fix: generate handlers with correct site root (#235)

* fix: generate handlers dynamically

* fix: chdir into site root

* chore: handler fixes

* fix: copy api handler

* fix: only clear require cache in local dev

* chore: changes from review

Co-authored-by: kodiakhq[bot] <49736102+kodiakhq[bot]@users.noreply.github.com>

Author: ascorbic

.eslintrc.js

@@ -9,6 +9,7 @@ module.exports = {
     'node/no-unsupported-features/es-syntax': 'off',
     // This is a duplicate of `import/no-duplicates` but can handle "import type"
     'no-duplicate-imports': 'off',
+    'max-depth': ['error', 4],
   },
   env: {
     jest: true,
@@ -37,6 +38,9 @@ module.exports = {
         'node/no-unpublished-require': 'off',
         'node/no-missing-require': 'off',
         'max-lines': 'off',
+        complexity: 'off',
+        'max-statements': 'off',
+        'node/prefer-global/process': 'off',
         'unicorn/filename-case': 'off',
       },
     },

plugin/package-lock.json

@@ -50,6 +50,7 @@
     "linkfs": "^2.1.0",
     "multer": "^1.4.2",
     "node-fetch": "^2.6.1",
+    "pathe": "^0.2.0",
     "tempy": "^1.0.0"
   },
   "devDependencies": {
@@ -64,6 +65,7 @@
   },
   "peerDependencies": {
     "@gatsbyjs/reach-router": "^1.3.6",
+    "common-tags": "^1.8.2",
     "execa": "^5.0.0"
   }
 }

plugin/package.json

@@ -112,6 +112,7 @@ export function mutateConfig({
       path.posix.join(CACHE_DIR, 'page-ssr', '**'),
     ],
     external_node_modules: ['msgpackr-extract'],
+    node_bundler: 'esbuild',
   }
 
   netlifyConfig.functions.__ssr = { ...netlifyConfig.functions.__dsg }

plugin/src/helpers/config.ts

@@ -0,0 +1,50 @@
+import process from 'process'
+
+import { NetlifyPluginConstants } from '@netlify/build'
+import { copy, copyFile, ensureDir, writeFile } from 'fs-extra'
+import { resolve, join, relative } from 'pathe'
+
+import { makeHandler } from '../templates/handlers'
+
+const writeFunction = async ({
+  renderMode,
+  handlerName,
+  appDir,
+  functionsSrc,
+}) => {
+  const source = makeHandler(appDir, renderMode)
+  await ensureDir(join(functionsSrc, handlerName))
+  await writeFile(join(functionsSrc, handlerName, `${handlerName}.js`), source)
+  await copyFile(
+    join(__dirname, '..', '..', 'lib', 'templates', 'utils.js'),
+    join(functionsSrc, handlerName, 'utils.js'),
+  )
+}
+
+export const writeFunctions = async ({
+  INTERNAL_FUNCTIONS_SRC,
+  PUBLISH_DIR,
+}: NetlifyPluginConstants): Promise<void> => {
+  const siteRoot = resolve(process.cwd(), PUBLISH_DIR, '..')
+  const functionDir = join(process.cwd(), INTERNAL_FUNCTIONS_SRC, '__api')
+  const appDir = relative(functionDir, siteRoot)
+
+  await writeFunction({
+    renderMode: 'SSR',
+    handlerName: '__ssr',
+    appDir,
+    functionsSrc: INTERNAL_FUNCTIONS_SRC,
+  })
+
+  await writeFunction({
+    renderMode: 'DSG',
+    handlerName: '__dsg',
+    appDir,
+    functionsSrc: INTERNAL_FUNCTIONS_SRC,
+  })
+
+  await copy(
+    join(__dirname, '..', '..', 'lib', 'templates', 'api'),
+    functionDir,
+  )
+}

plugin/src/helpers/functions.ts

@@ -5,6 +5,7 @@ import fs from 'fs-extra'
 
 import { normalizedCacheDir, restoreCache, saveCache } from './helpers/cache'
 import { checkGatsbyConfig, mutateConfig, spliceConfig } from './helpers/config'
+import { writeFunctions } from './helpers/functions'
 
 // eslint-disable-next-line no-template-curly-in-string
 const lmdbCacheString = 'process.cwd(), `.cache/${cacheDbFile}`'
@@ -45,34 +46,23 @@ export async function onPreBuild({
   checkGatsbyConfig({ utils, netlifyConfig })
 }
 
-export async function onBuild({
-  constants: {
+export async function onBuild({ constants, netlifyConfig }): Promise<void> {
+  const {
     PUBLISH_DIR,
     FUNCTIONS_SRC = DEFAULT_FUNCTIONS_SRC,
     INTERNAL_FUNCTIONS_SRC,
-  },
-  netlifyConfig,
-}): Promise<void> {
+  } = constants
   const CACHE_DIR = normalizedCacheDir(PUBLISH_DIR)
   const compiledFunctionsDir = path.join(CACHE_DIR, '/functions')
   // eslint-disable-next-line node/no-sync
   if (!fs.existsSync(compiledFunctionsDir)) {
     return
   }
 
-  const functionsSrcDir = INTERNAL_FUNCTIONS_SRC || FUNCTIONS_SRC
+  await writeFunctions(constants)
 
   // copying Netlify wrapper function into functions directory
 
-  await Promise.all(
-    ['api', 'dsg', 'ssr'].map((func) =>
-      fs.copy(
-        path.join(__dirname, '..', 'src', 'templates', func),
-        path.join(functionsSrcDir, `__${func}`),
-      ),
-    ),
-  )
-
   if (
     INTERNAL_FUNCTIONS_SRC &&
     // eslint-disable-next-line node/no-sync

plugin/src/index.ts

@@ -19,7 +19,6 @@ type MulterRes = Parameters<typeof parseForm>[1]
 /**
  * Execute a Gatsby function
  */
-// eslint-disable-next-line complexity, max-statements
 export async function gatsbyFunction(
   req: AugmentedGatsbyFunctionRequest,
   res: AugmentedGatsbyFunctionResponse,
@@ -70,7 +69,7 @@ export async function gatsbyFunction(
         const matchResult = reachMatch(func.matchPath, pathFragment)
         if (matchResult) {
           req.params = matchResult.params
-          // eslint-disable-next-line max-depth
+
           if (req.params[`*`]) {
             // Backwards compatability for v3
             // TODO remove in v5
@@ -112,7 +111,11 @@ export async function gatsbyFunction(
     }
 
     try {
-      // Make sure it's hot and fresh from the filesystem
+      if (process.env.NETLIFY_LOCAL) {
+        // Make sure it's hot and fresh from the filesystem
+        delete require.cache[require.resolve(pathToFunction)]
+      }
+
       const fn = require(pathToFunction)
 
       const fnToExecute = (fn && fn.default) || fn
@@ -121,7 +124,6 @@ export async function gatsbyFunction(
     } catch (error) {
       console.error(error)
       // Don't send the error if that would cause another error.
-      // eslint-disable-next-line max-depth
       if (!res.headersSent) {
         res
           .status(500)

plugin/src/templates/api/gatsbyFunction.ts

@@ -34,7 +34,6 @@ export interface AugmentedGatsbyFunctionRequest extends GatsbyFunctionRequest {
 // Based on API Gateway Lambda Compat
 // Source: https://github.com/serverless-nextjs/serverless-next.js/blob/master/packages/compat-layers/apigw-lambda-compat/lib/compatLayer.js
 
-// eslint-disable-next-line complexity, max-statements
 export const createRequestObject = ({
   event,
   context,
@@ -118,7 +117,7 @@ interface IntermediateHandlerResponse
 // Based on API Gateway Lambda Compat
 // Source: https://github.com/serverless-nextjs/serverless-next.js/blob/master/packages/compat-layers/apigw-lambda-compat/lib/compatLayer.js
 
-// eslint-disable-next-line max-statements, max-lines-per-function
+// eslint-disable-next-line  max-lines-per-function
 export const createResponseObject = ({ onResEnd }) => {
   const response: IntermediateHandlerResponse = {
     isBase64Encoded: true,
@@ -170,7 +169,6 @@ export const createResponseObject = ({ onResEnd }) => {
   res.getHeader = (name) => res.headers[name.toLowerCase()]
   res.getHeaders = () => res.headers
   res.hasHeader = (name) => Boolean(res.getHeader(name))
-  // eslint-disable-next-line complexity
   res.end = (text) => {
     if (text) res.write(text)
     if (!res.statusCode) {
@@ -247,7 +245,6 @@ export const createResponseObject = ({ onResEnd }) => {
  * During `netlify dev` we proxy requests to the `gatsby develop` server instead of
  * serving them ourselves.
  */
-// eslint-disable-next-line max-statements
 export const proxyRequest = async (event: HandlerEvent, res) => {
   // todo: get this from config
   const port = `8000`