Everything You Need to Know About WebSocket On Close

WebSocket is a protocol that enables two-way communication between a server and a client over a single, long-lived connection. It provides a low-latency, high-performance channel for data exchange, making it the preferred choice for real-time web applications. However, WebSocket connections can be interrupted for various reasons, such as network errors, server crashes, or user logout. When this happens, the WebSocket on close event is triggered, indicating that the connection has been closed. In this article, we’ll explore the WebSocket on close event in detail, covering its definition, causes, handling, and best practices.

What Is WebSocket On Close?

WebSocket on close is an event that occurs when a WebSocket connection is terminated. It can happen either intentionally or unexpectedly. When a WebSocket connection is closed, both the server and the client are notified of the closure, and any data that was being transmitted at the time is lost. WebSocket on close is a crucial event in WebSocket programming, as it enables developers to handle connection errors and recover gracefully from them.

What Causes WebSocket On Close?

There are several reasons why a WebSocket connection may be closed, including:

• User logout: When a user logs out of an application, their WebSocket connection is terminated to prevent unauthorized access.
• Server crash: If the server hosting the WebSocket application crashes, all active WebSocket connections are closed.
• Network error: If there is a network error, such as a dropped connection or a timeout, the WebSocket connection may be closed.
• Idle timeout: Some WebSocket servers have an idle timeout setting that automatically closes connections that have been inactive for a specified period.
• Manual close: A WebSocket connection can also be closed manually by either the server or the client.

How to Handle WebSocket On Close?

Handling WebSocket on close is essential to ensure the smooth operation of WebSocket applications. When a WebSocket connection is closed, the server and the client need to take appropriate actions to close any associated resources and clean up any pending tasks. Here are some best practices for handling WebSocket on close:

1. Capture the onclose event: The first step in handling WebSocket on close is to capture the onclose event. This event is fired when the WebSocket connection is closed, and it provides information about the reason for the closure.
2. Close all resources: When the onclose event is triggered, the server and the client should close all associated resources, such as file handles, database connections, and memory allocations. This ensures that no resources are left open and vulnerable to attacks.
3. Notify users: If the WebSocket connection is closed due to an error, the server should notify the user of the reason for the closure. This can be done through a pop-up message or an error page.
4. Reconnect: If the WebSocket connection is closed due to a network error or an idle timeout, the client should try to reconnect to the server. This can be done by creating a new WebSocket object and reconnecting to the same URL.
5. Graceful degradation: If the WebSocket connection cannot be established or is closed, the application should gracefully degrade to a non-real-time mode. This ensures that the application remains functional even if the WebSocket connection is not available.

WebSocket On Close Error Codes

When a WebSocket connection is closed, an error code is usually provided to indicate the reason for the closure. These error codes can be used to diagnose and troubleshoot WebSocket connection issues. Here are some of the most common WebSocket on close error codes:

• 1000: Normal closure.
• 1001: Endpoint is going away.
• 1002: Protocol error.
• 1003: Unsupported data type.
• 1005: No status code was provided.
• 1006: Abnormal closure.
• 1007: Invalid frame payload data.
• 1008: Policy violation.
• 1010: Mandatory extension missing.
• 1011: Internal server error.
• 1012: Service restart.
• 1013: Try again later.
• 1015: TLS handshake failed.

WebSocket On Close Best Practices

WebSocket on close is a critical event in WebSocket programming, and it is crucial to handle it correctly to ensure the smooth operation of WebSocket applications. Here are some best practices for handling WebSocket on close:

• Always capture the onclose event: This event provides valuable information about the reason for the closure, and it is essential to capture it to handle WebSocket on close correctly.
• Close all resources: When the WebSocket connection is closed, all associated resources should be closed to prevent security vulnerabilities.
• Notify users: If the WebSocket connection is closed due to an error, users should be notified of the reason for the closure to prevent confusion.
• Reconnect: If the WebSocket connection is closed due to a network error or an idle timeout, the client should try to reconnect to the server to ensure uninterrupted communication.
• Graceful degradation: WebSocket applications should be designed to gracefully degrade to a non-real-time mode if the WebSocket connection is not available.

FAQ

What is WebSocket?

WebSocket is a protocol that enables two-way communication between a server and a client over a single, long-lived connection. It provides a low-latency, high-performance channel for data exchange, making it the preferred choice for real-time web applications.

What is WebSocket On Close?

WebSocket on close is an event that occurs when a WebSocket connection is terminated. It can happen either intentionally or unexpectedly. When a WebSocket connection is closed, both the server and the client are notified of the closure.

What Causes WebSocket On Close?

WebSocket connections can be closed for various reasons, such as network errors, server crashes, or user logout. When this happens, the WebSocket on close event is triggered, indicating that the connection has been closed.

How to Handle WebSocket On Close?

Handling WebSocket on close involves capturing the onclose event, closing all associated resources, notifying users of the reason for the closure, reconnecting if possible, and gracefully degrading the application if necessary.

What Are WebSocket On Close Error Codes?

WebSocket on close error codes are provided to indicate the reason for the closure. Some of the most common WebSocket on close error codes include normal closure, protocol error, unsupported data type, and internal server error.

What Are WebSocket On Close Best Practices?

WebSocket on close best practices include capturing the onclose event, closing all associated resources, notifying users of the reason for the closure, reconnecting if possible, and gracefully degrading the application if necessary.