use validToDate if present, otherwise more explicitly parse validTo format, add unit test

Author: noahw3

src/certificate-expiration.ts

@@ -0,0 +1,40 @@
+import { X509Certificate } from 'node:crypto'
+
+const MONTHS = [
+  'Jan',
+  'Feb',
+  'Mar',
+  'Apr',
+  'May',
+  'Jun',
+  'Jul',
+  'Aug',
+  'Sep',
+  'Oct',
+  'Nov',
+  'Dec',
+]
+
+export function isCertificateExpired(content: string): boolean {
+  const cert = new X509Certificate(content)
+  const expirationDate = getCertificateExpirationDate(cert)
+  return new Date() > expirationDate
+}
+
+function getCertificateExpirationDate(cert: X509Certificate): Date {
+  // validToDate is not available until node 22
+  if (cert.validToDate) {
+    return cert.validToDate
+  }
+
+  // validTo is a nonstandard format: %s %2d %02d:%02d:%02d %d%s GMT
+  // https://github.com/nodejs/node/issues/52931
+  const [month, day, time, year] = cert.validTo
+    .split(' ')
+    .filter((part) => !!part)
+  // convert string month to number
+  const monthIndex = MONTHS.indexOf(month) + 1
+  return new Date(
+    `${year}-${monthIndex.toString().padStart(2, '0')}-${day.padStart(2, '0')}T${time}Z`,
+  )
+}

src/index.ts

@@ -1,7 +1,7 @@
 import path from 'node:path'
-import { X509Certificate } from 'node:crypto'
 import { promises as fsp } from 'node:fs'
 import type { Plugin } from 'vite'
+import { isCertificateExpired } from './certificate-expiration'
 
 const defaultCacheDir = 'node_modules/.vite'
 
@@ -43,13 +43,10 @@ export async function getCertificate(
 
   try {
     const content = await fsp.readFile(cachePath, 'utf8')
-    const cert = new X509Certificate(content);
+    const isExpired = isCertificateExpired(content)
 
-    // validTo is a nonstandard format, but it successfully parses. validToDate
-    // is not available until node 22
-    // https://github.com/nodejs/node/issues/52931
-    if (Date.now() > Date.parse(cert.validTo)) {
-      throw new Error('cache is outdated.');
+    if (isExpired) {
+      throw new Error('cache is outdated.')
     }
 
     return content

test/test.spec.ts

@@ -1,5 +1,7 @@
-import { test, expect } from 'vitest'
+import { beforeEach, describe, test, expect, vi, Mock } from 'vitest'
+import { X509Certificate } from 'node:crypto'
 import { createCertificate } from '../src/certificate'
+import { isCertificateExpired } from '../src/certificate-expiration'
 
 test('create certificate', () => {
   const content = createCertificate()
@@ -10,3 +12,51 @@ test('create certificate', () => {
     /-----BEGIN CERTIFICATE-----(\n|\r|.)*-----END CERTIFICATE-----/,
   )
 })
+
+describe('isCertificateExpired', () => {
+  let validToDateMock: Mock
+  let validToMock: Mock
+
+  beforeEach(() => {
+    validToDateMock = vi.spyOn(X509Certificate.prototype, 'validToDate', 'get')
+    validToMock = vi.spyOn(X509Certificate.prototype, 'validTo', 'get')
+  })
+
+  describe('with validToDate', () => {
+    test('returns false', () => {
+      validToDateMock.mockReturnValue(new Date(Date.now() + 10000))
+
+      const content = createCertificate()
+      const isExpired = isCertificateExpired(content)
+      expect(isExpired).toBe(false)
+    })
+
+     test('returns true', () => {
+      validToDateMock.mockReturnValue(new Date(Date.now() - 10000))
+
+      const content = createCertificate()
+      const isExpired = isCertificateExpired(content)
+      expect(isExpired).toBe(true)
+    })
+  })
+
+  describe('with validTo', () => {
+    test('returns false', () => {
+      validToDateMock.mockReturnValue(undefined)
+      validToMock.mockReturnValue('Sep  3 21:40:37 2296 GMT')
+
+      const content = createCertificate()
+      const isExpired = isCertificateExpired(content)
+      expect(isExpired).toBe(false)
+    })
+    
+    test('returns true', () => {
+      validToDateMock.mockReturnValue(undefined)
+      validToMock.mockReturnValue('Jan 22 08:20:44 2022 GMT')
+
+      const content = createCertificate()
+      const isExpired = isCertificateExpired(content)
+      expect(isExpired).toBe(true)
+    })
+  })
+})

test/vitest.config.ts

@@ -4,5 +4,6 @@ import { defineConfig } from 'vite'
 export default defineConfig({
   test: {
     testTimeout: 100000,
+    restoreMocks: true,
   },
 })