blob: 742bd8b00cf2581ae21b7d9e2051222086a39251 [file] [log] [blame]
// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
import 'dart:async';
import '../base/context.dart';
import '../globals.dart';
import 'common.dart';
import 'io.dart';
const int kNetworkProblemExitCode = 50;
typedef HttpClientFactory = HttpClient Function();
/// Download a file from the given URL and return the bytes.
Future<List<int>> fetchUrl(Uri url) async {
int attempts = 0;
int duration = 1;
while (true) {
attempts += 1;
final List<int> result = await _attempt(url);
if (result != null)
return result;
printStatus('Download failed -- attempting retry $attempts in $duration second${ duration == 1 ? "" : "s"}...');
await Future<void>.delayed(Duration(seconds: duration));
if (duration < 64)
duration *= 2;
}
}
/// Check if the given URL points to a valid endpoint.
Future<bool> doesRemoteFileExist(Uri url) async =>
(await _attempt(url, onlyHeaders: true)) != null;
Future<List<int>> _attempt(Uri url, { bool onlyHeaders = false }) async {
printTrace('Downloading: $url');
HttpClient httpClient;
if (context[HttpClientFactory] != null) {
httpClient = (context[HttpClientFactory] as HttpClientFactory)(); // ignore: avoid_as
} else {
httpClient = HttpClient();
}
HttpClientRequest request;
try {
if (onlyHeaders) {
request = await httpClient.headUrl(url);
} else {
request = await httpClient.getUrl(url);
}
} on HandshakeException catch (error) {
printTrace(error.toString());
throwToolExit(
'Could not authenticate download server. You may be experiencing a man-in-the-middle attack,\n'
'your network may be compromised, or you may have malware installed on your computer.\n'
'URL: $url',
exitCode: kNetworkProblemExitCode,
);
} on SocketException catch (error) {
printTrace('Download error: $error');
return null;
}
final HttpClientResponse response = await request.close();
// If we're making a HEAD request, we're only checking to see if the URL is
// valid.
if (onlyHeaders) {
return (response.statusCode == 200) ? <int>[] : null;
}
if (response.statusCode != 200) {
if (response.statusCode > 0 && response.statusCode < 500) {
throwToolExit(
'Download failed.\n'
'URL: $url\n'
'Error: ${response.statusCode} ${response.reasonPhrase}',
exitCode: kNetworkProblemExitCode,
);
}
// 5xx errors are server errors and we can try again
printTrace('Download error: ${response.statusCode} ${response.reasonPhrase}');
return null;
}
printTrace('Received response from server, collecting bytes...');
try {
final BytesBuilder responseBody = BytesBuilder(copy: false);
await response.forEach(responseBody.add);
return responseBody.takeBytes();
} on IOException catch (error) {
printTrace('Download error: $error');
return null;
}
}