adapter.ts

import type { RequestData, FetchEventResult } from './types'
import { DeprecationError } from './error'
import { fromNodeHeaders } from './utils'
import { NextFetchEvent } from './spec-extension/fetch-event'
import { NextRequest, RequestInit } from './spec-extension/request'
import { NextResponse } from './spec-extension/response'
import { waitUntilSymbol } from './spec-compliant/fetch-event'

export async function adapter(params: {
  handler: (request: NextRequest, event: NextFetchEvent) => Promise<Response>
  request: RequestData
}): Promise<FetchEventResult> {
  const url = params.request.url.startsWith('/')
    ? `https://${params.request.headers.host}${params.request.url}`
    : params.request.url

  const request = new NextRequestHint(url, {
    geo: params.request.geo,
    headers: fromNodeHeaders(params.request.headers),
    ip: params.request.ip,
    method: params.request.method,
    nextConfig: params.request.nextConfig,
    page: params.request.page,
  })

  const event = new NextFetchEvent(request)
  const original = await params.handler(request, event)

  return {
    response: original || NextResponse.next(),
    waitUntil: Promise.all(event[waitUntilSymbol]),
  }
}

class NextRequestHint extends NextRequest {
  constructor(input: Request | string, init: RequestInit = {}) {
    super(input, init)
  }

  get request() {
    throw new DeprecationError()
  }

  respondWith() {
    throw new DeprecationError()
  }

  waitUntil() {
    throw new DeprecationError()
  }
}