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[操作系统]iOS实现OAuth2.0中刷新access token并重新请求数据操作


一、简要概述

  OAuth2.0是OAuth协议的下一版本,时常用于移动客户端的开发,是一种比较安全的机制。在OAuth 2.0中,server将发行一个短有效期的access token和长生命期的refresh token。这将允许客户端无需用户再次操作而获取一个新的access token,并且也限制了access token的有效期。即当sever发送的access token过期之后,客户端会调用方法,将access token和refresh token发送给服务端,服务端将会返回新的access token和refresh token。

二、应用场景

  用户登录后,服务端会发行一个有效时间的access token,同时也会发行一个长生命期的refresh token。用户在进行其他网络请求时,会把access token加入请求体中(并不需要加入refresh token)。如果在请求过程中,access token过期,返回相应的状态码。这时就回调用一个回调方法,在回调方法体中将原来的access token和refresh token发送给服务端,获取新的access token和refresh token。然后把新的access token加入刚才的请求体中,重新加载网络请求。

  限定access token的有效时间,只是为了提高安全性。access token过期后重新获取并重新加载请求这一操作,用户是察觉不到的。这种机制在微信、QQ、微博等客户端中尤为常见。

三、实例代码

  (1)此类继承了AFNetworking中的AFHTTPSessionManager类,并重写了里面的方法。

  NetWorkCallBack.h:

  

1 #import <Foundation/Foundation.h>2 #import <AFNetworking.h>3 @interface NetWorkCallBack : AFHTTPSessionManager4 5 @end

  NetWorkCallBack.m:

  

 1 #import "NetWorkCallBack.h" 2 #import <SSKeychain.h> 3 @implementation NetWorkCallBack 4  5 - (NSURLSessionDataTask *)dataTaskWithRequest:(NSMutableURLRequest *)urlRequest completionHandler:(void (^)(NSURLResponse *response, id responseObject, NSError *error))originalCompletionHandler{ 6    7   //create a completion block that wraps the original 8   void (^authFailBlock)(NSURLResponse *response, id responseObject, NSError *error) = ^(NSURLResponse *response, id responseObject, NSError *error) 9   {10     NSHTTPURLResponse* httpResponse = (NSHTTPURLResponse*)response;11     if([httpResponse statusCode] == 401){12       13       //如果access token过期,返回错误,调用此block14       dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_LOW, 0), ^{15         16         //调用refreshAccesstoken方法,刷新access token。17         [self refreshAccessToken:^(AFHTTPRequestOperation *operation) {18           //存取新的access token,此处我使用了KeyChain存取19           NSDictionary *headerInfo = operation.response.allHeaderFields;20           NSString *newAccessToken = [headerInfo objectForKey:@"access-token"];21           NSString *newRefreshToken = [headerInfo objectForKey:@"refresh-token"];22           [SSKeychain deletePasswordForService:@"<key>" account:@"access-token"];23           [SSKeychain deletePasswordForService:@"<key>" account:@"refresh-token"];24           [SSKeychain setPassword:newAccessToken forService:@"<key>" account:@"access-token"];25           [SSKeychain setPassword:newRefreshToken forService:@"<key>" account:@"refresh-token"];26           27           //将新的access token加入到原来的请求体中,重新发送请求。28           [urlRequest setValue:newAccessToken forHTTPHeaderField:@"access-token"];29           30           NSURLSessionDataTask *originalTask = [super dataTaskWithRequest:urlRequest completionHandler:originalCompletionHandler];31           [originalTask resume];32         }];33       });34     }else{35       NSLog(@"no auth error");36       originalCompletionHandler(response, responseObject, error);37     }38   };39 40   NSURLSessionDataTask *stask = [super dataTaskWithRequest:urlRequest completionHandler:authFailBlock];41   42   return stask;43   44 };45 46 47 /*48  *获取新的token的方法。如何获取可以自定义,我这里用了AFNetWorking的AFHTTPRequestOperation类49 */50 -(void)refreshAccessToken:(void(^)(AFHTTPRequestOperation *responseObject))refresh{51   NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:@"<yourURL>"];52   53   [request setValue:@"application/json" forHTTPHeaderField:@"Content-Type"];54   55   //将原来的access token和refresh token发送给服务器,以获取新的token56   NSString *accessToken = [SSKeychain passwordForService:@"<key>" account:@"access-token"];57   NSString *refreshToken = [SSKeychain passwordForService:@"<key>" account:@"refresh-token"];58   59   [request setValue:accessToken forHTTPHeaderField:@"access-token"];60   [request setValue:refreshToken forHTTPHeaderField:@"refresh-token"];61   62   //执行网络方法63   AFHTTPRequestOperation *httpRequestOperation = [[AFHTTPRequestOperation alloc] initWithRequest:request];64   [httpRequestOperation setCompletionBlockWithSuccess:^(AFHTTPRequestOperation * operation, id responseObject) {65     refresh(operation);66   } failure:^(AFHTTPRequestOperation * operation, NSError * error) {67     refresh(operation);68   }];69   [httpRequestOperation start];70 }71 @end