jorgen-k/node-red-contrib-tcp-client2

Working and improved version of nonmaintained node-red-contrib-tcp-client and node-red-contrib-tcp-server

node-red-contrib-tcp-client2

Node Red Dynamic TCP communication

This package provides a TCP client and a TCP server node for Node-RED, enabling connections to and from designated hosts. It serves as a replacement for the deprecated node-red-contrib-tcp-client by Tiago Costa.

Description

The TCP client and TCP server nodes allows seamless integration of TCP connections within Node-RED flows. It provides flexibility in establishing dynamic connections and transmitting data over TCP protocols. In contrast to the built in tcp nodes, these nodes can be configured via the msg object, flow or global context data, or even via enviroment variables.

Features

• Establish dynamic TCP connections with designated hosts.
• Dynamically manage connections using provided arguments.
• Receive data from hosts and ports with ease.

Usage Guide for TCP Client

This guide provides instructions on how to use the TCP Client within Node-RED to establish TCP connections, send data, and manage data streams effectively.

Configuration

To configure the TCP Client node in your Node-RED flow, use the configuration option in node-red. Note that most parameters can be set as string values, or from the msg object, flow or global contexts and even environment. Hence "Dynamic".

1. Drag the TCP Client node onto your flow canvas from the palette.
2. Double-click the node to open its configuration settings.
3. Set the Connection Parameters:
   • Action: connect, close or write.
   • Host: The hostname or IP address of the TCP server.
   • Port: The port number on which the TCP server is listening.
4. Data Handling Options:
   • Output: Stream or single message of the data you're sending/receiving (String, Buffer (binary) or Base64 (encoded binary)).
   • Delimiter: (For String and Base64 data types) Specify the delimiter for splitting incoming data streams. Commonly, \r\n.
5. Retry Logic:
   • Max Retries: The maximum number of reconnection attempts after a connection loss.
   • Retry Delay: Time in milliseconds before attempting a reconnection.
   • Indefinite Retries: Enable this option for the node to continuously attempt to reconnect until successful.
6. Advanced Settings:
   • Socket Timeout: Time in milliseconds after which an idle connection will be closed.
   • Stream Mode: Enable this to process data as a continuous stream; otherwise, data will be treated as single, discrete messages.

Dynamically connecting and close connections

To programmatically open or close a connection, see to that the "action" configuration is set to msg and action. Send a message with the msg.action equal to connect, close to connect or close the connection.

Sending Data

To send data through the TCP Client node, it first must be connected to a server. Then:

1. Prepare the Payload: Ensure your message payload matches the expected data type. Node objects will be translated to string ending with \r\n for conveinience. Use a function node before the TCP Client node to format the data according to your protocol if needed.
2. Inject Data: Use an inject node or any other node that can trigger sending data, and connect it to the TCP Client node. Be sure to set action to write, dynamically via the msg object or other way depending on your usage.

Receiving Data

The TCP Client node will emit messages as it receives data:

• For Stream Mode: Data will be split according to the specified delimiter and each piece will be emitted as a separate message.
• For Single Message Mode: Each data event triggers a message emission without splitting.
• Use a function node to convert data as needed depending on your protocol.

Handling Connections and Retries

The TCP Client node automatically manages connections and retries based on the configured parameters. Monitor the node status indicators for connection status:

• Green Dot: Connection established.
• Yellow Dot: Attempting to connect or reconnect.
• Red Dot: Disconnected or connection failed.

Error Handling

Errors, such as connection failures or data send/receive issues, are logged in the Node-RED debug sidebar. Implement error handling flows by connecting a Catch node to the TCP Client node to manage exceptions gracefully.

Summary

The TCP Client node offers a flexible and powerful way to integrate TCP networking into your Node-RED flows. By properly configuring and managing the node, you can achieve reliable data communication with TCP servers.

Usage - TCP Server

This section provides a comprehensive guide on how to effectively use the TCP Server within Node-RED, enabling you to accept TCP connections, process incoming data, and communicate with clients.

Configuration

To add and configure the TCP Server node in your Node-RED flow, follow these steps:

1. Add the TCP Server Node: Drag the TCP Server node from the palette to your flow.
2. Configure the Node: Double-click on the node to open its configuration settings.
   • Action: Specify the operation (open, close, or write) to dynamically control the server.
   • Port: Enter the port number where the server listens for incoming connections.

Data Handling Options

Configure how the server handles incoming data:

• Output Mode: Choose between streaming data continuously or processing single messages. Select the data format (String, Buffer, or Base64).
• Delimiter: For String and Base64 data formats, set a delimiter (e.g., \r\n) for segmenting incoming data streams.

Timeout Settings

Set timeouts to manage connection lifecycles:

• TCP Keep-Alive Timeout: Time in milliseconds before sending a keep-alive probe if no data has been transmitted.
• Application-Level Timeout: Duration in milliseconds after which an idle connection is considered stale and may be closed.

Other Configuration

• Name: Assign a descriptive name to the node for easy identification within your flows.
• Log-level: Adjust the verbosity of the log output (error, warning, info, debug) for monitoring and troubleshooting.

Receiving and Processing Data

The TCP Server node will listen on the specified port for incoming connections, handling data as configured:

• Stream Mode: Processes and emits data continuously according to the set delimiter.
• Single Message Mode: Treats each data packet as a separate message without segmentation.

Responding to Clients

To send responses to connected clients:

1. Prepare the Response: Ensure the response is correctly formatted to meet client expectations.
2. Function Node: Optionally, use a function node to tailor the response based on specific logic.
3. Send the Response: Configure the node to write and transmit the response through the TCP Server node.

Connection and Error Management

• The TCP Server node autonomously manages connections based on your configurations, with visual indicators for its status.
• Monitor the debug sidebar for any operational errors.
• Implement error-handling flows by connecting a Catch node to manage exceptions gracefully.

Dynamically open and close the server

To programmatically open or close the server, see to that the "action" configuration is set to msg and action. Send a message with the msg.action equal to open, close to open or close the TCP Client node. Use write to write the data in msg.payload. To have the server start automatically, preceed it with an inject node that sends open, perhaps after a certain delay.

Summary

The TCP Server node is a powerful tool for integrating server-side TCP functionalities into your Node-RED flows. Proper configuration and management enable reliable data communication and client-server interactions.

Examples

For additional examples and usage scenarios, refer to the EXAMPLES.md file.

Installation:

You can install this package either by using npm install node-red-contrib-tcp-client --save in ~./node-red or through the Palette Manager in Node-RED.

Upon successful installation, you should find the new TCP client node under the network category.

Node-RED Contrib TCP Client Package

Dependencies:

• Node.js
• Node-RED

Contributing

Contributions to this project are welcome! Please refer to the CONTRIBUTING.md file for guidelines.

License

This project is licensed under the MIT License.

Credits

• Author: Jörgen Karlsson inspired by Tiago Costa
• Maintainer: jorgen-k
• Contributors: jorgen-k

Changelog

Refer to the CHANGELOG.md file for details on changes, updates, and bug fixes.

Support

For any issues or questions related to using the TCP client node, please visit the project's GitHub Issues page.

Testing

Testing procedures and frameworks used for this project are documented in the TESTING.md file.

Security

For best practices on securing Node-RED flows and using the TCP client node securely, please refer to the SECURITY.md file.

Feedback

We welcome your feedback, suggestions, and bug reports! Please feel free to open an issue on the project's GitHub Issues page.

node-red-contrib-tcp-client2's Issues

original input msg obj gets lost

The original input msg object with all other information (for example return node information) is getting lost.
The better way would be to update msg.payload and keep the other information.

Sending msg.action "

Sending msg.action "close" causes to raise error with "connection lost" & catch not working on this tcp-client

Hi,
When sending msg.action "close" my NR instance is raising error in debug window with "connection lost".

And also (might be not related) catch node is not actually catching any errors when they are rised in the debug window.
Not catching erros was tested:

• Sending msg.action "close" - debug window shows error but there are no actual errors catched by "catch" node.
• Cutting off connection on the tcp server side - i've literally disabled the tcp server, tcp-client tried to reconnect but at the end threw an error but only in debug window (not an actual error I guess).