CORS setup for API route

[nikolalsvk]

Hey @dulnan, great project here 🙌

I'm running into an issue where I'm calling the purge API from another server. For that, I had to configure CORS for my purge route.

This is what I added:

// ~/server/middleware/cors.ts

export default defineEventHandler((event) => {
  if (!event.req.url?.startsWith('/__cache/')) return

  setResponseHeaders(event, {
    'Access-Control-Allow-Methods': 'GET,HEAD,PUT,PATCH,POST,DELETE',
    'Access-Control-Allow-Origin': '*',
    'Access-Control-Allow-Credentials': 'true',
    'Access-Control-Allow-Headers': '*',
    'Access-Control-Expose-Headers': '*',
  })

  if (event.method === 'OPTIONS') {
    event.node.res.statusCode = 204
    event.node.res.statusMessage = 'No Content.'
    return 'OK'
  }
})

I can add it to docs if you agree. It might be useful to other people.