Current File : //lib/node_modules/pm2/node_modules/get-uri/http.js
/**
* Module dependencies.
*/
var url = require('url');
var http = require('http');
var https = require('https');
var extend = require('extend');
var NotFoundError = require('./notfound');
var NotModifiedError = require('./notmodified');
var debug = require('debug')('get-uri:http');
/**
* Module exports.
*/
module.exports = get;
/**
* Returns a Readable stream from an "http:" URI.
*
* @api protected
*/
function get (parsed, opts, fn) {
debug('GET %o', parsed.href);
var cache = getCache(parsed, opts.cache);
// 5 redirects allowed by default
var maxRedirects = opts.hasOwnProperty('maxRedirects') ? opts.maxRedirects : 5;
debug('allowing %o max redirects', maxRedirects);
// first check the previous Expires and/or Cache-Control headers
// of a previous response if a `cache` was provided
if (cache && isFresh(cache)) {
// check for a 3xx "redirect" status code on the previous cache
var location = cache.headers.location;
var type = (cache.statusCode / 100 | 0);
if (3 == type && location) {
debug('cached redirect');
fn(new Error('TODO: implement cached redirects!'));
} else {
// otherwise we assume that it's the destination endpoint,
// since there's nowhere else to redirect to
fn(new NotModifiedError());
}
return;
}
var 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;
debug('using `http` core module');
}
var options = extend({}, opts, parsed);
// add "cache validation" headers if a `cache` was provided
if (cache) {
if (!options.headers) options.headers = {};
var lastModified = cache.headers['last-modified'];
if (lastModified != null) {
options.headers['If-Modified-Since'] = lastModified;
debug('added "If-Modified-Since" request header: %o', lastModified);
}
var etag = cache.headers.etag;
if (etag != null) {
options.headers['If-None-Match'] = etag;
debug('added "If-None-Match" request header: %o', etag);
}
}
var req = mod.get(options);
req.once('error', onerror);
req.once('response', onresponse);
// http.ClientRequest "error" event handler
function onerror (err) {
debug('http.ClientRequest "error" event: %o', err.stack || err);
fn(err);
}
// http.ClientRequest "response" event handler
function onresponse (res) {
var code = res.statusCode;
// assign a Date to this response for the "Cache-Control" delta calculation
res.date = new Date();
res.parsed = parsed;
debug('got %o response status code', code);
// any 2xx response is a "success" code
var type = (code / 100 | 0);
// check for a 3xx "redirect" status code
var location = res.headers.location;
if (3 == type && location) {
if (!opts.redirects) opts.redirects = [];
var 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);
var newUri = url.resolve(parsed, location);
debug('resolved redirect URL: %o', newUri);
var left = maxRedirects - redirects.length;
debug('%o more redirects allowed after this one', left);
// check if redirecting to a different protocol
var parsedUrl = url.parse(newUri);
if (parsedUrl.protocol !== parsed.protocol) {
opts.http = parsedUrl.protocol === 'https:' ? https : undefined;
}
return get(parsedUrl, opts, fn);
}
}
// if we didn't get a 2xx "success" status code, then create an Error object
if (2 != type) {
var err;
if (304 == code) {
err = new NotModifiedError();
} else if (404 == code) {
err = new NotFoundError();
} else {
// other HTTP-level error
var message = http.STATUS_CODES[code];
err = new Error(message);
err.statusCode = code;
err.code = code;
}
res.resume();
return fn(err);
}
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;
}
fn(null, res);
}
}
/**
* 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) {
var cacheControl = cache.headers['cache-control'];
var expires = cache.headers.expires;
var fresh;
if (cacheControl) {
// for Cache-Control rules, see: http://www.mnot.net/cache_docs/#CACHE-CONTROL
debug('Cache-Control: %o', cacheControl);
var parts = cacheControl.split(/,\s*?\b/);
for (var i = 0; i < parts.length; i++) {
var part = parts[i];
var subparts = part.split('=');
var name = subparts[0];
switch (name) {
case 'max-age':
var val = +subparts[1];
expires = new Date(+cache.date + (val * 1000));
fresh = new Date() < 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;
}
}
} else if (expires) {
// for Expires rules, see: http://www.mnot.net/cache_docs/#EXPIRES
debug('Expires: %o', expires);
fresh = new Date() < new Date(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) return;
var href = parsed.href;
if (cache.parsed.href == href) {
return cache;
}
var redirects = cache.redirects;
if (redirects) {
for (var i = 0; i < redirects.length; i++) {
var c = getCache(parsed, redirects[i]);
if (c) return c;
}
}
}
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