Barback transformer

lib/browser.dart

@@ -0,0 +1 @@
+external dynamic config(String key);

lib/transformer.dart

@@ -0,0 +1,93 @@
+import 'dart:async';
+import 'dart:convert';
+import 'package:barback/barback.dart';
+import 'package:analyzer/analyzer.dart';
+import 'package:angel_framework/angel_framework.dart';
+import 'angel_configuration.dart';
+
+class ConfigurationTransformer extends Transformer {
+  final BarbackSettings _settings;
+
+  @override
+  String get allowedExtensions => ".dart";
+
+  ConfigurationTransformer.asPlugin(this._settings) {}
+
+  Future apply(Transform transform) async {
+    var app = new Angel();
+
+    await app.configure(loadConfigurationFile(
+        directoryPath: _settings.configuration["dir"] ?? "./config",
+        overrideEnvironmentName: _settings.configuration["env"]));
+
+    var text = await transform.primaryInput.readAsString();
+    var compilationUnit = parseCompilationUnit(text);
+    var visitor = new ConfigAstVisitor(app.properties);
+    visitor.visitCompilationUnit(compilationUnit);
+
+    await for (Map replaced in visitor.onReplaced) {
+        text = text.replaceAll(replaced["needle"], replaced["with"]);
+    }
+
+    transform.addOutput(new Asset.fromString(transform.primaryInput.id, text));
+  }
+}
+
+class ConfigAstVisitor extends GeneralizingAstVisitor {
+  Map _config;
+  var _onReplaced = new StreamController<Map>();
+  String _prefix = "";
+  Stream<Map> get onReplaced => _onReplaced.stream;
+
+  ConfigAstVisitor(this._config);
+
+  bool isConfigMethod(Expression function) =>
+      function is SimpleIdentifier && function.name == "${_prefix}config";
+
+  resolveItem(String key) {
+    var split = key.split(".");
+    var parent = _config;
+
+    for (int i = 0; i < split.length; i++) {
+      if (parent != null && parent is Map) parent = parent[split[i]];
+    }
+    
+    return parent;
+  }
+
+  @override
+  visitCompilationUnit(CompilationUnit ctx) {
+      var result = super.visitCompilationUnit(ctx);
+      _onReplaced.close();
+      return result;
+  }
+
+  @override
+  visitImportDirective(ImportDirective ctx) {
+    String uri = ctx.uri.stringValue;
+
+    if (uri == "package:angel_configuration/browser.dart") {
+      _onReplaced.add({"needle": ctx.toString(), "with": ""});
+
+      if (ctx.asKeyword != null) {
+          _prefix = ctx.prefix.name;
+      }
+    }
+
+    return super.visitImportDirective(ctx);
+  }
+
+  @override
+  visitExpression(Expression ctx) {
+    if (ctx is MethodInvocation) {
+      if (isConfigMethod(ctx.function)) {
+        StringLiteral key = ctx.argumentList.arguments[0];
+        var resolved = resolveItem(key.stringValue);
+
+        _onReplaced
+            .add({"needle": ctx.toString(), "with": JSON.encode(resolved)});
+      }
+    }
+    return super.visitExpression(ctx);
+  }
+}

pubspec.yaml

@@ -1,10 +1,12 @@
 name: angel_configuration
 description: YAML configuration loader for Angel.
-version: 1.0.1
+version: 1.0.1+1
 author: thosakwe <thosakwe@gmail.com>
 homepage: https://github.com/angel-dart/angel_configuration
 dependencies:
+  analyzer: ">=0.28.1 <0.29.0"
   angel_framework: ">=1.0.0-dev < 2.0.0"
+  barback: ">=0.15.2 < 0.16.0"
   yaml: ">= 2.1.8 < 2.2.0"
 dev_dependencies:
   test: ">= 0.12.13 < 0.13.0"

test/all_tests.dart

@@ -1,6 +1,7 @@
 import 'package:angel_framework/angel_framework.dart';
 import 'package:angel_configuration/angel_configuration.dart';
 import 'package:test/test.dart';
+import 'transformer.dart' as transformer;
 
 main() async {
   // Note: Set ANGEL_ENV to 'development'
@@ -25,4 +26,6 @@ main() async {
     expect(angel.properties['hello'], equals('goodbye'));
     expect(angel.properties['foo']['version'], equals('baz'));
   });
+
+  group("transformer", transformer.main);
 }

test/transformer.dart

@@ -0,0 +1,26 @@
+import 'package:analyzer/analyzer.dart';
+import 'package:angel_configuration/transformer.dart';
+import 'package:test/test.dart';
+
+main() {
+  test("simple replacement", () async {
+    var visitor = new ConfigAstVisitor({"foo": "bar"});
+    var source = '''
+    import 'package:angel_configuration/browser.dart';
+
+    main() async {
+        var foo = config('foo');
+    }
+    ''';
+
+    var compilationUnit = parseCompilationUnit(source);
+    visitor.visitCompilationUnit(compilationUnit);
+
+    var replaced = await visitor.onReplaced.take(2).last;
+
+    expect(replaced["needle"], equals("config('foo')"));
+    expect(replaced["with"], equals('"bar"'));
+
+    print(source.replaceAll(replaced["needle"], replaced["with"]));
+  });
+}