TCP server

Listens for TCP connections on an address and port, emits all received data as TcpDatagram records and sends data back to a specific client through the Response pin. Use it to accept connections from devices or services that speak a raw TCP protocol. The component keeps the flow running.

Pins

Pin	Kind	Types	Description
Start	start	any	Intended to start the server. When unconnected, the server starts with the flow (see Notes).
Request	output	Viaducta.Plugins.UdpTypes.TcpDatagram	Data received from a client, with new metadata.
Response	input	Viaducta.Plugins.UdpTypes.TcpDatagram	Data to send to a client, identified by SessionId.
Tcp events	continue	Viaducta.Plugins.UdpTypes.TcpEvent	Intended for client connect / disconnect events (see Notes).

Configuration

Field	Type	Default	Description
Address	string	127.0.0.1	Required. Local IP address or host name to listen on. 127.0.0.1 accepts only local connections; use the machine's IP (or 0.0.0.0 / *) for remote clients.
Port	integer (1-65535)	7000	Required. Port to listen on.

Behaviour

• The server starts when the flow starts (with Start unconnected) and stops when the flow stops.
• Every chunk of data received from a client is emitted on Request as a TcpDatagram, processed in the background (several chunks can be processed in parallel):
  • SessionId and IP: the client's ip:port string,
  • Port: always 0,
  • Data: the received bytes.
• There is no framing: a client message can be split over several datagrams, or several messages can arrive in one. Reassemble downstream if your protocol needs it.
• To answer, send a TcpDatagram to Response with the SessionId of the request and the bytes in Data. Keep SessionId from the request (a mapper that copies it). A missing SessionId throws an exception; a client that has already closed the connection is ignored.

Notes

• Connecting the Start pin breaks the component: the server is then never started (an internal flag is never set), and Response fails. Leave Start unconnected.
• Tcp events is never called: connect / disconnect events are not emitted in the current code. When it works, TcpEvent.Kind is 1 CLIENT_CONNECTED or 2 CLIENT_DISCONNECTED, Address is ip:port and Port is 0.
• Responses are written as they are; add your protocol's delimiter (for example \r\n) to Data yourself.

Example

{ "Address": "0.0.0.0", "Port": 7000 }

TCP server Request → (decode Data, build answer, keep SessionId) → TCP server Response