四好公路
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"use strict";
var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
return new (P || (P = Promise))(function (resolve, reject) {
function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
function step(result) { result.done ? resolve(result.value) : adopt(result.value).then(fulfilled, rejected); }
step((generator = generator.apply(thisArg, _arguments || [])).next());
});
};
var __importDefault = (this && this.__importDefault) || function (mod) {
return (mod && mod.__esModule) ? mod : { "default": mod };
};
Object.defineProperty(exports, "__esModule", { value: true });
const http_1 = __importDefault(require("http"));
const https_1 = __importDefault(require("https"));
const once_1 = __importDefault(require("@tootallnate/once"));
const debug_1 = __importDefault(require("debug"));
const url_1 = require("url");
const http_error_1 = __importDefault(require("./http-error"));
const notfound_1 = __importDefault(require("./notfound"));
const notmodified_1 = __importDefault(require("./notmodified"));
const debug = debug_1.default('get-uri:http');
/**
* Returns a Readable stream from an "http:" URI.
*/
function get(parsed, opts) {
return __awaiter(this, void 0, void 0, function* () {
debug('GET %o', parsed.href);
const cache = getCache(parsed, opts.cache);
// first check the previous Expires and/or Cache-Control headers
// of a previous response if a `cache` was provided
if (cache && isFresh(cache) && typeof cache.statusCode === 'number') {
// check for a 3xx "redirect" status code on the previous cache
const type = (cache.statusCode / 100) | 0;
if (type === 3 && cache.headers.location) {
debug('cached redirect');
throw new Error('TODO: implement cached redirects!');
}
// otherwise we assume that it's the destination endpoint,
// since there's nowhere else to redirect to
throw new notmodified_1.default();
}
// 5 redirects allowed by default
const maxRedirects = typeof opts.maxRedirects === 'number' ? opts.maxRedirects : 5;
debug('allowing %o max redirects', maxRedirects);
let mod;
if (opts.http) {
// the `https` module passed in from the "http.js" file
mod = opts.http;
debug('using secure `https` core module');
}
else {
mod = http_1.default;
debug('using `http` core module');
}
const options = Object.assign(Object.assign({}, opts), parsed);
// add "cache validation" headers if a `cache` was provided
if (cache) {
if (!options.headers) {
options.headers = {};
}
const lastModified = cache.headers['last-modified'];
if (lastModified) {
options.headers['If-Modified-Since'] = lastModified;
debug('added "If-Modified-Since" request header: %o', lastModified);
}
const etag = cache.headers.etag;
if (etag) {
options.headers['If-None-Match'] = etag;
debug('added "If-None-Match" request header: %o', etag);
}
}
const req = mod.get(options);
const res = yield once_1.default(req, 'response');
const code = res.statusCode || 0;
// assign a Date to this response for the "Cache-Control" delta calculation
res.date = Date.now();
res.parsed = parsed;
debug('got %o response status code', code);
// any 2xx response is a "success" code
let type = (code / 100) | 0;
// check for a 3xx "redirect" status code
let location = res.headers.location;
if (type === 3 && location) {
if (!opts.redirects)
opts.redirects = [];
let redirects = opts.redirects;
if (redirects.length < maxRedirects) {
debug('got a "redirect" status code with Location: %o', location);
// flush this response - we're not going to use it
res.resume();
// hang on to this Response object for the "redirects" Array
redirects.push(res);
let newUri = url_1.resolve(parsed.href, location);
debug('resolved redirect URL: %o', newUri);
let left = maxRedirects - redirects.length;
debug('%o more redirects allowed after this one', left);
// check if redirecting to a different protocol
let parsedUrl = url_1.parse(newUri);
if (parsedUrl.protocol !== parsed.protocol) {
opts.http = parsedUrl.protocol === 'https:' ? https_1.default : undefined;
}
return get(parsedUrl, opts);
}
}
// if we didn't get a 2xx "success" status code, then create an Error object
if (type !== 2) {
res.resume();
if (code === 304) {
throw new notmodified_1.default();
}
else if (code === 404) {
throw new notfound_1.default();
}
// other HTTP-level error
throw new http_error_1.default(code);
}
if (opts.redirects) {
// store a reference to the "redirects" Array on the Response object so that
// they can be inspected during a subsequent call to GET the same URI
res.redirects = opts.redirects;
}
return res;
});
}
exports.default = get;
/**
* Returns `true` if the provided cache's "freshness" is valid. That is, either
* the Cache-Control header or Expires header values are still within the allowed
* time period.
*
* @return {Boolean}
* @api private
*/
function isFresh(cache) {
let fresh = false;
let expires = parseInt(cache.headers.expires || '', 10);
const cacheControl = cache.headers['cache-control'];
if (cacheControl) {
// for Cache-Control rules, see: http://www.mnot.net/cache_docs/#CACHE-CONTROL
debug('Cache-Control: %o', cacheControl);
const parts = cacheControl.split(/,\s*?\b/);
for (let i = 0; i < parts.length; i++) {
const part = parts[i];
const subparts = part.split('=');
const name = subparts[0];
switch (name) {
case 'max-age':
expires = (cache.date || 0) + parseInt(subparts[1], 10) * 1000;
fresh = Date.now() < expires;
if (fresh) {
debug('cache is "fresh" due to previous %o Cache-Control param', part);
}
return fresh;
case 'must-revalidate':
// XXX: what we supposed to do here?
break;
case 'no-cache':
case 'no-store':
debug('cache is "stale" due to explicit %o Cache-Control param', name);
return false;
default:
// ignore unknown cache value
break;
}
}
}
else if (expires) {
// for Expires rules, see: http://www.mnot.net/cache_docs/#EXPIRES
debug('Expires: %o', expires);
fresh = Date.now() < expires;
if (fresh) {
debug('cache is "fresh" due to previous Expires response header');
}
return fresh;
}
return false;
}
/**
* Attempts to return a previous Response object from a previous GET call to the
* same URI.
*
* @api private
*/
function getCache(parsed, cache) {
if (cache) {
if (cache.parsed && cache.parsed.href === parsed.href) {
return cache;
}
if (cache.redirects) {
for (let i = 0; i < cache.redirects.length; i++) {
const c = getCache(parsed, cache.redirects[i]);
if (c) {
return c;
}
}
}
}
return null;
}
//# sourceMappingURL=http.js.map