oc 解析jwt

oc 解析jwt 和过期时间计算

- (void)viewDidLoad {
    [super viewDidLoad];
    
    NSString *jwt_str = @"eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJ1c2VyX2lkIjoyLCJ1c2VybmFtZSI6ImtlZXBfaXQiLCJleHAiOjE1NTk0ODcyODIsImVtYWlsIjoiZG9uZ3NoYW5ndG9uZ0AxNjMuY29tIn0.BuP6QJlnY-UWtpzh4H2_ippVoLCNWGgon8jp1dBVWPE";
    
    NSLog(@"%@", [self jwtDecodeWithJwtString:jwt_str]);
    

}


-(id)jwtDecodeWithJwtString:(NSString *)jwtStr {
    NSArray * segments = [jwtStr componentsSeparatedByString:@"."];
    NSString * base64String = [segments objectAtIndex:1];
    int requiredLength = (int)(4 *ceil((float)[base64String length]/4.0));
    int nbrPaddings = requiredLength - (int)[base64String length];
    if(nbrPaddings > 0){
        NSString * pading = [[NSString string] stringByPaddingToLength:nbrPaddings withString:@"=" startingAtIndex:0];
        base64String = [base64String stringByAppendingString:pading];
    }
    base64String = [base64String stringByReplacingOccurrencesOfString:@"-" withString:@"+"];
    base64String = [base64String stringByReplacingOccurrencesOfString:@"_" withString:@"/"];
    NSData * decodeData = [[NSData alloc] initWithBase64EncodedData:base64String options:0];
    NSString * decodeString = [[NSString alloc] initWithData:decodeData encoding:NSUTF8StringEncoding];
    NSDictionary * jsonDict = [NSJSONSerialization JSONObjectWithData:[decodeString dataUsingEncoding:NSUTF8StringEncoding] options:0 error:nil];
    return jsonDict;
}


-(NSString *)token {
    
    
    NSString *token = [[NSUserDefaults standardUserDefaults] objectForKey:@"kLoginToken"];
    NSLog(@"server token %@",token);
    if (token) {
        NSDictionary *dict = [self jwtDecodeWithJwtString:token];
        NSLog(@"server token dict %@",dict);
        if ([dict objectForKey:@"exp"]) {
            NSNumber *exp = [dict objectForKey:@"exp"];//时间戳
            NSTimeInterval time = exp.floatValue + 28800;//因为时差问题要加8小时 == 28800 sec
            NSDate *detaildate = [NSDate dateWithTimeIntervalSince1970:time];
            NSLog(@"server token date:%@",[detaildate description]);
            //日历
            NSCalendar *calendar = [NSCalendar currentCalendar];
            NSDate *currentDate = [NSDate date];
            //计算两个日期的差值
            NSDateComponents*cmps= [calendar components:NSCalendarUnitDay fromDate:currentDate toDate:detaildate options:NSCalendarMatchStrictly];
            NSLog(@"server token 时间差值--->%@",cmps);
            if (cmps.day <= 1) {
                //如果token过期，则清除token
               // [self clearToken];
                return nil;
            }
        }
    }
    return token;
}