update size limit (#28917)

extensions/amp-consent/0.1/consent-state-manager.js

@@ -31,12 +31,13 @@ import {Deferred} from '../../../src/utils/promise';
 import {Services} from '../../../src/services';
 import {assertHttpsUrl} from '../../../src/url';
 import {dev, devAssert, user} from '../../../src/log';
+import {dict} from '../../../src/utils/object';
 import {expandConsentEndpointUrl, getConsentCID} from './consent-config';
 
 const TAG = 'CONSENT-STATE-MANAGER';
 
 /** @visibleForTesting */
-export const CONSENT_STRING_MAX_LENGTH = 1024;
+export const CONSENT_STORAGE_MAX = 1200;
 
 export class ConsentStateManager {
   /**
@@ -364,31 +365,34 @@ export class ConsentInstance {
         return;
       }
 
-      const consentStr = consentInfo['consentString'];
-      if (consentStr && consentStr.length > CONSENT_STRING_MAX_LENGTH) {
-        // Verify the length of consentString.
-        // 1024 * 4/3 (base64) = 1336 bytes.
+      const value = composeStoreValue(consentInfo);
+      if (value == null) {
+        // Value can be false, do not use !value check
+        // Nothing to store to localStorage
+        return;
+      }
+
+      // Check size
+      const size = JSON.stringify(
+        dict({
+          [this.storageKey_]: value,
+        })
+      ).length;
+
+      if (size > CONSENT_STORAGE_MAX) {
+        // 1200 * 4/3 (base64) = 1600 bytes
         user().error(
           TAG,
-          'Cannot store consentString which length exceeds %s. ' +
+          'Cannot store consent information which length exceeds %s. ' +
             'Previous stored consentInfo will be cleared',
-          CONSENT_STRING_MAX_LENGTH
+          CONSENT_STORAGE_MAX
         );
         // If new consentInfo value cannot be stored, need to remove previous
         // value
         storage.remove(this.storageKey_);
         // TODO: Good to have a way to inform CMP service in this case
         return;
       }
-
-      // TODO: enforce metadata limits here (if any)
-
-      const value = composeStoreValue(consentInfo);
-      if (value == null) {
-        // Value can be false, do not use !value check
-        // Nothing to store to localStorage
-        return;
-      }
       this.savedConsentInfo_ = consentInfo;
       storage.setNonBoolean(this.storageKey_, value);
       this.sendUpdateHrefRequest_(consentInfo);

extensions/amp-consent/0.1/test/test-consent-state-manager.js

@@ -20,7 +20,7 @@ import {
   constructMetadata,
 } from '../consent-info';
 import {
-  CONSENT_STRING_MAX_LENGTH,
+  CONSENT_STORAGE_MAX,
   ConsentInstance,
   ConsentStateManager,
 } from '../consent-state-manager';
@@ -175,16 +175,19 @@ describes.realWin('ConsentStateManager', {amp: 1}, (env) => {
       });
 
       it('update consent string that exceeds max size', function* () {
-        expectAsyncConsoleError(/Cannot store consentString/);
+        expectAsyncConsoleError(/Cannot store consent information/);
         manager.registerConsentInstance('test', {});
         let testStr = 'a';
-        for (let i = 0; i < CONSENT_STRING_MAX_LENGTH; i++) {
+        // Reserve 26 chars to metadata size `"m":{"cst":1,"ac":"12345"}`
+        // Reserve 36 chars to the storage key, `''` and `{}`
+        // Leaves CONSENT_STORAGE_MAX - 62 chars to consent string
+        for (let i = 0; i < CONSENT_STORAGE_MAX - 62; i++) {
           testStr += 'a';
         }
         manager.updateConsentInstanceState(
           CONSENT_ITEM_STATE.ACCEPTED,
           testStr,
-          constructMetadata()
+          constructMetadata(CONSENT_STRING_TYPE.TCF_V1, '12345')
         );
         let value;
         const p = manager.getConsentInstanceInfo().then((v) => (value = v));
@@ -193,7 +196,7 @@ describes.realWin('ConsentStateManager', {amp: 1}, (env) => {
           constructConsentInfo(
             CONSENT_ITEM_STATE.ACCEPTED,
             testStr,
-            constructMetadata()
+            constructMetadata(CONSENT_STRING_TYPE.TCF_V1, '12345')
           )
         );
       });
@@ -356,12 +359,19 @@ describes.realWin('ConsentStateManager', {amp: 1}, (env) => {
         });
 
         it('remove consentInfo when consentStr length exceeds', function* () {
-          expectAsyncConsoleError(/Cannot store consentString/);
+          expectAsyncConsoleError(/Cannot store consent information/);
           let testStr = 'a';
-          for (let i = 0; i < CONSENT_STRING_MAX_LENGTH; i++) {
+          // Reserve 26 chars to metadata size `"m":{"cst":1,"ac":"12345"}`
+          // Reserve 36 chars to the storage key, `''` and `{}`
+          // Leaves CONSENT_STORAGE_MAX - 62 chars to consent string
+          for (let i = 0; i < CONSENT_STORAGE_MAX - 62; i++) {
             testStr += 'a';
           }
-          instance.update(CONSENT_ITEM_STATE.ACCEPTED, testStr);
+          instance.update(
+            CONSENT_ITEM_STATE.ACCEPTED,
+            testStr,
+            constructMetadata(CONSENT_STRING_TYPE.TCF_V1, '12345')
+          );
           yield macroTask();
           expect(storageSetSpy).to.not.be.called;
           expect(storageRemoveSpy).to.be.calledOnce;

extensions/amp-consent/integrating-consent.md

@@ -14,7 +14,7 @@ To add your consent management service to AMP runtime, it is expected that you:
 - Meet the restrictions that the AMP runtime applies to ensure a good user experience. These includes
   - Enforce the size of the consent prompt. The only two allowed sizes are the initial size (`width: 100vw`, `height: 30vh`), and the full screen size (`width: 100vw`, `height: 100%`) after user interactions.
   - A default placeholder will be displayed before the consent prompt iframe is ready.
-  - Enforce the size of the stored consent information. 1024 character length is the limit. Please [file an issue](https://github.com/ampproject/amphtml/issues/new) if you find that not sufficient.
+  - Enforce the size of the stored consent information. 1200 character length including storage key, consent string and additional metadata is the limit. Please [file an issue](https://github.com/ampproject/amphtml/issues/new) if you find that not sufficient.
 - Understand that including `<amp-consent type='yourName'></amp-consent>` on the page won't block any components by default. **Please make sure to inform your service users to block AMP components either by the `<meta name="amp-consent-blocking">` metaTag, or the `data-block-on-consent` attribute.**
 - Understand that AMP Consent doesn't attempt to interpret the consent info string from the CMP. Vendors can access the consent info string from CMPs via [provided APIs](https://github.com/ampproject/amphtml/blob/master/ads/README.md#amp-consent-integration). It's up to the CMP and service provider vendors to agree on the format of the consent info string.
 - Create an [Intent-To-Implement issue](../../CONTRIBUTING.md#contributing-features) stating that you'll be adding support to your CMP service to AMP. A great start point is to follow the `_ping_` CMP service implementation that the AMP team creates for testing purpose.