Is there any way to establish a telnet connection in dart?
Basically what I want to achive it's to create a teamspeak 3 bot using Dart.
I tought about using socket with I have no idea about how to go on.
EDIT: I managed to estabilish a socket connection to the ts3 but I cannot make dart to keep the connection open:
EDIT: Managed to keep the connection open
EDIT: Now the commands are sent but the spaces are not recognized.
EDIT: \u0020 made the space work but the param(login) it's not read
EDIT: Finally all it's working, \n was required at the string end.
import 'dart:io';
import 'dart:async';
const String user = "serveradmin";
const String pass = "------";
Socket socket;
void main() async {
await Socket.connect("localhost", 10011)
.then((Socket sock) {
socket = sock;
socket.listen(dataHandler,
onError: errorHandler,
onDone: doneHandler,
cancelOnError: false);
})
.catchError((AsyncError e) {
print("Unable to connect: $e");
exit(1);
});
socket.write('help login\n');
print("End main");
}
void dataHandler(data){
print("Data Handler!");
print(" ${new String.fromCharCodes(data).trim()}");
socket.write(new String.fromCharCodes(data).trim() + 'help login');
}
void errorHandler(error, StackTrace trace){
print(error);
}
void doneHandler(){
print("Done Handler!");
socket.destroy();
exit(0);
}
Also seems like to login command it's not sent.
Related
I'm trying to build a Dart HTTP server and I want to test the API. I'm not able to set up the tests, though.
Here is what I have so far in my_server_test.dart:
import 'dart:io';
import 'package:my_server/my_server.dart';
import 'package:test/test.dart';
void main() {
HttpServer server;
setUp(() async {
final server = await createServer();
await handleRequests(server);
});
tearDown(() async {
await server.close(force: true);
server = null;
});
test('First try', () async {
final client = HttpClient();
final request = await client.get(InternetAddress.loopbackIPv4.host, 4040, '/');
final response = await request.close();
print(response);
});
}
And here is the server code in my_server.dart:
import 'dart:io';
import 'package:hundetgel_server/routes/handle_get.dart';
Future<HttpServer> createServer() async {
final address = InternetAddress.loopbackIPv4;
const port = 4040;
return await HttpServer.bind(address, port);
}
Future<void> handleRequests(HttpServer server) async {
await for (HttpRequest request in server) {
switch (request.method) {
case 'GET':
handleGet(request);
break;
default:
handleDefault(request);
}
}
}
void handleGet(HttpRequest request) {
request.response
..write('Hello')
..close();
}
void handleDefault(HttpRequest request) {
request.response
..statusCode = HttpStatus.methodNotAllowed
..write('Unsupported request: ${request.method}.')
..close();
}
When I run the test I just get a timeout:
TimeoutException after 0:00:30.000000: Test timed out after 30 seconds. See https://pub.dev/packages/test#timeouts
dart:isolate _RawReceivePortImpl._handleMessage
NoSuchMethodError: The method 'close' was called on null.
Receiver: null
Tried calling: close(force: true)
dart:core Object.noSuchMethod
2
main.<fn>
test/my_server_test.dart:15
===== asynchronous gap ===========================
dart:async _completeOnAsyncError
test/my_server_test.dart main.<fn>
test/my_server_test.dart:1
main.<fn>
test/my_server_test.dart:14
2
✖ First try
Exited (1)
How do I set up the server so I can start testing it?
It seems that you are await handleRequests in your setUp. Your handleRequests is a forever loop waiting for incoming requests. So it never halts. So you setup never finishes. That is the problem.
Thus, try to change
await handleRequests(server);
to
handleRequests(server); // NO await
Thus the handleRequests will run in the "background".
EDIT about the null exception of server variable:
change
final server = await createServer();
to
server = await createServer();
because the old code shadows the outside server variable - that variable is never assigned a value.
I'm going through the Dart server documentation. I see I can await for an HttpRequest like this:
import 'dart:io';
Future main() async {
var server = await HttpServer.bind(
InternetAddress.loopbackIPv4,
4040,
);
print('Listening on localhost:${server.port}');
await for (HttpRequest request in server) {
request.response.write('Hello, world!');
await request.response.close();
}
}
That's because HttpServer implements Stream. But since a stream can return either a value or an error, I should catch exceptions like this, right:
try {
await for (HttpRequest request in server) {
request.response.write('Hello, world!');
await request.response.close();
}
} catch (e) {
// ???
}
But I'm not sure what kind of exceptions can be caught. Do the exceptions arise from the request (and warrant a 400 level response) or from the server (and warrant a 500 level response)? Or both?
Error status codes
On exception, a BAD_REQUEST status code will be set:
} catch (e) {
// Try to send BAD_REQUEST response.
request.response.statusCode = HttpStatus.badRequest;
(see source)
That would be 400 (see badRequest).
Stream errors
In that same catch block, the exceptions will be rethrown, which means that you will still receive all the errors on your stream. This happens in processRequest, which processes all requests in bind.
And you get the errors on your stream because they are forwarded to the sink in bind.
Kinds of errors
I could only find a single explicit exception type:
if (disposition == null) {
throw const HttpException(
"Mime Multipart doesn't contain a Content-Disposition header value");
}
if (encoding != null &&
!_transparentEncodings.contains(encoding.value.toLowerCase())) {
// TODO(ajohnsen): Support BASE64, etc.
throw HttpException('Unsupported contentTransferEncoding: '
'${encoding.value}');
}
(see source)
These are both HttpExceptions.
I'm having trouble trying to consume the Response of an HTTP Endpoint which Streams real-time events continously. It's actually one of Docker's endpoints: https://docs.docker.com/engine/api/v1.40/#operation/SystemEvents
I am using Apache HTTP Client 4.5.5 and it just halts indefinitely when I try to consume the content InputStream:
HttpEntity entity = resp.getEntity();
EntityUtils.consume(entity);//it just hangs here.
//Even if I don't call this method, Apache calls it automatically
//after running all my ResponseHandlers
Apparently, it can be done by using JDK's raw URL: Stream a HTTP response in Java
But I cannot do that since local Docker communicates over a Unix Socket which I only managed to configure in Apache's HTTP Client with a 3rd party library for Unix Sockets in Java.
If there is a smarter HTTP Client library which I could switch to, that would also be an option.
Any ideas would be greatly appreciated. Thank you!
I managed to solve this issue by generating an infinite java.util.stream.Stream of JsonObject from the response InputStream (I know the json reading part is not the most elegant solution but there is no better way with that API and also, Docker doesn't send any separator between the jsons).
final InputStream content = response.getEntity().getContent();
final Stream<JsonObject> stream = Stream.generate(
() -> {
JsonObject read = null;
try {
final byte[] tmp = new byte[4096];
while (content.read(tmp) != -1) {
try {
final JsonReader reader = Json.createReader(
new ByteArrayInputStream(tmp)
);
read = reader.readObject();
break;
} catch (final Exception exception) {
//Couldn't parse byte[] to Json,
//try to read more bytes.
}
}
} catch (final IOException ex) {
throw new IllegalStateException(
"IOException when reading streamed JsonObjects!"
);
}
return read;
}
).onClose(
() -> {
try {
((CloseableHttpResponse) response).close();
} catch (final IOException ex) {
//There is a bug in Apache HTTPClient, when closing
//an infinite InputStream: IOException is thrown
//because the client still tries to read the remainder
// of the closed Stream. We should ignore this case.
}
}
);
return stream;
i created a async/await function in another file thus its handler is returning a Future Object. Now i can't understand how to give response to client with content of that Future Object in Dart. I am using basic dart server with shelf package.Below is code where ht.handler('list') returns a Future Object and i want to send that string to client as response. But i am getting internal server error.
import 'dart:io';
import 'package:args/args.dart';
import 'package:shelf/shelf.dart' as shelf;
import 'package:shelf/shelf_io.dart' as io;
import 'HallTicket.dart' as ht;
// For Google Cloud Run, set _hostname to '0.0.0.0'.
const _hostname = 'localhost';
main(List<String> args) async {
var parser = ArgParser()..addOption('port', abbr: 'p');
var result = parser.parse(args);
// For Google Cloud Run, we respect the PORT environment variable
var portStr = result['port'] ?? Platform.environment['PORT'] ?? '8080';
var port = int.tryParse(portStr);
if (port == null) {
stdout.writeln('Could not parse port value "$portStr" into a number.');
// 64: command line usage error
exitCode = 64;
return;
}
var handler = const shelf.Pipeline()
.addMiddleware(shelf.logRequests())
.addHandler(_echoRequest);
var server = await io.serve(handler, _hostname, port);
print('Serving at http://${server.address.host}:${server.port}');
}
Future<shelf.Response> _echoRequest(shelf.Request request)async{
shelf.Response.ok('Request for "${request.url}"\n'+await ht.handler('list'));
}
The analyzer gives your the following warning for your _echoRequest method:
info: This function has a return type of 'Future', but
doesn't end with a return statement.
And if you check the requirement for addHandler you will see it expects a handler to be returned.
So you need to add the return which makes it work on my machine:
Future<shelf.Response> _echoRequest(shelf.Request request) async {
return shelf.Response.ok(
'Request for "${request.url}"\n' + await ht.handler('list2'),
headers: {'Content-Type': 'text/html'});
}
import 'dart:io';
import 'dart:async';
void main() {
HttpClient client = new HttpClient();
client.getUrl(Uri.parse('http://api.dartlang.org/docs/releases/latest/dart_io/HttpClientResponse.html'))
.then((HttpClientRequest request) => request.close())
.then((HttpClientResponse response) {
response.listen(print, onError: (e) {
print('error: $e');
});
});
}
The code above doesn't work, using similar method to listen like pipe and fold also throws an exception => Breaking on exception: The null object does not have a method 'cancel'.
Update
Here's the code example for when connect to local machine.
import 'dart:io';
import 'dart:async';
void main() {
HttpServer.bind('127.0.0.1', 8080)
.then((HttpServer server) {
server.listen((HttpRequest request) {
File f = new File('upload.html');
f.openRead().pipe(request.response);
});
HttpClient client = new HttpClient();
client.getUrl(Uri.parse('http://127.0.0.1:8080'))
.then((HttpClientRequest request) => request.close())
.then((HttpClientResponse response) {
response.listen(print, onError: (e) {
print('error: $e');
});
});
});
}
It prints out the bytes first and then throw an exception Breaking on exception: The null object does not have a method 'cancel'.
Dart Editor version 0.7.2_r27268. Dart SDK version 0.7.2.1_r27268. On Windows 64bit machine.
Your example works on my machine.
Please specify your Dart version and other system properties that could help debug the problem.
The code presented looks fine, and I have not been able to reproduce the error on either 0.7.2.1 nor bleeding edge. Do you know whether you network has any kind of proxy setup which could cause a direct HTTP connection to fail? You could try connecting to a server on your local machine instead. If it still fails I suggest opening a bug on https://code.google.com/p/dart/issues/list with detailed information.