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node_modules/make-fetch-happen/lib/fetch.js

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+'use strict'
+
+const { FetchError, Request, isRedirect } = require('minipass-fetch')
+const url = require('url')
+
+const CachePolicy = require('./cache/policy.js')
+const cache = require('./cache/index.js')
+const remote = require('./remote.js')
+
+// given a Request, a Response and user options
+// return true if the response is a redirect that
+// can be followed. we throw errors that will result
+// in the fetch being rejected if the redirect is
+// possible but invalid for some reason
+const canFollowRedirect = (request, response, options) => {
+  if (!isRedirect(response.status)) {
+    return false
+  }
+
+  if (options.redirect === 'manual') {
+    return false
+  }
+
+  if (options.redirect === 'error') {
+    throw new FetchError(`redirect mode is set to error: ${request.url}`,
+      'no-redirect', { code: 'ENOREDIRECT' })
+  }
+
+  if (!response.headers.has('location')) {
+    throw new FetchError(`redirect location header missing for: ${request.url}`,
+      'no-location', { code: 'EINVALIDREDIRECT' })
+  }
+
+  if (request.counter >= request.follow) {
+    throw new FetchError(`maximum redirect reached at: ${request.url}`,
+      'max-redirect', { code: 'EMAXREDIRECT' })
+  }
+
+  return true
+}
+
+// given a Request, a Response, and the user's options return an object
+// with a new Request and a new options object that will be used for
+// following the redirect
+const getRedirect = (request, response, options) => {
+  const _opts = { ...options }
+  const location = response.headers.get('location')
+  const redirectUrl = new url.URL(location, /^https?:/.test(location) ? undefined : request.url)
+  // Comment below is used under the following license:
+  /**
+   * @license
+   * Copyright (c) 2010-2012 Mikeal Rogers
+   * Licensed under the Apache License, Version 2.0 (the "License");
+   * you may not use this file except in compliance with the License.
+   * You may obtain a copy of the License at
+   * http://www.apache.org/licenses/LICENSE-2.0
+   * Unless required by applicable law or agreed to in writing,
+   * software distributed under the License is distributed on an "AS
+   * IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
+   * express or implied. See the License for the specific language
+   * governing permissions and limitations under the License.
+   */
+
+  // Remove authorization if changing hostnames (but not if just
+  // changing ports or protocols).  This matches the behavior of request:
+  // https://github.com/request/request/blob/b12a6245/lib/redirect.js#L134-L138
+  if (new url.URL(request.url).hostname !== redirectUrl.hostname) {
+    request.headers.delete('authorization')
+    request.headers.delete('cookie')
+  }
+
+  // for POST request with 301/302 response, or any request with 303 response,
+  // use GET when following redirect
+  if (
+    response.status === 303 ||
+    (request.method === 'POST' && [301, 302].includes(response.status))
+  ) {
+    _opts.method = 'GET'
+    _opts.body = null
+    request.headers.delete('content-length')
+  }
+
+  _opts.headers = {}
+  request.headers.forEach((value, key) => {
+    _opts.headers[key] = value
+  })
+
+  _opts.counter = ++request.counter
+  const redirectReq = new Request(url.format(redirectUrl), _opts)
+  return {
+    request: redirectReq,
+    options: _opts,
+  }
+}
+
+const fetch = async (request, options) => {
+  const response = CachePolicy.storable(request, options)
+    ? await cache(request, options)
+    : await remote(request, options)
+
+  // if the request wasn't a GET or HEAD, and the response
+  // status is between 200 and 399 inclusive, invalidate the
+  // request url
+  if (!['GET', 'HEAD'].includes(request.method) &&
+      response.status >= 200 &&
+      response.status <= 399) {
+    await cache.invalidate(request, options)
+  }
+
+  if (!canFollowRedirect(request, response, options)) {
+    return response
+  }
+
+  const redirect = getRedirect(request, response, options)
+  return fetch(redirect.request, redirect.options)
+}
+
+module.exports = fetch