# WebSocket Plugin Data Upload Walkthrough In this tutorial, we show how to upload data collected from south devices to a WebSocket server using the Neuron WebSocket plugin. ## Tutorial Setup We use two PCs connected to a local area network in this tutorial. - One is a Linux machine with Neuron installed - One is a Linux machine with a WebSocket server. Consult the [the installation instruction] on how to install Neuron. | | PC 1 | PC 2 | | ---------------- | ----------------- | ------------------- | | Operating System | Linux | Linux | | IP address | 192.168.1.152 | 192.168.1.107 | | Software | Neuron | Python 3.7 | | Network | Connected | Connected | For this demonstration, you'll need a WebSocket server that communicates using the WebSocket protocol. You have the flexibility to choose any server software that supports WebSocket. To keep things straightforward, we'll use a simple Python program in this tutorial. The Python server program requires Python version 3.7 or higher and relies on the [websockets package] for implementation. Run the following command to install the dependencies. ``` sh $ pip install websockets ``` ## Configure WebSocket Server Following is our python server program, it listens at TCP port *8000*. ``` python #!/usr/bin/env python import asyncio import websockets async def echo(websocket): async for message in websocket: print(message) async def main(): async with websockets.serve(echo, "0.0.0.0", 8000): await asyncio.Future() # run forever asyncio.run(main()) ``` Start the server program: ``` sh:no-line-numbers $ python websockets.py ``` ## Configure Neuron ### South devices We need some south devices to collect data from. Any Neuron southbound plugin will do for this tutorial, for example, the [Modbus TCP plugin]. In this tutorial, we will use the [File plugin] to create south devices collecting data from local files. This makes things simple since we don't need an actual device and we can fake tag data by just modifying file contents. #### Add the *file* Node In the Neuron dashboard, click **Configuration -> South Devices -> Add Device** to add a node using the File plugin.

Add file node in Neuron dashboard — _{Fig.1 - Add *file* node in Neuron dashboard}

Click the **Device configuration** icon to configure the *file* node.

_{Fig.2 - Neuron dashboard sourth devices tab}

Click **Submit** to keep the default settings.

Configure the file node in the Neuron dashboard — _{Fig.3 - Configure the *file* node in the Neuron dashboard}

#### Create a Group The *file* node should be in **Connected** state once configured. Click the *file* node to enter the **Group List** tab, then click **Create** to create a group.

Neuron dashboard sourth devices tab showing file node connected — _{Fig.4 - Neuron dashboard sourth devices tab showing *file* node connected}

We set the group name to *grp* and the interval to *1000*.

Add a group to the file node in Neuron dashboard — _{Fig.5 - Add a group to the *file* node in Neuron dashboard}

#### Add Tag Click the created *grp* group to enter the **Tag List** tab, then click **Create** to create a tag.

We name the tag *tag0* with type *STRING*. The tag address is set to *hello.txt* which represents the file in the working directory of the Neuron process.

Add a tag to the file node in Neuron dashboard — _{Fig.7 - Add a tag to the *file* node in Neuron dashboard}

### North app #### Add the *WebSocket* Node In the Neuron dashboard, click **Configuration -> North Apps -> Add Application** to add a node using the WebSocket plugin.

Add websocket node in Neuron dashboard — _{Fig.8 - Add *websocket* node in Neuron dashboard}

Click the **Application Configuration** icon to configure the *WebSocket* node.

_{Fig.9 - Neuron dashboard north apps tab}

We set the **host** parameter to *192.168.1.107* and **port** to *8000*, which is the address of our WebSocket server.

Configure websocket node in Neuron dashboard — _{Fig.10 - Configure *websocket* node in Neuron dashboard}

Once the configuration is submitted, the *WebSocket* node connects to the WebSocket server successfully.

websocket node connected state in Neuron dashboard — _{Fig.11 - Neuron dashboard north apps tab showing *websocket* node connected}

#### Subscribe to the *File* Node Click the *WebSocket* node to enter the **Subscription** tab. Then click **Add subscription**, select the *file* node and the *grp* group.

## Monitor Data After subscribing to the *grp* group of the *file* node, the *WebSocket* node will begin pushing data to the WebSocket server. In the Neuron dashboard, click **Monitoring -> Data monitoring**, then select the *file* node and the *grp* group. We see that Neuron reports an error code *1011* indicating the file *hello.txt* does not exist.

_{Fig.13 - Neuron dashboard data monitoring tab showing error}

We can check the server output that it receives the data correctly. And sure, the received data says that *tag0* encounters the error code *1011*.

_{Fig.14 - WebSocket server output showing error code 1011}

In the Neuron process working directory, create the *hello.txt* file with the content *world*. ``` sh:no-line-numbers $ echo world > hello.tx ``` Now we can see that Neuron updates *tag0* correctly in the **Data monitoring** tab.

And the WebSocket server receives the correct tag data, *world*, which is expected.

[websockets package]: https://websockets.readthedocs.io/en/stable/ [Modbus TCP plugin]: ../../south-devices/modbus-tcp/modbus-tcp.md [File plugin]: ../../south-devices/file/file.md [the installation instruction]: ../../../installation/installation.md