Malicious Site Protection - Make clientSideHit optional parameter

Sources/MaliciousSiteProtection/MaliciousSiteDetector.swift

@@ -113,7 +113,7 @@ public final class MaliciousSiteDetector: MaliciousSiteDetecting {
         for threatKind in hashPrefixMatchingThreatKinds {
             let matches = await checkLocalFilters(hostHash: hostHash, canonicalUrl: canonicalUrl, for: threatKind)
             if matches {
-                eventMapping.fire(.errorPageShown(category: threatKind, clientSideHit: true))
+                await fireErrorPageShown(threatKind: threatKind, clientSideHit: true)
                 return threatKind
             }
         }
@@ -123,11 +123,18 @@ public final class MaliciousSiteDetector: MaliciousSiteDetecting {
         let match = await checkApiMatches(hostHash: hostHash, canonicalUrl: canonicalUrl)
         if let match {
             let threatKind = match.category.flatMap(ThreatKind.init) ?? hashPrefixMatchingThreatKinds[0]
-            eventMapping.fire(.errorPageShown(category: threatKind, clientSideHit: false))
+            await fireErrorPageShown(threatKind: threatKind, clientSideHit: false)
             return threatKind
         }
 
         return .none
     }
 
+    private func fireErrorPageShown(threatKind: ThreatKind, clientSideHit: Bool) async {
+        let filterSet = await dataManager.dataSet(for: .filterSet(threatKind: threatKind))
+        // Send Pixel clientSideHit parameter only if filterSet size is greater than 100
+        // https://app.asana.com/0/0/1209113403594297/1209141231997704/f
+        let sanitisedClientSideHit = filterSet.filters.count > 100 ? clientSideHit : nil
+        eventMapping.fire(.errorPageShown(category: threatKind, clientSideHit: sanitisedClientSideHit))
+    }
 }

Sources/MaliciousSiteProtection/Model/Event.swift

@@ -29,7 +29,7 @@ public extension PixelKit {
 }
 
 public enum Event: PixelKitEventV2 {
-    case errorPageShown(category: ThreatKind, clientSideHit: Bool)
+    case errorPageShown(category: ThreatKind, clientSideHit: Bool?)
     case visitSite(category: ThreatKind)
     case iframeLoaded(category: ThreatKind)
     case settingToggled(to: Bool)
@@ -59,10 +59,17 @@ public enum Event: PixelKitEventV2 {
     public var parameters: [String: String]? {
         switch self {
         case .errorPageShown(category: let category, clientSideHit: let clientSideHit):
-            return [
-                PixelKit.Parameters.category: category.rawValue,
-                PixelKit.Parameters.clientSideHit: String(clientSideHit),
-            ]
+            let parameters = if let clientSideHit {
+                [
+                    PixelKit.Parameters.category: category.rawValue,
+                    PixelKit.Parameters.clientSideHit: String(clientSideHit),
+                ]
+            } else {
+                [
+                    PixelKit.Parameters.category: category.rawValue,
+                ]
+            }
+            return parameters
         case .visitSite(category: let category),
              .iframeLoaded(category: let category):
             return [

Tests/MaliciousSiteProtectionTests/MaliciousSiteDetectorTests.swift

@@ -157,4 +157,88 @@ class MaliciousSiteDetectorTests: XCTestCase {
             XCTFail("Unexpected event \(event)")
         }
     }
+
+    func testWhenLocalFilterHitAndFilterSetSmallerThanHundredThenClientSideHitParameterIsNil() async throws {
+        // GIVEN
+        let filter = Filter(hash: "255a8a793097aeea1f06a19c08cde28db0eb34c660c6e4e7480c9525d034b16d", regex: ".*malicious.*")
+        try await mockDataManager.store(FilterDictionary(revision: 0, items: [filter]), for: .filterSet(threatKind: .phishing))
+        try await mockDataManager.store(HashPrefixSet(revision: 0, items: ["255a8a79"]), for: .hashPrefixes(threatKind: .phishing))
+        let url = URL(string: "https://malicious.com/")!
+
+        // WHEN
+        _ = await detector.evaluate(url)
+
+        // THEN
+        XCTAssertEqual(mockEventMapping.events.count, 1)
+        switch mockEventMapping.events.last {
+        case let .errorPageShown(_, clientSideHit):
+            XCTAssertNil(clientSideHit)
+        default:
+            XCTFail("Wrong event fired")
+        }
+    }
+
+    func testWhenLocalFilterHitAndFilterSetGreaterThanHundredThenClientSideHitParameterIsSent() async throws {
+        // GIVEN
+        let maliciousFilter = Filter(hash: "255a8a793097aeea1f06a19c08cde28db0eb34c660c6e4e7480c9525d034b16d", regex: ".*malicious.*")
+        let filters = (1...100).map { i in
+            Filter(hash: "255a8a793097aeea1f06a19c08cde28db0eb34c660c6e4e7480c9525d034b16d\(i)", regex: ".*malicious.*")
+        } + [maliciousFilter]
+        try await mockDataManager.store(FilterDictionary(revision: 0, items: filters), for: .filterSet(threatKind: .phishing))
+        try await mockDataManager.store(HashPrefixSet(revision: 0, items: ["255a8a79"]), for: .hashPrefixes(threatKind: .phishing))
+        let url = URL(string: "https://malicious.com/")!
+
+        // WHEN
+        _ = await detector.evaluate(url)
+
+        // THEN
+        XCTAssertEqual(mockEventMapping.events.count, 1)
+        switch mockEventMapping.events.last {
+        case let .errorPageShown(_, clientSideHit):
+            XCTAssertNotNil(clientSideHit)
+        default:
+            XCTFail("Wrong event fired")
+        }
+    }
+
+    func testWhenMatchesAPIAndFilterSetSmallerThanHundredThenClientSideHitParameterIsNil() async throws {
+        // GIVEN
+        try await mockDataManager.store(HashPrefixSet(revision: 0, items: ["a379a6f6"]), for: .hashPrefixes(threatKind: .phishing))
+        let url = URL(string: "https://example.com/mal")!
+
+        // WHEN
+        _ = await detector.evaluate(url)
+
+        // THEN
+        XCTAssertEqual(mockEventMapping.events.count, 1)
+        switch mockEventMapping.events.last {
+        case let .errorPageShown(_, clientSideHit):
+            XCTAssertNil(clientSideHit)
+        default:
+            XCTFail("Wrong event fired")
+        }
+    }
+
+    func testWhenMatchesAPIAndFilterSetGreaterThanHundredThenClientSideHitParameterIsSet() async throws {
+        // GIVEN
+        let maliciousFilter = Filter(hash: "255a8a793097aeea1f06a19c08cde28db0eb34c660c6e4e7480c9525d034b16d", regex: ".*malicious.*")
+        let filters = (1...100).map { i in
+            Filter(hash: "255a8a793097aeea1f06a19c08cde28db0eb34c660c6e4e7480c9525d034b16d\(i)", regex: ".*malicious.*")
+        } + [maliciousFilter]
+        try await mockDataManager.store(FilterDictionary(revision: 0, items: filters), for: .filterSet(threatKind: .phishing))
+        try await mockDataManager.store(HashPrefixSet(revision: 0, items: ["a379a6f6"]), for: .hashPrefixes(threatKind: .phishing))
+        let url = URL(string: "https://example.com/mal")!
+
+        // WHEN
+         _ = await detector.evaluate(url)
+
+        // THEN
+        XCTAssertEqual(mockEventMapping.events.count, 1)
+        switch mockEventMapping.events.last {
+        case let .errorPageShown(_, clientSideHit):
+            XCTAssertNotNil(clientSideHit)
+        default:
+            XCTFail("Wrong event fired")
+        }
+    }
 }