Miscellaneous

Why do I get the error: module 'websockets' has no attribute '...'?

Often, this is because you created a script called websockets.py in your current working directory. Then import websockets imports this module instead of the websockets library.

Why is websockets slower than another library in my benchmark?

Not all libraries are as feature-complete as websockets. For a fair benchmark, you should disable features that the other library doesn’t provide. Typically, you must disable:

• Compression: set compression=None

• Keepalive: set ping_interval=None

• UTF-8 decoding: send bytes rather than str

Then, please consider whether websockets is the bottleneck of the performance of your application. Usually, in real-world applications, CPU time spent in websockets is negligible compared to time spent in the application logic.

Are there onopen, onmessage, onerror, and onclose callbacks?

No, there aren’t.

websockets provides high-level, coroutine-based APIs. Compared to callbacks, coroutines make it easier to manage control flow in concurrent code.

If you prefer callback-based APIs, you should use another library.