        $file->spurt(encode_json $data, "\n");
     }
     else { # get
         return defined $key ? $data->{$key} : $data;
     }
-};
+}
 
 
 sub register {
     my ($self, $app, $conf) = @_;
 
-    $self->session_directory($conf->{directory} || "/tmp/" . $app->moniker);
+    $self->session_directory(Mojo::File->new($conf->{directory} || "/tmp/" . $app->moniker));
     $self->expiration($conf->{expiration} || $app->sessions->default_expiration);
     $self->cleanup_interval($conf->{cleanup_interval} || $self->expiration);
-    $self->cleanup(time + $self->cleanup_interval);
 
     unless (-d $self->session_directory) {
         mkdir($self->session_directory)
             or $! ? die "failed to create directory: $!" : 1;
     }
 
+    $self->cleanup_files;
+
     $app->helper( s3d => sub { $self->s3d(@_) } );
 }
 
@@ -110,7 +162,7 @@ ServeSideSessionData - Stores session data on the server (alias SSSD or S3D)
 
 =head1 SYNOPSIS
 
-  $app->plugin('ServeSideSessionData');
+  $app->plugin('ServeSideSessionData', {expiration => 20*60});
 
   $c->s3d(data => 'Hello, S3D');
   $c->s3d('data');
@@ -118,21 +170,28 @@ ServeSideSessionData - Stores session data on the server (alias SSSD or S3D)
 =head1 DESCRIPTION
 
 Store data temporarily on the server.
-The only protetction on the server are struct user access rights.
+The only protection on the server are strict user access rights
+so you need to still be careful with your secrets.
 
 =head1 OPTIONS
 
 =head2 directory
 
+directory where session data is stored
+
 default C<< 'tmp/' . $app->moniker >>
 
 =head2 expiration
 
-default session expiration
+how long is a server side session valid in seconds (calculated after last access)
+
+defaults to session expiration
 
 =head2 cleanup_interval
 
-default session expiration
+a recurring time interval when old session data gets cleaned up
+
+defaults to expiration
 
 =head1 HELPERS
 
@@ -144,4 +203,4 @@ Stores and retrieves values.
   $c->s3d('data');
   $c->s3d->{data};
 
-=cut
\ No newline at end of file
+=cut