First push of a new 'http_server' dart package.

pkg/http_server/lib/src/virtual_directory.dart

Index: pkg/http_server/lib/src/virtual_directory.dart
diff --git a/pkg/http_server/lib/src/virtual_directory.dart b/pkg/http_server/lib/src/virtual_directory.dart
new file mode 100644
index 0000000000000000000000000000000000000000..a09613527008cdebc12d9ea51a3f1192fe9c0cbd
--- /dev/null
+++ b/pkg/http_server/lib/src/virtual_directory.dart
@@ -0,0 +1,122 @@
+// Copyright (c) 2013, 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.
+
+part of http_server;
+
+/**
+ * A [VirtualDirectory] can serve files and directory-listing from a root path,
+ * to [HttpRequest]s.
+ *
+ * The [VirtualDirectory] providing secure handling of request uris and
+ * file-system links, correct mime-types and custom error pages.
+ */
+abstract class VirtualDirectory {
+  final String root;
+
+  /**
+   * Set or get if the [VirtualDirectory] should list the content of
+   * directories.
+   */
+  bool allowDirectoryListing = false;
+
+  /**
+   * Set or get if the [VirtualDirectory] should follow links, that point
+   * to other resources within the [root] directory.
+   */
+  bool followLinks = true;
+
+  /*
+   * Create a new [VirtualDirectory] for serving static file content of
+   * the path [root].
+   *
+   * The [root] is not required to exist. If the [root] doesn't exist at time of
+   * a request, a 404 is generated.
+   */
+  factory VirtualDirectory(String root) => new _VirtualDirectory(root);
+
+  /**
+   * Serve a [Stream] of [HttpRequest]s, in this [VirtualDirectory].
+   */
+  void serve(Stream<HttpRequest> requests);
+
+  /**
+   * Serve a single [HttpRequest], in this [VirtualDirectory].
+   */
+  void serveRequest(HttpRequest request);
+
+  /**
+   * Set the [callback] to override the error page handler. When [callback] is
+   * invoked, the `statusCode` property of the response is set.
+   */
+  void setErrorPageHandler(void callback(HttpResponse response));
+}
+
+class _VirtualDirectory implements VirtualDirectory {
+  final String root;
+
+  bool _allowDirectoryListing = false;
+  bool _followLinks = true;
+
+  _VirtualDirectory(this.root);
+
+  void serve(Stream<HttpRequest> requests) {
+    requests.listen(serveRequest);
+  }
+
+  void serveRequest(HttpRequest request) {
+    var path = new Path(request.uri.path).canonicalize();
+
+    if (!path.isAbsolute) {
+      return _serveErrorPage(HttpStatus.NOT_FOUND, request);
+    }
+
+    _locateResource(new Path(root), path.segments())
+        .then((entity) {
+          if (entity == null) {
+            _serveErrorPage(HttpStatus.NOT_FOUND, request);
+            return;
+          }
+          if (entity is File) {
+            entity.openRead().pipe(request.response).catchError((_) {});
+          } else {
+            _serveErrorPage(HttpStatus.NOT_FOUND, request);
+          }
+        });
+  }
+
+  Future<FileSystemEntity> _locateResource(Path path,
+                                           Iterable<String> segments) {
+    return FileSystemEntity.type(path.toString(), followLinks: false)
+        .then((type) {
+          switch (type) {
+            case FileSystemEntityType.FILE:
+              if (segments.isEmpty) return new File.fromPath(path);
+              break;
+
+            case FileSystemEntityType.DIRECTORY:
+              if (segments.isEmpty) {
+                if (_allowDirectoryListing) return new Directory.fromPath(path);
+              } else {
+                return _locateResource(path.append(segments.first),
+                                       segments.skip(1));
+              }
+              break;
+
+            case FileSystemEntityType.LINK:
+              if (followLinks) {
+                // TODO
+              }
+              break;
+
+          }
+          // Return `null` on fall-through, to indicate NOT_FOUND.
+          return null;
+        });
+  }
+
+  void _serveErrorPage(int error, HttpRequest request) {
+    request.response.statusCode = error;
+    request.response.close();
+  }
+}