Asynchronous Server Gateway Interface
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| Version | 3.0 |
|---|---|
| Developer | ASGI Team |
| Release date | 2019年03月04日[1] |
| Website | asgi |
| License | public domain [2] |
| Status | Draft |
The Asynchronous Server Gateway Interface (ASGI) is a calling convention for web servers to forward requests to asynchronous-capable Python frameworks, and applications. It is built as a successor to the Web Server Gateway Interface (WSGI).
Where WSGI provided a standard for synchronous Python applications, ASGI provides one for both asynchronous and synchronous applications, with a WSGI backwards-compatibility implementation and multiple servers and application frameworks.
Example
[edit ]An ASGI-compatible "Hello, World!" application written in Python:
async defapplication(scope, receive, send): event = await receive() ... await send({"type": "websocket.send", ...})
Where:
- Line 1 defines an asynchronous function named
application, which takes three parameters (unlike in WSGI which takes only two),scope,receiveandsend.scopeis adictcontaining details about current connection, like the protocol, headers, etc.receiveandsendare asynchronous callables which let the application receive and send messages from/to the client.
- Line 2 receives an incoming event, for example, HTTP request or WebSocket message. The
awaitkeyword is used because the operation is asynchronous. - Line 4 asynchronously sends a response back to the client. In this case, it is a WebSocket communication.
Web Server Gateway Interface (WSGI) compatibility
[edit ]ASGI is also designed to be a superset of WSGI, and there's a defined way of translating between the two, allowing WSGI applications to be run inside ASGI servers through a translation wrapper (provided in the asgiref library). A threadpool can be used to run the synchronous WSGI applications away from the async event loop.
See also
[edit ]- Comparison of web frameworks
- FastCGI
- Python (programming language)
- Web Server Gateway Interface (WSGI)
References
[edit ]- ^ "Version History".
- ^ "Copyright". GitHub . Retrieved 2022年09月14日.
