app-check/AppCheckCore/Sources/DeviceCheckProvider/API/GACDeviceCheckAPIService.m

/*
 * Copyright 2020 Google LLC
 *
 * 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 "AppCheckCore/Sources/DeviceCheckProvider/API/GACDeviceCheckAPIService.h"

#if __has_include(<FBLPromises/FBLPromises.h>)
#import <FBLPromises/FBLPromises.h>
#else
#import "FBLPromises.h"
#endif

#import "AppCheckCore/Sources/Core/APIService/GACAppCheckToken+APIResponse.h"
#import "AppCheckCore/Sources/Public/AppCheckCore/_GACAppCheckAPIService.h"

#import "AppCheckCore/Sources/Core/GACAppCheckLogger+Internal.h"
#import "AppCheckCore/Sources/Public/AppCheckCore/_GACAppCheckErrorUtil.h"

NS_ASSUME_NONNULL_BEGIN

static NSString *const kContentTypeKey = @"Content-Type";
static NSString *const kJSONContentType = @"application/json";
static NSString *const kDeviceTokenField = @"device_token";
static NSString *const kLimitedUseField = @"limited_use";

@interface GACDeviceCheckAPIService ()

@property(nonatomic, readonly) id<_GACAppCheckAPIServiceProtocol> APIService;

@property(nonatomic, readonly) NSString *resourceName;

@end

@implementation GACDeviceCheckAPIService

- (instancetype)initWithAPIService:(id<_GACAppCheckAPIServiceProtocol>)APIService
                      resourceName:(NSString *)resourceName {
  self = [super init];
  if (self) {
    _APIService = APIService;
    _resourceName = resourceName;
  }
  return self;
}

#pragma mark - Public API

- (FBLPromise<GACAppCheckToken *> *)appCheckTokenWithDeviceToken:(NSData *)deviceToken
                                                      limitedUse:(BOOL)limitedUse {
  NSString *URLString = [NSString stringWithFormat:@"%@/%@:exchangeDeviceCheckToken",
                                                   self.APIService.baseURL, self.resourceName];
  NSURL *URL = [NSURL URLWithString:URLString];

  return [self HTTPBodyWithDeviceToken:deviceToken limitedUse:limitedUse]
      .then(^FBLPromise<_GACURLSessionDataResponse *> *(NSData *HTTPBody) {
        return [self.APIService sendRequestWithURL:URL
                                        HTTPMethod:@"POST"
                                              body:HTTPBody
                                 additionalHeaders:@{kContentTypeKey : kJSONContentType}];
      })
      .then(^id _Nullable(_GACURLSessionDataResponse *_Nullable response) {
        return [self.APIService appCheckTokenWithAPIResponse:response];
      });
}

- (FBLPromise<NSData *> *)HTTPBodyWithDeviceToken:(NSData *)deviceToken
                                       limitedUse:(BOOL)limitedUse {
  if (deviceToken.length <= 0) {
    FBLPromise *rejectedPromise = [FBLPromise pendingPromise];
    [rejectedPromise reject:[_GACAppCheckErrorUtil
                                errorWithFailureReason:@"DeviceCheck token must not be empty."]];
    return rejectedPromise;
  }

  NSString *base64EncodedToken = [deviceToken base64EncodedStringWithOptions:0];

  NSError *encodingError;
  NSData *payloadJSON = [NSJSONSerialization
      dataWithJSONObject:@{kDeviceTokenField : base64EncodedToken, kLimitedUseField : @(limitedUse)}
                 options:0
                   error:&encodingError];

  FBLPromise<NSData *> *payloadPromise = [FBLPromise pendingPromise];
  if (payloadJSON != nil) {
    [payloadPromise fulfill:payloadJSON];
  } else {
    [payloadPromise reject:[_GACAppCheckErrorUtil JSONSerializationError:encodingError]];
  }
  return payloadPromise;
}

@end

NS_ASSUME_NONNULL_END