I have a setup right now where I am running a flask server that handles websocket communication between and android phone and a raspberry pi node.js socket.io client. The android socket.io can connect to the flask server, the node.js client can connect, and I can emit messages between all 3, however my android studio socket.io client is disconnecting every 5-10 seconds and reconnecting. It continues to do this even when I leave the activity that causes it to connect, it will connect and disconnect from the server continuously. Here is the Java code in android studio:
import io.socket.client.IO;
import io.socket.client.Socket;
import io.socket.emitter.Emitter;
public class ControlPage extends AppCompatActivity {
Button greenButton;
Button redButton;
private Socket mSocket; {
try {
mSocket = IO.socket("http://192.168.1.2:5000");
} catch (URISyntaxException e) {}
}
//private EditText mInputMessageView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_control_page);
mSocket.connect();
mSocket.on(Socket.EVENT_CONNECT, onConnect);
greenButton = (Button) findViewById(R.id.sendButtonGreen);
greenButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
attemptSendGreen();
}
});
redButton = (Button) findViewById(R.id.sendButtonRed);
redButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
attemptSendRed();
}
});
}
Server side in my flask code I have:
import flask
from flask_socketio import SocketIO, emit
from flask import request
import json
app = flask.Flask(__name__)
socketio = SocketIO(app)
clients = {}
sessions = {}
@app.route('/')
def hello():
return "<h1> Hello World! </h1>"
@socketio.on('connect')
def testConnect():
print('connected')
emit('connected')
@socketio.on('disconnect')
def testDisconnect():
userSID = request.sid
print('disconnected ' + str(userSID))
UserID = sessions[str(userSID)][0]
UserType = sessions[str(userSID)][1]
clients[UserID][UserType]=''
sessions.pop(str(userSID))
@socketio.on('config')
def handle_config(data):
print('received message: ' + str(data)+ str(type(data)))
userSID = request.sid
if type(data) == str:
jsonData = eval(data)
else:
jsonData = data
print(userSID)
if jsonData['USER_KEY'] in clients:
clients[jsonData['USER_KEY']][jsonData['USER_TYPE']]=userSID
else:
clients[jsonData['USER_KEY']] = {'USER':'',
'HARDWARE':''}
clients[jsonData['USER_KEY']][jsonData['USER_TYPE']]=userSID
sessions[str(userSID)] = [jsonData['USER_KEY'], jsonData['USER_TYPE']]
@socketio.on('transfer')
def transfer(data):
jsonData = eval(data)
print(jsonData)
UserID = jsonData['USER_KEY']
UserType = jsonData['USER_TYPE']
color = jsonData['MESSAGE']
#message = data['MESSAGE']
message = {'COLOR': color,
'STATE': 1
}
jsonMessage = json.dumps(message)
if UserType == 'USER':
transferID = clients[UserID]['HARDWARE']
else:
transferID = clients[UserID]['USER']
emit('serverTransfer', jsonMessage, to=transferID)
socketio.run(app,host='192.168.1.2',port='5000') #remove this line when using gunicorn deployment
Everything server side is working fine with my node.js client, so I don't think that the problem is coming from the server.
This is the information I get back from my server that shows the android client disconnecting and reconnecting every few seconds:
WebSocket transport not available. Install eventlet or gevent and gevent-websocket for improved performance.
* Serving Flask app "websocketTest" (lazy loading)
* Environment: production
WARNING: This is a development server. Do not use it in a production deployment.
Use a production WSGI server instead.
* Debug mode: off
* Running on http://192.168.1.2:5000/ (Press CTRL+C to quit)
192.168.1.5 - - [18/Apr/2021 18:15:23] "GET /socket.io/?EIO=4&transport=polling HTTP/1.1" 200 -
192.168.1.5 - - [18/Apr/2021 18:15:23] "POST /socket.io/?EIO=4&transport=polling&sid=mO35rQ0Mi_5ZxYFXAAAA HTTP/1.1" 200 -
192.168.1.5 - - [18/Apr/2021 18:15:23] "GET /socket.io/?EIO=4&transport=polling&sid=mO35rQ0Mi_5ZxYFXAAAA HTTP/1.1" 200 -
192.168.1.5 - - [18/Apr/2021 18:15:23] "POST /socket.io/?EIO=4&transport=polling&sid=mO35rQ0Mi_5ZxYFXAAAA HTTP/1.1" 200 -
connected
received message: { "USER_KEY": "TEST_USER", "MESSAGE": "asdfasdfasdf", "USER_TYPE":"USER"}<class 'str'>
6pKGg55-qcP9rejgAAAB
192.168.1.5 - - [18/Apr/2021 18:15:33] "POST /socket.io/?EIO=4&transport=polling&sid=mO35rQ0Mi_5ZxYFXAAAA HTTP/1.1" 200 -
192.168.1.5 - - [18/Apr/2021 18:15:33] "GET /socket.io/?EIO=4&transport=polling&sid=mO35rQ0Mi_5ZxYFXAAAA HTTP/1.1" 200 -
disconnected6pKGg55-qcP9rejgAAAB
192.168.1.6 - - [18/Apr/2021 18:15:33] "GET /socket.io/?EIO=4&transport=polling&t=NZdidCS&b64=1 HTTP/1.1" 200 -
192.168.1.6 - - [18/Apr/2021 18:15:34] "POST /socket.io/?EIO=4&transport=polling&t=NZdidEm&b64=1&sid=6pJ6UIkNrvOanjMwAAAC HTTP/1.1" 200 -
192.168.1.6 - - [18/Apr/2021 18:15:34] "GET /socket.io/?EIO=4&transport=polling&t=NZdidEx&b64=1&sid=6pJ6UIkNrvOanjMwAAAC HTTP/1.1" 200 -
192.168.1.6 - - [18/Apr/2021 18:15:34] "POST /socket.io/?EIO=4&transport=polling&t=NZdidFW&b64=1&sid=6pJ6UIkNrvOanjMwAAAC HTTP/1.1" 200 -
192.168.1.6 - - [18/Apr/2021 18:15:34] "POST /socket.io/?EIO=4&transport=polling&t=NZdidFx&b64=1&sid=6pJ6UIkNrvOanjMwAAAC HTTP/1.1" 200 -
connected
received message: {'USER_KEY': 'TEST_USER', 'USER_TYPE': 'HARDWARE'}<class 'dict'>
1nrEBb6Xny3dpELEAAAD
192.168.1.5 - - [18/Apr/2021 18:15:35] "GET /socket.io/?EIO=4&transport=polling HTTP/1.1" 200 -
192.168.1.5 - - [18/Apr/2021 18:15:35] "POST /socket.io/?EIO=4&transport=polling&sid=Vo6Qo1Suk5U6dnG0AAAE HTTP/1.1" 200 -
192.168.1.5 - - [18/Apr/2021 18:15:35] "GET /socket.io/?EIO=4&transport=polling&sid=Vo6Qo1Suk5U6dnG0AAAE HTTP/1.1" 200 -
192.168.1.5 - - [18/Apr/2021 18:15:35] "POST /socket.io/?EIO=4&transport=polling&sid=Vo6Qo1Suk5U6dnG0AAAE HTTP/1.1" 200 -
connected
received message: { "USER_KEY": "TEST_USER", "MESSAGE": "asdfasdfasdf", "USER_TYPE":"USER"}<class 'str'>
85Gy1EZr-XWm32-6AAAF
192.168.1.5 - - [18/Apr/2021 18:15:39] "POST /socket.io/?EIO=4&transport=polling&sid=Vo6Qo1Suk5U6dnG0AAAE HTTP/1.1" 200 -
192.168.1.6 - - [18/Apr/2021 18:15:39] "GET /socket.io/?EIO=4&transport=polling&t=NZdidFj&b64=1&sid=6pJ6UIkNrvOanjMwAAAC HTTP/1.1" 200 -
{'USER_KEY': 'TEST_USER', 'MESSAGE': 'GREEN', 'USER_TYPE': 'USER'}
192.168.1.6 - - [18/Apr/2021 18:15:40] "GET /socket.io/?EIO=4&transport=polling&t=NZdieaT&b64=1&sid=6pJ6UIkNrvOanjMwAAAC HTTP/1.1" 200 -
192.168.1.5 - - [18/Apr/2021 18:15:40] "POST /socket.io/?EIO=4&transport=polling&sid=Vo6Qo1Suk5U6dnG0AAAE HTTP/1.1" 200 -
{'USER_KEY': 'TEST_USER', 'MESSAGE': 'GREEN', 'USER_TYPE': 'USER'}
192.168.1.5 - - [18/Apr/2021 18:15:41] "POST /socket.io/?EIO=4&transport=polling&sid=Vo6Qo1Suk5U6dnG0AAAE HTTP/1.1" 200 -
192.168.1.6 - - [18/Apr/2021 18:15:41] "GET /socket.io/?EIO=4&transport=polling&t=NZdiejT&b64=1&sid=6pJ6UIkNrvOanjMwAAAC HTTP/1.1" 200 -
{'USER_KEY': 'TEST_USER', 'MESSAGE': 'RED', 'USER_TYPE': 'USER'}
192.168.1.5 - - [18/Apr/2021 18:15:42] "POST /socket.io/?EIO=4&transport=polling&sid=Vo6Qo1Suk5U6dnG0AAAE HTTP/1.1" 200 -
192.168.1.6 - - [18/Apr/2021 18:15:42] "GET /socket.io/?EIO=4&transport=polling&t=NZdif2X&b64=1&sid=6pJ6UIkNrvOanjMwAAAC HTTP/1.1" 200 -
{'USER_KEY': 'TEST_USER', 'MESSAGE': 'RED', 'USER_TYPE': 'USER'}
192.168.1.5 - - [18/Apr/2021 18:15:45] "POST /socket.io/?EIO=4&transport=polling&sid=Vo6Qo1Suk5U6dnG0AAAE HTTP/1.1" 200 -
192.168.1.5 - - [18/Apr/2021 18:15:45] "GET /socket.io/?EIO=4&transport=polling&sid=Vo6Qo1Suk5U6dnG0AAAE HTTP/1.1" 200 -
disconnected85Gy1EZr-XWm32-6AAAF
192.168.1.5 - - [18/Apr/2021 18:15:47] "GET /socket.io/?EIO=4&transport=polling HTTP/1.1" 200 -
192.168.1.5 - - [18/Apr/2021 18:15:47] "POST /socket.io/?EIO=4&transport=polling&sid=Axb2tK8BaYqGqrgGAAAG HTTP/1.1" 200 -
192.168.1.5 - - [18/Apr/2021 18:15:47] "GET /socket.io/?EIO=4&transport=polling&sid=Axb2tK8BaYqGqrgGAAAG HTTP/1.1" 200 -
192.168.1.5 - - [18/Apr/2021 18:15:47] "POST /socket.io/?EIO=4&transport=polling&sid=Axb2tK8BaYqGqrgGAAAG HTTP/1.1" 200 -
connected
received message: { "USER_KEY": "TEST_USER", "MESSAGE": "asdfasdfasdf", "USER_TYPE":"USER"}<class 'str'>
RLGgcjYRr3G8437zAAAH
192.168.1.6 - - [18/Apr/2021 18:15:58] "GET /socket.io/?EIO=4&transport=polling&t=NZdifE4&b64=1&sid=6pJ6UIkNrvOanjMwAAAC HTTP/1.1" 200 -
disconnected1nrEBb6Xny3dpELEAAAD
192.168.1.5 - - [18/Apr/2021 18:16:12] "GET /socket.io/?EIO=4&transport=polling&sid=Axb2tK8BaYqGqrgGAAAG HTTP/1.1" 200 -
disconnectedRLGgcjYRr3G8437zAAAH
The library I'm using to handle my socket.io in Java is imported as:
implementation ('io.socket:socket.io-client:2.0.0') {
exclude group: 'org.json', module: 'json'
}
Any insight into what is causing my android client to disconnect would be greatly appreciated.
Update: This problem goes away when I run my server in its deployed state in the Nginx, gunicorn, flask stack on port 80. The problem only persists when running flask directly on port 5000.