Implement scriptlet download and storage by CrisBarreiro · Pull Request #8557 · duckduckgo/Android

CrisBarreiro · 2026-05-14T11:51:42Z

Task/Issue URL: https://app.asana.com/1/137249556945/project/488551667048375/task/1214486375443736?focus=true

Description

Steps to test this PR

Tip

Feature 1 - RC flag disabled

Install the app
Check logs for onPrivacyConfigDownloaded
Check no logs for files actually downloaded
Open database inspector and check ad_blocking_extension.db doesn't exist

Feature 2 - RC flag disabled with settings

Apply Patch 1 - update privacy-config
Fresh install the app
Check logs for onPrivacyConfigDownloaded
Check no logs for files actually downloaded
Open database inspector and check ad_blocking_extension.db doesn't exist

Feature 3 - Kill-switch on, operational flag off (feature is discoverable but dormant)

From the previous scenario, enable adBlockingExtension -> isDiscoverable from the feature flags inventory
Kill and reopen the app
Check logs for onPrivacyConfigDownloaded
Check no logs for files actually downloaded
Open database inspector and check ad_blocking_extension.db doesn't exist

Feature 4 - Both flags enabled (full operational path)

From the previous scenario, enable adBlockingExtension from the feature flags inventory
Check logs for onPrivacyConfigDownloaded, Validating scriptlet succeeded (x4), and Storing scriptlets
Open database inspector and check ad_blocking_extension.db exists, and has the following contents:
- name: scriptlets/isolated/ublock-filters.js, version: 2026.5.12, content: {some bytes}
- name: scriptlets/main/ublock-filters.js, version: 2026.5.12, content: {some bytes}
Kill and reopen the app
Check logs for Version matches stored. Skipping

Feature 5 - RC flag disabled with settings

Patches

Patch 1 - update privacy-config

Subject: [PATCH] Update privacy-config URL
---
Index: privacy-config/privacy-config-api/src/main/java/com/duckduckgo/privacy/config/api/PrivacyFeatureName.kt
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/privacy-config/privacy-config-api/src/main/java/com/duckduckgo/privacy/config/api/PrivacyFeatureName.kt b/privacy-config/privacy-config-api/src/main/java/com/duckduckgo/privacy/config/api/PrivacyFeatureName.kt
--- a/privacy-config/privacy-config-api/src/main/java/com/duckduckgo/privacy/config/api/PrivacyFeatureName.kt	(revision 476d1a965596de1bab6c642a9b023d708bd86f04)
+++ b/privacy-config/privacy-config-api/src/main/java/com/duckduckgo/privacy/config/api/PrivacyFeatureName.kt	(date 1778775474685)
@@ -29,4 +29,4 @@
     TrackingParametersFeatureName("trackingParameters"),
 }
 
-const val PRIVACY_REMOTE_CONFIG_URL = "https://staticcdn.duckduckgo.com/trackerblocking/config/v5/android-config.json"
+const val PRIVACY_REMOTE_CONFIG_URL = "https://duckduckgo.github.io/privacy-configuration/pr-5175/v4/android-config.json"

UI changes

n/a

Note

Medium Risk
Adds new background download + signature verification and persists content to a new Room database, so failures could impact update reliability and introduces new network/storage paths. Feature is gated by remote toggles (kill-switch/contingency) which reduces blast radius but the crypto/WorkManager logic is still moderately risk-prone.

Overview
Implements end-to-end remote scriptlet update for the ad-blocking extension: parses settings from remote config, schedules a WorkManager job when the feature is discoverable (and not in contingency mode), downloads scriptlets, validates them via ECDSA signature + UTF-8 checks, and stores the resulting versioned scriptlets.

Adds a new Room-backed store (ad_blocking_extension.db) with DAO/repository plumbing and DI wiring, plus new module dependencies and comprehensive unit tests for config parsing, worker scheduling/execution, updating logic, and signature validation. Also wires :ad-blocking-impl into the main app module build.

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CrisBarreiro · 2026-05-14T11:51:58Z

Add settings infra for ad blocking #8660
Add core ad blocking capabilities #8622
Implement scriptlet download and storage #8557 👈 (View in Graphite)
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cmonfortep

Great work @CrisBarreiro
Just some comments, but overall this is super well done and solid!

cmonfortep · 2026-05-21T21:34:09Z

-    @Toggle.DefaultValue(DefaultFeatureValue.FALSE)
+    /**
+     * @return `true` when the feature is operational.
+     * When false, feature is still accessible, but not working as expected.


Can we clarify what means "not working as expected"?

Sure, will do

For reference, this is the contingency path, so we'd want to still show the settings entry, but show some contingency messaging to the user

cmonfortep · 2026-05-21T21:35:09Z


-    @Toggle.DefaultValue(DefaultFeatureValue.FALSE)
+    /**
+     * Kill-switch. When false, the feature is completely inaccessible.


is it a kill switch? I assume this is the one we will use for phase rollout? It seems the real kill switch is self(), but this one serve us more for FF and rollout. Just to confirm this.

It's a kill-switch. There are 3 different relevant flags here:

self -> If enabled, we can inject the scripts (provided the user settings allow us to). If disabled, we won't inject the scripts, and we'll show contingency messaging instead

isDiscoverable -> This is mainly meant to be used during development, so we can hide the entry from settings. I decided to use a sub-feature because then it's easier to remove it later

enabledByDefault -> This is the one we'll use for the rollout

Phase 1, we'll enable both self and isDiscoverable. We can also perform a gradual rollout on isDiscoverable for extra safety
Then, if all looks good, we'll enable enabledByDefault as a gradual rollout

cmonfortep · 2026-05-21T21:41:20Z

+
+@ContributesBinding(AppScope::class)
+class RealScriptletDownloader @Inject constructor(
+    @Named("nonCaching") private val okHttpClient: Lazy<OkHttpClient>,


Can we double check this is actually expected? Mostly to be sure the BE can hold the load on requests here. Do they offer cache policy in their response?

We'll only try to refresh the scripts when privacy config has changed, the feature status allows for it, and there's a new version, so we won't be calling the endpoint that frequently. I disabled caching here because we're already effectively caching the response in the database, so this would be redundant.

The only edge case I can think of is #8557 (comment), but other than that, I don't see any other issues

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…ed ANRs

cursor

Cursor Bugbot has reviewed your changes and found 1 potential issue.

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cursor · 2026-05-22T10:38:02Z

+    private fun buildJsonAdapter(): JsonAdapter<AdBlockingExtensionSettings> {
+        val moshi = Moshi.Builder().add(KotlinJsonAdapterFactory()).build()
+        return moshi.adapter(AdBlockingExtensionSettings::class.java)
+    }


Identical buildJsonAdapter() method duplicated three times

Low Severity

The buildJsonAdapter() method — creating a Moshi instance with KotlinJsonAdapterFactory() and building an AdBlockingExtensionSettings adapter — is identically duplicated in ScriptletDownloadWorker, ScriptletDownloadWorkerScheduler, and RealAdBlockingExtensionConfigProvider. Each copy allocates its own Moshi instance. Extracting this into a shared provider or companion function would reduce maintenance burden and risk of inconsistent future changes.

Additional Locations (2)

ad-blocking/ad-blocking-impl/src/main/java/com/duckduckgo/adblocking/impl/ScriptletDownloadWorker.kt#L135-L139

ad-blocking/ad-blocking-impl/src/main/java/com/duckduckgo/adblocking/impl/remoteconfig/AdBlockingExtensionConfigProvider.kt#L86-L90

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aibrahim- force-pushed the develop branch 2 times, most recently from 231d816 to d08fbc3 Compare May 14, 2026 14:06

CrisBarreiro force-pushed the feature/cris/ad-blocking/download-store-scriptlets branch from 5e042be to 476d1a9 Compare May 14, 2026 16:13

CrisBarreiro marked this pull request as ready for review May 14, 2026 17:03

cursor Bot reviewed May 14, 2026

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Comment thread ad-blocking/ad-blocking-impl/build.gradle Outdated

Comment thread ...d-blocking-impl/src/main/java/com/duckduckgo/adblocking/impl/di/AdBlockingExtensionModule.kt Outdated

CrisBarreiro marked this pull request as draft May 14, 2026 17:15

CrisBarreiro force-pushed the feature/cris/ad-blocking/download-store-scriptlets branch from 476d1a9 to f113371 Compare May 18, 2026 10:28

CrisBarreiro marked this pull request as ready for review May 18, 2026 13:54

cursor Bot reviewed May 18, 2026

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Comment thread ...d-blocking-impl/src/main/java/com/duckduckgo/adblocking/impl/di/AdBlockingExtensionModule.kt Outdated

CrisBarreiro requested a review from cmonfortep May 18, 2026 16:44

CrisBarreiro assigned cmonfortep May 18, 2026

CrisBarreiro force-pushed the feature/cris/ad-blocking/download-store-scriptlets branch from 7213cde to 3b6160c Compare May 19, 2026 15:07

CrisBarreiro mentioned this pull request May 19, 2026

Add core ad blocking capabilities #8622

Open

18 tasks

cursor Bot reviewed May 19, 2026

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Comment thread ...ing/ad-blocking-impl/src/main/java/com/duckduckgo/adblocking/impl/domain/ScriptletUpdater.kt

CrisBarreiro force-pushed the feature/cris/ad-blocking/download-store-scriptlets branch from 3b6160c to f23bf2f Compare May 21, 2026 10:41

cursor Bot reviewed May 21, 2026

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Comment thread ...d-blocking-impl/src/main/java/com/duckduckgo/adblocking/impl/store/AdBlockingExtensionDao.kt

CrisBarreiro mentioned this pull request May 21, 2026

Add settings infra for ad blocking #8660

Draft

cmonfortep approved these changes May 21, 2026

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CrisBarreiro added 11 commits May 22, 2026 09:40

Add store classes

f34cced

Expose config changes

a292d9d

Add downloader

268de81

Add signature validator

44abee7

Add repository

a04d285

Update config provider so we expose domains and scriptlets settings s…

6a7e2d6

…eparately

Add updater and worker logic

175a513

Add ad blocking module to app module

2cee2a0

Map settings to null if feature disabled

2b4cb38

Don't store empty files

791c813

Fix CI issues

66cf85b

CrisBarreiro added 6 commits May 22, 2026 09:40

Add separate flag for kill-switch

7e80467

gate doWork on kill-switch enabled to prevent stale workers

83d8953

Make changes reactive even when using FF inventory

7edea70

Refactor tests

99da31b

Don't use unqualified generic types for validator

27800a7

Don't expose domains

feaa42c

CrisBarreiro force-pushed the feature/cris/ad-blocking/download-store-scriptlets branch from f23bf2f to 5142d91 Compare May 22, 2026 07:41

Fix missing version on empty scriptlets

8a3a2a0

CrisBarreiro force-pushed the feature/cris/ad-blocking/download-store-scriptlets branch from 5142d91 to 8a3a2a0 Compare May 22, 2026 08:12

CrisBarreiro added 2 commits May 22, 2026 11:35

Simplify JSON models and guard against KotlinJsonAdapterFactory induc…

87bf24c

…ed ANRs

Simplify RC flags setup

87c9397

cursor Bot reviewed May 22, 2026

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CrisBarreiro commented May 14, 2026 • edited by cursor Bot Loading Uh oh! There was an error while loading. Please reload this page.

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Description

Steps to test this PR

Patches

UI changes

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CrisBarreiro commented May 14, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Identical buildJsonAdapter() method duplicated three times

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CrisBarreiro commented May 14, 2026 •

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CrisBarreiro commented May 14, 2026 •

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Identical `buildJsonAdapter()` method duplicated three times