edge.ts

/* eslint-disable max-lines */
import { promises as fs, existsSync } from 'fs'
import { resolve, join } from 'path'

import type { NetlifyConfig, NetlifyPluginConstants } from '@netlify/build'
import { greenBright } from 'chalk'
import destr from 'destr'
import { copy, copyFile, emptyDir, ensureDir, readJSON, readJson, writeJSON, writeJson } from 'fs-extra'
import type { MiddlewareManifest } from 'next/dist/build/webpack/plugins/middleware-plugin'
import type { RouteHas } from 'next/dist/lib/load-custom-routes'
import { outdent } from 'outdent'

import { getRequiredServerFiles } from './config'

// This is the format as of next@12.2
interface EdgeFunctionDefinitionV1 {
  env: string[]
  files: string[]
  name: string
  page: string
  regexp: string
}

export interface MiddlewareMatcher {
  regexp: string
  locale?: false
  has?: RouteHas[]
}

// This is the format after next@12.3.0
interface EdgeFunctionDefinitionV2 {
  env: string[]
  files: string[]
  name: string
  page: string
  matchers: MiddlewareMatcher[]
}

type EdgeFunctionDefinition = EdgeFunctionDefinitionV1 | EdgeFunctionDefinitionV2

export interface FunctionManifest {
  version: 1
  functions: Array<
    | {
        function: string
        name?: string
        path: string
      }
    | {
        function: string
        name?: string
        pattern: string
      }
  >
  import_map?: string
}

export const loadMiddlewareManifest = (netlifyConfig: NetlifyConfig): Promise<MiddlewareManifest | null> => {
  const middlewarePath = resolve(netlifyConfig.build.publish, 'server', 'middleware-manifest.json')
  if (!existsSync(middlewarePath)) {
    return null
  }
  return readJson(middlewarePath)
}

/**
 * Convert the Next middleware name into a valid Edge Function name
 */
const sanitizeName = (name: string) => `next_${name.replace(/\W/g, '_')}`

/**
 * Initialization added to the top of the edge function bundle
 */
const bootstrap = /* js */ `
globalThis.process = { env: {...Deno.env.toObject(), NEXT_RUNTIME: 'edge', 'NEXT_PRIVATE_MINIMAL_MODE': '1' } }
globalThis._ENTRIES ||= {}
// Deno defines "window", but naughty libraries think this means it's a browser
delete globalThis.window

`

/**
 * Concatenates the Next edge function code with the required chunks and adds an export
 */
const getMiddlewareBundle = async ({
  edgeFunctionDefinition,
  netlifyConfig,
}: {
  edgeFunctionDefinition: EdgeFunctionDefinition
  netlifyConfig: NetlifyConfig
}): Promise<string> => {
  const { publish } = netlifyConfig.build
  const chunks: Array<string> = [bootstrap]
  for (const file of edgeFunctionDefinition.files) {
    const filePath = join(publish, file)
    const data = await fs.readFile(filePath, 'utf8')
    chunks.push('{', data, '}')
  }

  const middleware = await fs.readFile(join(publish, `server`, `${edgeFunctionDefinition.name}.js`), 'utf8')

  chunks.push(middleware)

  const exports = /* js */ `export default _ENTRIES["middleware_${edgeFunctionDefinition.name}"].default;`
  chunks.push(exports)
  return chunks.join('\n')
}

const getEdgeTemplatePath = (file: string) => join(__dirname, '..', '..', 'src', 'templates', 'edge', file)

const copyEdgeSourceFile = ({
  file,
  target,
  edgeFunctionDir,
}: {
  file: string
  edgeFunctionDir: string
  target?: string
}) => fs.copyFile(getEdgeTemplatePath(file), join(edgeFunctionDir, target ?? file))

const writeEdgeFunction = async ({
  edgeFunctionDefinition,
  edgeFunctionRoot,
  netlifyConfig,
}: {
  edgeFunctionDefinition: EdgeFunctionDefinition
  edgeFunctionRoot: string
  netlifyConfig: NetlifyConfig
}): Promise<
  Array<{
    function: string
    name: string
    pattern: string
  }>
> => {
  const name = sanitizeName(edgeFunctionDefinition.name)
  const edgeFunctionDir = join(edgeFunctionRoot, name)

  const bundle = await getMiddlewareBundle({
    edgeFunctionDefinition,
    netlifyConfig,
  })

  await ensureDir(edgeFunctionDir)
  await fs.writeFile(join(edgeFunctionDir, 'bundle.js'), bundle)

  await copyEdgeSourceFile({
    edgeFunctionDir,
    file: 'runtime.ts',
    target: 'index.ts',
  })

  const matchers: EdgeFunctionDefinitionV2['matchers'] = []

  // The v1 middleware manifest has a single regexp, but the v2 has an array of matchers
  if ('regexp' in edgeFunctionDefinition) {
    matchers.push({ regexp: edgeFunctionDefinition.regexp })
  } else {
    matchers.push(...edgeFunctionDefinition.matchers)
  }
  await writeJson(join(edgeFunctionDir, 'matchers.json'), matchers)

  // We add a defintion for each matching path
  return matchers.map((matcher) => {
    const pattern = matcher.regexp
    return { function: name, pattern, name: edgeFunctionDefinition.name }
  })
}
export const cleanupEdgeFunctions = ({
  INTERNAL_EDGE_FUNCTIONS_SRC = '.netlify/edge-functions',
}: NetlifyPluginConstants) => emptyDir(INTERNAL_EDGE_FUNCTIONS_SRC)

export const writeDevEdgeFunction = async ({
  INTERNAL_EDGE_FUNCTIONS_SRC = '.netlify/edge-functions',
}: NetlifyPluginConstants) => {
  const manifest: FunctionManifest = {
    functions: [
      {
        function: 'next-dev',
        name: 'netlify dev handler',
        path: '/*',
      },
    ],
    version: 1,
  }
  const edgeFunctionRoot = resolve(INTERNAL_EDGE_FUNCTIONS_SRC)
  await emptyDir(edgeFunctionRoot)
  await writeJson(join(edgeFunctionRoot, 'manifest.json'), manifest)
  await copy(getEdgeTemplatePath('../edge-shared'), join(edgeFunctionRoot, 'edge-shared'))

  const edgeFunctionDir = join(edgeFunctionRoot, 'next-dev')
  await ensureDir(edgeFunctionDir)
  await copyEdgeSourceFile({ edgeFunctionDir, file: 'next-dev.js', target: 'index.js' })
}

/**
 * Writes Edge Functions for the Next middleware
 */
export const writeEdgeFunctions = async (netlifyConfig: NetlifyConfig) => {
  const manifest: FunctionManifest = {
    functions: [],
    version: 1,
  }

  const edgeFunctionRoot = resolve('.netlify', 'edge-functions')
  await emptyDir(edgeFunctionRoot)

  const { publish } = netlifyConfig.build
  const nextConfigFile = await getRequiredServerFiles(publish)
  const nextConfig = nextConfigFile.config
  await copy(getEdgeTemplatePath('../edge-shared'), join(edgeFunctionRoot, 'edge-shared'))
  await writeJSON(join(edgeFunctionRoot, 'edge-shared', 'nextConfig.json'), nextConfig)

  if (
    !destr(process.env.NEXT_DISABLE_EDGE_IMAGES) &&
    !destr(process.env.NEXT_DISABLE_NETLIFY_EDGE) &&
    !destr(process.env.DISABLE_IPX)
  ) {
    console.log(
      'Using Netlify Edge Functions for image format detection. Set env var "NEXT_DISABLE_EDGE_IMAGES=true" to disable.',
    )
    const edgeFunctionDir = join(edgeFunctionRoot, 'ipx')
    await ensureDir(edgeFunctionDir)
    await copyEdgeSourceFile({ edgeFunctionDir, file: 'ipx.ts', target: 'index.ts' })
    await copyFile(
      join('.netlify', 'functions-internal', '_ipx', 'imageconfig.json'),
      join(edgeFunctionDir, 'imageconfig.json'),
    )
    manifest.functions.push({
      function: 'ipx',
      name: 'next/image handler',
      path: '/_next/image*',
    })
  }
  if (!destr(process.env.NEXT_DISABLE_NETLIFY_EDGE)) {
    const middlewareManifest = await loadMiddlewareManifest(netlifyConfig)
    if (!middlewareManifest) {
      console.error("Couldn't find the middleware manifest")
      return
    }

    let usesEdge = false

    for (const middleware of middlewareManifest.sortedMiddleware) {
      usesEdge = true
      const edgeFunctionDefinition = middlewareManifest.middleware[middleware]
      const functionDefinitions = await writeEdgeFunction({
        edgeFunctionDefinition,
        edgeFunctionRoot,
        netlifyConfig,
      })
      manifest.functions.push(...functionDefinitions)
    }
    // Older versions of the manifest format don't have the functions field
    // No, the version field was not incremented
    if (typeof middlewareManifest.functions === 'object') {
      for (const edgeFunctionDefinition of Object.values(middlewareManifest.functions)) {
        usesEdge = true
        const functionDefinitions = await writeEdgeFunction({
          edgeFunctionDefinition,
          edgeFunctionRoot,
          netlifyConfig,
        })
        manifest.functions.push(...functionDefinitions)
      }
    }
    if (usesEdge) {
      console.log(outdent`
        ✨ Deploying middleware and functions to ${greenBright`Netlify Edge Functions`} ✨
        This feature is in beta. Please share your feedback here: https://ntl.fyi/next-netlify-edge
      `)
    }
  }
  await writeJson(join(edgeFunctionRoot, 'manifest.json'), manifest)
}

export const enableEdgeInNextConfig = async (publish: string) => {
  const configFile = join(publish, 'required-server-files.json')
  const config = await readJSON(configFile)
  await writeJSON(configFile, config)
}
/* eslint-enable max-lines */