feat(server): support multiple hosts in __VITE_ADDITIONAL_SERVER_ALLOWED_HOSTS

docs/config/server-options.md

@@ -70,7 +70,7 @@ Setting `server.allowedHosts` to `true` allows any website to send requests to y
 :::
 
 ::: details Configure via environment variable
-You can set the environment variable `__VITE_ADDITIONAL_SERVER_ALLOWED_HOSTS` to add an additional allowed host.
+You can set the environment variable `__VITE_ADDITIONAL_SERVER_ALLOWED_HOSTS` to add additional allowed hosts. Use commas to separate multiple hosts (e.g., `host1.example.com,host2.example.com`).
 :::
 
 ## server.port

packages/vite/src/node/__tests__/config.spec.ts

@@ -5,6 +5,7 @@ import { afterEach, describe, expect, test, vi } from 'vitest'
 import type { InlineConfig, PluginOption } from '..'
 import type { UserConfig, UserConfigExport } from '../config'
 import { defineConfig, loadConfigFromFile, resolveConfig } from '../config'
+import { resolveServerOptions } from '../server'
 import { resolveEnvPrefix } from '../env'
 import { mergeConfig } from '../utils'
 import { createLogger } from '../logger'
@@ -1221,3 +1222,70 @@ describe('loadConfigFromFile', () => {
     })
   })
 })
+
+describe('resolveServerOptions', () => {
+  const logger = createLogger()
+
+  afterEach(() => {
+    delete process.env.__VITE_ADDITIONAL_SERVER_ALLOWED_HOSTS
+  })
+
+  test('adds single host from __VITE_ADDITIONAL_SERVER_ALLOWED_HOSTS', () => {
+    process.env.__VITE_ADDITIONAL_SERVER_ALLOWED_HOSTS = 'example.com'
+    const resolved = resolveServerOptions('/root', { allowedHosts: [] }, logger)
+    expect(resolved.allowedHosts).toEqual(['example.com'])
+  })
+
+  test('adds multiple hosts from __VITE_ADDITIONAL_SERVER_ALLOWED_HOSTS', () => {
+    process.env.__VITE_ADDITIONAL_SERVER_ALLOWED_HOSTS =
+      'example.com,test.com,dev.example.org'
+    const resolved = resolveServerOptions('/root', { allowedHosts: [] }, logger)
+    expect(resolved.allowedHosts).toEqual([
+      'example.com',
+      'test.com',
+      'dev.example.org',
+    ])
+  })
+
+  test('trims whitespace from hosts in __VITE_ADDITIONAL_SERVER_ALLOWED_HOSTS', () => {
+    process.env.__VITE_ADDITIONAL_SERVER_ALLOWED_HOSTS =
+      ' example.com , test.com , dev.example.org '
+    const resolved = resolveServerOptions('/root', { allowedHosts: [] }, logger)
+    expect(resolved.allowedHosts).toEqual([
+      'example.com',
+      'test.com',
+      'dev.example.org',
+    ])
+  })
+
+  test('filters empty hosts from __VITE_ADDITIONAL_SERVER_ALLOWED_HOSTS', () => {
+    process.env.__VITE_ADDITIONAL_SERVER_ALLOWED_HOSTS =
+      'example.com,,test.com,,'
+    const resolved = resolveServerOptions('/root', { allowedHosts: [] }, logger)
+    expect(resolved.allowedHosts).toEqual(['example.com', 'test.com'])
+  })
+
+  test('appends to existing allowedHosts', () => {
+    process.env.__VITE_ADDITIONAL_SERVER_ALLOWED_HOSTS = 'new.com,another.com'
+    const resolved = resolveServerOptions(
+      '/root',
+      { allowedHosts: ['existing.com'] },
+      logger,
+    )
+    expect(resolved.allowedHosts).toEqual([
+      'existing.com',
+      'new.com',
+      'another.com',
+    ])
+  })
+
+  test('does not modify allowedHosts when set to true', () => {
+    process.env.__VITE_ADDITIONAL_SERVER_ALLOWED_HOSTS = 'example.com'
+    const resolved = resolveServerOptions(
+      '/root',
+      { allowedHosts: true },
+      logger,
+    )
+    expect(resolved.allowedHosts).toBe(true)
+  })
+})

packages/vite/src/node/server/index.ts

@@ -1219,8 +1219,11 @@ export function resolveServerOptions(
     process.env.__VITE_ADDITIONAL_SERVER_ALLOWED_HOSTS &&
     Array.isArray(server.allowedHosts)
   ) {
-    const additionalHost = process.env.__VITE_ADDITIONAL_SERVER_ALLOWED_HOSTS
-    server.allowedHosts = [...server.allowedHosts, additionalHost]
+    const additionalHosts = process.env.__VITE_ADDITIONAL_SERVER_ALLOWED_HOSTS
+      .split(',')
+      .map((host) => host.trim())
+      .filter(Boolean)
+    server.allowedHosts = [...server.allowedHosts, ...additionalHosts]
   }
 
   return server