/**
* @license
* Copyright The Closure Library Authors.
* SPDX-License-Identifier: Apache-2.0
*/
/**
* @fileoverview A single module to define user-agent specific environment
* details.
*
*/
goog.module('goog.labs.net.webChannel.environment');
goog.module.declareLegacyNamespace();
var userAgent = goog.require('goog.userAgent');
/**
* The default polling interval in millis for Edge.
*
* Currently on edge, new-chunk events may be not be fired (at all) if a new
* chunk arrives within 50ms following the previous chunk. This may be fixed
* in future, which requires changes to the whatwg spec too.
*
* @private @const {number}
*/
var EDGE_POLLING_INTERVAL_ = 125;
/**
* History:
*
* IE11 is still using Trident, the traditional engine for IE.
* Edge is using EdgeHTML, a fork of Trident. We are seeing the same issue
* on IE-11 (reported in 2017), so treat IE the same as Edge for now.
*
* We used to do polling for Opera (only) with an 250ms interval, because Opera
* only fires readyState == INTERACTIVE once. Opera switched to WebKit in 2013,
* and then to Blink (chrome).
*
* TODO(user): check the raw UA string to keep polling for old, mobile operas
* that may still be affected. For old Opera, double the polling interval
* to 250ms.
*
* @return {boolean} True if polling is required with XHR.
*/
exports.isPollingRequired = function() {
return userAgent.EDGE_OR_IE;
};
/**
* How often to poll (in MS) for changes to responseText in browsers that don't
* fire onreadystatechange during incremental loading of the response body.
*
* @return {number|undefined} The polling interval (MS) for the current U-A;
* or undefined if polling is not supposed to be enabled.
*/
exports.getPollingInterval = function() {
if (userAgent.EDGE_OR_IE) {
return EDGE_POLLING_INTERVAL_;
}
return undefined;
};
/**
* Origin trial token for google.com
*
* https://developers.chrome.com/origintrials/#/trials
*
* http://googlechrome.github.io/OriginTrials/check-token.html
* Origin: https://google.com:443
* Matches Subdomains? Yes
* Matches Third-party? Yes
* Feature: FetchUploadStreaming
* Expires: 7/14/2021, 8:59:59 AM
*
* Token for googleapis.com will be registered after google.com's is deployed.
*
*/
const OT_TOKEN_GOOGLE_COM =
"A70X6iKIlnS3U/OFBWYlZCJ6rRlXum75MZ6pvi68FKsnyeL+XPCA7KWBMeW75d2+xNHMEeFOWjfqMS+34jdvrw4AAAB/eyJvcmlnaW4iOiJodHRwczovL2dvb2dsZS5jb206NDQzIiwiZmVhdHVyZSI6IkZldGNoVXBsb2FkU3RyZWFtaW5nIiwiZXhwaXJ5IjoxNjI2MjIwNzk5LCJpc1N1YmRvbWFpbiI6dHJ1ZSwiaXNUaGlyZFBhcnR5Ijp0cnVlfQ==";
/**
* Creates ReadableStream to upload
* @return {!ReadableStream} ReadableStream to upload
*/
function createStream() {
const encoder = new goog.global.TextEncoder();
return new goog.global.ReadableStream({
start: controller => {
for (const obj of ['test\r\n', 'test\r\n']) {
controller.enqueue(encoder.encode(obj));
}
controller.close();
}
});
}
/**
* Detect the user agent is chrome and its version is higher than M90.
* This code is hard-coded from goog.labs.userAgent.browser to avoid file size
* increasing.
* @return {boolean} Whether the above is true.
*/
function isChromeM90OrHigher() {
const userAgentStr = function() {
const navigator = goog.global.navigator;
if (navigator) {
const userAgent = navigator.userAgent;
if (userAgent) {
return userAgent;
}
}
return '';
}();
const matchUserAgent = function (str) {
return userAgentStr.indexOf(str) != -1;
};
if (!matchUserAgent('Chrome') || matchUserAgent('Edg')) {
return false;
}
const match = /Chrome\/(\d+)/.exec(userAgentStr);
const chromeVersion = parseInt(match[1], 10);
return chromeVersion >= 90;
}
/**
* Detect the URL origin is *.google.com.
* @param {string} url The target URL.
* @return {boolean} Whether the above is true.
*/
function isUrlGoogle(url) {
const match = /\/\/([^\/]+)\//.exec(url);
if (!match) {
return false;
}
const origin = match[1];
return origin.endsWith("google.com");
}
/**
* The flag to run the origin trials code only once.
*/
let isStartOriginTrialsCalled = false;
/**
* For Fetch/upload OT, make three requests against the server endpoint.
* POST requests contain only dummy payload.
*
* https://developers.chrome.com/origintrials/#/view_trial/3524066708417413121
*
* This function is expected to be called from background during the handshake.
* Exceptions will be logged by the caller.
*
* No stats or logs are collected on the client-side. To be disabled once the
* OT is expired.
*
* @param {string} path The base URL path for the requests
* @param {function(*)} logError A function to execute when exceptions are
* caught.
*/
exports.startOriginTrials = function(path, logError) {
if (isStartOriginTrialsCalled) {
return;
}
isStartOriginTrialsCalled = true;
// NE: may need check if path has already contains query params?
// Accept only Chrome M90 or later due to service worker support.
if (!isChromeM90OrHigher()) {
return;
}
// Accept only only google.com and subdoamins.
if(!isUrlGoogle(path)) {
return;
}
// Since 3P OT is not supported yet, we should check the current page matches
// the path (absolute one?) to disable this OT for cross-origin calls
if(!window || !window.document || !isUrlGoogle(window.document.URL)) {
return;
}
// Enable origin trial by injecting OT <meta> tag
const tokenElement =
/** @type {! HTMLMetaElement} */ (document.createElement('meta'));
tokenElement.httpEquiv = 'origin-trial';
tokenElement.content = OT_TOKEN_GOOGLE_COM;
// appendChild() synchronously enables OT.
document.head.appendChild(tokenElement);
// Check if fetch upload stream is actually enabled.
// By the spec, Streaming request doesn't has the Content-Type header:
// https://fetch.spec.whatwg.org/#concept-bodyinit-extract
// If Chrome doesn't support Streaming, the body stream is converted to a
// string "[object ReadableStream]" for fallback then it has "Content-Type:
// text/plain;charset=UTF-8".
const supportsRequestStreams = !new Request('', {
body: new ReadableStream(),
method: 'POST',
}).headers.has('Content-Type');
if (!supportsRequestStreams) {
return;
}
// 1st req: path?ot=1
// non-streaming upload request
goog.global.fetch(`${path}?ot=1`, {method: 'POST', body: 'test\r\n'})
.catch(logError);
// 2nd req: path?ot=2
// h2-only streaming upload request
goog.global.fetch(`${path}?ot=2`, {
method: 'POST',
body: createStream(),
allowHTTP1ForStreamingUpload: false,
}).catch(logError);
// 3rd req: path?ot=3
// h1-allowed streaming upload request
goog.global.fetch(`${path}?ot=3`, {
method: 'POST',
body: createStream(),
allowHTTP1ForStreamingUpload: true,
}).catch(logError);
// Example calling a Chrome API:
// goog.global.chrome.loadTimes().wasFetchedViaSpdy
};
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