Client: C++ client connections lost upon migration from 2.3.0 to 3.0.1

[AdrianDC]

You want to:

• report a bug
• request a feature

Current behaviour

Upon migration from Socket.IO 2.3.0 to 3.0.1 and related adaptations,
the socket.io-client-cpp connections are no longer detected by the server.

Only a new socket("/namespace/") call in C++ triggers an event.

Steps to reproduce (if the current behaviour is a bug)

File test.js : test.js

File test.cpp : test.cpp

Compile socket.io-client-cpp and test :

git clone --recurse-submodules https://github.com/socketio/socket.io-client-cpp.git

docker run -i --entrypoint bash --rm -v "$PWD:$PWD" -w "$PWD" node:12-stretch <<EOF
cd ./socket.io-client-cpp/
apt update
apt install -y libboost-all-dev build-essential cmake libssl1.0-dev make
cmake .
make install
cd ../
g++ -std=c++11 -Isocket.io-client-cpp/build/include -lboost_system -lpthread -o test test.cpp ./socket.io-client-cpp/build/lib/Release/libsioclient.a
EOF

Run with socket.io@2.3.0 and results :

docker run -i --entrypoint bash --rm -v "$PWD:$PWD" -w "$PWD" node:12-stretch <<EOF
apt update
apt install libboost-system1.62.0
npm install express http socket.io@2.3.0
echo ''
{
  node ./test.js &
  server=${!}
  sleep 2
  timeout 3 ./test
  echo ''
  timeout 3 ./test true
  echo ''
  timeout 3 ./test true true
  kill -9 "${server}"
}
EOF

Run with socket.io@3.0.1 :

docker run -i --entrypoint bash --rm -v "$PWD:$PWD" -w "$PWD" node:12-stretch <<EOF
apt update
apt install libboost-system1.62.0
npm install express http socket.io@3.0.1
echo ''
{
  node ./test.js &
  server=${!}
  sleep 2
  timeout 3 ./test
  echo ''
  timeout 3 ./test true
  echo ''
  timeout 3 ./test true true
  kill -9 "${server}"
}
EOF

Results with socket.io@2.3.0 :

[SERVER] Using socket.io@2.3.0 syntax 
[SERVER] Server listening on http://127.0.0.1:3000
[CLIENT] Connecting to http://127.0.0.1:3000...
[CLIENT] Connected                                        
[SERVER] Expected "use()" {"EIO":"4","transport":"websocket","t":"1605634708","query1":"data1","query2":"data2"}
[SERVER] Expected "of("").use()" {"EIO":"4","transport":"websocket","t":"1605634708","query1":"data1","query2":"data2"} 
[SERVER] Expected "of("/").use()" {"EIO":"4","transport":"websocket","t":"1605634708","query1":"data1","query2":"data2"}
[SERVER] Expected "connect" {"EIO":"4","transport":"websocket","t":"1605634708","query1":"data1","query2":"data2"}
[SERVER] Expected "connection" {"EIO":"4","transport":"websocket","t":"1605634708","query1":"data1","query2":"data2"}
[CLIENT] Interrupting...
[CLIENT] State: Connected
[CLIENT] Disconnected
[SERVER] Expected "disconnect" (use())
[SERVER] Expected "disconnect" ("")
[SERVER] Expected "disconnect" ("/")
[SERVER] Expected "disconnect" ("connect")
[SERVER] Expected "disconnect" ("connection")

[CLIENT] Connecting to http://127.0.0.1:3000...
[CLIENT] Connected
[SERVER] Expected "use()" {"EIO":"4","transport":"websocket","t":"1605634714","query1":"data1","query2":"data2"}
[SERVER] Expected "of("").use()" {"EIO":"4","transport":"websocket","t":"1605634714","query1":"data1","query2":"data2"}
[SERVER] Expected "of("/").use()" {"EIO":"4","transport":"websocket","t":"1605634714","query1":"data1","query2":"data2"}
[SERVER] Expected "connect" {"EIO":"4","transport":"websocket","t":"1605634714","query1":"data1","query2":"data2"}
[SERVER] Expected "connection" {"EIO":"4","transport":"websocket","t":"1605634714","query1":"data1","query2":"data2"}
[SERVER] Expected "of("/user/").use()" {"EIO":"4","transport":"websocket","t":"1605634714","query1":"data1","query2":"data2"}
[CLIENT] Interrupting...
[CLIENT] State: Connected
[CLIENT] Disconnected
[SERVER] Expected "disconnect" (use())
[SERVER] Expected "disconnect" ("")
[SERVER] Expected "disconnect" ("/")
[SERVER] Expected "disconnect" ("connect")
[SERVER] Expected "disconnect" ("connection")
[SERVER] Expected "disconnect" ("/user/")

[CLIENT] Connecting to http://127.0.0.1:3000...
[CLIENT] Connected
[SERVER] Expected "use()" {"EIO":"4","transport":"websocket","t":"1605634720","query1":"data1","query2":"data2"}
[SERVER] Expected "of("").use()" {"EIO":"4","transport":"websocket","t":"1605634720","query1":"data1","query2":"data2"}
[SERVER] Expected "of("/").use()" {"EIO":"4","transport":"websocket","t":"1605634720","query1":"data1","query2":"data2"}
[SERVER] Expected "connect" {"EIO":"4","transport":"websocket","t":"1605634720","query1":"data1","query2":"data2"}
[SERVER] Expected "connection" {"EIO":"4","transport":"websocket","t":"1605634720","query1":"data1","query2":"data2"}
[CLIENT] Interrupting...
[CLIENT] State: Connected
[CLIENT] Disconnected
[SERVER] Expected "disconnect" (use())
[SERVER] Expected "disconnect" ("")
[SERVER] Expected "disconnect" ("/")
[SERVER] Expected "disconnect" ("connect")
[SERVER] Expected "disconnect" ("connection")

Results with socket.io@3.0.1 :

[SERVER] Using socket.io@3.0.1 syntax
[SERVER] Server listening on http://127.0.0.1:3000
[CLIENT] Connecting to http://127.0.0.1:3000...
[CLIENT] Connected
[CLIENT] Interrupting...
[CLIENT] State: Connected
[CLIENT] Disconnected

[CLIENT] Connecting to http://127.0.0.1:3000...
[CLIENT] Connected
[SERVER] Expected "of("/user/").use()" {"EIO":"4","transport":"websocket","t":"1605634663","query1":"data1","query2":"data2"}
[CLIENT] Interrupting...
[CLIENT] State: Connected
[CLIENT] Disconnected
[SERVER] Expected "disconnect" ("/user/")

[CLIENT] Connecting to http://127.0.0.1:3000...
[CLIENT] Connected
[CLIENT] Interrupting...
[CLIENT] State: Connected
[CLIENT] Disconnected

Expected behaviour

While the default namespace is no longer detected on socket.io@3.0,
I need a way to detect the connection regardless of the namespace to register the existing C++ clients.

Changes introduced in the 3289f7e commit now prevents us
from detecting an "incoming" Client connection, although it does not open a Socket on a namespace,
this is valuable information for specific use cases.

I restored compatibility with the 2.3.0 server by applying this patch after installations :

sed -i "s#\(        \)\(new client_1.Client.*\)#\1const client = \2\n        client.connect(\"/\");#g" ./node_modules/socket.io/dist/index.js

Per the https://socket.io/docs/v3/namespaces/index.html#Default-namespace documentation,
the default namespace "/" should be at least accessible, even explicitly.

Setup

• OS: Debian Stretch and CentOS 7
• Node.js : 12.19.1
• socket.io version: 3.0.1 and 2.3.0

Other information (e.g. stacktraces, related issues, suggestions how to fix)

For CentOS 7 targets, compatibility for socket.io-client-cpp : socketio/socket.io-client-cpp#271

[darrachequesne]

The C++ client now supports Socket.IO v3: https://github.com/socketio/socket.io-client-cpp/releases/tag/3.0.0