firebase-ios-sdk/FirebaseDynamicLinks/Sources/Utilities/FDLUtilities.m

/*
 * Copyright 2018 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 <TargetConditionals.h>
#if TARGET_OS_IOS

#import "FirebaseDynamicLinks/Sources/Utilities/FDLUtilities.h"

#import <UIKit/UIDevice.h>
#include <sys/sysctl.h>

NS_ASSUME_NONNULL_BEGIN

NSString *const kFIRDLParameterDeepLinkIdentifier = @"deep_link_id";
NSString *const kFIRDLParameterLink = @"link";
NSString *const kFIRDLParameterMinimumAppVersion = @"imv";
NSString *const kFIRDLParameterCampaign = @"utm_campaign";
NSString *const kFIRDLParameterContent = @"utm_content";
NSString *const kFIRDLParameterMedium = @"utm_medium";
NSString *const kFIRDLParameterSource = @"utm_source";
NSString *const kFIRDLParameterTerm = @"utm_term";
NSString *const kFIRDLParameterMatchType = @"match_type";
NSString *const kFIRDLParameterInviteId = @"invitation_id";
NSString *const kFIRDLParameterWeakMatchEndpoint = @"invitation_weakMatchEndpoint";
NSString *const kFIRDLParameterMatchMessage = @"match_message";
NSString *const kFIRDLParameterRequestIPVersion = @"request_ip_version";
static NSSet *FIRDLCustomDomains = nil;

NSURL *FIRDLCookieRetrievalURL(NSString *urlScheme, NSString *bundleID) {
  static NSString *const kFDLBundleIDQueryParameterName = @"fdl_ios_bundle_id";
  static NSString *const kFDLURLSchemeQueryParameterName = @"fdl_ios_url_scheme";

  NSURLComponents *components = [[NSURLComponents alloc] init];
  components.scheme = @"https";
  components.host = @"goo.gl";
  components.path = @"/app/_/deeplink";
  NSMutableArray *queryItems = [NSMutableArray array];

  [queryItems addObject:[NSURLQueryItem queryItemWithName:kFDLBundleIDQueryParameterName
                                                    value:bundleID]];
  [queryItems addObject:[NSURLQueryItem queryItemWithName:kFDLURLSchemeQueryParameterName
                                                    value:urlScheme]];
  [components setQueryItems:queryItems];

  return [components URL];
}

NSString *FIRDLURLQueryStringFromDictionary(NSDictionary<NSString *, NSString *> *dictionary) {
  NSMutableString *parameters = [NSMutableString string];

  NSCharacterSet *queryCharacterSet = [NSCharacterSet alphanumericCharacterSet];
  NSString *parameterFormatString = @"%@%@=%@";
  __block NSUInteger index = 0;
  [dictionary enumerateKeysAndObjectsUsingBlock:^(NSString *_Nonnull key, NSString *_Nonnull value,
                                                  BOOL *_Nonnull stop) {
    NSString *delimiter = index++ == 0 ? @"?" : @"&";
    NSString *encodedValue =
        [value stringByAddingPercentEncodingWithAllowedCharacters:queryCharacterSet];
    NSString *parameter =
        [NSString stringWithFormat:parameterFormatString, delimiter, key, encodedValue];
    [parameters appendString:parameter];
  }];

  return parameters;
}

NSDictionary *FIRDLDictionaryFromQuery(NSString *queryString) {
  NSArray<NSString *> *keyValuePairs = [queryString componentsSeparatedByString:@"&"];

  NSMutableDictionary *queryDictionary =
      [NSMutableDictionary dictionaryWithCapacity:keyValuePairs.count];

  for (NSString *pair in keyValuePairs) {
    NSArray *keyValuePair = [pair componentsSeparatedByString:@"="];
    if (keyValuePair.count == 2) {
      NSString *key = keyValuePair[0];
      NSString *value = [keyValuePair[1] stringByRemovingPercentEncoding];
      [queryDictionary setObject:value forKey:key];
    }
  }

  return [queryDictionary copy];
}

NSURL *FIRDLDeepLinkURLWithInviteID(NSString *_Nullable inviteID,
                                    NSString *_Nullable deepLinkString,
                                    NSString *_Nullable utmSource,
                                    NSString *_Nullable utmMedium,
                                    NSString *_Nullable utmCampaign,
                                    NSString *_Nullable utmContent,
                                    NSString *_Nullable utmTerm,
                                    BOOL isWeakLink,
                                    NSString *_Nullable weakMatchEndpoint,
                                    NSString *_Nullable minAppVersion,
                                    NSString *URLScheme,
                                    NSString *_Nullable matchMessage) {
  // We are unable to use NSURLComponents as NSURLQueryItem is avilable beginning in iOS 8 and
  // appending our query string with NSURLComponents improperly formats the query by adding
  // a second '?' in the query.
  NSMutableDictionary *queryDictionary = [NSMutableDictionary dictionary];
  if (inviteID != nil) {
    queryDictionary[kFIRDLParameterInviteId] = inviteID;
  }
  if (deepLinkString != nil) {
    queryDictionary[kFIRDLParameterDeepLinkIdentifier] = deepLinkString;
  }
  if (utmSource != nil) {
    queryDictionary[kFIRDLParameterSource] = utmSource;
  }
  if (utmMedium != nil) {
    queryDictionary[kFIRDLParameterMedium] = utmMedium;
  }
  if (utmCampaign != nil) {
    queryDictionary[kFIRDLParameterCampaign] = utmCampaign;
  }

  if (utmContent != nil) {
    queryDictionary[kFIRDLParameterContent] = utmContent;
  }

  if (utmTerm != nil) {
    queryDictionary[kFIRDLParameterTerm] = utmTerm;
  }

  if (isWeakLink) {
    queryDictionary[kFIRDLParameterMatchType] = @"weak";
  } else {
    queryDictionary[kFIRDLParameterMatchType] = @"unique";
  }
  if (weakMatchEndpoint != nil) {
    queryDictionary[kFIRDLParameterWeakMatchEndpoint] = weakMatchEndpoint;
  }
  if (minAppVersion != nil) {
    queryDictionary[kFIRDLParameterMinimumAppVersion] = minAppVersion;
  }
  if (matchMessage != nil) {
    queryDictionary[kFIRDLParameterMatchMessage] = matchMessage;
  }

  NSString *scheme = [URLScheme lowercaseString];
  NSString *queryString = FIRDLURLQueryStringFromDictionary(queryDictionary);
  NSString *urlString = [NSString stringWithFormat:@"%@://google/link/%@", scheme, queryString];

  return [NSURL URLWithString:urlString];
}

BOOL FIRDLOSVersionSupported(NSString *_Nullable systemVersion, NSString *minSupportedVersion) {
  systemVersion = systemVersion ?: [UIDevice currentDevice].systemVersion;
  return [systemVersion compare:minSupportedVersion options:NSNumericSearch] != NSOrderedAscending;
}

NSDate *_Nullable FIRDLAppInstallationDate() {
  NSURL *documentsDirectoryURL =
      [[[NSFileManager defaultManager] URLsForDirectory:NSApplicationSupportDirectory
                                              inDomains:NSUserDomainMask] firstObject];
  if (!documentsDirectoryURL) {
    return nil;
  }
  NSDictionary<NSString *, id> *attributes =
      [[NSFileManager defaultManager] attributesOfItemAtPath:documentsDirectoryURL.path error:NULL];
  if (attributes[NSFileCreationDate] &&
      [attributes[NSFileCreationDate] isKindOfClass:[NSDate class]]) {
    return attributes[NSFileCreationDate];
  }
  return nil;
}

NSString *FIRDLDeviceModelName() {
  // this method will return string like iPad3,3
  // for Simulator this will be x86_64
  static NSString *machineString = @"";
  static dispatch_once_t onceToken;
  dispatch_once(&onceToken, ^{
    size_t size;

    // compute string size
    if (sysctlbyname("hw.machine", NULL, &size, NULL, 0) == 0) {
      // get device name
      char *machine = calloc(1, size);
      if (sysctlbyname("hw.machine", machine, &size, NULL, 0) == 0) {
        machineString = [NSString stringWithCString:machine encoding:NSUTF8StringEncoding];
      }
      free(machine);
    }
  });
  return machineString;
}

NSString *FIRDLDeviceLocale() {
  // expected return value from this method looks like: @"en-US"
  return [[[NSLocale currentLocale] localeIdentifier] stringByReplacingOccurrencesOfString:@"_"
                                                                                withString:@"-"];
}

NSString *FIRDLDeviceLocaleRaw() {
  return [[NSLocale currentLocale] localeIdentifier];
}

NSString *FIRDLDeviceTimezone() {
  NSString *timeZoneName = [[NSTimeZone localTimeZone] name];
  return timeZoneName;
}

BOOL FIRDLIsURLForAllowedCustomDomain(NSURL *URL) {
  if (URL) {
    for (NSURL *allowedCustomDomain in FIRDLCustomDomains) {
      // At least one custom domain host name should match at a minimum.
      if ([URL.absoluteString hasPrefix:allowedCustomDomain.absoluteString]) {
        NSString *urlWithoutDomainURIPrefix =
            [URL.absoluteString substringFromIndex:allowedCustomDomain.absoluteString.length];

        // The urlWithoutDomainURIPrefix should be starting with '/' or '?' otherwise it means the
        // allowed domain is not exactly matching the incoming URL domain prefix.
        if ([urlWithoutDomainURIPrefix hasPrefix:@"/"] ||
            [urlWithoutDomainURIPrefix hasPrefix:@"?"]) {
          //  For a valid custom domain DL Suffix the urlWithoutDomainURIPrefix should have:
          //  1. At least one path exists OR
          //  2. Should have a link query param with an http/https link

          NSURLComponents *components =
              [[NSURLComponents alloc] initWithString:urlWithoutDomainURIPrefix];
          if (components.path && components.path.length > 1) {
            // Have a path exists. So valid custom domain.
            return true;
          }

          if (components.queryItems && components.queryItems.count > 0) {
            for (NSURLQueryItem *queryItem in components.queryItems) {
              // Checks whether we have a link query param
              if ([queryItem.name caseInsensitiveCompare:@"link"] == NSOrderedSame) {
                // Checks whether link query param value starts with http/https
                if (queryItem.value && ([queryItem.value hasPrefix:@"http://"] ||
                                        [queryItem.value hasPrefix:@"https://"])) {
                  return true;
                }
              }
            }
          }
        }
      }
    }
  }
  return false;
}

/* We are validating following domains in proper format.
 *.page.link
 *.app.goo.gl
 *.page.link/i/
 *.app.goo.gl/i/
 */
BOOL FIRDLIsAValidDLWithFDLDomain(NSURL *_Nullable URL) {
  BOOL matchesRegularExpression = false;
  NSString *urlStr = URL.absoluteString;

  if ([URL.host containsString:@".page.link"] || [URL.host containsString:@".app.goo.gl"] ||
      [URL.host containsString:@".app.google"]) {
    // Matches the *.page.link and *.app.goo.gl domains.
    matchesRegularExpression =
        ([urlStr rangeOfString:
                     @"^https?://"
                     @"[a-zA-Z0-9]+((\\.app\\.goo\\.gl)|(\\.page\\.link)|(\\.app\\.google))((\\/"
                     @"?\\?.*link=https?.*)|(\\/[a-zA-Z0-9-_]+)((\\/?\\?.*=.*)?$|$))"
                       options:NSRegularExpressionSearch]
             .location != NSNotFound);

    if (!matchesRegularExpression) {
      // Matches the *.page.link/i/ and *.app.goo.gl/i/ domains.
      // Checks whether the URL is of the format :
      // http(s)://$DOMAIN(.page.link or .app.goo.gl)/i/$ANYTHING
      matchesRegularExpression =
          ([urlStr
               rangeOfString:
                   @"^https?:\\/\\/"
                   @"[a-zA-Z0-9]+((\\.app\\.goo\\.gl)|(\\.page\\.link)|(\\.app\\.google))\\/i\\/.*$"
                     options:NSRegularExpressionSearch]
               .location != NSNotFound);
    }
  }

  return matchesRegularExpression;
}

/*
 DL can be parsed if it :
 1. Has http(s)://goo.gl/app* or http(s)://page.link/app* format
 2. OR http(s)://$DomainPrefix.page.link or http(s)://$DomainPrefix.app.goo.gl domain with specific
 format
 3. OR the domain is a listed custom domain
 */
BOOL FIRDLCanParseUniversalLinkURL(NSURL *_Nullable URL) {
  // Handle universal links with format |https://goo.gl/app/<appcode>?<parameters>|.
  // Also support page.link format.
  BOOL isDDLWithAppcodeInPath = ([URL.host isEqual:@"goo.gl"] || [URL.host isEqual:@"page.link"] ||
                                 [URL.host isEqual:@"app.google"]) &&
                                [URL.path hasPrefix:@"/app"];

  return isDDLWithAppcodeInPath || FIRDLIsAValidDLWithFDLDomain(URL) ||
         FIRDLIsURLForAllowedCustomDomain(URL);
}

BOOL FIRDLMatchesShortLinkFormat(NSURL *URL) {
  // Short Durable Link URLs always have a path or it should be a custom domain.
  BOOL hasPathOrCustomDomain = URL.path.length > 0 || FIRDLIsURLForAllowedCustomDomain(URL);

  // Must be able to parse (also checks if the URL conforms to *.app.goo.gl/* or goo.gl/app/* or
  // *.page.link or custom domain with valid suffix)
  BOOL canParse = FIRDLCanParseUniversalLinkURL(URL);

  // Path cannot be prefixed with /link/dismiss
  BOOL isDismiss = [[URL.path lowercaseString] hasPrefix:@"/link/dismiss"];

  // Checks short link format by having only one path after domain prefix.
  BOOL matchesRegularExpression =
      ([URL.path rangeOfString:@"/[^/]+" options:NSRegularExpressionSearch].location != NSNotFound);

  return hasPathOrCustomDomain && !isDismiss && canParse && matchesRegularExpression;
}

NSString *FIRDLMatchTypeStringFromServerString(NSString *_Nullable serverMatchTypeString) {
  static NSDictionary *matchMap;
  static dispatch_once_t onceToken;
  dispatch_once(&onceToken, ^{
    matchMap = @{
      @"WEAK" : @"weak",
      @"DEFAULT" : @"default",
      @"UNIQUE" : @"unique",
    };
  });
  return matchMap[serverMatchTypeString] ?: @"none";
}

void FIRDLAddToAllowListForCustomDomainsArray(NSArray *_Nonnull customDomains) {
  // Duplicates will be weeded out when converting to a set.
  NSMutableArray *validCustomDomains =
      [[NSMutableArray alloc] initWithCapacity:customDomains.count];
  for (NSString *customDomainEntry in customDomains) {
    // We remove trailing slashes in the path if present.
    NSString *domainEntry =
        [customDomainEntry hasSuffix:@"/"]
            ? [customDomainEntry substringToIndex:[customDomainEntry length] - 1]
            : customDomainEntry;
    NSURL *customDomainURL = [NSURL URLWithString:domainEntry];
    // We require a valid scheme for each custom domain enumerated in the info.plist file.
    if (customDomainURL && customDomainURL.scheme) {
      [validCustomDomains addObject:customDomainURL];
    }
  }
  // Duplicates will be weeded out when converting to a set.
  FIRDLCustomDomains = [NSSet setWithArray:validCustomDomains];
}

NS_ASSUME_NONNULL_END

#endif  // TARGET_OS_IOS