spawn subprocess with promise

fotostore.pl

@@ -4,6 +4,8 @@ use warnings;
 
 use lib 'lib';
 use Mojolicious::Lite;    # app, get, post is exported.
+use Mojo::Promise;
+use Mojo::IOLoop;
 
 use File::Basename qw/basename fileparse/;
 use File::Path 'mkpath';
@@ -255,22 +257,12 @@ post '/upload' => ( authenticated => 1 ) => sub {
     # Save to file
     $image->move_to($image_file);
 
-    # Operation that would block the event loop for 5 seconds
+    $log->debug("Spwan subprocess");
-    my $subprocess = Mojo::IOLoop::Subprocess->new;
-    $subprocess->run(
-        sub {
-            my $subprocess = shift;
-            store_image($image_file, $image->filename, $user_id);
-        },
-        sub {
-            my ($subprocess, $err, @results) = @_;
-            say "Subprocess error: $err" and return if $err;
-            say "I $results[0] $results[1]!";
-        }
-    );
     
-    $subprocess->ioloop->start unless $subprocess->ioloop->is_running;
+    my $promise = store_image($image_file, $image->filename, $user_id);
     
+
+    Mojo::Promise->all($promise)->then(sub {
         $self->render(
                 json => {
                     files => [
@@ -283,6 +275,30 @@ post '/upload' => ( authenticated => 1 ) => sub {
                     ]
                 }
             );
+    })->wait;
+
+    
+    # $log->debug("wait for promise");
+    # Mojo::Promise->all($spawn_subprocess)->then(sub {
+    #     $self->render(
+    #         json => {
+    #             files => [
+    #                 {
+    #                     name         => $image->filename,
+    #                     size         => $image->size,
+    #                     url          => sprintf( '/images/orig/%s', $filename ),
+    #                     thumbnailUrl => sprintf( '/images/200/%s', $filename ),
+    #                 }
+    #             ]
+    #         }
+    #     );
+
+    # })->catch(sub {
+    #     my $err = shift;
+    #     warn "Something went wrong: $err";
+    # })->wait;
+
+    
 
     # Redirect to top page
     # $self->redirect_to('index');
@@ -310,6 +326,11 @@ sub store_image {
     my $original_filename = shift;
     my $user_id = shift;
 
+    my $promise = Mojo::Promise->new;
+    # Operation that would block the event loop for 5 seconds
+    Mojo::IOLoop->subprocess(
+        sub {
+            my $subprocess = shift;
 
             my $filename = fileparse($image_file);
             my $imager = Imager->new();
@@ -350,7 +371,20 @@ sub store_image {
                 die sprintf('Can\'t save file %s', $filename);
             }
 
+            $log->debug("done!");
             return $filename;
+        },
+        sub {
+            my ($subprocess, $err, @results) = @_;
+            say "Subprocess error: $err" and return if $err;
+            $promise->reject("I $results[0] $results[1]!") if $err;
+            $promise->resolve(@results);
+        }
+    );
+
+    return $promise;
+    
 }
 
+Mojo::IOLoop->start;
 app->start;