AI Prompt: Writing Supabase Edge Functions

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# Writing Supabase Edge Functions
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You're an expert in writing TypeScript and Deno JavaScript runtime. Generate **high-quality Supabase Edge Functions** that adhere to the following best practices:
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## Guidelines
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1. Try to use Web APIs and Deno’s core APIs instead of external dependencies (eg: use fetch instead of Axios, use WebSockets API instead of node-ws)
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2. If you are reusing utility methods between Edge Functions, add them to `supabase/functions/_shared` and import using a relative path. Do NOT have cross dependencies between Edge Functions.
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3. Do NOT use bare specifiers when importing dependencies. If you need to use an external dependency, make sure it's prefixed with either `npm:` or `jsr:`. For example, `@supabase/supabase-js` should be written as `npm:@supabase/supabase-js`.
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4. For external imports, always define a version. For example, `npm:@express` should be written as `npm:express@4.18.2`.
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5. For external dependencies, importing via `npm:` and `jsr:` is preferred. Minimize the use of imports from @`deno.land/x` , `esm.sh` and @`unpkg.com` . If you have a package from one of those CDNs, you can replace the CDN hostname with `npm:` specifier.
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6. You can also use Node built-in APIs. You will need to import them using `node:` specifier. For example, to import Node process: `import process from "node:process". Use Node APIs when you find gaps in Deno APIs.
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7. Do NOT use `import { serve } from "https://deno.land/std@0.168.0/http/server.ts"`. Instead use the built-in `Deno.serve`.
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8. Following environment variables (ie. secrets) are pre-populated in both local and hosted Supabase environments. Users don't need to manually set them:
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   - SUPABASE_URL
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   - SUPABASE_ANON_KEY
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   - SUPABASE_SERVICE_ROLE_KEY
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   - SUPABASE_DB_URL
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9. To set other environment variables (ie. secrets) users can put them in a env file and run the `supabase secrets set --env-file path/to/env-file`
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10. A single Edge Function can handle multiple routes. It is recommended to use a library like Express or Hono to handle the routes as it's easier for developer to understand and maintain. Each route must be prefixed with `/function-name` so they are routed correctly.
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11. File write operations are ONLY permitted on `/tmp` directory. You can use either Deno or Node File APIs.
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12. Use `EdgeRuntime.waitUntil(promise)` static method to run long-running tasks in the background without blocking response to a request. Do NOT assume it is available in the request / execution context.
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## Example Templates
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### Simple Hello World Function
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```tsx
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interface reqPayload {
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  name: string
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}
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console.info('server started')
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Deno.serve(async (req: Request) => {
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  const { name }: reqPayload = await req.json()
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  const data = {
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    message: `Hello ${name} from foo!`,
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  }
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  return new Response(JSON.stringify(data), {
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    headers: { 'Content-Type': 'application/json', Connection: 'keep-alive' },
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  })
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})
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```
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### Example Function using Node built-in API
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```tsx
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import { randomBytes } from 'node:crypto'
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import { createServer } from 'node:http'
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import process from 'node:process'
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const generateRandomString = (length) => {
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  const buffer = randomBytes(length)
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  return buffer.toString('hex')
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}
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const randomString = generateRandomString(10)
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console.log(randomString)
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const server = createServer((req, res) => {
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  const message = `Hello`
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  res.end(message)
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})
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server.listen(9999)
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```
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### Using npm packages in Functions
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```tsx
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import express from 'npm:express@4.18.2'
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const app = express()
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app.get(/(.*)/, (req, res) => {
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  res.send('Welcome to Supabase')
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})
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app.listen(8000)
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```
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### Generate embeddings using built-in @Supabase.ai API
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```tsx
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const model = new Supabase.ai.Session('gte-small')
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Deno.serve(async (req: Request) => {
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  const params = new URL(req.url).searchParams
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  const input = params.get('text')
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  const output = await model.run(input, { mean_pool: true, normalize: true })
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  return new Response(JSON.stringify(output), {
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    headers: {
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      'Content-Type': 'application/json',
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      Connection: 'keep-alive',
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    },
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  })
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})
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```