Index: packages/barback/example/aggregate_transformer/lib/transformer.dart |
diff --git a/packages/barback/example/aggregate_transformer/lib/transformer.dart b/packages/barback/example/aggregate_transformer/lib/transformer.dart |
new file mode 100644 |
index 0000000000000000000000000000000000000000..35634dc9120cc522d4b87088ffded39e53b79bb2 |
--- /dev/null |
+++ b/packages/barback/example/aggregate_transformer/lib/transformer.dart |
@@ -0,0 +1,47 @@ |
+// Copyright (c) 2014, the Dart project authors. Please see the AUTHORS file |
+// for details. All rights reserved. Use of this source code is governed by a |
+// BSD-style license that can be found in the LICENSE file. |
+ |
+import 'package:barback/barback.dart'; |
+import 'package:path/path.dart' as p; |
+ |
+import 'dart:async'; |
+ |
+class MakeBook extends AggregateTransformer { |
+ // All transformers need to implement "asPlugin" to let Pub know that they |
+ // are transformers. |
+ MakeBook.asPlugin(); |
+ |
+ // Implement the classifyPrimary method to claim any assets that you want |
+ // to handle. Return a value for the assets you want to handle, |
+ // or null for those that you do not want to handle. |
+ classifyPrimary(AssetId id) { |
+ |
+ // Only process assets where the filename ends with "recipe.html". |
+ if (!id.path.endsWith('recipe.html')) return null; |
+ |
+ // Return the path string, minus the recipe itself. |
+ // This is where the output asset will be written. |
+ return p.url.dirname(id.path); |
+ } |
+ |
+ // Implement the apply method to process the assets and create the |
+ // output asset. |
+ Future apply(AggregateTransform transform) async { |
+ var buffer = new StringBuffer()..write('<html><body>'); |
+ |
+ var assets = await transform.primaryInputs.toList(); |
+ assets.sort((x, y) => x.id.compareTo(y.id)); |
+ for (var asset in assets) { |
+ var content = await asset.readAsString(); |
+ buffer.write(content); |
+ buffer.write('<hr>'); |
+ } |
+ buffer.write('</body></html>'); |
+ // Write the output back to the same directory, |
+ // in a file named recipes.html. |
+ var id = new AssetId( |
+ transform.package, p.url.join(transform.key, "recipes.html")); |
+ transform.addOutput(new Asset.fromString(id, buffer.toString())); |
+ } |
+} |