Ethereum: Viem’s PublicClient#Watch contract event with wss Transport: Socket closed
As developers, we all want to ensure that our ethereum-based applications are running smoothly and securely. Recently, I Encountered an Issue with the PublicClient#Watch contractevent method in My Application, which LED me to investigate further.
The Problem Lies in the way we set up the websocket (wss) transport when creating a new publicclient instance. Specifically, When Using Websockets, If the Client is not created or used for an extended period of time Between app startups, it can lead to socket closure issues.
The issue
Here’s what happened:
- I created two instances of
public clientwith the same options (E.G., Same Wallet Address and Network).
- I then connected one instance to a web socket endpoint use wss transport.
- Later on, when my app Became Inactive for Several Hours or Even Days, Neinder Client was Able to Establish A Connection to the Websocket Server.
The Solution
To Resolve This Issue, You Need to Ensure That Both PublicClient Instances are created with the same options and Used SimultaneUously Before Entering an Extended Period of Inactivity. Here’s how you can modify your code to achieve this:
- Create Both
PublicClientinstances Using the Same Options:
`Javascript
Const PublicClient1 = New Publicclient ({
… Options1,
// Same Wallet Address As Options1
});
Const PublicClient2 = New PublicClient ({
… Options2,
// Same Wallet Address As Options2
});
`
- Use Both Clients SimultaneUously Before Entering an Extended Period of Inactivity:
`Javascript
set interval (() => {
publicclient1.connect ();
publicclient2.connect ();
// Continue with your app’s logic here …
}, 10000); // Connect Every 10 Seconds For A Short Duration
// When you’re ready to disconnect, call disconnect on one or both Both clients.
Setimeout (() => {
publicclient1.disconnect ();
publicclient2.disconnect ();
}, 60000); // Disconnect after 60 Seconds
`
Additional recommendations
To Further Optimize Your Application’s Performance and Reduce Socket Closure Issues:
- Consider Using A More Robust Websocket Library That Provides Better Error Handling and Connection Management, Such as
Wsor ‘Websocket client’.
- Implement a more advanced polling mechanism to detect when the client is no longer connected. You can use libraries like
Connect-Socket pollerto create a custom poller.
- Regularly Clean Up Stale Connections by Periodicalally Disconnecting Disconnected Clients.
By following these Recommendations, You Should Be Able to Resolve the Issue with the `Publicclient#Watch Contracton ‘Method and Ensure That Your Ethereum-Based Applications Run Smoothly and Securely.