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amp-a4a.js
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amp-a4a.js
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/**
* Copyright 2016 The AMP HTML Authors. All Rights Reserved.
*
* 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.
*/
import {Services} from '../../../src/services';
import {
verifyHashVersion,
LegacySignatureVerifier,
PublicKeyInfoDef,
} from './legacy-signature-verifier';
import {
is3pThrottled,
getAmpAdRenderOutsideViewport,
incrementLoadingAds,
} from '../../amp-ad/0.1/concurrent-load';
import {signingServerURLs} from '../../../ads/_a4a-config';
import {createElementWithAttributes} from '../../../src/dom';
import {cancellation, isCancellation} from '../../../src/error';
import {
installAnchorClickInterceptor,
} from '../../../src/anchor-click-interceptor';
import {
installFriendlyIframeEmbed,
setFriendlyIframeEmbedVisible,
} from '../../../src/friendly-iframe-embed';
import {isLayoutSizeDefined} from '../../../src/layout';
import {isAdPositionAllowed} from '../../../src/ad-helper';
import {dev, user, duplicateErrorIfNecessary} from '../../../src/log';
import {dict} from '../../../src/utils/object';
import {getMode} from '../../../src/mode';
import {isArray, isObject, isEnumValue} from '../../../src/types';
import {some} from '../../../src/utils/promise';
import {base64UrlDecodeToBytes} from '../../../src/utils/base64';
import {utf8Decode} from '../../../src/utils/bytes';
import {endsWith} from '../../../src/string';
import {isExperimentOn} from '../../../src/experiments';
import {setStyle} from '../../../src/style';
import {assertHttpsUrl} from '../../../src/url';
import {parseJson} from '../../../src/json';
import {handleClick} from '../../../ads/alp/handler';
import {
getDefaultBootstrapBaseUrl,
generateSentinel,
} from '../../../src/3p-frame';
import {
installUrlReplacementsForEmbed,
} from '../../../src/service/url-replacements-impl';
import {A4AVariableSource} from './a4a-variable-source';
// TODO(tdrl): Temporary. Remove when we migrate to using amp-analytics.
import {getTimingDataAsync} from '../../../src/service/variable-source';
import {getContextMetadata} from '../../../src/iframe-attributes';
// Uncomment the next two lines when testing locally.
// import '../../amp-ad/0.1/amp-ad-ui';
// import '../../amp-ad/0.1/amp-ad-xorigin-iframe-handler';
/** @type {Array<string>} */
const METADATA_STRINGS = [
'<script amp-ad-metadata type=application/json>',
'<script type="application/json" amp-ad-metadata>',
'<script type=application/json amp-ad-metadata>'];
// TODO(tdrl): Temporary, while we're verifying whether SafeFrame is an
// acceptable solution to the 'Safari on iOS doesn't fetch iframe src from
// cache' issue. See https://github.com/ampproject/amphtml/issues/5614
/** @type {string} */
export const DEFAULT_SAFEFRAME_VERSION = '1-0-9';
/** @const {string} @visibleForTesting */
export const AMP_SIGNATURE_HEADER = 'X-AmpAdSignature';
/** @const {string} */
export const CREATIVE_SIZE_HEADER = 'X-CreativeSize';
/** @type {string} @visibleForTesting */
export const RENDERING_TYPE_HEADER = 'X-AmpAdRender';
/** @type {string} @visibleForTesting */
export const SAFEFRAME_VERSION_HEADER = 'X-AmpSafeFrameVersion';
/** @type {string} */
const TAG = 'amp-a4a';
/** @type {string} */
const NO_CONTENT_RESPONSE = 'NO-CONTENT-RESPONSE';
/** @enum {string} */
export const XORIGIN_MODE = {
CLIENT_CACHE: 'client_cache',
SAFEFRAME: 'safeframe',
NAMEFRAME: 'nameframe',
};
/** @type {!Object} @private */
const SHARED_IFRAME_PROPERTIES = dict({
'frameborder': '0',
'allowfullscreen': '',
'allowtransparency': '',
'scrolling': 'no',
'marginwidth': '0',
'marginheight': '0',
});
/** @typedef {{
* creative: ArrayBuffer,
* signature: ?Uint8Array,
* }} */
export let AdResponseDef;
/** @typedef {{width: number, height: number}} */
export let SizeInfoDef;
/** @typedef {{
minifiedCreative: string,
customElementExtensions: !Array<string>,
customStylesheets: !Array<{href: string}>
}} */
let CreativeMetaDataDef;
/**
* A set of public keys for a single AMP signing service. A single service may
* return more than one key if, e.g., they're rotating keys and they serve
* the current and upcoming keys. A CryptoKeysDef stores one or more
* (promises to) keys, in the order given by the return value from the
* signing service.
*
* @typedef {{serviceName: string, keys: !Array<!Promise<!PublicKeyInfoDef>>}}
*/
let CryptoKeysDef;
/**
* The public keys for all signing services. This is an array of promises,
* one per signing service, in the order given by the array returned by
* #getSigningServiceNames(). Each entry resolves to the keys returned by
* that service, represented by a `CryptoKeysDef` object.
*
* @typedef {Array<!Promise<!CryptoKeysDef>>}
*/
let AllServicesCryptoKeysDef;
/** @private */
export const LIFECYCLE_STAGES = {
// Note: Use strings as values here, rather than numbers, so that "0" does
// not test as `false` later.
adSlotCleared: '-1',
urlBuilt: '1',
adRequestStart: '2',
adRequestEnd: '3',
extractCreativeAndSignature: '4',
adResponseValidateStart: '5',
renderFriendlyStart: '6', // TODO(dvoytenko): this signal and similar are actually "embed-create", not "render-start".
renderCrossDomainStart: '7',
renderFriendlyEnd: '8',
renderCrossDomainEnd: '9',
preAdThrottle: '10',
renderSafeFrameStart: '11',
throttled3p: '12',
adResponseValidateEnd: '13',
xDomIframeLoaded: '14',
friendlyIframeLoaded: '15',
adSlotCollapsed: '16',
adSlotUnhidden: '17',
layoutAdPromiseDelay: '18',
signatureVerifySuccess: '19',
networkError: '20',
friendlyIframeIniLoad: '21',
visHalf: '22',
visHalfIniLoad: '23',
firstVisible: '24',
visLoadAndOneSec: '25',
iniLoad: '26',
resumeCallback: '27',
visIniLoad: '29',
};
/**
* Utility function that ensures any error thrown is handled by optional
* onError handler (if none provided or handler throws, error is swallowed and
* undefined is returned).
* @param {!Function} fn to protect
* @param {T=} inThis An optional object to use as the 'this' object
* when calling the function. If not provided, undefined is bound as this
* when calling function.
* @param {function(this:T, !Error, ...*):?=} onError function given error
* and arguments provided to function call.
* @return {!Function} protected function
* @template T
* @visibleForTesting
*/
export function protectFunctionWrapper(
fn, inThis = undefined, onError = undefined) {
return (...fnArgs) => {
try {
return fn.apply(inThis, fnArgs);
} catch (err) {
if (onError) {
try {
// Ideally we could use [err, ...var_args] but linter disallows
// spread so instead using unshift :(
fnArgs.unshift(err);
return onError.apply(inThis, fnArgs);
} catch (captureErr) {
// swallow error if error handler throws.
}
}
// In the event of no optional on error function or its execution throws,
// return undefined.
return undefined;
}
};
};
export class AmpA4A extends AMP.BaseElement {
// TODO: Add more error handling throughout code.
// TODO: Handle creatives that do not fill.
/**
* @param {!Element} element
*/
constructor(element) {
super(element);
dev().assert(AMP.AmpAdUIHandler);
dev().assert(AMP.AmpAdXOriginIframeHandler);
/** @private {?Promise<?CreativeMetaDataDef>} */
this.adPromise_ = null;
/**
* @private {number} unique ID of the currently executing promise to allow
* for cancellation.
*/
this.promiseId_ = 0;
/** {?Object} */
this.config = null;
/** @private {?string} */
this.adUrl_ = null;
/** @private {?../../../src/friendly-iframe-embed.FriendlyIframeEmbed} */
this.friendlyIframeEmbed_ = null;
/** {?AMP.AmpAdUIHandler} */
this.uiHandler = null;
/** @private {?AMP.AmpAdXOriginIframeHandler} */
this.xOriginIframeHandler_ = null;
/** @const @private {!../../../src/service/vsync-impl.Vsync} */
this.vsync_ = this.getVsync();
/** @private {boolean} whether creative has been verified as AMP */
this.isVerifiedAmpCreative_ = false;
/** @private @const {!LegacySignatureVerifier} */
this.signatureVerifier_ = new LegacySignatureVerifier(this.win);
/** @private {?ArrayBuffer} */
this.creativeBody_ = null;
/**
* Initialize this with the slot width/height attributes, and override
* later with what the network implementation returns via
* extractCreativeAndSignature. Note: Either value may be 'auto' (i.e.,
* non-numeric).
*
* @private {?({width, height}|../../../src/layout-rect.LayoutRectDef)}
*/
this.creativeSize_ = null;
/** @private {?../../../src/layout-rect.LayoutRectDef} */
this.originalSlotSize_ = null;
/**
* Note(keithwrightbos) - ensure the default here is null so that ios
* uses safeframe when response header is not specified.
* @private {?XORIGIN_MODE}
*/
this.experimentalNonAmpCreativeRenderMethod_ =
Services.platformFor(this.win).isIos() ? XORIGIN_MODE.SAFEFRAME : null;
/**
* Gets a notion of current time, in ms. The value is not necessarily
* absolute, so should be used only for computing deltas. When available,
* the performance system will be used; otherwise Date.now() will be
* returned.
*
* @const {function():number}
* @private
*/
this.getNow_ = (this.win.performance && this.win.performance.now) ?
this.win.performance.now.bind(this.win.performance) : Date.now;
/**
* Protected version of emitLifecycleEvent that ensures error does not
* cause promise chain to reject.
* @private {?function(string, !Object=)}
*/
this.protectedEmitLifecycleEvent_ = null;
/** @const {string} */
this.sentinel = generateSentinel(window);
/**
* Used to indicate whether this slot should be collapsed or not. Marked
* true if the ad response has status 204, is null, or has a null
* arrayBuffer.
* @private {boolean}
*/
this.isCollapsed_ = false;
/**
* Frame in which the creative renders (friendly if validated AMP, xdomain
* otherwise).
* {?HTMLIframeElement}
*/
this.iframe = null;
/**
* TODO(keithwrightbos) - remove once resume behavior is verified.
* {boolean} whether most recent ad request was generated as part
* of resume callback.
*/
this.fromResumeCallback = false;
/** @private {string} */
this.safeframeVersion_ = DEFAULT_SAFEFRAME_VERSION;
/**
* @protected {boolean} Indicates whether the ad is currently in the
* process of being refreshed.
*/
this.isRefreshing = false;
/** @protected {boolean} */
this.isRelayoutNeededFlag = false;
}
/** @override */
getPriority() {
// Priority used for scheduling preload and layout callback. Because
// AMP creatives will be injected as part of the promise chain created
// within onLayoutMeasure, this is only relevant to non-AMP creatives
// therefore we want this to match the 3p priority.
return 2;
}
/** @override */
isLayoutSupported(layout) {
return isLayoutSizeDefined(layout);
}
/** @override */
isRelayoutNeeded() {
return this.isRelayoutNeededFlag;
}
/** @override */
buildCallback() {
this.creativeSize_ = {
width: this.element.getAttribute('width'),
height: this.element.getAttribute('height'),
};
this.protectedEmitLifecycleEvent_ = protectFunctionWrapper(
this.emitLifecycleEvent, this,
(err, varArgs) => {
dev().error(TAG, this.element.getAttribute('type'),
'Error on emitLifecycleEvent', err, varArgs) ;
});
this.uiHandler = new AMP.AmpAdUIHandler(this);
if (!this.win.ampA4aValidationKeys) {
// Without the following variable assignment, there's no way to apply a
// type annotation to a win-scoped variable, so the type checker doesn't
// catch type errors here. This no-op allows us to enforce some type
// expectations. The const assignment will hopefully be optimized
// away by the compiler. *fingers crossed*
/** @type {!AllServicesCryptoKeysDef} */
const forTypeSafety = this.getKeyInfoSets_();
this.win.ampA4aValidationKeys = forTypeSafety;
}
}
/** @override */
renderOutsideViewport() {
// Ensure non-verified AMP creatives are throttled.
if (!this.isVerifiedAmpCreative_ && is3pThrottled(this.win)) {
this.protectedEmitLifecycleEvent_('throttled3p');
return false;
}
// Otherwise the ad is good to go.
const elementCheck = getAmpAdRenderOutsideViewport(this.element);
return elementCheck !== null ?
elementCheck : super.renderOutsideViewport();
}
/**
* To be overridden by network specific implementation indicating if element
* (and environment generally) are valid for sending XHR queries.
* @return {boolean} whether element is valid and ad request should be
* sent. If false, no ad request is sent and slot will be collapsed if
* possible.
*/
isValidElement() {
return true;
}
/**
* @return {boolean} whether ad request should be delayed until
* renderOutsideViewport is met.
*/
delayAdRequestEnabled() {
return false;
}
/**
* Returns preconnect urls for A4A. Ad network should overwrite in their
* Fast Fetch implementation and return an array of urls for the runtime to
* preconnect to.
* @return {!Array<string>}
*/
getPreconnectUrls() {
return [];
}
/**
* Returns prefetch urls for A4A. Ad network should overwrite in their
* Fast Fetch implementation and return an array of urls for the runtime to
* prefetch.
* @return {!Array<string>}
*/
getPrefetchUrls() {
return [];
}
/**
* Returns true if this element was loaded from an amp-ad element. For use by
* network-specific implementations that don't want to allow themselves to be
* embedded directly into a page.
* @return {boolean}
*/
isAmpAdElement() {
return this.element.tagName == 'AMP-AD' ||
this.element.tagName == 'AMP-EMBED';
}
/**
* Prefetches and preconnects URLs related to the ad using adPreconnect
* registration which assumes ad request domain used for 3p is applicable.
* @param {boolean=} unusedOnLayout
* @override
*/
preconnectCallback(unusedOnLayout) {
this.preconnect.preload(this.getSafeframePath_());
this.preconnect.preload(getDefaultBootstrapBaseUrl(this.win, 'nameframe'));
const preconnect = this.getPreconnectUrls();
// NOTE(keithwrightbos): using onLayout to indicate if preconnect should be
// given preferential treatment. Currently this would be false when
// relevant (i.e. want to preconnect on or before onLayoutMeasure) which
// causes preconnect to delay for 1 sec (see custom-element#preconnect)
// therefore hard coding to true.
// NOTE(keithwrightbos): Does not take isValidElement into account so could
// preconnect unnecessarily, however it is assumed that isValidElement
// matches amp-ad loader predicate such that A4A impl does not load.
if (preconnect) {
preconnect.forEach(p => {
this.preconnect.url(p, true);
});
}
}
/** @override */
resumeCallback() {
// FIE that was not destroyed on unlayoutCallback does not require a new
// ad request.
if (this.friendlyIframeEmbed_) {
return;
}
this.protectedEmitLifecycleEvent_('resumeCallback');
this.fromResumeCallback = true;
// If layout of page has not changed, onLayoutMeasure will not be called
// so do so explicitly.
const resource = this.getResource();
if (resource.hasBeenMeasured() && !resource.isMeasureRequested()) {
this.onLayoutMeasure();
}
}
/**
* @return {!../../../src/service/resource.Resource}
* @visibileForTesting
*/
getResource() {
return this.element.getResources().getResourceForElement(this.element);
}
/**
* @return {boolean} whether adPromise was initialized (indicator of
* element validity).
* @protected
*/
hasAdPromise() {
return !!this.adPromise_;
}
/**
* @return {boolean} whether environment/element should initialize ad request
* promise chain.
* @private
*/
shouldInitializePromiseChain_() {
if (!this.signatureVerifier_.isAvailable()) {
return false;
}
const slotRect = this.getIntersectionElementLayoutBox();
if (slotRect.height == 0 || slotRect.width == 0) {
dev().fine(
TAG, 'onLayoutMeasure canceled due height/width 0', this.element);
return false;
}
if (!isAdPositionAllowed(this.element, this.win)) {
user().warn(TAG, `<${this.element.tagName}> is not allowed to be ` +
`placed in elements with position:fixed: ${this.element}`);
return false;
}
// OnLayoutMeasure can be called when page is in prerender so delay until
// visible. Assume that it is ok to call isValidElement as it should
// only being looking at window, immutable properties (i.e. location) and
// its element ancestry.
if (!this.isValidElement()) {
// TODO(kjwright): collapse?
user().warn(TAG, this.element.getAttribute('type'),
'Amp ad element ignored as invalid', this.element);
return false;
}
return true;
}
/** @override */
onLayoutMeasure() {
this.initiateAdRequest();
}
/**
* This is the entry point into the ad promise chain.
*
* Calling this function will initiate the following sequence of events: ad
* url construction, ad request issuance, creative verification, and metadata
* parsing.
*
* @protected
*/
initiateAdRequest() {
if (this.xOriginIframeHandler_) {
this.xOriginIframeHandler_.onLayoutMeasure();
}
if (this.adPromise_ || !this.shouldInitializePromiseChain_()) {
return;
}
// If in localDev `type=fake` Ad specifies `force3p`, it will be forced
// to go via 3p.
if (getMode().localDev &&
this.element.getAttribute('type') == 'fake' &&
this.element.getAttribute('force3p') == 'true') {
this.adUrl_ = this.getAdUrl();
this.adPromise_ = Promise.resolve();
return;
}
// Increment unique promise ID so that if its value changes within the
// promise chain due to cancel from unlayout, the promise will be rejected.
++this.promiseId_;
// Shorthand for: reject promise if current promise chain is out of date.
const checkStillCurrent = this.verifyStillCurrent();
// Return value from this chain: True iff rendering was "successful"
// (i.e., shouldn't try to render later via iframe); false iff should
// try to render later in iframe.
// Cases to handle in this chain:
// - Everything ok => Render; return true
// - Empty network response returned => Don't render; return true
// - Can't parse creative out of response => Don't render; return false
// - Can parse, but creative is empty => Don't render; return true
// - Validation fails => return false
// - Rendering fails => return false
// - Chain cancelled => don't return; drop error
// - Uncaught error otherwise => don't return; percolate error up
this.adPromise_ = Services.viewerForDoc(this.getAmpDoc()).whenFirstVisible()
.then(() => {
checkStillCurrent();
// See if experiment that delays request until slot is within
// renderOutsideViewport. Within render outside viewport will not
// resolve if already within viewport thus the check for already
// meeting the definition as opposed to waiting on the promise.
if (this.delayAdRequestEnabled() &&
!this.getResource().renderOutsideViewport()) {
return this.getResource().whenWithinRenderOutsideViewport();
}
})
// This block returns the ad URL, if one is available.
/** @return {!Promise<?string>} */
.then(() => {
checkStillCurrent();
return /** @type {!Promise<?string>} */(this.getAdUrl());
})
// This block returns the (possibly empty) response to the XHR request.
/** @return {!Promise<?Response>} */
.then(adUrl => {
checkStillCurrent();
this.adUrl_ = adUrl;
this.protectedEmitLifecycleEvent_('urlBuilt');
return adUrl && this.sendXhrRequest(adUrl);
})
// The following block returns either the response (as a {bytes, headers}
// object), or null if no response is available / response is empty.
/** @return {?Promise<?{bytes: !ArrayBuffer, headers: !Headers}>} */
.then(fetchResponse => {
checkStillCurrent();
this.protectedEmitLifecycleEvent_('adRequestEnd');
// If the response is null, we want to return null so that
// unlayoutCallback will attempt to render via x-domain iframe,
// assuming ad url or creative exist.
if (!fetchResponse) {
return null;
}
// If the response has response code 204, or arrayBuffer is null,
// collapse it.
if (!fetchResponse.arrayBuffer || fetchResponse.status == 204) {
this.forceCollapse();
return Promise.reject(NO_CONTENT_RESPONSE);
}
// TODO(tdrl): Temporary, while we're verifying whether SafeFrame is
// an acceptable solution to the 'Safari on iOS doesn't fetch
// iframe src from cache' issue. See
// https://github.com/ampproject/amphtml/issues/5614
const method = fetchResponse.headers.get(RENDERING_TYPE_HEADER) ||
this.experimentalNonAmpCreativeRenderMethod_;
this.experimentalNonAmpCreativeRenderMethod_ = method;
if (method && !isEnumValue(XORIGIN_MODE, method)) {
dev().error('AMP-A4A', `cross-origin render mode header ${method}`);
}
const safeframeVersionHeader =
fetchResponse.headers.get(SAFEFRAME_VERSION_HEADER);
if (/^[0-9-]+$/.test(safeframeVersionHeader) &&
safeframeVersionHeader != DEFAULT_SAFEFRAME_VERSION) {
this.safeframeVersion_ = safeframeVersionHeader;
this.preconnect.preload(this.getSafeframePath_());
}
// Note: Resolving a .then inside a .then because we need to capture
// two fields of fetchResponse, one of which is, itself, a promise,
// and one of which isn't. If we just return
// fetchResponse.arrayBuffer(), the next step in the chain will
// resolve it to a concrete value, but we'll lose track of
// fetchResponse.headers.
return fetchResponse.arrayBuffer().then(bytes => {
if (bytes.byteLength == 0) {
// The server returned no content. Instead of displaying a blank
// rectangle, we collapse the slot instead.
this.forceCollapse();
return Promise.reject(NO_CONTENT_RESPONSE);
}
return {
bytes,
headers: fetchResponse.headers,
};
});
})
// This block returns the ad creative, signature, and size, if
// available; null otherwise.
/**
* @return {?Promise<{creativeParts: !AdResponseDef, size: ?SizeInfoDef}>}
*/
.then(responseParts => {
checkStillCurrent();
if (!responseParts) {
return null;
}
this.protectedEmitLifecycleEvent_('extractCreativeAndSignature');
const size = this.extractSize(responseParts.headers);
return this.extractCreativeAndSignature(
responseParts.bytes, responseParts.headers)
.then(creativeParts => ({creativeParts, size}));
})
// This block returns the ad creative if it exists and validates as AMP;
// null otherwise.
/** @return {!Promise<?ArrayBuffer>} */
.then(creativeData => {
checkStillCurrent();
// Keep a handle to the creative body so that we can render into
// SafeFrame or NameFrame later, if necessary. TODO(tdrl): Temporary,
// while we
// assess whether this is the right solution to the Safari+iOS iframe
// src cache issue. If we decide to keep a SafeFrame-like solution,
// we should restructure the promise chain to pass this info along
// more cleanly, without use of an object variable outside the chain.
if (!creativeData) {
return Promise.resolve();
}
const {creativeParts, size} = creativeData;
this.creativeSize_ = size || this.creativeSize_;
if (this.experimentalNonAmpCreativeRenderMethod_ !=
XORIGIN_MODE.CLIENT_CACHE &&
creativeParts.creative) {
this.creativeBody_ = creativeParts.creative;
}
if (!creativeParts.signature) {
return Promise.resolve();
}
this.protectedEmitLifecycleEvent_('adResponseValidateStart');
return this.verifyCreativeSignature_(
creativeParts.creative, creativeParts.signature)
.then(creative => {
if (creative) {
return creative;
}
user().error(TAG, this.element.getAttribute('type'),
'Unable to validate AMP creative against key providers');
// Attempt to re-fetch the keys in case our locally cached
// batch has expired.
this.win.ampA4aValidationKeys = this.getKeyInfoSets_();
return this.verifyCreativeSignature_(
creativeParts.creative, creativeParts.signature);
});
})
.then(creative => {
checkStillCurrent();
// Need to know if creative was verified as part of render outside
// viewport but cannot wait on promise. Sadly, need a state a
// variable.
this.isVerifiedAmpCreative_ = !!creative;
// TODO(levitzky) If creative comes back null, we should consider re-
// fetching the signing server public keys and try the verification
// step again.
return creative && utf8Decode(creative);
})
// This block returns CreativeMetaDataDef iff the creative was verified
// as AMP and could be properly parsed for friendly iframe render.
/** @return {?CreativeMetaDataDef} */
.then(creativeDecoded => {
checkStillCurrent();
// Note: It's critical that #getAmpAdMetadata_ be called
// on precisely the same creative that was validated
// via #validateAdResponse_. See GitHub issue
// https://github.com/ampproject/amphtml/issues/4187
let creativeMetaDataDef;
if (!creativeDecoded ||
!(creativeMetaDataDef = this.getAmpAdMetadata_(creativeDecoded))) {
return null;
}
// Update priority.
this.updatePriority(0);
// Load any extensions; do not wait on their promises as this
// is just to prefetch.
const extensions = Services.extensionsFor(this.win);
creativeMetaDataDef.customElementExtensions.forEach(
extensionId => extensions.loadExtension(extensionId));
return creativeMetaDataDef;
})
.catch(error => {
if (error == NO_CONTENT_RESPONSE) {
return {
minifiedCreative: '',
customElementExtensions: [],
customStylesheets: [],
};
}
// If error in chain occurs, report it and return null so that
// layoutCallback can render via cross domain iframe assuming ad
// url or creative exist.
this.promiseErrorHandler_(error);
return null;
});
}
/**
* Refreshes ad slot by fetching a new creative and rendering it. This leaves
* the current creative displayed until the next one is ready.
*
* @param {function()} refreshEndCallback When called, this function will
* restart the refresh cycle.
* @return {Promise} A promise that resolves when all asynchronous portions of
* the refresh function complete. This is particularly handy for testing.
*/
refresh(refreshEndCallback) {
dev().assert(!this.isRefreshing);
this.isRefreshing = true;
this.tearDownSlot();
this.initiateAdRequest();
dev().assert(this.adPromise_);
const promiseId = this.promiseId_;
return this.adPromise_.then(() => {
if (!this.isRefreshing || promiseId != this.promiseId_) {
// If this refresh cycle was canceled, such as in a no-content
// response case, keep showing the old creative.
refreshEndCallback();
return;
}
return this.mutateElement(() => {
this.togglePlaceholder(true);
// This delay provides a 1 second buffer where the ad loader is
// displayed in between the creatives.
return Services.timerFor(this.win).promise(1000).then(() => {
this.isRelayoutNeededFlag = true;
this.getResource().layoutCanceled();
Services.resourcesForDoc(this.getAmpDoc())
./*OK*/requireLayout(this.element);
});
});
});
}
/**
* Attempts to validate the creative signature against every key currently in
* our possession. This should never be called before at least one key fetch
* attempt is made.
*
* @param {!ArrayBuffer} creative
* @param {!Uint8Array} signature
* @return {!Promise<!ArrayBuffer>} The creative.
*/
verifyCreativeSignature_(creative, signature) {
if (getMode().localDev) {
// localDev mode allows "FAKESIG" signature for the "fake" network.
if (signature == 'FAKESIG' &&
this.element.getAttribute('type') == 'fake') {
return Promise.resolve(creative);
}
}
// For each signing service, we have exactly one Promise,
// keyInfoSetPromise, that holds an Array of Promises of signing keys.
// So long as any one of these signing services can verify the
// signature, then the creative is valid AMP.
/** @type {!AllServicesCryptoKeysDef} */
const keyInfoSetPromises = this.win.ampA4aValidationKeys;
// Track if verification found, as it will ensure that promises yet to
// resolve will "cancel" as soon as possible saving unnecessary resource
// allocation.
let verified = false;
return some(keyInfoSetPromises.map(keyInfoSetPromise => {
// Resolve Promise into an object containing a 'keys' field, which
// is an Array of Promises of signing keys. *whew*
return keyInfoSetPromise.then(keyInfoSet => {
// As long as any one individual key of a particular signing
// service, keyInfoPromise, can verify the signature, then the
// creative is valid AMP.
if (verified) {
return Promise.reject('noop');
}
return some(keyInfoSet.keys.map(keyInfoPromise => {
// Resolve Promise into signing key.
return keyInfoPromise.then(keyInfo => {
if (verified) {
return Promise.reject('noop');
}
if (!keyInfo) {
return Promise.reject('Promise resolved to null key.');
}
const signatureVerifyStartTime = this.getNow_();
// If the key exists, try verifying with it.
return this.signatureVerifier_.verifySignature(
new Uint8Array(creative),
signature,
keyInfo)
.then(isValid => {
if (isValid) {
verified = true;
this.protectedEmitLifecycleEvent_(
'signatureVerifySuccess', {
'met.delta.AD_SLOT_ID': Math.round(
this.getNow_() - signatureVerifyStartTime),
'signingServiceName.AD_SLOT_ID': keyInfo.serviceName,
});
return creative;
}
// Only report if signature is expected to match, given that
// multiple key providers could have been specified.
// Note: the 'keyInfo &&' check here is not strictly
// necessary, because we checked that above. But
// Closure type compiler can't seem to recognize that, so
// this guarantees it to the compiler.
if (keyInfo && verifyHashVersion(signature, keyInfo)) {
user().error(TAG, this.element.getAttribute('type'),
'Key failed to validate creative\'s signature',
keyInfo.serviceName, keyInfo.cryptoKey);
}
// Reject to ensure the some operation waits for other
// possible providers to properly verify and resolve.
return Promise.reject(
`${keyInfo.serviceName} key failed to verify`);
},
err => {
dev().error(
TAG, this.element.getAttribute('type'),
keyInfo.serviceName, err, this.element);
});
});
}))
// some() returns an array of which we only need a single value.
.then(returnedArray => returnedArray[0], () => {
// Rejection occurs if all keys for this provider fail to validate.
return Promise.reject(
`All keys for ${keyInfoSet.serviceName} failed to verify`);
});
});
}))
.then(returnedArray => {
this.protectedEmitLifecycleEvent_('adResponseValidateEnd');
return returnedArray[0];
}, () => {
// rejection occurs if all providers fail to verify.
this.protectedEmitLifecycleEvent_('adResponseValidateEnd');
return Promise.reject('No validation service could verify this key');
});
}
/**
* Handles uncaught errors within promise flow.
* @param {*} error
* @param {boolean=} opt_ignoreStack
* @private
*/
promiseErrorHandler_(error, opt_ignoreStack) {
if (isCancellation(error)) {
// Rethrow if cancellation.
throw error;
}
if (error && error.message) {
error = duplicateErrorIfNecessary(/** @type {!Error} */(error));
} else {
error = new Error('unknown error ' + error);
}
if (opt_ignoreStack) {
error.ignoreStack = opt_ignoreStack;
}
// Add `type` to the message. Ensure to preserve the original stack.
const type = this.element.getAttribute('type') || 'notype';
if (error.message.indexOf(`${TAG}: ${type}:`) != 0) {
error.message = `${TAG}: ${type}: ${error.message}`;
}
// Additional arguments.
assignAdUrlToError(/** @type {!Error} */(error), this.adUrl_);
if (getMode().development || getMode().localDev || getMode().log) {
user().error(TAG, error);
} else {
user().warn(TAG, error);
// Report with 1% sampling as an expected dev error.
if (Math.random() < 0.01) {
dev().expectedError(TAG, error);
}
}
}
/** @override */
layoutCallback() {
if (this.isRefreshing) {
this.destroyFrame(true);
}
return this.attemptToRenderCreative();
}
/**
* Attemps to render the returned creative following the resolution of the
* adPromise.
*
* @return {!Promise<boolean>|!Promise<undefined>} A promise that resolves
* when the rendering attempt has finished.
* @protected
*/
attemptToRenderCreative() {
// Promise may be null if element was determined to be invalid for A4A.
if (!this.adPromise_) {
if (this.shouldInitializePromiseChain_()) {
dev().error(TAG, 'Null promise in layoutCallback');
}
return Promise.resolve();
}
// There's no real throttling with A4A, but this is the signal that is
// most comparable with the layout callback for 3p ads.
this.protectedEmitLifecycleEvent_('preAdThrottle');
const layoutCallbackStart = this.getNow_();