enable ai binding in next-dev module

internal-packages/next-dev/src/ai.ts

@@ -0,0 +1,44 @@
+import { Response } from 'miniflare';
+import type { Request } from 'miniflare';
+
+import { cloneHeaders } from "./wrangler";
+
+type Fetcher = (req: Request) => Promise<Response>;
+
+export function getAIFetcher({ accountId, apiToken }: {accountId: string, apiToken: string}): Fetcher {
+    // Tweaked version of the wrangler ai fetcher
+    // (source: https://github.com/cloudflare/workers-sdk/blob/912bfe/packages/wrangler/src/ai/fetcher.ts)
+    return async function AIFetcher(request: Request) {
+        request.headers.delete("Host");
+        request.headers.delete("Content-Length");
+
+        const res = await performApiFetch(`/accounts/${accountId}/ai/run/proxy`, {
+            method: "POST",
+            headers: Object.fromEntries(request.headers.entries()),
+            body: request.body as BodyInit,
+            // eslint-disable-next-line @typescript-eslint/ban-ts-comment
+            // @ts-ignore
+            duplex: "half",
+        }, apiToken);
+
+        return new Response(res.body, { status: res.status });
+    };
+}
+
+// (Heavily) Simplified version of performApiFetch from wrangler
+// (source: https://github.com/cloudflare/workers-sdk/blob/912bfe/packages/wrangler/src/cfetch/internal.ts#L18)
+export async function performApiFetch(
+	resource: string,
+	init: RequestInit = {},
+    apiToken: string,
+) {
+	const method = init.method ?? "GET";
+	const headers = cloneHeaders(init.headers);
+	headers["Authorization"] = `Bearer ${apiToken}`;
+
+	return fetch(`https://api.cloudflare.com/client/v4${resource}`, {
+		method,
+		...init,
+		headers,
+	});
+}

internal-packages/next-dev/src/index.ts

@@ -2,6 +2,7 @@ import type { WorkerOptions } from 'miniflare';
 import { Miniflare, Request, Response, Headers } from 'miniflare';
 import { getDOBindingInfo } from './durableObjects';
 import { getServiceBindings } from './services';
+import { getAIFetcher } from './ai';
 
 /**
  * Sets up the bindings that need to be available during development time (using
@@ -54,6 +55,11 @@ export type DevBindingsOptions = {
 			className: string;
 		}
 	>;
+	ai?: {
+		bindingName: string;
+		accountId: string;
+		apiToken: string;
+	};
 	/**
 	 * Record mapping binding names to R2 bucket names to inject as R2Bucket.
 	 * If a `string[]` of binding names is specified, the binding name and bucket name are assumed to be the same.
@@ -84,6 +90,10 @@ async function instantiateMiniflare(
 	const { workerOptions, durableObjects } =
 		(await getDOBindingInfo(options.durableObjects)) ?? {};
 
+	const aiBindingObj = options.ai ? {
+		[options.ai.bindingName]: getAIFetcher(options.ai),
+	} : {};
+
 	const { kvNamespaces, r2Buckets, d1Databases, services, textBindings } =
 		options;
 	const bindings = {
@@ -102,7 +112,10 @@ async function instantiateMiniflare(
 			...bindings,
 			modules: true,
 			script: '',
-			serviceBindings,
+			serviceBindings: {
+				...serviceBindings,
+				...aiBindingObj
+			},
 		},
 		...(workerOptions ? [workerOptions] : []),
 	];

internal-packages/next-dev/src/wrangler.ts

@@ -97,3 +97,14 @@ const IDENTIFIER_UNSAFE_REGEXP = /[^a-zA-Z0-9_$]/g;
 export function getIdentifier(name: string) {
 	return name.replace(IDENTIFIER_UNSAFE_REGEXP, '_');
 }
+
+// https://github.com/cloudflare/workers-sdk/blob/912bfe/packages/wrangler/src/cfetch/internal.ts#L119
+export function cloneHeaders(
+	headers: HeadersInit | undefined
+): Record<string, string> {
+	return headers instanceof Headers
+		? Object.fromEntries(headers.entries())
+		: Array.isArray(headers)
+		? Object.fromEntries(headers)
+		: { ...headers };
+}