chore(release): bump package version(s) [skip ci]

* fix(core): preserve `set-cookie` by the user

* add test

* improve req/res mocking

* refactor

* fix comment typo

docs/docs/tutorials.md

@@ -46,6 +46,10 @@ title: Tutorials and Explainers
 - Learn how to use Sign-In With Ethereum to authenticate your users with their existing Ethereum wallets - identifiers they personally control.
 - Example application: [spruceid/siwe-next-auth-example](https://github.com/spruceid/siwe-next-auth-example)
 
+#### [Next.js Authentication with Okta and NextAuth.js 4.0](https://thetombomb.com/posts/nextjs-nextauth-okta) <svg xmlns="http://www.w3.org/2000/svg" style={{ marginLeft: '5px', marginBottom:'-6px'}} height="20" width="20" fill="none" viewBox="0 0 24 24" stroke="currentColor"><title>External</title> <path strokeLinecap="round" strokeLinejoin="round" strokeWidth="2" d="M10 6H6a2 2 0 00-2 2v10a2 2 0 002 2h10a2 2 0 002-2v-4M14 4h6m0 0v6m0-6L10 14" /> </svg>
+
+- Learn how to perform authentication with an OIDC Application in Okta and NextAuth.js.
+
 ## Fullstack
 
 #### [Build a FullStack App with Next.js, NextAuth.js, Supabase & Prisma](https://themodern.dev/courses/build-a-fullstack-app-with-nextjs-supabase-and-prisma-322389284337222224) <svg xmlns="http://www.w3.org/2000/svg" style={{ marginLeft: '5px', marginBottom:'-6px'}} height="20" width="20" fill="none" viewBox="0 0 24 24" stroke="currentColor"><title>External</title> <path strokeLinecap="round" strokeLinejoin="round" strokeWidth="2" d="M10 6H6a2 2 0 00-2 2v10a2 2 0 002 2h10a2 2 0 002-2v-4M14 4h6m0 0v6m0-6L10 14" /> </svg>

docs/versioned_docs/version-beta/guides/09-resources.md

@@ -14,6 +14,10 @@ If you did not find a guide or tutorial covering your use case, please [open an
   - How to restrict access to pages and API routes.
 - [Usage with class components](/tutorials/usage-with-class-components)
   - How to use `useSession()` hook with class components.
+- [Next.js Authentication with Okta and NextAuth.js 4.0](https://thetombomb.com/posts/nextjs-nextauth-okta)
+  - Learn how to perform authentication with an OIDC Application in Okta and NextAuth.js.
+
+  
 
 ### Advanced
 

packages/adapter-sequelize/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@next-auth/sequelize-adapter",
-  "version": "1.0.6",
+  "version": "1.0.7",
   "description": "Sequelize adapter for next-auth.",
   "homepage": "https://next-auth.js.org",
   "repository": "https://github.com/nextauthjs/next-auth",
@@ -42,4 +42,4 @@
   "jest": {
     "preset": "@next-auth/adapter-test/jest"
   }
-}
+}

packages/adapter-sequelize/src/models.ts

@@ -14,7 +14,7 @@ export const Account = {
   expires_at: { type: DataTypes.INTEGER },
   token_type: { type: DataTypes.STRING },
   scope: { type: DataTypes.STRING },
-  id_token: { type: DataTypes.STRING },
+  id_token: { type: DataTypes.TEXT },
   session_state: { type: DataTypes.STRING },
   userId: { type: DataTypes.UUID },
 }

packages/next-auth/package.json

@@ -1,6 +1,6 @@
 {
   "name": "next-auth",
-  "version": "4.18.3",
+  "version": "4.18.6",
   "description": "Authentication for Next.js",
   "homepage": "https://next-auth.js.org",
   "repository": "https://github.com/nextauthjs/next-auth.git",

packages/next-auth/src/core/errors.ts

@@ -72,6 +72,16 @@ export class InvalidCallbackUrl extends UnknownError {
   code = "INVALID_CALLBACK_URL_ERROR"
 }
 
+export class UnknownAction extends UnknownError {
+  name = "UnknownAction"
+  code = "UNKNOWN_ACTION_ERROR"
+}
+
+export class UntrustedHost extends UnknownError {
+  name = "UntrustedHost"
+  code = "UNTRUST_HOST_ERROR"
+}
+
 type Method = (...args: any[]) => Promise<any>
 
 export function upperSnake(s: string) {

packages/next-auth/src/core/index.ts

@@ -1,19 +1,21 @@
 import logger, { setLogger } from "../utils/logger"
 import { toInternalRequest, toResponse } from "../utils/web"
-import * as routes from "./routes"
-import renderPage from "./pages"
 import { init } from "./init"
 import { assertConfig } from "./lib/assert"
 import { SessionStore } from "./lib/cookie"
+import renderPage from "./pages"
+import * as routes from "./routes"
 
-import type { AuthAction, AuthOptions } from "./types"
+import { UntrustedHost } from "./errors"
 import type { Cookie } from "./lib/cookie"
 import type { ErrorType } from "./pages/error"
+import type { AuthAction, AuthOptions } from "./types"
 
+/** @internal */
 export interface RequestInternal {
-  /** @default "http://localhost:3000" */
-  host?: string
-  method?: string
+  url: URL
+  /** @default "GET" */
+  method: string
   cookies?: Partial<Record<string, string>>
   headers?: Record<string, any>
   query?: Record<string, any>
@@ -23,22 +25,20 @@ export interface RequestInternal {
   error?: string
 }
 
-export interface NextAuthHeader {
-  key: string
-  value: string
-}
-
-// TODO: Rename to `ResponseInternal`
+/** @internal */
 export interface ResponseInternal<
   Body extends string | Record<string, any> | any[] = any
 > {
   status?: number
-  headers?: NextAuthHeader[]
+  headers?: Record<string, string>
   body?: Body
   redirect?: string
   cookies?: Cookie[]
 }
 
+const configErrorMessage =
+  "There is a problem with the server configuration. Check the server logs for more information."
+
 async function AuthHandlerInternal<
   Body extends string | Record<string, any> | any[]
 >(params: {
@@ -47,10 +47,9 @@ async function AuthHandlerInternal<
   /** REVIEW: Is this the best way to skip parsing the body in Node.js? */
   parsedBody?: any
 }): Promise<ResponseInternal<Body>> {
-  const { options: userOptions, req } = params
-  setLogger(userOptions.logger, userOptions.debug)
+  const { options: authOptions, req } = params
 
-  const assertionResult = assertConfig({ options: userOptions, req })
+  const assertionResult = assertConfig({ options: authOptions, req })
 
   if (Array.isArray(assertionResult)) {
     assertionResult.forEach(logger.warn)
@@ -60,14 +59,13 @@ async function AuthHandlerInternal<
 
     const htmlPages = ["signin", "signout", "error", "verify-request"]
     if (!htmlPages.includes(req.action) || req.method !== "GET") {
-      const message = `There is a problem with the server configuration. Check the server logs for more information.`
       return {
         status: 500,
-        headers: [{ key: "Content-Type", value: "application/json" }],
-        body: { message } as any,
+        headers: { "Content-Type": "application/json" },
+        body: { message: configErrorMessage } as any,
       }
     }
-    const { pages, theme } = userOptions
+    const { pages, theme } = authOptions
 
     const authOnErrorPage =
       pages?.error && req.query?.callbackUrl?.startsWith(pages.error)
@@ -90,13 +88,13 @@ async function AuthHandlerInternal<
     }
   }
 
-  const { action, providerId, error, method = "GET" } = req
+  const { action, providerId, error, method } = req
 
   const { options, cookies } = await init({
-    userOptions,
+    authOptions,
     action,
     providerId,
-    host: req.host,
+    url: req.url,
     callbackUrl: req.body?.callbackUrl ?? req.query?.callbackUrl,
     csrfToken: req.body?.csrfToken,
     cookies: req.cookies,
@@ -123,7 +121,7 @@ async function AuthHandlerInternal<
       }
       case "csrf":
         return {
-          headers: [{ key: "Content-Type", value: "application/json" }],
+          headers: { "Content-Type": "application/json" },
           body: { csrfToken: options.csrfToken } as any,
           cookies,
         }
@@ -240,7 +238,7 @@ async function AuthHandlerInternal<
         }
         break
       case "_log":
-        if (userOptions.logger) {
+        if (authOptions.logger) {
           try {
             const { code, level, ...metadata } = req.body ?? {}
             logger[level](code, metadata)
@@ -269,7 +267,41 @@ export async function AuthHandler(
   request: Request,
   options: AuthOptions
 ): Promise<Response> {
+  setLogger(options.logger, options.debug)
+
+  if (!options.trustHost) {
+    const error = new UntrustedHost(
+      `Host must be trusted. URL was: ${request.url}`
+    )
+    logger.error(error.code, error)
+
+    return new Response(JSON.stringify({ message: configErrorMessage }), {
+      status: 500,
+      headers: { "Content-Type": "application/json" },
+    })
+  }
+
   const req = await toInternalRequest(request)
+  if (req instanceof Error) {
+    logger.error((req as any).code, req)
+    return new Response(
+      `Error: This action with HTTP ${request.method} is not supported.`,
+      { status: 400 }
+    )
+  }
   const internalResponse = await AuthHandlerInternal({ req, options })
-  return toResponse(internalResponse)
+
+  const response = await toResponse(internalResponse)
+
+  // If the request expects a return URL, send it as JSON
+  // instead of doing an actual redirect.
+  const redirect = response.headers.get("Location")
+  if (request.headers.has("X-Auth-Return-Redirect") && redirect) {
+    response.headers.delete("Location")
+    response.headers.set("Content-Type", "application/json")
+    return new Response(JSON.stringify({ url: redirect }), {
+      headers: response.headers,
+    })
+  }
+  return response
 }

packages/next-auth/src/core/init.ts

@@ -1,7 +1,6 @@
 import { randomBytes, randomUUID } from "crypto"
 import { AuthOptions } from ".."
 import logger from "../utils/logger"
-import parseUrl from "../utils/parse-url"
 import { adapterErrorHandler, eventsErrorHandler } from "./errors"
 import parseProviders from "./lib/providers"
 import { createSecret } from "./lib/utils"
@@ -13,10 +12,11 @@ import { createCallbackUrl } from "./lib/callback-url"
 import { RequestInternal } from "."
 
 import type { InternalOptions } from "./types"
+import parseUrl from "../utils/parse-url"
 
 interface InitParams {
-  host?: string
-  userOptions: AuthOptions
+  url: URL
+  authOptions: AuthOptions
   providerId?: string
   action: InternalOptions["action"]
   /** Callback URL value extracted from the incoming request. */
@@ -30,10 +30,10 @@ interface InitParams {
 
 /** Initialize all internal options and cookies. */
 export async function init({
-  userOptions,
+  authOptions,
   providerId,
   action,
-  host,
+  url: reqUrl,
   cookies: reqCookies,
   callbackUrl: reqCallbackUrl,
   csrfToken: reqCsrfToken,
@@ -42,12 +42,17 @@ export async function init({
   options: InternalOptions
   cookies: cookie.Cookie[]
 }> {
-  const url = parseUrl(host)
+  // TODO: move this to web.ts
+  const parsed = parseUrl(
+    reqUrl.origin +
+      reqUrl.pathname.replace(`/${action}`, "").replace(`/${providerId}`, "")
+  )
+  const url = new URL(parsed.toString())
 
-  const secret = createSecret({ userOptions, url })
+  const secret = createSecret({ authOptions, url })
 
   const { providers, provider } = parseProviders({
-    providers: userOptions.providers,
+    providers: authOptions.providers,
     url,
     providerId,
   })
@@ -66,7 +71,7 @@ export async function init({
       buttonText: "",
     },
     // Custom options override defaults
-    ...userOptions,
+    ...authOptions,
     // These computed settings can have values in userOptions but we override them
     // and are request-specific.
     url,
@@ -75,24 +80,24 @@ export async function init({
     provider,
     cookies: {
       ...cookie.defaultCookies(
-        userOptions.useSecureCookies ?? url.base.startsWith("https://")
+        authOptions.useSecureCookies ?? url.protocol === "https:"
       ),
       // Allow user cookie options to override any cookie settings above
-      ...userOptions.cookies,
+      ...authOptions.cookies,
     },
     secret,
     providers,
     // Session options
     session: {
       // If no adapter specified, force use of JSON Web Tokens (stateless)
-      strategy: userOptions.adapter ? "database" : "jwt",
+      strategy: authOptions.adapter ? "database" : "jwt",
       maxAge,
       updateAge: 24 * 60 * 60,
       generateSessionToken: () => {
         // Use `randomUUID` if available. (Node 15.6+)
         return randomUUID?.() ?? randomBytes(32).toString("hex")
       },
-      ...userOptions.session,
+      ...authOptions.session,
     },
     // JWT options
     jwt: {
@@ -100,13 +105,13 @@ export async function init({
       maxAge, // same as session maxAge,
       encode: jwt.encode,
       decode: jwt.decode,
-      ...userOptions.jwt,
+      ...authOptions.jwt,
     },
     // Event messages
-    events: eventsErrorHandler(userOptions.events ?? {}, logger),
-    adapter: adapterErrorHandler(userOptions.adapter, logger),
+    events: eventsErrorHandler(authOptions.events ?? {}, logger),
+    adapter: adapterErrorHandler(authOptions.adapter, logger),
     // Callback functions
-    callbacks: { ...defaultCallbacks, ...userOptions.callbacks },
+    callbacks: { ...defaultCallbacks, ...authOptions.callbacks },
     logger,
     callbackUrl: url.origin,
   }

packages/next-auth/src/core/lib/assert.ts

@@ -7,7 +7,6 @@ import {
   InvalidCallbackUrl,
   MissingAdapterMethods,
 } from "../errors"
-import parseUrl from "../../utils/parse-url"
 import { defaultCookies } from "./cookie"
 
 import type { RequestInternal } from ".."
@@ -44,11 +43,11 @@ export function assertConfig(params: {
   req: RequestInternal
 }): ConfigError | WarningCode[] {
   const { options, req } = params
-
+  const { url } = req
   const warnings: WarningCode[] = []
 
   if (!warned) {
-    if (!req.host) warnings.push("NEXTAUTH_URL")
+    if (!url.origin) warnings.push("NEXTAUTH_URL")
 
     // TODO: Make this throw an error in next major. This will also get rid of `NODE_ENV`
     if (!options.secret && process.env.NODE_ENV !== "production")
@@ -70,21 +69,19 @@ export function assertConfig(params: {
 
   const callbackUrlParam = req.query?.callbackUrl as string | undefined
 
-  const url = parseUrl(req.host)
-
-  if (callbackUrlParam && !isValidHttpUrl(callbackUrlParam, url.base)) {
+  if (callbackUrlParam && !isValidHttpUrl(callbackUrlParam, url.origin)) {
     return new InvalidCallbackUrl(
       `Invalid callback URL. Received: ${callbackUrlParam}`
     )
   }
 
   const { callbackUrl: defaultCallbackUrl } = defaultCookies(
-    options.useSecureCookies ?? url.base.startsWith("https://")
+    options.useSecureCookies ?? url.protocol === "https://"
   )
   const callbackUrlCookie =
     req.cookies?.[options.cookies?.callbackUrl?.name ?? defaultCallbackUrl.name]
 
-  if (callbackUrlCookie && !isValidHttpUrl(callbackUrlCookie, url.base)) {
+  if (callbackUrlCookie && !isValidHttpUrl(callbackUrlCookie, url.origin)) {
     return new InvalidCallbackUrl(
       `Invalid callback URL. Received: ${callbackUrlCookie}`
     )

packages/next-auth/src/core/lib/providers.ts

@@ -6,7 +6,6 @@ import type {
   OAuthConfig,
   Provider,
 } from "../../providers"
-import type { InternalUrl } from "../../utils/parse-url"
 
 /**
  * Adds `signinUrl` and `callbackUrl` to each provider
@@ -14,7 +13,7 @@ import type { InternalUrl } from "../../utils/parse-url"
  */
 export default function parseProviders(params: {
   providers: Provider[]
-  url: InternalUrl
+  url: URL
   providerId?: string
 }): {
   providers: InternalProvider[]

packages/next-auth/src/core/lib/utils.ts

@@ -2,7 +2,6 @@ import { createHash } from "crypto"
 
 import type { AuthOptions } from "../.."
 import type { InternalOptions } from "../types"
-import type { InternalUrl } from "../../utils/parse-url"
 
 /**
  * Takes a number in seconds and returns the date in the future.
@@ -28,17 +27,14 @@ export function hashToken(token: string, options: InternalOptions<"email">) {
  * If no secret option is specified then it creates one on the fly
  * based on options passed here. If options contains unique data, such as
  * OAuth provider secrets and database credentials it should be sufficent. If no secret provided in production, we throw an error. */
-export function createSecret(params: {
-  userOptions: AuthOptions
-  url: InternalUrl
-}) {
-  const { userOptions, url } = params
+export function createSecret(params: { authOptions: AuthOptions; url: URL }) {
+  const { authOptions, url } = params
 
   return (
-    userOptions.secret ??
+    authOptions.secret ??
     // TODO: Remove falling back to default secret, and error in dev if one isn't provided
     createHash("sha256")
-      .update(JSON.stringify({ ...url, ...userOptions }))
+      .update(JSON.stringify({ ...url, ...authOptions }))
       .digest("hex")
   )
 }

packages/next-auth/src/core/pages/error.tsx

@@ -1,5 +1,4 @@
 import { Theme } from "../.."
-import { InternalUrl } from "../../utils/parse-url"
 
 /**
  * The following errors are passed as error query parameters to the default or overridden error page.
@@ -12,7 +11,7 @@ export type ErrorType =
   | "verification"
 
 export interface ErrorProps {
-  url?: InternalUrl
+  url?: URL
   theme?: Theme
   error?: ErrorType
 }

packages/next-auth/src/core/pages/index.ts

@@ -31,7 +31,7 @@ export default function renderPage(params: RenderPageParams) {
     return {
       cookies,
       status,
-      headers: [{ key: "Content-Type", value: "text/html" }],
+      headers: { "Content-Type": "text/html" },
       body: `<!DOCTYPE html><html lang="en"><head><meta charset="UTF-8"><meta http-equiv="X-UA-Compatible" content="IE=edge"><meta name="viewport" content="width=device-width, initial-scale=1.0"><style>${css()}</style><title>${title}</title></head><body class="__next-auth-theme-${
         theme?.colorScheme ?? "auto"
       }"><div class="page">${renderToString(html)}</div></body></html>`,

packages/next-auth/src/core/pages/signout.tsx

@@ -1,8 +1,7 @@
 import { Theme } from "../.."
-import { InternalUrl } from "../../utils/parse-url"
 
 export interface SignoutProps {
-  url: InternalUrl
+  url: URL
   csrfToken: string
   theme: Theme
 }

packages/next-auth/src/core/routes/providers.ts

@@ -18,7 +18,7 @@ export default function providers(
   providers: InternalProvider[]
 ): ResponseInternal<Record<string, PublicProvider>> {
   return {
-    headers: [{ key: "Content-Type", value: "application/json" }],
+    headers: { "Content-Type": "application/json" },
     body: providers.reduce<Record<string, PublicProvider>>(
       (acc, { id, name, type, signinUrl, callbackUrl }) => {
         acc[id] = { id, name, type, signinUrl, callbackUrl }

packages/next-auth/src/core/routes/session.ts

@@ -31,7 +31,7 @@ export default async function session(
 
   const response: ResponseInternal<Session | {}> = {
     body: {},
-    headers: [{ key: "Content-Type", value: "application/json" }],
+    headers: { "Content-Type": "application/json" },
     cookies: [],
   }
 

packages/next-auth/src/core/types.ts

@@ -14,8 +14,6 @@ import type { CookieSerializeOptions } from "cookie"
 
 import type { NextApiRequest, NextApiResponse } from "next"
 
-import type { InternalUrl } from "../utils/parse-url"
-
 export type Awaitable<T> = T | PromiseLike<T>
 
 export type { LoggerInstance }
@@ -210,7 +208,7 @@ export interface AuthOptions {
    * - ⚠ **This is an advanced option.** Advanced options are passed the same way as basic options,
    * but **may have complex implications** or side effects.
    * You should **try to avoid using advanced options** unless you are very comfortable using them.
-   * @default Boolean(process.env.AUTH_TRUST_HOST ?? process.env.VERCEL)
+   * @default Boolean(process.env.NEXTAUTH_URL ?? process.env.AUTH_TRUST_HOST ?? process.env.VERCEL)
    */
   trustHost?: boolean
 }
@@ -528,11 +526,7 @@ export interface InternalOptions<
   WithVerificationToken = TProviderType extends "email" ? true : false
 > {
   providers: InternalProvider[]
-  /**
-   * Parsed from `NEXTAUTH_URL` or `x-forwarded-host` on Vercel.
-   * @default "http://localhost:3000/api/auth"
-   */
-  url: InternalUrl
+  url: URL
   action: AuthAction
   provider: InternalProvider<TProviderType>
   csrfToken?: string

packages/next-auth/src/jwt/index.ts

@@ -94,7 +94,7 @@ export async function getToken<R extends boolean = false>(
   const authorizationHeader =
     req.headers instanceof Headers
       ? req.headers.get("authorization")
-      : req.headers.authorization
+      : req.headers?.authorization
 
   if (!token && authorizationHeader?.split(" ")[0] === "Bearer") {
     const urlEncodedToken = authorizationHeader.split(" ")[1]

packages/next-auth/src/next/index.ts

@@ -1,5 +1,5 @@
 import { AuthHandler } from "../core"
-import { getURL, getBody } from "../utils/node"
+import { getBody, getURL, setHeaders } from "../utils/node"
 
 import type {
   GetServerSidePropsContext,
@@ -18,38 +18,36 @@ async function NextAuthHandler(
   res: NextApiResponse,
   options: AuthOptions
 ) {
-  const url = getURL(
-    req.url,
-    options.trustHost,
-    req.headers["x-forwarded-host"] ?? req.headers.host
-  )
-
-  if (url instanceof Error) return res.status(400).end()
+  const headers = new Headers(req.headers as any)
+  const url = getURL(req.url, headers)
+  if (url instanceof Error) {
+    if (process.env.NODE_ENV !== "production") throw url
+    const errorLogger = options.logger?.error ?? console.error
+    errorLogger("INVALID_URL", url)
+    res.status(400)
+    return res.json({
+      message:
+        "There is a problem with the server configuration. Check the server logs for more information.",
+    })
+  }
 
   const request = new Request(url, {
-    headers: new Headers(req.headers as any),
+    headers,
     method: req.method,
     ...getBody(req),
   })
 
   options.secret ??= options.jwt?.secret ?? process.env.NEXTAUTH_SECRET
+  options.trustHost ??= !!(
+    process.env.NEXTAUTH_URL ??
+    process.env.AUTH_TRUST_HOST ??
+    process.env.VERCEL ??
+    process.env.NODE_ENV !== "production"
+  )
+
   const response = await AuthHandler(request, options)
-  const { status, headers } = response
-  res.status(status)
-
-  for (const [key, val] of headers.entries()) {
-    const value = key === "set-cookie" ? val.split(",") : val
-    res.setHeader(key, value)
-  }
-
-  // If the request expects a return URL, send it as JSON
-  // instead of doing an actual redirect.
-  const redirect = headers.get("Location")
-
-  if (req.body?.json === "true" && redirect) {
-    res.removeHeader("Location")
-    return res.json({ url: redirect })
-  }
+  res.status(response.status)
+  setHeaders(response.headers, res)
 
   return res.send(await response.text())
 }
@@ -142,26 +140,31 @@ export async function unstable_getServerSession<
     options = Object.assign({}, args[2], { providers: [] })
   }
 
-  const urlOrError = getURL(
-    "/api/auth/session",
-    options.trustHost,
-    req.headers["x-forwarded-host"] ?? req.headers.host
-  )
+  const url = getURL("/api/auth/session", new Headers(req.headers))
+  if (url instanceof Error) {
+    if (process.env.NODE_ENV !== "production") throw url
+    const errorLogger = options.logger?.error ?? console.error
+    errorLogger("INVALID_URL", url)
+    res.status(400)
+    return res.json({
+      message:
+        "There is a problem with the server configuration. Check the server logs for more information.",
+    })
+  }
 
-  if (urlOrError instanceof Error) throw urlOrError
+  const request = new Request(url, { headers: new Headers(req.headers) })
 
   options.secret ??= process.env.NEXTAUTH_SECRET
-  const response = await AuthHandler(
-    new Request(urlOrError, { headers: req.headers }),
-    options
-  )
+  options.trustHost = true
+  const response = await AuthHandler(request, options)
 
   const { status = 200, headers } = response
 
-  for (const [key, val] of headers.entries()) {
-    const value = key === "set-cookie" ? val.split(",") : val
-    res.setHeader(key, value)
-  }
+  setHeaders(headers, res)
+
+  // This would otherwise break rendering
+  // with `getServerSideProps` that needs to always return HTML
+  res.removeHeader?.("Content-Type")
 
   const data = await response.json()
 

packages/next-auth/src/next/middleware.ts

@@ -6,7 +6,17 @@ import { NextResponse, NextRequest } from "next/server"
 
 import { getToken } from "../jwt"
 import parseUrl from "../utils/parse-url"
-import { getURL } from "../utils/node"
+
+// // TODO: Remove
+/** Extract the host from the environment */
+export function detectHost(
+  trusted: boolean,
+  forwardedValue: string | null,
+  defaultValue: string | false
+): string | undefined {
+  if (trusted && forwardedValue) return forwardedValue
+  return defaultValue || undefined
+}
 
 type AuthorizedCallback = (params: {
   token: JWT | null
@@ -113,18 +123,19 @@ async function handleMiddleware(
   const signInPage = options?.pages?.signIn ?? "/api/auth/signin"
   const errorPage = options?.pages?.error ?? "/api/auth/error"
 
-  options.trustHost = Boolean(
-    options.trustHost ?? process.env.VERCEL ?? process.env.AUTH_TRUST_HOST
+  options.trustHost ??= !!(
+    process.env.NEXTAUTH_URL ??
+    process.env.VERCEL ??
+    process.env.AUTH_TRUST_HOST
   )
 
-  let authPath
-  const url = getURL(
-    null,
+  const host = detectHost(
     options.trustHost,
-    req.headers.get("x-forwarded-host") ?? req.headers.get("host")
+    req.headers?.get("x-forwarded-host"),
+    process.env.NEXTAUTH_URL ??
+      (process.env.NODE_ENV !== "production" && "http://localhost:3000")
   )
-  if (url instanceof URL) authPath = parseUrl(url).path
-  else authPath = "/api/auth"
+  const authPath = parseUrl(host).path
 
   const publicPaths = ["/_next", "/favicon.ico"]
 

packages/next-auth/src/react/index.tsx

@@ -241,13 +241,13 @@ export async function signIn<
     method: "post",
     headers: {
       "Content-Type": "application/x-www-form-urlencoded",
+      "X-Auth-Return-Redirect": "1",
     },
     // @ts-expect-error
     body: new URLSearchParams({
       ...options,
       csrfToken: await getCsrfToken(),
       callbackUrl,
-      json: true,
     }),
   })
 
@@ -291,12 +291,11 @@ export async function signOut<R extends boolean = true>(
     method: "post",
     headers: {
       "Content-Type": "application/x-www-form-urlencoded",
+      "X-Auth-Return-Redirect": "1",
     },
-    // @ts-expect-error
     body: new URLSearchParams({
-      csrfToken: await getCsrfToken(),
+      csrfToken: (await getCsrfToken()) ?? "",
       callbackUrl,
-      json: true,
     }),
   }
   const res = await fetch(`${baseUrl}/signout`, fetchOptions)

packages/next-auth/src/utils/node.ts

@@ -1,4 +1,4 @@
-import type { IncomingMessage } from "http"
+import type { IncomingMessage, ServerResponse } from "http"
 import type { GetServerSidePropsContext, NextApiRequest } from "next"
 
 export function setCookie(res, value: string) {
@@ -25,35 +25,135 @@ export function getBody(
   return { body: JSON.stringify(req.body) }
 }
 
-/** Extract the host from the environment */
-export function getURL(
-  url: string | undefined | null,
-  trusted: boolean | undefined = !!(
-    process.env.AUTH_TRUST_HOST ?? process.env.VERCEL
-  ),
-  forwardedValue: string | string[] | undefined | null
-): URL | Error {
+/**
+ * Extract the full request URL from the environment.
+ * NOTE: It does not verify if the host should be trusted.
+ */
+export function getURL(url: string | undefined, headers: Headers): URL | Error {
   try {
-    let host =
-      process.env.NEXTAUTH_URL ??
-      (process.env.NODE_ENV !== "production" && "http://localhost:3000")
+    if (!url) throw new Error("Missing url")
+    if (process.env.NEXTAUTH_URL) {
+      const base = new URL(process.env.NEXTAUTH_URL)
+      if (!["http:", "https:"].includes(base.protocol)) {
+        throw new Error("Invalid protocol")
+      }
+      const hasCustomPath = base.pathname !== "/"
 
-    if (trusted && forwardedValue) {
-      host = Array.isArray(forwardedValue) ? forwardedValue[0] : forwardedValue
+      if (hasCustomPath) {
+        const apiAuthRe = /\/api\/auth\/?$/
+        const basePathname = base.pathname.match(apiAuthRe)
+          ? base.pathname.replace(apiAuthRe, "")
+          : base.pathname
+        return new URL(basePathname.replace(/\/$/, "") + url, base.origin)
+      }
+      return new URL(url, base)
     }
-
-    if (!host) throw new TypeError("Invalid host")
-    if (!url) throw new TypeError("Invalid URL, cannot determine action")
-
-    if (host.startsWith("http://") || host.startsWith("https://")) {
-      return new URL(`${host}${url}`)
-    }
-    return new URL(`https://${host}${url}`)
+    const proto =
+      headers.get("x-forwarded-proto") ??
+      (process.env.NODE_ENV !== "production" ? "http" : "https")
+    const host = headers.get("x-forwarded-host") ?? headers.get("host")
+    if (!["http", "https"].includes(proto)) throw new Error("Invalid protocol")
+    const origin = `${proto}://${host}`
+    if (!host) throw new Error("Missing host")
+    return new URL(url, origin)
   } catch (error) {
     return error as Error
   }
 }
 
+/**
+ * Set-Cookie header field-values are sometimes comma joined in one string. This splits them without choking on commas
+ * that are within a single set-cookie field-value, such as in the Expires portion.
+ * This is uncommon, but explicitly allowed - see https://tools.ietf.org/html/rfc2616#section-4.2
+ * Node.js does this for every header *except* set-cookie - see https://github.com/nodejs/node/blob/d5e363b77ebaf1caf67cd7528224b651c86815c1/lib/_http_incoming.js#L128
+ * Based on: https://github.com/google/j2objc/commit/16820fdbc8f76ca0c33472810ce0cb03d20efe25
+ * Credits to: https://github.com/tomball for original and https://github.com/chrusart for JavaScript implementation
+ * @source https://github.com/nfriedly/set-cookie-parser/blob/3eab8b7d5d12c8ed87832532861c1a35520cf5b3/lib/set-cookie.js#L144
+ */
+function getSetCookies(cookiesString: string) {
+  if (typeof cookiesString !== "string") {
+    return []
+  }
+
+  const cookiesStrings: string[] = []
+  let pos = 0
+  let start
+  let ch
+  let lastComma: number
+  let nextStart
+  let cookiesSeparatorFound
+
+  function skipWhitespace() {
+    while (pos < cookiesString.length && /\s/.test(cookiesString.charAt(pos))) {
+      pos += 1
+    }
+    return pos < cookiesString.length
+  }
+
+  function notSpecialChar() {
+    ch = cookiesString.charAt(pos)
+
+    return ch !== "=" && ch !== ";" && ch !== ","
+  }
+
+  while (pos < cookiesString.length) {
+    start = pos
+    cookiesSeparatorFound = false
+
+    while (skipWhitespace()) {
+      ch = cookiesString.charAt(pos)
+      if (ch === ",") {
+        // ',' is a cookie separator if we have later first '=', not ';' or ','
+        lastComma = pos
+        pos += 1
+
+        skipWhitespace()
+        nextStart = pos
+
+        while (pos < cookiesString.length && notSpecialChar()) {
+          pos += 1
+        }
+
+        // currently special character
+        if (pos < cookiesString.length && cookiesString.charAt(pos) === "=") {
+          // we found cookies separator
+          cookiesSeparatorFound = true
+          // pos is inside the next cookie, so back up and return it.
+          pos = nextStart
+          cookiesStrings.push(cookiesString.substring(start, lastComma))
+          start = pos
+        } else {
+          // in param ',' or param separator ';',
+          // we continue from that comma
+          pos = lastComma + 1
+        }
+      } else {
+        pos += 1
+      }
+    }
+
+    if (!cookiesSeparatorFound || pos >= cookiesString.length) {
+      cookiesStrings.push(cookiesString.substring(start, cookiesString.length))
+    }
+  }
+
+  return cookiesStrings
+}
+
+export function setHeaders(headers: Headers, res: ServerResponse) {
+  for (const [key, val] of headers.entries()) {
+    let value: string | string[] = val
+    // See: https://github.com/whatwg/fetch/issues/973
+    if (key === "set-cookie") {
+      const cookies = getSetCookies(value)
+      let original = res.getHeader("set-cookie") as string[] | string
+      original = Array.isArray(original) ? original : [original]
+      value = original.concat(cookies).filter(Boolean)
+    }
+    res.setHeader(key, value)
+  }
+}
+
 declare global {
   // eslint-disable-next-line @typescript-eslint/no-namespace
   namespace NodeJS {

packages/next-auth/src/utils/parse-url.ts

@@ -11,7 +11,10 @@ export interface InternalUrl {
   toString: () => string
 }
 
-/** Returns an `URL` like object to make requests/redirects from server-side */
+/**
+ * TODO: Can we remove this?
+ * Returns an `URL` like object to make requests/redirects from server-side
+ */
 export default function parseUrl(url?: string | URL): InternalUrl {
   const defaultUrl = new URL("http://localhost:3000/api/auth")
 

packages/next-auth/src/utils/web.ts

@@ -1,4 +1,5 @@
 import { serialize, parse as parseCookie } from "cookie"
+import { UnknownAction } from "../core/errors"
 import type { ResponseInternal, RequestInternal } from "../core"
 import type { AuthAction } from "../core/types"
 
@@ -41,40 +42,51 @@ async function readJSONBody(
   }
 }
 
+// prettier-ignore
+const actions: AuthAction[] = [ "providers", "session", "csrf", "signin", "signout", "callback", "verify-request", "error", "_log" ]
+
 export async function toInternalRequest(
   req: Request
-): Promise<RequestInternal> {
-  const url = new URL(req.url)
-  const nextauth = url.pathname.split("/").slice(3)
-  const headers = Object.fromEntries(req.headers)
-  const query: Record<string, any> = Object.fromEntries(url.searchParams)
+): Promise<RequestInternal | Error> {
+  try {
+    // TODO: url.toString() should not include action and providerId
+    // see init.ts
+    const url = new URL(req.url.replace(/\/$/, ""))
+    const { pathname } = url
 
-  const cookieHeader = req.headers.get("cookie") ?? ""
-  const cookies =
-    parseCookie(
-      Array.isArray(cookieHeader) ? cookieHeader.join(";") : cookieHeader
-    ) ?? {}
+    const action = actions.find((a) => pathname.includes(a))
+    if (!action) {
+      throw new UnknownAction("Cannot detect action.")
+    }
 
-  return {
-    action: nextauth[0] as AuthAction,
-    method: req.method,
-    headers,
-    body: req.body ? await readJSONBody(req.body) : undefined,
-    cookies: cookies,
-    providerId: nextauth[1],
-    error: url.searchParams.get("error") ?? undefined,
-    host: new URL(req.url).origin,
-    query,
+    const providerIdOrAction = pathname.split("/").pop()
+    let providerId
+    if (
+      providerIdOrAction &&
+      !action.includes(providerIdOrAction) &&
+      ["signin", "callback"].includes(action)
+    ) {
+      providerId = providerIdOrAction
+    }
+
+    return {
+      url,
+      action,
+      providerId,
+      method: req.method ?? "GET",
+      headers: Object.fromEntries(req.headers),
+      body: req.body ? await readJSONBody(req.body) : undefined,
+      cookies: parseCookie(req.headers.get("cookie") ?? "") ?? {},
+      error: url.searchParams.get("error") ?? undefined,
+      query: Object.fromEntries(url.searchParams),
+    }
+  } catch (error) {
+    return error
   }
 }
 
 export function toResponse(res: ResponseInternal): Response {
-  const headers = new Headers(
-    res.headers?.reduce((acc, { key, value }) => {
-      acc[key] = value
-      return acc
-    }, {})
-  )
+  const headers = new Headers(res.headers)
 
   res.cookies?.forEach((cookie) => {
     const { name, value, options } = cookie

packages/next-auth/tests/assert.test.ts

@@ -9,7 +9,7 @@ import EmailProvider from "../src/providers/email"
 
 it("Show error page if secret is not defined", async () => {
   const { res, log } = await handler(
-    { providers: [], secret: undefined },
+    { providers: [], secret: undefined, trustHost: true },
     { prod: true }
   )
 
@@ -28,6 +28,7 @@ it("Show error page if adapter is missing functions when using with email", asyn
       adapter: missingFunctionAdapter,
       providers: [EmailProvider({ sendVerificationRequest })],
       secret: "secret",
+      trustHost: true,
     },
     { prod: true }
   )
@@ -48,6 +49,7 @@ it("Show error page if adapter is not configured when using with email", async (
     {
       providers: [EmailProvider({ sendVerificationRequest })],
       secret: "secret",
+      trustHost: true,
     },
     { prod: true }
   )
@@ -64,7 +66,7 @@ it("Show error page if adapter is not configured when using with email", async (
 
 it("Should show configuration error page on invalid `callbackUrl`", async () => {
   const { res, log } = await handler(
-    { providers: [] },
+    { providers: [], trustHost: true },
     { prod: true, params: { callbackUrl: "invalid-callback" } }
   )
 
@@ -80,7 +82,7 @@ it("Should show configuration error page on invalid `callbackUrl`", async () =>
 
 it("Allow relative `callbackUrl`", async () => {
   const { res, log } = await handler(
-    { providers: [] },
+    { providers: [], trustHost: true },
     { prod: true, params: { callbackUrl: "/callback" } }
   )
 

packages/next-auth/tests/email.test.ts

@@ -14,6 +14,7 @@ it("Send e-mail to the only address correctly", async () => {
       providers: [EmailProvider({ sendVerificationRequest })],
       callbacks: { signIn },
       secret,
+      trustHost: true,
     },
     {
       path: "signin/email",
@@ -54,6 +55,7 @@ it("Send e-mail to first address only", async () => {
       providers: [EmailProvider({ sendVerificationRequest })],
       callbacks: { signIn },
       secret,
+      trustHost: true,
     },
     {
       path: "signin/email",
@@ -94,6 +96,7 @@ it("Send e-mail to address with first domain", async () => {
       providers: [EmailProvider({ sendVerificationRequest })],
       callbacks: { signIn },
       secret,
+      trustHost: true,
     },
     {
       path: "signin/email",
@@ -140,6 +143,7 @@ it("Redirect to error page if multiple addresses aren't allowed", async () => {
         }),
       ],
       secret,
+      trustHost: true,
     },
     {
       path: "signin/email",

packages/next-auth/tests/getURL.test.ts

@@ -0,0 +1,138 @@
+import { getURL as getURLOriginal } from "../src/utils/node"
+
+it("Should return error when missing url", () => {
+  expect(getURL(undefined, {})).toEqual(new Error("Missing url"))
+})
+
+it("Should return error when missing host", () => {
+  expect(getURL("/", {})).toEqual(new Error("Missing host"))
+})
+
+it("Should return error when invalid protocol", () => {
+  expect(
+    getURL("/", { host: "localhost", "x-forwarded-proto": "file" })
+  ).toEqual(new Error("Invalid protocol"))
+})
+
+it("Should return error when invalid host", () => {
+  expect(getURL("/", { host: "/" })).toEqual(
+    new TypeError("Invalid base URL: http:///")
+  )
+})
+
+it("Should read host headers", () => {
+  expect(getURL("/api/auth/session", { host: "localhost" })).toBeURL(
+    "http://localhost/api/auth/session"
+  )
+
+  expect(
+    getURL("/custom/api/auth/session", { "x-forwarded-host": "localhost:3000" })
+  ).toBeURL("http://localhost:3000/custom/api/auth/session")
+
+  // Prefer x-forwarded-host over host
+  expect(
+    getURL("/", { host: "localhost", "x-forwarded-host": "localhost:3000" })
+  ).toBeURL("http://localhost:3000/")
+})
+
+it("Should read protocol headers", () => {
+  expect(
+    getURL("/", { host: "localhost", "x-forwarded-proto": "http" })
+  ).toBeURL("http://localhost/")
+})
+
+describe("process.env.NEXTAUTH_URL", () => {
+  afterEach(() => delete process.env.NEXTAUTH_URL)
+
+  it("Should prefer over headers if present", () => {
+    process.env.NEXTAUTH_URL = "http://localhost:3000"
+    expect(getURL("/api/auth/session", { host: "localhost" })).toBeURL(
+      "http://localhost:3000/api/auth/session"
+    )
+  })
+
+  it("catch errors", () => {
+    process.env.NEXTAUTH_URL = "invald-url"
+    expect(getURL("/api/auth/session", {})).toEqual(
+      new TypeError("Invalid URL: invald-url")
+    )
+
+    process.env.NEXTAUTH_URL = "file://localhost"
+    expect(getURL("/api/auth/session", {})).toEqual(
+      new TypeError("Invalid protocol")
+    )
+  })
+
+  it("Supports custom base path", () => {
+    process.env.NEXTAUTH_URL = "http://localhost:3000/custom/api/auth"
+    expect(getURL("/api/auth/session", {})).toBeURL(
+      "http://localhost:3000/custom/api/auth/session"
+    )
+
+    // With trailing slash
+    process.env.NEXTAUTH_URL = "http://localhost:3000/custom/api/auth/"
+    expect(getURL("/api/auth/session", {})).toBeURL(
+      "http://localhost:3000/custom/api/auth/session"
+    )
+
+    // Multiple custom segments
+    process.env.NEXTAUTH_URL = "http://localhost:3000/custom/path/api/auth"
+    expect(getURL("/api/auth/session", {})).toBeURL(
+      "http://localhost:3000/custom/path/api/auth/session"
+    )
+
+    process.env.NEXTAUTH_URL = "http://localhost:3000/custom/path/api/auth/"
+    expect(getURL("/api/auth/session", {})).toBeURL(
+      "http://localhost:3000/custom/path/api/auth/session"
+    )
+
+    // No /api/auth
+    process.env.NEXTAUTH_URL = "http://localhost:3000/custom/nextauth"
+    expect(getURL("/session", {})).toBeURL(
+      "http://localhost:3000/custom/nextauth/session"
+    )
+
+    // No /api/auth, with trailing slash
+    process.env.NEXTAUTH_URL = "http://localhost:3000/custom/nextauth/"
+    expect(getURL("/session", {})).toBeURL(
+      "http://localhost:3000/custom/nextauth/session"
+    )
+  })
+})
+
+// Utils
+
+function getURL(
+  url: Parameters<typeof getURLOriginal>[0],
+  headers: HeadersInit
+) {
+  return getURLOriginal(url, new Headers(headers))
+}
+
+expect.extend({
+  toBeURL(rec, exp) {
+    const r = rec.toString()
+    const e = exp.toString()
+    const printR = this.utils.printReceived
+    const printE = this.utils.printExpected
+    if (r === e) {
+      return {
+        message: () => `expected ${printE(e)} not to be ${printR(r)}`,
+        pass: true,
+      }
+    }
+    return {
+      message: () => `expected ${printE(e)}, got ${printR(r)}`,
+      pass: false,
+    }
+  },
+})
+
+declare global {
+  // eslint-disable-next-line @typescript-eslint/no-namespace
+  namespace jest {
+    interface Matchers<R> {
+      toBeURL: (expected: string) => R
+    }
+  }
+}

packages/next-auth/tests/middleware.test.ts

@@ -6,91 +6,64 @@ it("should not match pages as public paths", async () => {
     pages: { signIn: "/", error: "/" },
     secret: "secret",
   }
-
-  const req = new NextRequest("http://127.0.0.1/protected/pathA", {
-    headers: { authorization: "" },
-  })
-
   const handleMiddleware = withAuth(options) as NextMiddleware
-  const res = await handleMiddleware(req, null as any)
-  expect(res).toBeDefined()
-  expect(res?.status).toBe(307)
+
+  const response = await handleMiddleware(
+    new NextRequest("http://127.0.0.1/protected/pathA"),
+    null as any
+  )
+
+  expect(response?.status).toBe(307)
+  expect(response?.headers.get("location")).toBe(
+    "http://localhost/?callbackUrl=%2Fprotected%2FpathA"
+  )
 })
 
 it("should not redirect on public paths", async () => {
   const options: NextAuthMiddlewareOptions = { secret: "secret" }
 
-  const req = new NextRequest("http://127.0.0.1/_next/foo", {
-    headers: { authorization: "" },
-  })
+  const req = new NextRequest("http://127.0.0.1/_next/foo")
 
   const handleMiddleware = withAuth(options) as NextMiddleware
   const res = await handleMiddleware(req, null as any)
   expect(res).toBeUndefined()
 })
 
-it("should redirect according to nextUrl basePath", async () => {
+it("should respect NextURL#basePath when redirecting", async () => {
   const options: NextAuthMiddlewareOptions = { secret: "secret" }
-
-  const req = {
-    nextUrl: {
-      pathname: "/protected/pathA",
-      search: "",
-      origin: "http://127.0.0.1",
-      basePath: "/custom-base-path",
-    },
-    headers: new Headers({ authorization: "" }),
-  }
-
   const handleMiddleware = withAuth(options) as NextMiddleware
-  const res = await handleMiddleware(req as NextRequest, null as any)
-  expect(res).toBeDefined()
-  expect(res?.status).toEqual(307)
-  expect(res?.headers.get("location")).toContain(
-    "http://127.0.0.1/custom-base-path/api/auth/signin?callbackUrl=%2Fcustom-base-path%2Fprotected%2FpathA"
+
+  const response1 = await handleMiddleware(
+    {
+      nextUrl: {
+        pathname: "/protected/pathA",
+        search: "",
+        origin: "http://127.0.0.1",
+        basePath: "/custom-base-path",
+      },
+    } as unknown as NextRequest,
+    null as any
   )
-})
-
-it("should redirect according to nextUrl basePath", async () => {
-  // given
-  const options: NextAuthMiddlewareOptions = { secret: "secret" }
-
-  const handleMiddleware = withAuth(options) as NextMiddleware
-
-  const req1 = {
-    nextUrl: {
-      pathname: "/protected/pathA",
-      search: "",
-      origin: "http://127.0.0.1",
-      basePath: "/custom-base-path",
-    },
-    headers: new Headers({ authorization: "" }),
-  }
-  // when
-  const res = await handleMiddleware(req1 as NextRequest, null as any)
-
-  // then
-  expect(res).toBeDefined()
-  expect(res?.status).toEqual(307)
-  expect(res?.headers.get("location")).toContain(
+  expect(response1?.status).toEqual(307)
+  expect(response1?.headers.get("location")).toBe(
     "http://127.0.0.1/custom-base-path/api/auth/signin?callbackUrl=%2Fcustom-base-path%2Fprotected%2FpathA"
   )
 
-  const req2 = {
-    nextUrl: {
-      pathname: "/api/auth/signin",
-      search: "callbackUrl=%2Fcustom-base-path%2Fprotected%2FpathA",
-      origin: "http://127.0.0.1",
-      basePath: "/custom-base-path",
-    },
-    headers: new Headers({ authorization: "" }),
-  }
-  // and when follow redirect
-  const resFromRedirectedUrl = await handleMiddleware(
-    req2 as NextRequest,
+  // Should not redirect when invoked on sign in page
+
+  const response2 = await handleMiddleware(
+    {
+      nextUrl: {
+        pathname: "/api/auth/signin",
+        searchParams: new URLSearchParams({
+          callbackUrl: "/custom-base-path/protected/pathA",
+        }),
+        origin: "http://127.0.0.1",
+        basePath: "/custom-base-path",
+      },
+    } as unknown as NextRequest,
     null as any
   )
 
-  // then return sign in page
-  expect(resFromRedirectedUrl).toBeUndefined()
+  expect(response2).toBeUndefined()
 })

packages/next-auth/tests/next.test.ts

@@ -1,29 +1,47 @@
-// import { MissingAPIRoute } from "../src/core/errors"
-import { nodeHandler } from "./utils"
+import { mockReqRes, nextHandler } from "./utils"
 
-it("Missing req.url throws MISSING_NEXTAUTH_API_ROUTE_ERROR", async () => {
-  const { res } = await nodeHandler()
-
-  expect(res.status).toBeCalledWith(400)
-  // Moved to host detection in getUrl
-  // expect(logger.error).toBeCalledTimes(1)
-  // expect(logger.error).toBeCalledWith(
-  //   "MISSING_NEXTAUTH_API_ROUTE_ERROR",
-  //   expect.any(MissingAPIRoute)
-  // )
-  // expect(res.setHeader).toBeCalledWith("content-type", "application/json")
-  // const body = res.send.mock.calls[0][0]
-  // expect(JSON.parse(body)).toEqual({
-  //   message:
-  //     "There is a problem with the server configuration. Check the server logs for more information.",
-  // })
+it("Missing req.url throws in dev", async () => {
+  await expect(nextHandler).rejects.toThrow(new Error("Missing url"))
 })
 
-it("Missing host throws 400 in production", async () => {
+const configErrorMessage =
+  "There is a problem with the server configuration. Check the server logs for more information."
+
+it("Missing req.url returns config error in prod", async () => {
   // @ts-expect-error
   process.env.NODE_ENV = "production"
-  const { res } = await nodeHandler()
+  const { res, logger } = await nextHandler()
+
+  expect(logger.error).toBeCalledTimes(1)
+  const error = new Error("Missing url")
+  expect(logger.error).toBeCalledWith("INVALID_URL", error)
+
   expect(res.status).toBeCalledWith(400)
+  expect(res.json).toBeCalledWith({ message: configErrorMessage })
+
+  // @ts-expect-error
+  process.env.NODE_ENV = "test"
+})
+
+it("Missing host throws in dev", async () => {
+  await expect(
+    async () =>
+      await nextHandler({
+        req: { query: { nextauth: ["session"] } },
+      })
+  ).rejects.toThrow(Error)
+})
+
+it("Missing host config error in prod", async () => {
+  // @ts-expect-error
+  process.env.NODE_ENV = "production"
+  const { res, logger } = await nextHandler({
+    req: { query: { nextauth: ["session"] } },
+  })
+  expect(res.status).toBeCalledWith(400)
+  expect(res.json).toBeCalledWith({ message: configErrorMessage })
+
+  expect(logger.error).toBeCalledWith("INVALID_URL", new Error("Missing url"))
   // @ts-expect-error
   process.env.NODE_ENV = "test"
 })
@@ -31,7 +49,7 @@ it("Missing host throws 400 in production", async () => {
 it("Defined host throws 400 in production if not trusted", async () => {
   // @ts-expect-error
   process.env.NODE_ENV = "production"
-  const { res } = await nodeHandler({
+  const { res } = await nextHandler({
     req: { headers: { host: "http://localhost" } },
   })
   expect(res.status).toBeCalledWith(400)
@@ -42,7 +60,7 @@ it("Defined host throws 400 in production if not trusted", async () => {
 it("Defined host throws 400 in production if trusted but invalid URL", async () => {
   // @ts-expect-error
   process.env.NODE_ENV = "production"
-  const { res } = await nodeHandler({
+  const { res } = await nextHandler({
     req: { headers: { host: "localhost" } },
     options: { trustHost: true },
   })
@@ -54,7 +72,7 @@ it("Defined host throws 400 in production if trusted but invalid URL", async ()
 it("Defined host does not throw in production if trusted and valid URL", async () => {
   // @ts-expect-error
   process.env.NODE_ENV = "production"
-  const { res } = await nodeHandler({
+  const { res } = await nextHandler({
     req: {
       url: "/api/auth/session",
       headers: { host: "http://localhost" },
@@ -62,6 +80,7 @@ it("Defined host does not throw in production if trusted and valid URL", async (
     options: { trustHost: true },
   })
   expect(res.status).toBeCalledWith(200)
+  // @ts-expect-error
   expect(JSON.parse(res.send.mock.calls[0][0])).toEqual({})
   // @ts-expect-error
   process.env.NODE_ENV = "test"
@@ -69,25 +88,92 @@ it("Defined host does not throw in production if trusted and valid URL", async (
 
 it("Use process.env.NEXTAUTH_URL for host if present", async () => {
   process.env.NEXTAUTH_URL = "http://localhost"
-  const { res } = await nodeHandler({
+  const { res } = await nextHandler({
     req: { url: "/api/auth/session" },
   })
   expect(res.status).toBeCalledWith(200)
+  // @ts-expect-error
   expect(JSON.parse(res.send.mock.calls[0][0])).toEqual({})
 })
 
 it("Redirects if necessary", async () => {
   process.env.NEXTAUTH_URL = "http://localhost"
-  const { res } = await nodeHandler({
+  const { res } = await nextHandler({
     req: {
       method: "post",
       url: "/api/auth/signin/github",
-      body: { json: "true" },
     },
   })
   expect(res.status).toBeCalledWith(302)
-  expect(res.removeHeader).toBeCalledWith("Location")
-  expect(res.json).toBeCalledWith({
-    url: "http://localhost/api/auth/signin?csrf=true",
+  expect(res.getHeaders()).toEqual({
+    location: "http://localhost/api/auth/signin?csrf=true",
+    "set-cookie": [
+      expect.stringMatching(
+        /next-auth.csrf-token=.*; Path=\/; HttpOnly; SameSite=Lax/
+      ),
+      `next-auth.callback-url=${encodeURIComponent(
+        process.env.NEXTAUTH_URL
+      )}; Path=/; HttpOnly; SameSite=Lax`,
+    ],
   })
+
+  expect(res.send).toBeCalledWith("")
+})
+
+it("Returns redirect if `X-Auth-Return-Redirect` header is present", async () => {
+  process.env.NEXTAUTH_URL = "http://localhost"
+  const { res } = await nextHandler({
+    req: {
+      method: "post",
+      url: "/api/auth/signin/github",
+      headers: { "X-Auth-Return-Redirect": "1" },
+    },
+  })
+
+  expect(res.status).toBeCalledWith(200)
+
+  expect(res.getHeaders()).toEqual({
+    "content-type": "application/json",
+    "set-cookie": [
+      expect.stringMatching(
+        /next-auth.csrf-token=.*; Path=\/; HttpOnly; SameSite=Lax/
+      ),
+      `next-auth.callback-url=${encodeURIComponent(
+        process.env.NEXTAUTH_URL
+      )}; Path=/; HttpOnly; SameSite=Lax`,
+    ],
+  })
+
+  expect(res.send).toBeCalledWith(
+    JSON.stringify({ url: "http://localhost/api/auth/signin?csrf=true" })
+  )
+})
+
+it("Should preserve user's `set-cookie` headers", async () => {
+  const { req, res } = mockReqRes({
+    method: "post",
+    url: "/api/auth/signin/credentials",
+    headers: { host: "localhost", "X-Auth-Return-Redirect": "1" },
+  })
+  res.setHeader("set-cookie", ["foo=bar", "bar=baz"])
+
+  await nextHandler({ req, res })
+
+  expect(res.getHeaders()).toEqual({
+    "content-type": "application/json",
+    "set-cookie": [
+      "foo=bar",
+      "bar=baz",
+      expect.stringMatching(
+        /next-auth.csrf-token=.*; Path=\/; HttpOnly; SameSite=Lax/
+      ),
+      `next-auth.callback-url=${encodeURIComponent(
+        "http://localhost"
+      )}; Path=/; HttpOnly; SameSite=Lax`,
+    ],
+  })
+
+  expect(res.send).toBeCalledWith(
+    JSON.stringify({ url: "http://localhost/api/auth/signin?csrf=true" })
+  )
 })

packages/next-auth/tests/utils.ts

@@ -1,11 +1,14 @@
-import { createHash } from "crypto"
-import { AuthHandler } from "../src/core"
-import type { LoggerInstance, AuthOptions } from "../src"
+import { createHash } from "node:crypto"
+import { IncomingMessage, ServerResponse } from "node:http"
+import { Socket } from "node:net"
+import type { AuthOptions, LoggerInstance } from "../src"
 import type { Adapter } from "../src/adapters"
+import { AuthHandler } from "../src/core"
 
 import NextAuth from "../src/next"
 
 import type { NextApiRequest, NextApiResponse } from "next"
+import { Stream } from "node:stream"
 
 export function mockLogger(): Record<keyof LoggerInstance, jest.Mock> {
   return {
@@ -79,38 +82,143 @@ export function mockAdapter(): Adapter {
   return adapter
 }
 
-export async function nodeHandler(
+export async function nextHandler(
   params: {
     req?: Partial<NextApiRequest>
     res?: Partial<NextApiResponse>
     options?: Partial<AuthOptions>
   } = {}
 ) {
-  const req = {
-    body: {},
-    cookies: {},
-    headers: {},
-    method: "GET",
-    ...params.req,
-  }
-
-  const res = {
-    ...params.res,
-    end: jest.fn(),
-    json: jest.fn(),
-    status: jest.fn().mockReturnValue({ end: jest.fn() }),
-    setHeader: jest.fn(),
-    removeHeader: jest.fn(),
-    send: jest.fn(),
+  let req = params.req
+  // @ts-expect-error
+  let res: NextApiResponse = params.res
+  if (!params.res) {
+    ;({ req, res } = mockReqRes(params.req))
   }
 
   const logger = mockLogger()
-
-  await NextAuth(req as any, res as any, {
+  // @ts-expect-error
+  await NextAuth(req, res, {
     providers: [],
     secret: "secret",
     logger,
     ...params.options,
   })
+
   return { req, res, logger }
 }
+
+export function mockReqRes(req?: Partial<NextApiRequest>): {
+  req: NextApiRequest
+  res: NextApiResponse
+} {
+  const request = new IncomingMessage(new Socket())
+  request.headers = req?.headers ?? {}
+  request.method = req?.method
+  request.url = req?.url
+
+  const response = new ServerResponse(request)
+  // @ts-expect-error
+  response.status = (code) => (response.statusCode = code)
+  // @ts-expect-error
+  response.send = (data) => sendData(request, response, data)
+  // @ts-expect-error
+  response.json = (data) => sendJson(response, data)
+
+  const res: NextApiResponse = {
+    ...response,
+    // @ts-expect-error
+    setHeader: jest.spyOn(response, "setHeader"),
+    // @ts-expect-error
+    getHeader: jest.spyOn(response, "getHeader"),
+    // @ts-expect-error
+    removeHeader: jest.spyOn(response, "removeHeader"),
+    // @ts-expect-error
+    status: jest.spyOn(response, "status"),
+    // @ts-expect-error
+    send: jest.spyOn(response, "send"),
+    // @ts-expect-error
+    json: jest.spyOn(response, "json"),
+    // @ts-expect-error
+    end: jest.spyOn(response, "end"),
+    // @ts-expect-error
+    getHeaders: jest.spyOn(response, "getHeaders"),
+  }
+
+  return { req: request as any, res }
+}
+
+// Code below is copied from Next.js
+// https://github.com/vercel/next.js/tree/canary/packages/next/server/api-utils
+// TODO: Remove
+
+/**
+ * Send `any` body to response
+ * @param req request object
+ * @param res response object
+ * @param body of response
+ */
+function sendData(req: NextApiRequest, res: NextApiResponse, body: any): void {
+  if (body === null || body === undefined) {
+    res.end()
+    return
+  }
+
+  // strip irrelevant headers/body
+  if (res.statusCode === 204 || res.statusCode === 304) {
+    res.removeHeader("Content-Type")
+    res.removeHeader("Content-Length")
+    res.removeHeader("Transfer-Encoding")
+
+    if (process.env.NODE_ENV === "development" && body) {
+      console.warn(
+        `A body was attempted to be set with a 204 statusCode for ${req.url}, this is invalid and the body was ignored.\n` +
+          `See more info here https://nextjs.org/docs/messages/invalid-api-status-body`
+      )
+    }
+    res.end()
+    return
+  }
+
+  const contentType = res.getHeader("Content-Type")
+
+  if (body instanceof Stream) {
+    if (!contentType) {
+      res.setHeader("Content-Type", "application/octet-stream")
+    }
+    body.pipe(res)
+    return
+  }
+
+  const isJSONLike = ["object", "number", "boolean"].includes(typeof body)
+  const stringifiedBody = isJSONLike ? JSON.stringify(body) : body
+
+  if (Buffer.isBuffer(body)) {
+    if (!contentType) {
+      res.setHeader("Content-Type", "application/octet-stream")
+    }
+    res.setHeader("Content-Length", body.length)
+    res.end(body)
+    return
+  }
+
+  if (isJSONLike) {
+    res.setHeader("Content-Type", "application/json; charset=utf-8")
+  }
+
+  res.setHeader("Content-Length", Buffer.byteLength(stringifiedBody))
+  res.end(stringifiedBody)
+}
+
+/**
+ * Send `JSON` object
+ * @param res response object
+ * @param jsonBody of data
+ */
+function sendJson(res: NextApiResponse, jsonBody: any): void {
+  // Set header to application/json
+  res.setHeader("Content-Type", "application/json; charset=utf-8")
+
+  // Use send to handle request
+  res.send(JSON.stringify(jsonBody))
+}