Web Socket step
Last updated
Last updated
The WebSocket step enables real-time, bidirectional communication testing by allowing you to connect to WebSocket endpoints, send messages, and validate responses. This step is particularly useful for testing applications that require persistent connections and real-time data exchange.
A WebSocket step can perform three main operations:
Connect - Establishes a WebSocket connection to the specified endpoint
Send - Transmits messages through an established WebSocket connection
Receive - Listens for and validates incoming WebSocket messages
When establishing a connection:
The URL format follows: wss://<your-websocket-endpoint>
Headers can be added to the WebSocket handshake request for authentication or custom protocols
A timeout value (in seconds) can be set for the connection attempt
For sending messages:
Supports two data types:
Text (JSON, plain text)
Binary data
Messages can include dynamic parameters
Headers can be included with the message
Used for both sending data and subscribing to channels
A timeout can be specified for the send operation
Note: A Send step without a preceding Connect step will automatically create a new WebSocket connection.
When receiving messages:
Messages are fetched based on the WebSocket URL
Use URL query parameters (e.g., wss://example.com/ws?userId=1) to send and filter messages by specific properties
Message retrieval options:
Last - Returns the most recent single message
Last 10 - Returns an array of the last 10 messages
Last 50 - Returns an array of the last 50 messages
Extractions support all standard Loadmill extraction methods
Example JSONPath for array filtering: $[?(@.id == "${my_id}")]
Wait for extractions to be resolved - Since WebSocket connections are asynchronous, this setting defines how long to wait for messages that match your extraction criteria. Default is 5 seconds, but you may need to adjust this based on your application's behavior.
The Flow Control section allows to repeat the request until the parameter's value meets the requirement or number of iteration reached.
Let's look at a simple WebSocket test flow in action:
This example demonstrates a complete WebSocket interaction:
Establishes connection to a WebSocket server
Sends a message on the connection
Waits for all extractions to be resolved
Once resolved, validates that the extracted ${message} exists
Received messages are displayed for easy debugging
Assertions - Use the same powerful assertion capabilities as HTTP requests to validate your WebSocket messages, including JSON/XML validation, value comparisons, and regex matching.
