import { Hono } from "npm:hono"; import { cors } from 'npm:hono/cors'; import { stream } from "https://deno.land/x/hono@v4.3.11/helper.ts"; import { OpenAI } from "npm:openai"; const app = new Hono(); const openai = new OpenAI(); app.use('*', cors({ origin: '*', allowMethods: ['GET'], allowHeaders: ['Content-Type'], })) // Set CORS and headers for SSE app.use('/chat, /chat/*', async (c, next) => { c.header('Content-Type', 'text/event-stream'); c.header('Cache-Control', 'no-cache'); c.header('Connection', 'keep-alive'); await next(); }); const SOURCE_URL = ""; // leave blank for deno deploy / native // const SOURCE_URL = "https://yawnxyz-openAIHonoChatStreamSample.web.val.run"; // valtown as generator - no SSE // const SOURCE_URL = "https://funny-crow-81.deno.dev"; // deno deploy as generator const htmlContent = ` OpenAI Streaming Example

OpenAI Streaming Example

Prompt:

`; const htmlContent2 = ` Hono Streaming Example

Hono Streaming Example

`; app.get('/chat/test', (c) => { c.header('Content-Type', 'text/event-stream'); c.header('Cache-Control', 'no-cache'); c.header('Connection', 'keep-alive'); return stream(c, async (stream) => { await stream.write('data: Hello\n\n'); await stream.sleep(1000); await stream.write('data: Hono!\n\n'); await stream.write('data: [DONE]\n\n'); }); }); app.get('/chat', (c) => { const prompt = c.req.query('p') || "Tell me a joke"; c.header('Content-Type', 'text/event-stream'); // Set Content-Type header return stream(c, async (stream) => { try { const chatStream = await openai.chat.completions.create({ model: "gpt-4", messages: [{ role: "user", content: prompt }], stream: true, }); for await (const chunk of chatStream) { if (chunk.choices[0]?.delta?.content) { console.log('>>', chunk.choices[0].delta.content); stream.write(`data: ${JSON.stringify({ token: chunk.choices[0].delta.content })}\n\n`); } } stream.write(`data: [DONE]\n\n`); // Send a completion event } catch (error) { stream.write(`data: ${JSON.stringify({ error: error.message })}\n\n`); } }); }); app.get('/', (c) => c.html(htmlContent)); app.get('/test', (c) => c.html(htmlContent2)); export default app.fetch; // val.town // Deno.serve(app.fetch); // deno.deploy

openAIHonoChatStreamExample