| // Copyright 2019 Google LLC |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // https://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| import 'dart:async'; |
| import 'dart:io'; |
| import 'package:retry/retry.dart'; |
| |
| Future<void> main() async { |
| // Create an HttpClient. |
| final client = HttpClient(); |
| |
| try { |
| // Get statusCode by retrying a function |
| final statusCode = await retry( |
| () async { |
| // Make a HTTP request and return the status code. |
| final request = await client |
| .getUrl(Uri.parse('https://www.google.com')) |
| .timeout(Duration(seconds: 5)); |
| final response = await request.close().timeout(Duration(seconds: 5)); |
| await response.drain(); |
| return response.statusCode; |
| }, |
| // Retry on SocketException or TimeoutException |
| retryIf: (e) => e is SocketException || e is TimeoutException, |
| ); |
| |
| // Print result from status code |
| if (statusCode == 200) { |
| print('google.com is running'); |
| } else { |
| print('google.com is not availble...'); |
| } |
| } finally { |
| // Always close an HttpClient from dart:io, to close TCP connections in the |
| // connection pool. Many servers has keep-alive to reduce round-trip time |
| // for additional requests and avoid that clients run out of port and |
| // end up in WAIT_TIME unpleasantries... |
| client.close(); |
| } |
| } |