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updated userid module to stop caching the entire consent object (preb…
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…id#5641)

* updated userid module to stop caching the entire consent object but rather just a hash of it, since all we need it for is comparison purposes.

* IE doesn't support Math.imul, so providing a polyfill for it when necessary

* use `===` to compare consent values; convert hashes to a string when returning them

* add test for string response and fix @returns doc

* don't use polyfills!
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@smenzer
smenzer authored Aug 20, 2020
1 parent a1692da commit 0d8d9bf
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Showing 4 changed files with 65 additions and 43 deletions.
13 changes: 5 additions & 8 deletions modules/userId/index.js
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Original file line number Diff line number Diff line change
Expand Up @@ -232,7 +232,7 @@ function getStoredValue(storage, key = undefined) {
* @param consentData
* @returns {{apiVersion: number, gdprApplies: boolean, consentString: string}}
*/
function makeStoredConsentDataObject(consentData) {
function makeStoredConsentDataHash(consentData) {
const storedConsentData = {
consentString: '',
gdprApplies: false,
Expand All @@ -244,8 +244,7 @@ function makeStoredConsentDataObject(consentData) {
storedConsentData.gdprApplies = consentData.gdprApplies;
storedConsentData.apiVersion = consentData.apiVersion;
}

return storedConsentData;
return utils.simpleHash(JSON.stringify(storedConsentData));
}

/**
Expand All @@ -255,7 +254,7 @@ function makeStoredConsentDataObject(consentData) {
export function setStoredConsentData(consentData) {
try {
const expiresStr = (new Date(Date.now() + (CONSENT_DATA_COOKIE_STORAGE_CONFIG.expires * (60 * 60 * 24 * 1000)))).toUTCString();
coreStorage.setCookie(CONSENT_DATA_COOKIE_STORAGE_CONFIG.name, JSON.stringify(makeStoredConsentDataObject(consentData)), expiresStr, 'Lax');
coreStorage.setCookie(CONSENT_DATA_COOKIE_STORAGE_CONFIG.name, makeStoredConsentDataHash(consentData), expiresStr, 'Lax');
} catch (error) {
utils.logError(error);
}
Expand All @@ -266,13 +265,11 @@ export function setStoredConsentData(consentData) {
* @returns {string}
*/
function getStoredConsentData() {
let storedValue;
try {
storedValue = JSON.parse(coreStorage.getCookie(CONSENT_DATA_COOKIE_STORAGE_CONFIG.name));
return coreStorage.getCookie(CONSENT_DATA_COOKIE_STORAGE_CONFIG.name);
} catch (e) {
utils.logError(e);
}
return storedValue;
}

/**
Expand All @@ -287,7 +284,7 @@ function storedConsentDataMatchesConsentData(storedConsentData, consentData) {
return (
typeof storedConsentData === 'undefined' ||
storedConsentData === null ||
utils.deepEqual(storedConsentData, makeStoredConsentDataObject(consentData))
storedConsentData === makeStoredConsentDataHash(consentData)
);
}

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40 changes: 40 additions & 0 deletions src/utils.js
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Original file line number Diff line number Diff line change
Expand Up @@ -1215,3 +1215,43 @@ export function mergeDeep(target, ...sources) {

return mergeDeep(target, ...sources);
}

/**
* returns a hash of a string using a fast algorithm
* source: https://stackoverflow.com/a/52171480/845390
* @param str
* @param seed (optional)
* @returns {string}
*/
export function simpleHash(str, seed = 0) {
// IE doesn't support imul
// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/imul#Polyfill
let imul = function(opA, opB) {
if (isFn(Math.imul)) {
return Math.imul(opA, opB);
} else {
opB |= 0; // ensure that opB is an integer. opA will automatically be coerced.
// floating points give us 53 bits of precision to work with plus 1 sign bit
// automatically handled for our convienence:
// 1. 0x003fffff /*opA & 0x000fffff*/ * 0x7fffffff /*opB*/ = 0x1fffff7fc00001
// 0x1fffff7fc00001 < Number.MAX_SAFE_INTEGER /*0x1fffffffffffff*/
var result = (opA & 0x003fffff) * opB;
// 2. We can remove an integer coersion from the statement above because:
// 0x1fffff7fc00001 + 0xffc00000 = 0x1fffffff800001
// 0x1fffffff800001 < Number.MAX_SAFE_INTEGER /*0x1fffffffffffff*/
if (opA & 0xffc00000) result += (opA & 0xffc00000) * opB | 0;
return result | 0;
}
};

let h1 = 0xdeadbeef ^ seed;
let h2 = 0x41c6ce57 ^ seed;
for (let i = 0, ch; i < str.length; i++) {
ch = str.charCodeAt(i);
h1 = imul(h1 ^ ch, 2654435761);
h2 = imul(h2 ^ ch, 1597334677);
}
h1 = imul(h1 ^ (h1 >>> 16), 2246822507) ^ imul(h2 ^ (h2 >>> 13), 3266489909);
h2 = imul(h2 ^ (h2 >>> 16), 2246822507) ^ imul(h1 ^ (h1 >>> 13), 3266489909);
return (4294967296 * (2097151 & h2) + (h1 >>> 0)).toString();
}
35 changes: 0 additions & 35 deletions test/spec/modules/userId_spec.js
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Original file line number Diff line number Diff line change
Expand Up @@ -1591,13 +1591,6 @@ describe('User ID', function() {
sinon.assert.notCalled(mockGetId);
sinon.assert.calledOnce(mockDecode);
sinon.assert.calledOnce(mockExtendId);

let consent = gdprDataHandler.getConsentData();
let userIdStoredConsent = JSON.parse(coreStorage.getCookie(CONSENT_LOCAL_STORAGE_NAME));
expect(userIdStoredConsent.gdprApplies).to.equal(consent.gdprApplies);
expect(userIdStoredConsent.gdprApplies).to.equal(testConsentData.gdprApplies);
expect(userIdStoredConsent.consentString).to.equal(consent.consentString);
expect(userIdStoredConsent.consentString).to.equal(testConsentData.consentData);
});

it('calls getId if no stored consent data but refresh is needed', function () {
Expand All @@ -1611,13 +1604,6 @@ describe('User ID', function() {
sinon.assert.calledOnce(mockGetId);
sinon.assert.calledOnce(mockDecode);
sinon.assert.notCalled(mockExtendId);

let consent = gdprDataHandler.getConsentData();
let userIdStoredConsent = JSON.parse(coreStorage.getCookie(CONSENT_LOCAL_STORAGE_NAME));
expect(userIdStoredConsent.gdprApplies).to.equal(consent.gdprApplies);
expect(userIdStoredConsent.gdprApplies).to.equal(testConsentData.gdprApplies);
expect(userIdStoredConsent.consentString).to.equal(consent.consentString);
expect(userIdStoredConsent.consentString).to.equal(testConsentData.consentData);
});

it('calls getId if empty stored consent and refresh not needed', function () {
Expand All @@ -1633,13 +1619,6 @@ describe('User ID', function() {
sinon.assert.calledOnce(mockGetId);
sinon.assert.calledOnce(mockDecode);
sinon.assert.notCalled(mockExtendId);

let consent = gdprDataHandler.getConsentData();
let userIdStoredConsent = JSON.parse(coreStorage.getCookie(CONSENT_LOCAL_STORAGE_NAME));
expect(userIdStoredConsent.gdprApplies).to.equal(consent.gdprApplies);
expect(userIdStoredConsent.gdprApplies).to.equal(testConsentData.gdprApplies);
expect(userIdStoredConsent.consentString).to.equal(consent.consentString);
expect(userIdStoredConsent.consentString).to.equal(testConsentData.consentData);
});

it('calls getId if stored consent does not match current consent and refresh not needed', function () {
Expand All @@ -1659,13 +1638,6 @@ describe('User ID', function() {
sinon.assert.calledOnce(mockGetId);
sinon.assert.calledOnce(mockDecode);
sinon.assert.notCalled(mockExtendId);

let consent = gdprDataHandler.getConsentData();
let userIdStoredConsent = JSON.parse(coreStorage.getCookie(CONSENT_LOCAL_STORAGE_NAME));
expect(userIdStoredConsent.gdprApplies).to.equal(consent.gdprApplies);
expect(userIdStoredConsent.gdprApplies).to.equal(testConsentData.gdprApplies);
expect(userIdStoredConsent.consentString).to.equal(consent.consentString);
expect(userIdStoredConsent.consentString).to.equal(testConsentData.consentData);
});

it('does not call getId if stored consent matches current consent and refresh not needed', function () {
Expand All @@ -1685,13 +1657,6 @@ describe('User ID', function() {
sinon.assert.notCalled(mockGetId);
sinon.assert.calledOnce(mockDecode);
sinon.assert.calledOnce(mockExtendId);

let consent = gdprDataHandler.getConsentData();
let userIdStoredConsent = JSON.parse(coreStorage.getCookie(CONSENT_LOCAL_STORAGE_NAME));
expect(userIdStoredConsent.gdprApplies).to.equal(consent.gdprApplies);
expect(userIdStoredConsent.gdprApplies).to.equal(testConsentData.gdprApplies);
expect(userIdStoredConsent.consentString).to.equal(consent.consentString);
expect(userIdStoredConsent.consentString).to.equal(testConsentData.consentData);
});
});
});
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20 changes: 20 additions & 0 deletions test/spec/utils_spec.js
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Original file line number Diff line number Diff line change
Expand Up @@ -1177,5 +1177,25 @@ describe('Utils', function () {
}
expect(utils.deepEqual(obj1, obj2)).to.equal(false);
});

describe('simpleHash', function() {
it('should return the same hash for the same string', function() {
const stringOne = 'string1';
expect(utils.simpleHash(stringOne)).to.equal(utils.simpleHash(stringOne));
});
it('should return a different hash for the same string with different seeds', function() {
const stringOne = 'string1';
expect(utils.simpleHash(stringOne, 1)).to.not.equal(utils.simpleHash(stringOne, 2));
});
it('should return a different hash for different strings with the same seed', function() {
const stringOne = 'string1';
const stringTwo = 'string2';
expect(utils.simpleHash(stringOne)).to.not.equal(utils.simpleHash(stringTwo));
});
it('should return a string value, not a number', function() {
const stringOne = 'string1';
expect(typeof utils.simpleHash(stringOne)).to.equal('string');
});
});
});
});

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