Assets helper

[thekid]

With the introduction of asset bundling (see xp-forge/frontend#17) asset names can be resolved against the assets manifest by a) passing it to the frontend globals and b) using the lookup helper as follows:

In PHP

$manifest= new AssetsManifest($this->environment->path('src/main/webapp/static/manifest.json'));
$frontend= new Frontend(
  new HandlersIn('com.example.skills.web', [$inject, 'get']),
  new Handlebars($this->environment->path('src/main/handlebars')),
  ['manifest' => $manifest] // <-- Here
) ;

Inside our templates

<link href="/static/{{lookup manifest.assets 'vendor.css'}}" rel="stylesheet">

---

However, if we introduce a typo (e.g. by 'vendors.css'), the link will simply resolve to "/static/" and then try to serve the directory, resulting in a 404 (see xp-forge/frontend#19). This is because how the lookup helper is defined.

The suggestion would be to fail early and introduce an asset helper which would raise an exception in these cases.

[thekid]

If we use the log helper as follows:

yield 'asset' => function($in, $context, $options) {
  $name= (string)$options[0];

  // We can rely on a logger being present, web.frontend.Handlebars creates one
  return $this->manifest->assets[$name] ?? key([$name => $context->engine->helper('log')(
    $in,
    $context,
    ['Missing asset in `'.(string)$in.'`, manifest contains: ', $this->manifest->assets]
  )]);
};

...we would see the following:

Development

Production

[thekid]

Here's how to integrate this helper, moving away from the solution above:

diff --git a/src/main/handlebars/edit.handlebars b/src/main/handlebars/edit.handlebars
index bed8d63..36fb8e4 100755
--- a/src/main/handlebars/edit.handlebars
+++ b/src/main/handlebars/edit.handlebars
@@ -90,7 +90,7 @@
     <br clear="all"/>
   {{/inline}}
   {{#*inline "script"}}
-    <script src="/static/{{lookup manifest.assets 'editor.js'}}"></script>
+    <script src="/static/{{asset 'editor.js'}}"></script>
     <script type="text/javascript">
       let _debounce = null;
       let editor;
diff --git a/src/main/php/com/example/skills/App.php b/src/main/php/com/example/skills/App.php
index 8b13f03..eb17bda 100755
--- a/src/main/php/com/example/skills/App.php
+++ b/src/main/php/com/example/skills/App.php
@@ -2,7 +2,7 @@

 use inject\{Injector, Bindings};
 use security\credentials\{Credentials, FromEnvironment, FromFile};
-use web\frontend\helpers\Dates;
+use web\frontend\helpers\{Assets, Dates};
 use web\frontend\{Frontend, HandlersIn, AssetsFrom, AssetsManifest, Handlebars};
 use web\rest\{RestApi, ResourcesIn};
 use web\session\{Sessions, InFileSystem, Cookies};
@@ -44,11 +44,11 @@ class App extends Application {
         new HandlersIn('com.example.skills.web', [$inject, 'get']),
         new Handlebars($this->environment->path('src/main/handlebars'), [
           new Dates(),
+          new Assets($manifest),
           new Translations($this->environment->path('src/main/handlebars/texts.csv')),
           new RenderMarkdown(),
           new RenderContent(),
-        ]),
-        ['manifest' => $manifest]
+        ])
       ))
     ];
   }

[thekid]

Released in https://github.com/xp-forge/handlebars-templates/releases/tag/v0.7.0