Dart servers refusing connection in local network - dart

Question

I have Dart running on Mac Mavericks and Ubuntu Linux. I am just getting started;and, none of the examples will function through my local network. When I install a server on Ubuntu and try to access with the mac- nothing happens. When I try to access from Ubunutu, I get a "java.net Connection Refused error" Same goes for Curl on either machine, (connection refused). All of the samples run fine as client/server from localhost. Neither, Client apps or Browsers are able to connect. All other servers/clients working normally in the home network. Firewall is ok, and I double checked port numbers. There are no conflicting servers on the desired ports. I tried about 5 different scripts from the Dart site and others, each with a CORS function, but nothing connects, including the sample below, SimpleServer
-Github
Sample Code
/* A simple web server that responds to **ALL** GET requests by returning
* the contents of data.json file, and responds to ALL **POST** requests
* by overwriting the contents of the data.json file
*
* Browse to it using http://localhost:8080
*
* Provides CORS headers, so can be accessed from any other page
*/
import 'dart:io';
final HOST = "127.0.0.1"; // eg: localhost
final PORT = 8080;
final DATA_FILE = "data.json";
void main() {
HttpServer.bind(HOST, PORT).then((server) {
server.listen((HttpRequest request) {
switch (request.method) {
case "GET":
handleGet(request);
break;
case "POST":
handlePost(request);
break;
case "OPTIONS":
handleOptions(request);
break;
default: defaultHandler(request);
}
},
onError: printError);
print("Listening for GET and POST on http://$HOST:$PORT");
},
onError: printError);
}
/**
* Handle GET requests by reading the contents of data.json
* and returning it to the client
*/
void handleGet(HttpRequest req) {
HttpResponse res = req.response;
print("${req.method}: ${req.uri.path}");
addCorsHeaders(res);
var file = new File(DATA_FILE);
if (file.existsSync()) {
res.headers.add(HttpHeaders.CONTENT_TYPE, "application/json");
file.readAsBytes().asStream().pipe(res); // automatically close output stream
}
else {
var err = "Could not find file: $DATA_FILE";
res.write(err);
res.close();
}
}
/**
* Handle POST requests by overwriting the contents of data.json
* Return the same set of data back to the client.
*/
void handlePost(HttpRequest req) {
HttpResponse res = req.response;
print("${req.method}: ${req.uri.path}");
addCorsHeaders(res);
req.listen((List<int> buffer) {
var file = new File(DATA_FILE);
var ioSink = file.openWrite(); // save the data to the file
ioSink.add(buffer);
ioSink.close();
// return the same results back to the client
res.add(buffer);
res.close();
},
onError: printError);
}
/**
* Add Cross-site headers to enable accessing this server from pages
* not served by this server
*
* See: http://www.html5rocks.com/en/tutorials/cors/
* and http://enable-cors.org/server.html
*/
void addCorsHeaders(HttpResponse res) {
res.headers.add("Access-Control-Allow-Origin", "*");
res.headers.add("Access-Control-Allow-Methods", "POST, GET, OPTIONS");
res.headers.add("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
}
void handleOptions(HttpRequest req) {
HttpResponse res = req.response;
addCorsHeaders(res);
print("${req.method}: ${req.uri.path}");
res.statusCode = HttpStatus.NO_CONTENT;
res.close();
}
void defaultHandler(HttpRequest req) {
HttpResponse res = req.response;
addCorsHeaders(res);
res.statusCode = HttpStatus.NOT_FOUND;
res.write("Not found: ${req.method}, ${req.uri.path}");
res.close();
}
void printError(error) => print(error);
data.json
{
"language":"DART",
"targets":["dartium","javascript","Android?"],
"website":{
"homepage":"www.dartlang.org",
"api":"api.dartlang.org"
}
}

Answer 1

I think this is because the Dart server is configured to listen to only the clients on the localhost. You need to make it to listen to any IPv4/v6 client in order to receive any response from the server over the network.
Change the line final HOST = "127.0.0.1"; to final HOST = InternetAddress.ANY_IP_V4;
or final HOST = InternetAddress.ANY_IP_V6;
It should make it work.