85 lines
2.1 KiB
Markdown
85 lines
2.1 KiB
Markdown
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# Custom extensions
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It is possible to create your own custom extensions.
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Version 22.9 added the `Extend.register` [method](#extension-preregistration). This makes it extremely easy to add custom expensions to an application.
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## Anatomy of an extension
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All extensions must subclass `Extension`.
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### Required
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- `name`: By convention, the name is an all-lowercase string
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- `startup`: A method that runs when the extension is added
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### Optional
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- `label`: A method that returns additional information about the extension in the MOTD
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- `included`: A method that returns a boolean whether the extension should be enabled or not (could be used for example to check config state)
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### Example
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```python
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from sanic import Request, Sanic, json
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from sanic_ext import Extend, Extension
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app = Sanic(__name__)
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app.config.MONITOR = True
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class AutoMonitor(Extension):
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name = "automonitor"
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def startup(self, bootstrap) -> None:
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if self.included():
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self.app.before_server_start(self.ensure_monitor_set)
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self.app.on_request(self.monitor)
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@staticmethod
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async def monitor(request: Request):
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if request.route and request.route.ctx.monitor:
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print("....")
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@staticmethod
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async def ensure_monitor_set(app: Sanic):
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for route in app.router.routes:
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if not hasattr(route.ctx, "monitor"):
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route.ctx.monitor = False
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def label(self):
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has_monitor = [
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route
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for route in self.app.router.routes
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if getattr(route.ctx, "monitor", None)
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]
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return f"{len(has_monitor)} endpoint(s)"
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def included(self):
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return self.app.config.MONITOR
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Extend.register(AutoMonitor)
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@app.get("/", ctx_monitor=True)
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async def handler(request: Request):
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return json({"foo": "bar"})
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```
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## Extension preregistration
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.. column::
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`Extend.register` simplifies the addition of custom extensions.
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.. column::
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```python
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from sanic_ext import Extend, Extension
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class MyCustomExtension(Extension):
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...
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Extend.register(MyCustomExtension())
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```
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*Added in v22.9*
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