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AdClickAttributionLogic.swift
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AdClickAttributionLogic.swift
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//
// AdClickAttributionLogic.swift
// DuckDuckGo
//
// Copyright © 2022 DuckDuckGo. 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 Foundation
import os
public protocol AdClickAttributionLogicDelegate: AnyObject {
func attributionLogic(_ logic: AdClickAttributionLogic,
didRequestRuleApplication rules: ContentBlockerRulesManager.Rules?,
forVendor vendor: String?)
}
public class AdClickAttributionLogic {
public enum State {
case noAttribution
case preparingAttribution(vendor: String, session: SessionInfo, completionBlocks: [(() -> Void)])
case activeAttribution(vendor: String, session: SessionInfo, rules: ContentBlockerRulesManager.Rules)
}
public struct SessionInfo {
// Start of the attribution
public let attributionStartedAt: Date
// Present when we leave webpage associated with the attribution
public let leftAttributionContextAt: Date?
init(start: Date = Date(), leftContextAt: Date? = nil) {
attributionStartedAt = start
leftAttributionContextAt = leftContextAt
}
}
private let featureConfig: AdClickAttributing
private let rulesProvider: AdClickAttributionRulesProviding
private let tld: TLD
private let log: OSLog
private let eventReporting: EventMapping<AdClickAttributionEvents>?
private let errorReporting: EventMapping<AdClickAttributionDebugEvents>?
public private(set) var state = State.noAttribution
private var registerFirstActivity = false
private var attributionTimeout: DispatchWorkItem?
public weak var delegate: AdClickAttributionLogicDelegate?
public init(featureConfig: AdClickAttributing,
rulesProvider: AdClickAttributionRulesProviding,
tld: TLD,
eventReporting: EventMapping<AdClickAttributionEvents>? = nil,
errorReporting: EventMapping<AdClickAttributionDebugEvents>? = nil,
log: OSLog = .disabled) {
self.featureConfig = featureConfig
self.rulesProvider = rulesProvider
self.tld = tld
self.eventReporting = eventReporting
self.errorReporting = errorReporting
self.log = log
}
public func applyInheritedAttribution(state: State?) {
guard let state = state else { return }
if case .noAttribution = state {} else {
errorReporting?.fire(.adAttributionLogicUnexpectedStateOnInheritedAttribution)
}
switch state {
case .noAttribution:
self.state = state
case .preparingAttribution(let vendor, let info, _):
requestAttribution(forVendor: vendor,
attributionStartedAt: info.attributionStartedAt)
case .activeAttribution:
self.state = state
applyRules()
}
}
public func onRulesChanged(latestRules: [ContentBlockerRulesManager.Rules]) {
switch state {
case .noAttribution:
applyRules()
case .preparingAttribution(let vendor, _, let completionBlocks):
requestAttribution(forVendor: vendor, completionBlocks: completionBlocks)
case .activeAttribution(let vendor, _, _):
requestAttribution(forVendor: vendor)
}
}
public func reapplyCurrentRules() {
applyRules()
}
public func onProvisionalNavigation(completion: @escaping () -> Void, currentTime: Date = Date()) {
switch state {
case .noAttribution:
completion()
case .preparingAttribution(let vendor, let session, var completionBlocks):
os_log(.debug, log: log, "Suspending provisional navigation...")
completionBlocks.append(completion)
state = .preparingAttribution(vendor: vendor,
session: session,
completionBlocks: completionBlocks)
case .activeAttribution(_, let session, _):
if currentTime.timeIntervalSince(session.attributionStartedAt) >= featureConfig.totalExpiration {
os_log(.debug, log: log, "Attribution has expired - total expiration")
disableAttribution()
} else if let leftAttributionContextAt = session.leftAttributionContextAt,
currentTime.timeIntervalSince(leftAttributionContextAt) >= featureConfig.navigationExpiration {
os_log(.debug, log: log, "Attribution has expired - navigational expiration")
disableAttribution()
}
completion()
}
}
public func onDidFinishNavigation(host: String?, currentTime: Date = Date()) {
guard case .activeAttribution(let vendor, let session, let rules) = state else {
return
}
if currentTime.timeIntervalSince(session.attributionStartedAt) >= featureConfig.totalExpiration {
os_log(.debug, log: log, "Attribution has expired - total expiration")
disableAttribution()
return
}
if let leftAttributionContextAt = session.leftAttributionContextAt {
if currentTime.timeIntervalSince(leftAttributionContextAt) >= featureConfig.navigationExpiration {
os_log(.debug, log: log, "Attribution has expired - navigational expiration")
disableAttribution()
} else if tld.eTLDplus1(host) == vendor {
os_log(.debug, log: log, "Refreshing navigational duration for attribution")
state = .activeAttribution(vendor: vendor,
session: SessionInfo(start: session.attributionStartedAt),
rules: rules)
}
} else if tld.eTLDplus1(host) != vendor {
os_log(.debug, log: log, "Leaving attribution context")
state = .activeAttribution(vendor: vendor,
session: SessionInfo(start: session.attributionStartedAt,
leftContextAt: Date()),
rules: rules)
}
}
public func onRequestDetected(request: DetectedRequest) {
guard registerFirstActivity,
BlockingState.allowed(reason: .adClickAttribution) == request.state else { return }
eventReporting?.fire(.adAttributionActive)
registerFirstActivity = false
}
private func disableAttribution() {
state = .noAttribution
applyRules()
}
private func onAttributedRulesCompiled(forVendor vendor: String, _ rules: ContentBlockerRulesManager.Rules) {
guard case .preparingAttribution(let expectedVendor, let session, let completionBlocks) = state else {
os_log(.error, log: log, "Attributed Rules received unexpectedly")
errorReporting?.fire(.adAttributionLogicUnexpectedStateOnRulesCompiled)
return
}
guard expectedVendor == vendor else {
os_log(.debug, log: log, "Attributed Rules received for wrong vendor")
errorReporting?.fire(.adAttributionLogicWrongVendorOnSuccessfulCompilation)
return
}
state = .activeAttribution(vendor: vendor, session: session, rules: rules)
applyRules()
os_log(.debug, log: log, "Resuming provisional navigation for %{public}d requests", completionBlocks.count)
for completion in completionBlocks {
completion()
}
}
private func onAttributedRulesCompilationFailed(forVendor vendor: String) {
guard case .preparingAttribution(let expectedVendor, _, let completionBlocks) = state else {
os_log(.error, log: log, "Attributed Rules compilation failed")
errorReporting?.fire(.adAttributionLogicUnexpectedStateOnRulesCompilationFailed)
return
}
guard expectedVendor == vendor else {
errorReporting?.fire(.adAttributionLogicWrongVendorOnFailedCompilation)
return
}
state = .noAttribution
applyRules()
os_log(.debug, log: log, "Resuming provisional navigation for {public}%d requests", completionBlocks.count)
for completion in completionBlocks {
completion()
}
}
private func applyRules() {
if case .activeAttribution(let vendor, _, let rules) = state {
delegate?.attributionLogic(self, didRequestRuleApplication: rules, forVendor: vendor)
} else {
delegate?.attributionLogic(self, didRequestRuleApplication: rulesProvider.globalAttributionRules, forVendor: nil)
}
}
/// Request attribution when we detect it is needed
private func requestAttribution(forVendor vendorHost: String, attributionStartedAt: Date = Date(), completionBlocks: [() -> Void] = []) {
state = .preparingAttribution(vendor: vendorHost,
session: SessionInfo(start: attributionStartedAt),
completionBlocks: completionBlocks)
scheduleTimeout(forVendor: vendorHost)
rulesProvider.requestAttribution(forVendor: vendorHost) { [weak self] rules in
self?.cancelTimeout()
if let rules = rules {
self?.onAttributedRulesCompiled(forVendor: vendorHost, rules)
} else {
self?.onAttributedRulesCompilationFailed(forVendor: vendorHost)
}
}
}
private func scheduleTimeout(forVendor vendor: String) {
let timeoutWorkItem = DispatchWorkItem { [weak self] in
self?.onAttributedRulesCompilationFailed(forVendor: vendor)
self?.attributionTimeout = nil
self?.errorReporting?.fire(.adAttributionLogicRequestingAttributionTimedOut)
}
self.attributionTimeout?.cancel()
self.attributionTimeout = timeoutWorkItem
DispatchQueue.main.asyncAfter(deadline: .now() + 4.0,
execute: timeoutWorkItem)
}
private func cancelTimeout() {
attributionTimeout?.cancel()
attributionTimeout = nil
}
/// Respond to new requests for attribution
private func onAttributionRequested(forVendor vendorHost: String) {
switch state {
case .noAttribution:
os_log(.debug, log: log, "Preparing attribution for %{private}s", vendorHost)
requestAttribution(forVendor: vendorHost)
case .preparingAttribution(let expectedVendor, _, let completionBlocks):
if expectedVendor != vendorHost {
os_log(.debug, log: log, "Preparing attributon for %{private}s replacing pending one for %{private}s", vendorHost, expectedVendor)
requestAttribution(forVendor: vendorHost, completionBlocks: completionBlocks)
} else {
os_log(.debug, log: log, "Preparing attribution for %{private}s already in progress", vendorHost)
}
case .activeAttribution(let expectedVendor, _, _):
if expectedVendor != vendorHost {
os_log(.debug, log: log, "Preparing attributon for %{private}s replacing %{private}s", vendorHost, expectedVendor)
requestAttribution(forVendor: vendorHost)
} else {
os_log(.debug, log: log, "Attribution for %{private}s already active", vendorHost)
}
}
}
}
extension AdClickAttributionLogic: AdClickAttributionDetectionDelegate {
public func attributionDetection(_ detection: AdClickAttributionDetection,
didDetectVendor vendorHost: String) {
os_log(.debug, log: log, "Detected attribution requests for %{private}s", vendorHost)
onAttributionRequested(forVendor: vendorHost)
registerFirstActivity = true
}
}