next.js/packages/next/src/server/api-utils/index.ts

import type { IncomingMessage } from 'http'
import type { BaseNextRequest } from '../base-http'
import type { CookieSerializeOptions } from 'next/dist/compiled/cookie'
import type { NextApiResponse } from '../../shared/lib/utils'

import { HeadersAdapter } from '../web/spec-extension/adapters/headers'
import {
  PRERENDER_REVALIDATE_HEADER,
  PRERENDER_REVALIDATE_ONLY_GENERATED_HEADER,
} from '../../lib/constants'
import { getTracer } from '../lib/trace/tracer'
import { NodeSpan } from '../lib/trace/constants'

export type NextApiRequestCookies = Partial<{ [key: string]: string }>
export type NextApiRequestQuery = Partial<{ [key: string]: string | string[] }>

export type __ApiPreviewProps = {
  previewModeId: string
  previewModeEncryptionKey: string
  previewModeSigningKey: string
}

export function wrapApiHandler<T extends (...args: any[]) => any>(
  page: string,
  handler: T
): T {
  return ((...args) => {
    getTracer().setRootSpanAttribute('next.route', page)
    // Call API route method
    return getTracer().trace(
      NodeSpan.runHandler,
      {
        spanName: `executing api route (pages) ${page}`,
      },
      () => handler(...args)
    )
  }) as T
}

/**
 *
 * @param res response object
 * @param statusCode `HTTP` status code of response
 */
export function sendStatusCode(
  res: NextApiResponse,
  statusCode: number
): NextApiResponse<any> {
  res.statusCode = statusCode
  return res
}

/**
 *
 * @param res response object
 * @param [statusOrUrl] `HTTP` status code of redirect
 * @param url URL of redirect
 */
export function redirect(
  res: NextApiResponse,
  statusOrUrl: string | number,
  url?: string
): NextApiResponse<any> {
  if (typeof statusOrUrl === 'string') {
    url = statusOrUrl
    statusOrUrl = 307
  }
  if (typeof statusOrUrl !== 'number' || typeof url !== 'string') {
    throw new Error(
      `Invalid redirect arguments. Please use a single argument URL, e.g. res.redirect('/destination') or use a status code and URL, e.g. res.redirect(307, '/destination').`
    )
  }
  res.writeHead(statusOrUrl, { Location: url })
  res.write(url)
  res.end()
  return res
}

export function checkIsOnDemandRevalidate(
  req: Request | IncomingMessage | BaseNextRequest,
  previewProps: __ApiPreviewProps
): {
  isOnDemandRevalidate: boolean
  revalidateOnlyGenerated: boolean
} {
  const headers = HeadersAdapter.from(req.headers)

  const previewModeId = headers.get(PRERENDER_REVALIDATE_HEADER)
  const isOnDemandRevalidate = previewModeId === previewProps.previewModeId

  const revalidateOnlyGenerated = headers.has(
    PRERENDER_REVALIDATE_ONLY_GENERATED_HEADER
  )

  return { isOnDemandRevalidate, revalidateOnlyGenerated }
}

export const COOKIE_NAME_PRERENDER_BYPASS = `__prerender_bypass`
export const COOKIE_NAME_PRERENDER_DATA = `__next_preview_data`

export const RESPONSE_LIMIT_DEFAULT = 4 * 1024 * 1024

export const SYMBOL_PREVIEW_DATA = Symbol(COOKIE_NAME_PRERENDER_DATA)
export const SYMBOL_CLEARED_COOKIES = Symbol(COOKIE_NAME_PRERENDER_BYPASS)

export function clearPreviewData<T>(
  res: NextApiResponse<T>,
  options: {
    path?: string
  } = {}
): NextApiResponse<T> {
  if (SYMBOL_CLEARED_COOKIES in res) {
    return res
  }

  const { serialize } =
    require('next/dist/compiled/cookie') as typeof import('next/dist/compiled/cookie')
  const previous = res.getHeader('Set-Cookie')
  res.setHeader(`Set-Cookie`, [
    ...(typeof previous === 'string'
      ? [previous]
      : Array.isArray(previous)
        ? previous
        : []),
    serialize(COOKIE_NAME_PRERENDER_BYPASS, '', {
      // To delete a cookie, set `expires` to a date in the past:
      // https://tools.ietf.org/html/rfc6265#section-4.1.1
      // `Max-Age: 0` is not valid, thus ignored, and the cookie is persisted.
      expires: new Date(0),
      httpOnly: true,
      sameSite: process.env.NODE_ENV !== 'development' ? 'none' : 'lax',
      secure: process.env.NODE_ENV !== 'development',
      path: '/',
      ...(options.path !== undefined
        ? ({ path: options.path } as CookieSerializeOptions)
        : undefined),
    }),
    serialize(COOKIE_NAME_PRERENDER_DATA, '', {
      // To delete a cookie, set `expires` to a date in the past:
      // https://tools.ietf.org/html/rfc6265#section-4.1.1
      // `Max-Age: 0` is not valid, thus ignored, and the cookie is persisted.
      expires: new Date(0),
      httpOnly: true,
      sameSite: process.env.NODE_ENV !== 'development' ? 'none' : 'lax',
      secure: process.env.NODE_ENV !== 'development',
      path: '/',
      ...(options.path !== undefined
        ? ({ path: options.path } as CookieSerializeOptions)
        : undefined),
    }),
  ])

  Object.defineProperty(res, SYMBOL_CLEARED_COOKIES, {
    value: true,
    enumerable: false,
  })
  return res
}

/**
 * Custom error class
 */
export class ApiError extends Error {
  readonly statusCode: number

  constructor(statusCode: number, message: string) {
    super(message)
    this.statusCode = statusCode
  }
}

/**
 * Sends error in `response`
 * @param res response object
 * @param statusCode of response
 * @param message of response
 */
export function sendError(
  res: NextApiResponse,
  statusCode: number,
  message: string
): void {
  res.statusCode = statusCode
  res.statusMessage = message
  res.end(message)
}

interface LazyProps {
  req: IncomingMessage
}

/**
 * Execute getter function only if its needed
 * @param LazyProps `req` and `params` for lazyProp
 * @param prop name of property
 * @param getter function to get data
 */
export function setLazyProp<T>(
  { req }: LazyProps,
  prop: string,
  getter: () => T
): void {
  const opts = { configurable: true, enumerable: true }
  const optsReset = { ...opts, writable: true }

  Object.defineProperty(req, prop, {
    ...opts,
    get: () => {
      const value = getter()
      // we set the property on the object to avoid recalculating it
      Object.defineProperty(req, prop, { ...optsReset, value })
      return value
    },
    set: (value) => {
      Object.defineProperty(req, prop, { ...optsReset, value })
    },
  })
}