Cloudflare AI · Streaming Explorer

// Cloudflare Worker — SSE Streaming with OpenAI SDK
import OpenAI from "openai";

export interface Env {
  CLOUDFLARE_API_KEY: string;
  CLOUDFLARE_ACCOUNT_ID: string;
}

export default {
  async fetch(request: Request, env: Env): Promise<Response> {
    // Parse optional body for dynamic prompts
    let userMessage = "Write a short sci-fi greeting";
    let model = "@cf/meta/llama-3.1-8b-instruct";
    if (request.method === "POST") {
      const body = await request.json().catch(() => ({}));
      if (body.prompt) userMessage = body.prompt;
      if (body.model)  model = body.model;
    }

    const openai = new OpenAI({
      apiKey: env.CLOUDFLARE_API_KEY,
      baseURL: `https://api.cloudflare.com/client/v4/accounts/${env.CLOUDFLARE_ACCOUNT_ID}/ai/v1`,
    });

    const stream = await openai.chat.completions.create({
      model,
      messages: [{ role: "user", content: userMessage }],
      stream: true,
    });

    const encoder = new TextEncoder();

    const readable = new ReadableStream({
      async start(controller) {
        try {
          for await (const chunk of stream) {
            const token = chunk.choices?.[0]?.delta?.content ?? "";
            if (token) controller.enqueue(encoder.encode(token));
          }
          controller.close();
        } catch (err) {
          controller.error(err);
        }
      },
    });

    return new Response(readable, {
      headers: {
        "Content-Type": "text/plain; charset=utf-8",
        "Cache-Control": "no-cache",
        "Access-Control-Allow-Origin": "*", // ← add for browser access
      },
    });
  },
};