resolve-url.ts

import path from '../../../shared/lib/isomorphic/path'
import * as Log from '../../../build/output/log'

function isStringOrURL(icon: any): icon is string | URL {
  return typeof icon === 'string' || icon instanceof URL
}

function createLocalMetadataBase() {
  return new URL(`http://localhost:${process.env.PORT || 3000}`)
}

// For deployment url for metadata routes, prefer to use the deployment url if possible
// as these routes are unique to the deployments url.
export function getSocialImageFallbackMetadataBase(
  metadataBase: URL | null
): URL | null {
  const isMetadataBaseMissing = !metadataBase
  const defaultMetadataBase = createLocalMetadataBase()
  const deploymentUrl =
    process.env.VERCEL_URL && new URL(`https://${process.env.VERCEL_URL}`)

  let fallbackMetadata
  if (process.env.NODE_ENV === 'development') {
    fallbackMetadata = defaultMetadataBase
  } else {
    fallbackMetadata =
      process.env.NODE_ENV === 'production' &&
      deploymentUrl &&
      process.env.VERCEL_ENV === 'preview'
        ? deploymentUrl
        : metadataBase || deploymentUrl || defaultMetadataBase
  }

  if (isMetadataBaseMissing) {
    Log.warnOnce('')
    Log.warnOnce(
      `metadata.metadataBase is not set for resolving social open graph or twitter images, using "${fallbackMetadata.origin}". See https://nextjs.org/docs/app/api-reference/functions/generate-metadata#metadatabase`
    )
  }

  return fallbackMetadata
}

function resolveUrl(url: null | undefined, metadataBase: URL | null): null
function resolveUrl(url: string | URL, metadataBase: URL | null): URL
function resolveUrl(
  url: string | URL | null | undefined,
  metadataBase: URL | null
): URL | null
function resolveUrl(
  url: string | URL | null | undefined,
  metadataBase: URL | null
): URL | null {
  if (url instanceof URL) return url
  if (!url) return null

  try {
    // If we can construct a URL instance from url, ignore metadataBase
    const parsedUrl = new URL(url)
    return parsedUrl
  } catch (_) {}

  if (!metadataBase) {
    metadataBase = createLocalMetadataBase()
  }

  // Handle relative or absolute paths
  const basePath = metadataBase.pathname || ''
  const joinedPath = path.join(basePath, url)

  return new URL(joinedPath, metadataBase)
}

// Resolve with `pathname` if `url` is a relative path.
function resolveRelativeUrl(url: string | URL, pathname: string): string | URL {
  if (typeof url === 'string' && url.startsWith('./')) {
    return path.resolve(pathname, url)
  }
  return url
}

// Resolve `pathname` if `url` is a relative path the compose with `metadataBase`.
function resolveAbsoluteUrlWithPathname(
  url: string | URL,
  metadataBase: URL | null,
  pathname: string
) {
  url = resolveRelativeUrl(url, pathname)

  const result = metadataBase ? resolveUrl(url, metadataBase) : url
  return result.toString()
}

export {
  isStringOrURL,
  resolveUrl,
  resolveRelativeUrl,
  resolveAbsoluteUrlWithPathname,
}