SignalR Echo Server

SignalR dynamic echo server for testing SignalR WebSocket functionality.

This server is made to be a test tool for testing SignalR socket functionalities in responsive clients.

Usage

Download and run the docker image to host your own SignalR echo server

docker pull ghcr.io/equinor/signalr-echo-server

docker run --rm -p 5000:5000 ghcr.io/equinor/signalr-echo-server

This will host a webserver on port 5000

The backend SignalR server can host the WebSocket URL on any endpoint, but defaults to /echo.

Test SignalR Reactive Clients

By connecting your SignalR application to the WebSocket endpoint (default /echo), you can test functionality by sending custom topics and payloads to the echo server, either by using the hosted web client, or by using Postman, or any other HTTP Tool.

This will then be published on SignalR with the desired data.

NB

Dynamic input body functionality (bring your own JSON), in combination with limitations in controlling the SignalR Serializer, means the payload of the WebSocket message is returned as a string.

If your client code treats the SignalR payload as a json document directly, the payload must be parsed to support testing:

JSON.parse(payload)

Adding this step will increase the input validation of your client, and should not affect your production functionality.

Using A Custom WebSocket Endpoint

To set something else that fits your client under test, set the environment variable ECHO_WS_ENDPOINT to the desired endpoint path for your WebSocket.

Example for setting a different ws endpoint:

docker run --rm -p 5000:5000 -e "ECHO_WS_ENDPOINT=/my-web-socket-endpoint" \
ghcr.io/equinor/signalr-echo-server

NB

Changing the default endpoint means that the Web UI hosted will not work.

Test UI

Open your web browser on http://localhost:5000. This will show a test page for sending and receiving SignalR messages over WebSocket.

Add Topics

Topics can be subscribed to in the client by using the Add button. This will append the topic to the Active subscriptions list. To remove an active subscription, just click on the item.

Send Payloads

When sending a Topic and a Payload from the client, that topic gets automatically added to the list of Active subscriptions, if it is not already part of the list. The resulting SignalR message should return and display in the client.

Receive Messages

All messages posted on topics that the client currently subscribes to, will be displayed in the Payload from WebSocket section on the client. The received message Topic will also show above the payload.

You can now subscribe to different topics in the client, post messages to the /api/echo endpoint, and see these messages show up in the web client when received on the SignalR subscription.

NB

When running the backend on a different endpoint the web console will not receive or display these messages.

HTTP Endpoint testing

It is possible to use Postman, or any other HTTP tool to append data for the SignalR server to send out.

The echo server understands the following POST Body

{
  "topic": "TopicToUseOnPayload",
  "payload": "AnyJsonStructureDynamically"
}

If the topic and payload is received and parsed successfully, it will send a SignalR ws message on the configured endpoint, with the topic field as a topic, and the payload field as the body.

Below is an example of a HTTP Request syntax.

POST http://localhost:5000/api/echo HTTP/1.1
content-type: application/json

{
    "topic": "ReceiveMessage",
    "payload": {
        "ArrayOfThings": [
            {
                "MyThingToTest": {
                    "id": "e46159b3-3304-4a4a-b161-cf3c9a82ec2a",
                    "version": 1,
                    "from": "2022-10-03T00:00:00+00:00",
                    "to": "2022-10-04T00:00:00+00:00",
                    "lastUpdated": "2022-10-03T07:48:24.335+00:00"
                },
                "someNumber": 84708
            }
        ],
        "SomeOtherArrayOfThins": []
    }
}

Example - Testing with the hosted web client

1. Start the echo server with default values:

docker run --rm -p 5000:5000 ghcr.io/equinor/signalr-echo-server

2. Navigate to http://localhost:5000 in you web browser
3. (Optional) Open the developer tools, and look in the WS part of the network tab.
4. (Optional) Reconnect if needed.
5. Paste the following payload in the Payload box, and press Send:

{
    "ArrayOfThings": [
        {
            "MyThingToTest": {
                "id": "e46159b3-3304-4a4a-b161-cf3c9a82ec2a",
                "version": 1,
                "from": "2022-10-03T00:00:00+00:00",
                "to": "2022-10-04T00:00:00+00:00",
                "lastUpdated": "2022-10-03T07:48:24.335+00:00"
            },
            "someNumber": 84708
        }
    ],
    "SomeOtherArrayOfThins": []
}

6. The resulting WebSocket JSON object payload received should now be displayed in the web client

Example - Testing with Postman

1. Start the echo server with default values:

docker run --rm -p 5000:5000 ghcr.io/equinor/signalr-echo-server

2. Navigate to http://localhost:5000 in you web browser

3. Add topics in the web client using the Add button. This example uses the YourExpectedTopic topic

4. Start postman and POST a request to http://localhost:5000/api/echo with the body you want to receive in the client.

   Example Body:

{
    "topic": "YourExpectedTopic",
    "payload": {"ExampleItems":  [
      {"Item":  {
         "Name": "Some Name"
      }},
      {"Item":  {
         "Name": "Some Other Name"
      }}
    ]}
}

4. Send the request and see the resulting SignalR message show up in the web client
5. The Postman Response will also contain the parsed payload for debugging