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

pkg/json_rpc_2/test/server/server_test.dart

+// 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.
+
+library json_rpc_2.test.server.server_test;
+
+import 'dart:convert';
+
+import 'package:unittest/unittest.dart';
+import 'package:json_rpc_2/error_code.dart' as error_code;
+import 'package:json_rpc_2/json_rpc_2.dart' as json_rpc;
+
+import 'utils.dart';
+
+void main() {
+  var server;
+  setUp(() => server = new json_rpc.Server());
+
+  test("calls a registered method with the given name", () {
+    server.registerMethod('foo', (params) {
+      return {'params': params.value};
+    });
+
+    expect(server.handleRequest({
+      'jsonrpc': '2.0',
+      'method': 'foo',
+      'params': {'param': 'value'},
+      'id': 1234
+    }), completion(equals({
+      'jsonrpc': '2.0',
+      'result': {'params': {'param': 'value'}},
+      'id': 1234
+    })));
+  });
+
+  test("calls a method that takes no parameters", () {
+    server.registerMethod('foo', () => 'foo');
+
+    expect(server.handleRequest({
+      'jsonrpc': '2.0',
+      'method': 'foo',
+      'id': 1234
+    }), completion(equals({
+      'jsonrpc': '2.0',
+      'result': 'foo',
+      'id': 1234
+    })));
+  });
+
+  test("a method that takes no parameters rejects parameters", () {
+    server.registerMethod('foo', () => 'foo');
+
+    expectErrorResponse(server, {
+      'jsonrpc': '2.0',
+      'method': 'foo',
+      'params': {},
+      'id': 1234
+    },
+        error_code.INVALID_PARAMS,
+        'No parameters are allowed for method "foo".');
+  });
+
+  test("an unexpected error in a method is captured", () {
+    server.registerMethod('foo', () => throw new FormatException('bad format'));
+
+    expect(server.handleRequest({
+      'jsonrpc': '2.0',
+      'method': 'foo',
+      'id': 1234
+    }), completion({
+      'jsonrpc': '2.0',
+      'id': 1234,
+      'error': {
+        'code': error_code.SERVER_ERROR,
+        'message': 'bad format',
+        'data': {
+          'request': {'jsonrpc': '2.0', 'method': 'foo', 'id': 1234},
+          'full': 'FormatException: bad format',
+          'stack': contains('server_test.dart')
+        }
+      }
+    }));
+  });
+
+  test("doesn't return a result for a notification", () {
+    server.registerMethod('foo', (args) => 'result');
+
+    expect(server.handleRequest({
+      'jsonrpc': '2.0',
+      'method': 'foo',
+      'params': {}
+    }), completion(isNull));
+  });
+
+  group("JSON", () {
+    test("handles a request parsed from JSON", () {
+      server.registerMethod('foo', (params) {
+        return {'params': params.value};
+      });
+
+      expect(server.parseRequest(JSON.encode({
+        'jsonrpc': '2.0',
+        'method': 'foo',
+        'params': {'param': 'value'},
+        'id': 1234
+      })), completion(equals(JSON.encode({
+        'jsonrpc': '2.0',
+        'result': {'params': {'param': 'value'}},
+        'id': 1234
+      }))));
+    });
+
+    test("handles a notification parsed from JSON", () {
+      server.registerMethod('foo', (params) {
+        return {'params': params};
+      });
+
+      expect(server.parseRequest(JSON.encode({
+        'jsonrpc': '2.0',
+        'method': 'foo',
+        'params': {'param': 'value'}
+      })), completion(isNull));
+    });
+
+    test("a JSON parse error is rejected", () {
+      expect(server.parseRequest('invalid json {'),
+          completion(equals(JSON.encode({
+        'jsonrpc': '2.0',
+        'error': {
+          'code': error_code.PARSE_ERROR,
+          'message': "Invalid JSON: Unexpected character at 0: 'invalid json "
+                     "{'",
+          'data': {'request': 'invalid json {'}
+        },
+        'id': null
+      }))));
+    });
+  });
+
+  group("fallbacks", () {
+    test("calls a fallback if no method matches", () {
+      server.registerMethod('foo', () => 'foo');
+      server.registerMethod('bar', () => 'foo');
+      server.registerFallback((params) => {'fallback': params.value});
+
+      expect(server.handleRequest({
+        'jsonrpc': '2.0',
+        'method': 'baz',
+        'params': {'param': 'value'},
+        'id': 1234
+      }), completion(equals({
+        'jsonrpc': '2.0',
+        'result': {'fallback': {'param': 'value'}},
+        'id': 1234
+      })));
+    });
+
+    test("calls the first matching fallback", () {
+      server.registerFallback((params) =>
+          throw new json_rpc.RpcException.methodNotFound(params.method));
+
+      server.registerFallback((params) => 'fallback 2');
+      server.registerFallback((params) => 'fallback 3');
+
+      expect(server.handleRequest({
+        'jsonrpc': '2.0',
+        'method': 'fallback 2',
+        'id': 1234
+      }), completion(equals({
+        'jsonrpc': '2.0',
+        'result': 'fallback 2',
+        'id': 1234
+      })));
+    });
+
+    test("an unexpected error in a fallback is captured", () {
+      server.registerFallback((_) => throw new FormatException('bad format'));
+
+      expect(server.handleRequest({
+        'jsonrpc': '2.0',
+        'method': 'foo',
+        'id': 1234
+      }), completion({
+        'jsonrpc': '2.0',
+        'id': 1234,
+        'error': {
+          'code': error_code.SERVER_ERROR,
+          'message': 'bad format',
+          'data': {
+            'request': {'jsonrpc': '2.0', 'method': 'foo', 'id': 1234},
+            'full': 'FormatException: bad format',
+            'stack': contains('server_test.dart')
+          }
+        }
+      }));
+    });
+  });
+
+  test("disallows multiple methods with the same name", () {
+    server.registerMethod('foo', () => null);
+    expect(() => server.registerMethod('foo', () => null), throwsArgumentError);
+  });
+}