firebase-ios-sdk/FirebaseMessaging/Sources/Token/FIRMessagingCheckinPreferences.m

/*
 * Copyright 2019 Google
 *
 * 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 "FirebaseMessaging/Sources/Token/FIRMessagingCheckinPreferences.h"

#import <GoogleUtilities/GULUserDefaults.h>
#import "FirebaseMessaging/Sources/FIRMessagingUtilities.h"
#import "FirebaseMessaging/Sources/Token/FIRMessagingCheckinService.h"

const NSTimeInterval kFIRMessagingDefaultCheckinInterval = 7 * 24 * 60 * 60;  // 7 days.
static NSString *const kCheckinKeychainContentSeparatorString = @"|";

@interface FIRMessagingCheckinPreferences ()

@property(nonatomic, readwrite, copy) NSString *deviceID;
@property(nonatomic, readwrite, copy) NSString *secretToken;
@property(nonatomic, readwrite, copy) NSString *digest;
@property(nonatomic, readwrite, copy) NSString *versionInfo;
@property(nonatomic, readwrite, copy) NSString *deviceDataVersion;

@property(nonatomic, readwrite, strong) NSMutableDictionary *gServicesData;
@property(nonatomic, readwrite, assign) int64_t lastCheckinTimestampMillis;

// This flag indicates that we have already saved the above deviceID and secret
// to our keychain and hence we don't need to save again. This is helpful since
// on checkin refresh we can avoid writing to the Keychain which can sometimes
// be very buggy. For info check this https://forums.developer.apple.com/thread/4743
@property(nonatomic, readwrite, assign) BOOL hasPreCachedAuthCredentials;

@end

@implementation FIRMessagingCheckinPreferences

+ (FIRMessagingCheckinPreferences *)preferencesFromKeychainContents:(NSString *)keychainContent {
  NSString *deviceID = [self checkinDeviceIDFromKeychainContent:keychainContent];
  NSString *secret = [self checkinSecretFromKeychainContent:keychainContent];
  if ([deviceID length] && [secret length]) {
    return [[FIRMessagingCheckinPreferences alloc] initWithDeviceID:deviceID secretToken:secret];
  } else {
    return nil;
  }
}

- (instancetype)initWithDeviceID:(NSString *)deviceID secretToken:(NSString *)secretToken {
  self = [super init];
  if (self) {
    self.deviceID = [deviceID copy];
    self.secretToken = [secretToken copy];
  }
  return self;
}

- (void)reset {
  self.deviceID = nil;
  self.secretToken = nil;
  self.digest = nil;
  self.versionInfo = nil;
  self.gServicesData = nil;
  self.deviceDataVersion = nil;
  self.lastCheckinTimestampMillis = 0;
}
- (NSDictionary *)checkinPlistContents {
  NSMutableDictionary *checkinPlistContents = [NSMutableDictionary dictionary];
  checkinPlistContents[kFIRMessagingDigestStringKey] = self.digest ?: @"";
  checkinPlistContents[kFIRMessagingVersionInfoStringKey] = self.versionInfo ?: @"";
  checkinPlistContents[kFIRMessagingDeviceDataVersionKey] = self.deviceDataVersion ?: @"";
  checkinPlistContents[kFIRMessagingLastCheckinTimeKey] = @(self.lastCheckinTimestampMillis);
  checkinPlistContents[kFIRMessagingGServicesDictionaryKey] =
      [self.gServicesData count] ? self.gServicesData : @{};
  return checkinPlistContents;
}

- (BOOL)hasCheckinInfo {
  return (self.deviceID.length && self.secretToken.length);
}

- (BOOL)hasValidCheckinInfo {
  int64_t currentTimestampInMillis = FIRMessagingCurrentTimestampInMilliseconds();
  int64_t timeSinceLastCheckinInMillis = currentTimestampInMillis - self.lastCheckinTimestampMillis;

  BOOL hasCheckinInfo = [self hasCheckinInfo];
  NSString *lastLocale = [[GULUserDefaults standardUserDefaults]
      stringForKey:kFIRMessagingInstanceIDUserDefaultsKeyLocale];
  // If it's app's first time open and checkin is already fetched and no locale information is
  // stored, then checkin info is valid. We should not checkin again because locale is considered
  // "changed".
  if (hasCheckinInfo && !lastLocale) {
    NSString *currentLocale = FIRMessagingCurrentLocale();
    [[GULUserDefaults standardUserDefaults] setObject:currentLocale
                                               forKey:kFIRMessagingInstanceIDUserDefaultsKeyLocale];
    return YES;
  }

  // If locale has changed, checkin info is no longer valid.
  // Also update locale information if changed. (Only do it here not in token refresh)
  if (FIRMessagingHasLocaleChanged()) {
    NSString *currentLocale = FIRMessagingCurrentLocale();
    [[GULUserDefaults standardUserDefaults] setObject:currentLocale
                                               forKey:kFIRMessagingInstanceIDUserDefaultsKeyLocale];
    return NO;
  }

  return (hasCheckinInfo &&
          (timeSinceLastCheckinInMillis / 1000.0 < kFIRMessagingDefaultCheckinInterval));
}

- (void)setHasPreCachedAuthCredentials:(BOOL)hasPreCachedAuthCredentials {
  _hasPreCachedAuthCredentials = hasPreCachedAuthCredentials;
}

- (NSString *)checkinKeychainContent {
  if ([self.deviceID length] && [self.secretToken length]) {
    return [NSString stringWithFormat:@"%@%@%@", self.deviceID,
                                      kCheckinKeychainContentSeparatorString, self.secretToken];
  } else {
    return nil;
  }
}

- (void)updateWithCheckinPlistContents:(NSDictionary *)checkinPlistContent {
  // These values come from the checkin server and are read from disk at every launch. Drop values
  // of an unexpected type (for example, saved by an older SDK version) instead of using them.
  for (NSString *key in checkinPlistContent) {
    id value = checkinPlistContent[key];
    if ([kFIRMessagingDigestStringKey isEqualToString:key]) {
      self.digest = [value isKindOfClass:[NSString class]] ? value : nil;
    } else if ([kFIRMessagingVersionInfoStringKey isEqualToString:key]) {
      self.versionInfo = [value isKindOfClass:[NSString class]] ? value : nil;
    } else if ([kFIRMessagingLastCheckinTimeKey isEqualToString:key]) {
      BOOL isTimestamp =
          [value isKindOfClass:[NSNumber class]] || [value isKindOfClass:[NSString class]];
      self.lastCheckinTimestampMillis = isTimestamp ? [value longLongValue] : 0;
    } else if ([kFIRMessagingGServicesDictionaryKey isEqualToString:key]) {
      self.gServicesData = [value isKindOfClass:[NSDictionary class]] ? [value mutableCopy] : nil;
    } else if ([kFIRMessagingDeviceDataVersionKey isEqualToString:key]) {
      self.deviceDataVersion = [value isKindOfClass:[NSString class]] ? value : nil;
    }
    // Otherwise we have some keys we don't care about
  }
}

+ (NSString *)checkinDeviceIDFromKeychainContent:(NSString *)keychainContent {
  return [self checkinKeychainContent:keychainContent forIndex:0];
}

+ (NSString *)checkinSecretFromKeychainContent:(NSString *)keychainContent {
  return [self checkinKeychainContent:keychainContent forIndex:1];
}

+ (NSString *)checkinKeychainContent:(NSString *)keychainContent forIndex:(int)index {
  NSArray *keychainComponents =
      [keychainContent componentsSeparatedByString:kCheckinKeychainContentSeparatorString];
  if (index >= 0 && index < 2 && [keychainComponents count] == 2) {
    return keychainComponents[index];
  } else {
    return nil;
  }
}

@end