datasette-configure-asgi by simonw

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README source code


PyPI CircleCI License

Datasette plugin for configuring arbitrary ASGI middleware


pip install datasette-configure-asgi


This plugin only takes effect if your metadata.json file contains relevant top-level plugin configuration in a "datasette-configure-asgi" configuration key.

For example, to wrap your Datasette instance in the asgi-log-to-sqlite middleware configured to write logs to /tmp/log.db you would use the following:

    "plugins": {
        "datasette-configure-asgi": [
                "class": "asgi_log_to_sqlite.AsgiLogToSqlite",
                "args": {
                    "file": "/tmp/log.db"

The "datasette-configure-asgi" key should be a list of JSON objects. Each object should have a "class" key indicating the class to be used, and an optional "args" key providing any necessary arguments to be passed to that class constructor.

Plugin structure

This plugin can be used to wrap your Datasette instance in any ASGI middleware that conforms to the following structure:

class SomeAsgiMiddleware:
    def __init__(self, app, arg1, arg2): = app
        self.arg1 = arg1
        self.arg2 = arg2

    async def __call__(self, scope, receive, send):
        start = time.time()
        await, receive, send)
        end = time.time()
        print("Time taken: {}".format(end - start))

So the middleware is a class with a constructor which takes the wrapped application as a first argument, app, followed by further named arguments to configure the middleware. It provides an async def __call__(self, scope, receive, send) method to implement the middleware's behavior.