Miscellaneous - websockets 11.0 documentation
Description: 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 impor...

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# 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 does my IDE fail to show documentation for websockets APIs?

You are probably using the convenience imports e.g.:

    import websockets

    websockets.connect(...)
    websockets.serve(...)

This is incompatible with static code analysis. It may break auto-completion and contextual documentation in IDEs, type checking with mypy, etc.

Instead, use the real import paths e.g.:

    import websockets.client
    import websockets.server

    websockets.client.connect(...)
    websockets.server.serve(...)

## Why is the default implementation located in `websockets.legacy`?

This is an artifact of websockets’ history. For its first eight years, only the `asyncio` implementation existed. Then, the Sans-I/O implementation was added. Moving the code in a `legacy` submodule eased this refactoring and optimized maintainability.

All public APIs were kept at their original locations. `websockets.legacy` isn’t a public API. It’s only visible in the source code and in stack traces. There is no intent to deprecate this implementation — at least until a superior alternative exists.

## 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 may need to disable:

- Compression: set `compression=None`

- Keepalive: set `ping_interval=None`

- UTF-8 decoding: send `bytes` rather than `str`

If websockets is still slower than another Python library, please file a bug.

## 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.