← Cloudflare Durable Objects / durable-objects / examples

Durable Object Time To Live

Mezi časté požadavky na funkce Durable Objects patří doba života (TTL) pro instance Durable Object. Durable Objects dávají vývojářům nástroje k implementaci vlastního TTL v pouhých několika řádcích kódu. Tento příklad ukazuje, jak TTL implementovat pomocí alarmy. Toto TTL se sice při každém novém požadavku na Durable Object prodlužuje, ale lze ho podle konkrétního případu použití přizpůsobit.

import { DurableObject } from "cloudflare:workers";

// Durable Object
export class MyDurableObject extends DurableObject {
  // Time To Live (TTL) in milliseconds
  timeToLiveMs = 1000;

  constructor(ctx, env) {
    super(ctx, env);
  }

  async fetch(_request) {
    // Extend the TTL immediately following every fetch request to a Durable Object.
    await this.ctx.storage.setAlarm(Date.now() + this.timeToLiveMs);
    ...
   }

  async alarm() {
    await this.ctx.storage.deleteAll();
  }
}

// Worker
export default {
  async fetch(request, env) {
    const stub = env.MY_DURABLE_OBJECT.getByName("foo");
    return await stub.fetch(request);
  },
};

import { DurableObject } from "cloudflare:workers";

export interface Env {
  MY_DURABLE_OBJECT: DurableObjectNamespace<MyDurableObject>;
}

// Durable Object
export class MyDurableObject extends DurableObject {
  // Time To Live (TTL) in milliseconds
  timeToLiveMs = 1000;

  constructor(ctx: DurableObjectState, env: Env) {
    super(ctx, env);
  }

  async fetch(_request: Request) {
    // Extend the TTL immediately following every fetch request to a Durable Object.
    await this.ctx.storage.setAlarm(Date.now() + this.timeToLiveMs);
    ...
   }

  async alarm() {
    await this.ctx.storage.deleteAll();
  }
}

// Worker
export default {
  async fetch(request, env) {
    const stub = env.MY_DURABLE_OBJECT.getByName("foo");
    return await stub.fetch(request);
  },
} satisfies ExportedHandler<Env>;

from workers import DurableObject, Response, WorkerEntrypoint
import time

# Durable Object
class MyDurableObject(DurableObject):
	# Time To Live (TTL) in milliseconds
	timeToLiveMs = 1000

	def __init__(self, ctx, env):
		super().__init__(ctx, env)

	async def fetch(self, _request):
		# Extend the TTL immediately following every fetch request to a Durable Object.
		await self.ctx.storage.setAlarm(int(time.time() * 1000) + self.timeToLiveMs)
		...

	async def alarm(self):
		await self.ctx.storage.deleteAll()

# Worker
class Default(WorkerEntrypoint):
	async def fetch(self, request):
		stub = self.env.MY_DURABLE_OBJECT.getByName("foo")
		return await stub.fetch(request)

Chcete-li tento příklad otestovat a nasadit, nastavte ve svém souboru Wrangler tak, aby obsahoval Durable Object binding a migrace na základě dříve zvoleného namespace a názvu třídy.

{
	"$schema": "./node_modules/wrangler/config-schema.json",
	"name": "durable-object-ttl",
	"main": "src/index.ts",
	"durable_objects": {
		"bindings": [
			{
				"name": "MY_DURABLE_OBJECT",
				"class_name": "MyDurableObject"
			}
		]
	},
	"migrations": [
		{
			"tag": "v1",
			"new_sqlite_classes": [
				"MyDurableObject"
			]
		}
	]
}

"$schema" = "./node_modules/wrangler/config-schema.json"
name = "durable-object-ttl"
main = "src/index.ts"

[[durable_objects.bindings]]
name = "MY_DURABLE_OBJECT"
class_name = "MyDurableObject"

[[migrations]]
tag = "v1"
new_sqlite_classes = [ "MyDurableObject" ]