Create a package that implements a JSON-RPC 2.0 server.

pkg/json_rpc_2/lib/error_code.dart

Index: pkg/json_rpc_2/lib/error_code.dart
diff --git a/pkg/json_rpc_2/lib/error_code.dart b/pkg/json_rpc_2/lib/error_code.dart
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+// 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.
+
+/// Error codes defined in the [JSON-RPC 2.0 specificiation][spec].
+///
+/// These codes are generally used for protocol-level communication. Most of
+/// them shouldn't be used by the application. Those that should have
+/// convenience constructors in [RpcException].
+///
+/// [spec]: http://www.jsonrpc.org/specification#error_object
+library json_rpc_2.error_code;
+
+/// An error code indicating that invalid JSON was received by the server.
+const PARSE_ERROR = -32700;
+
+/// An error code indicating that the request JSON was invalid according to the
+/// JSON-RPC 2.0 spec.
+const INVALID_REQUEST = -32600;
+
+/// An error code indicating that the requested method does not exist or is
+/// unavailable.
+const METHOD_NOT_FOUND = -32601;
+
+/// An error code indicating that the request paramaters are invalid for the
+/// requested method.
+const INVALID_PARAMS = -32602;
+
+/// An internal JSON-RPC error.
+const INTERNAL_ERROR = -32603;
+
+/// An unexpected error occurred on the server.
+///
+/// The spec reserves the range from -32000 to -32099 for implementation-defined
+/// server exceptions, but for now we only use one of those values.
+const SERVER_ERROR = -32000;