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119 lines
3.9 KiB
JavaScript

'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