Removing duplicate demo, using GitHubCode.

Author: Oxyjun

src/content/docs/d1/best-practices/read-replication.mdx

@@ -18,138 +18,14 @@ Deploy the following Worker code using Sessions API, which will prompt you to cr
 
    [![Deploy to Cloudflare](https://deploy.workers.cloudflare.com/button)](https://deploy.workers.cloudflare.com/?url=https://github.com/cloudflare/templates/tree/staging/d1-starter-sessions-api)
 
-```ts collapse={1-6, 34-130}
-import { D1Database, D1DatabaseSession } from "@cloudflare/workers-types";
-
-export type Env = {
-	DB01: D1Database;
-};
-
-export default {
-	async fetch(request, env, ctx): Promise<Response> {
-		const url = new URL(request.url);
-
-		// A. Create the session.
-		// When we create a D1 session, we can continue where we left off from a previous
-		// session if we have that session's last bookmark or use a constraint.
-		const bookmark = request.headers.get('x-d1-bookmark') ?? 'first-unconstrained';
-		const session = env.DB01.withSession(bookmark);
-
-		try {
-			// Use this session for all our Workers' routes.
-			const response = await withTablesInitialized(session, async () => await handleRequest(request, session));
-
-			// B. Return the bookmark so we can continue the session in another request.
-			response.headers.set('x-d1-bookmark', session.getBookmark() ?? "");
-
-			return response;
-
-		} catch (e) {
-			console.error({ message: "Failed to handle request", error: String(e), errorProps: e, url, bookmark });
-			return Response.json(
-				{ error: String(e), errorDetails: e },
-				{ status: 500 }
-			);
-		}
-	},
-} satisfies ExportedHandler<Env>;
-
-type Order = {
-	orderId: string,
-	customerId: string,
-	quantity: number,
-}
-
-async function handleRequest(request: Request, session: D1DatabaseSession) {
-	const { pathname } = new URL(request.url);
-
-	const tsStart = Date.now();
-
-	if (request.method === "GET" && pathname === '/api/orders') {
-		// C. session read query.
-		const resp = await session.prepare('SELECT * FROM Orders').all();
-		return Response.json(buildResponse(session, resp, tsStart));
-
-	} else if (request.method === "POST" && pathname === '/api/orders') {
-		const order = await request.json<Order>();
-
-		// D. session write query.
-		// Since this is a write query, D1 will transparently forward the query.
-		await session
-			.prepare('INSERT INTO Orders VALUES (?, ?, ?)')
-			.bind(order.customerId, order.orderId, order.quantity)
-			.run();
-
-		// E. session read-after-write query.
-		// In order for the application to be correct, this SELECT
-		// statement must see the results of the INSERT statement above.
-		const resp = await session
-			.prepare('SELECT * FROM Orders')
-			.all();
-
-		return Response.json(buildResponse(session, resp, tsStart));
-
-	} else if (request.method === "POST" && pathname === '/api/reset') {
-		const resp = await resetTables(session);
-
-		return Response.json(buildResponse(session, resp, tsStart));
-	}
-
-	return new Response('Not found', { status: 404 })
-}
-
-function buildResponse(session: D1DatabaseSession, res: D1Result, tsStart: number) {
-	return {
-		d1Latency: Date.now() - tsStart,
-
-		results: res.results,
-		servedByRegion: res.meta.served_by_region ?? "",
-		servedByPrimary: res.meta.served_by_primary ?? "",
-
-		// Add the session bookmark inside the response body too.
-		sessionBookmark: session.getBookmark(),
-	};
-}
-
-/**
- * This is mostly for DEMO purposes to avoid having to do separate schema migrations step.
- * This will check if the error is because our main table is missing, and if it is create the table
- * and rerun the handler.
- */
-async function withTablesInitialized(session: D1DatabaseSession, handler: () => Promise<Response>) {
-	try {
-		return await handler();
-	} catch (e) {
-		if (String(e).includes("no such table: Orders: SQLITE_ERROR")) {
-			await initTables(session);
-			return await handler();
-		}
-		throw e;
-	}
-}
-
-async function initTables(session: D1DatabaseSession) {
-	return await session
-		.prepare(`CREATE TABLE IF NOT EXISTS Orders(
-			customerId TEXT NOT NULL,
-			orderId TEXT NOT NULL,
-			quantity INTEGER NOT NULL,
-			PRIMARY KEY (customerId, orderId)
-		)`)
-		.all();
-}
-
-async function resetTables(session: D1DatabaseSession) {
-	return await session
-		.prepare(`DROP TABLE IF EXISTS Orders; CREATE TABLE IF NOT EXISTS Orders(
-			customerId TEXT NOT NULL,
-			orderId TEXT NOT NULL,
-			quantity INTEGER NOT NULL,
-			PRIMARY KEY (customerId, orderId)
-		)`)
-		.all();
-}
-```
+<GitHubCode
+repo="cloudflare/templates"
+file="d1-starter-sessions-api/src/index.ts"
+commit="3912e863acedd2be2438f8758f21374ed426fc54"
+lang="ts"
+useTypeScriptExample={true}
+lines="7-44"
+/>
 
 ## Primary database instance vs read replicas
 
@@ -587,5 +463,4 @@ You may wish to refer to the following resources:
 - Blog: [Building D1: a Global Database](https://blog.cloudflare.com/building-d1-a-global-database/)
 - [D1 Sessions API documentation](/d1/worker-api/d1-database#withsession)
 - [Starter code for D1 Sessions API demo](https://github.com/cloudflare/templates/tree/staging/d1-starter-sessions-api)
-- [E-commerce store read replication demo](https://github.com/harshil1712/e-com-d1)
 - [E-commerce store read replication tutorial](/d1/tutorials/using-read-replication-for-e-com)