fn project 扩展
- Listeners - listen to API events such as a route getting updated and react accordingly.
- Middleware - a chain of middleware is executed before an API handler is called.
- Add API Endpoints - extend the default Fn API.
Listeners
Listeners are the main way to extend Fn.
The following listener types are supported:
-
- App Listeners - GoDoc
- Runner Listeners - GoDoc
Creating a Listener
You can easily use app and runner listeners by creating a struct with valid methods satisfying the interface for the respective listener and adding it to the Fn API
Example:
package main
import (
"context"
"/fnproject/functions/api/server"
"/fnproject/functions/api/models"
)
type myCustomListener struct{}
func (c *myCustomListener) BeforeAppCreate(ctx context.Context, app *models.App) error { return nil }
func (c *myCustomListener) AfterAppCreate(ctx context.Context, app *models.App) error { return nil }
func (c *myCustomListener) BeforeAppUpdate(ctx context.Context, app *models.App) error { return nil }
func (c *myCustomListener) AfterAppUpdate(ctx context.Context, app *models.App) error { return nil }
func (c *myCustomListener) BeforeAppDelete(ctx context.Context, app *models.App) error { return nil }
func (c *myCustomListener) BeforeAppDelete(ctx context.Context, app *models.App) error { return nil }
function main () {
srv := server.New(/* Here all required parameters to initialize the server */)
srv.AddAppListener(myCustomListener)
srv.Run()
}
Middleware
Middleware enables you to add functionality to every API request. For every request, the chain of Middleware will be called in order, allowing you to modify or reject requests, as well as write output and cancel the chain.
NOTES:
-
-
- middleware is responsible for writing output if it's going to cancel the chain.
- cancel the chain by returning an error from your Middleware's Serve method.
-
See examples of this in examples/middleware/main.go.
Adding API Endpoints
You can add API endpoints to the Fn server by using the AddEndpoint
and AddEndpointFunc
methods.
See examples of this in examples/extensions/main.go.