streaming-deepseek.ts

import { Hono } from 'hono'
import { streamText } from 'hono/streaming'

type Env = {
  Bindings: {
    AI: Ai
  }
}

const app = new Hono<Env>()

app.get('/', async (c) => {
  const message = c.req.query('message') ?? 'Say hello!'

  const messages = [
    { role: 'system', content: 'You are a friendly assistant' },
    {
      role: 'user',
      content: message
    }
  ]

  const result = (await c.env.AI.run('@cf/deepseek-ai/deepseek-r1-distill-qwen-32b', {
    messages,
    stream: true
  })) as ReadableStream

  return streamText(c, async (writer) => {
    await writer.write('🤔')
    let thinking = true
    for await (const chunk of result.pipeThrough(new TextDecoderStream()).values()) {
      for (const line of chunk.split('\n')) {
        const jsonString = line.replace('data: ', '')
        try {
          const jsonData = JSON.parse(jsonString)
          if (jsonData.response.trim() === '</think>') {
            thinking = false
            await writer.write('💡')
          } else {
            thinking ? await writer.write('.') : await writer.write(jsonData.response)
          }
        } catch {}
      }
    }
  })
})

export default app