ios開髮網絡篇—Get請求和Post請求 - 轉

簡單說明：建議提交用戶的隱私數據一定要使用Post請求 
相對Post請求而言，Get請求的所有參數都直接暴露在URL中，請求的URL一般會記錄在伺服器的訪問日誌中，而伺服器的訪問日誌是黑客攻擊的重點對象之一 
用戶的隱私數據如登錄密碼，銀行帳號等

示例代碼

#define CURRENT_SCREEN_WIDTH     [UIScreen mainScreen].bounds.size.width
#define CURRENT_SCREEN_HEIGHT     ([UIScreen mainScreen].bounds.size.height - 64)
#define BUTTON_WIDTH     80
#define BUTTON_HEIGHT    40

@interface ViewController ()
//GET 請求
@property(nonatomic,strong) UIButton *getButton;
//POST 請求
@property(nonatomic,strong) UIButton *postButton;
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    _getButton = [[UIButton alloc] initWithFrame:CGRectMake(CURRENT_SCREEN_WIDTH/2 - BUTTON_WIDTH/2,
                                                             CURRENT_SCREEN_HEIGHT/2 - BUTTON_HEIGHT,
                                                             BUTTON_WIDTH,
                                                             BUTTON_HEIGHT)];
    [_getButton setTitle:@"GET 請求" forState:UIControlStateNormal];
    [_getButton setTitleColor:[UIColor redColor] forState:UIControlStateNormal];
    [_getButton addTarget:self
                    action:@selector(getClick)
          forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:_getButton];
    
    _postButton = [[UIButton alloc] initWithFrame:CGRectMake(CURRENT_SCREEN_WIDTH/2 - BUTTON_WIDTH/2,
                                                             _getButton.frame.origin.y + _getButton.frame.size.height + 60,
                                                             BUTTON_WIDTH,
                                                             BUTTON_HEIGHT)];
    [_postButton setTitle:@"POST 請求" forState:UIControlStateNormal];
    [_postButton setTitleColor:[UIColor redColor] forState:UIControlStateNormal];
    [_postButton addTarget:self
                    action:@selector(postClick)
          forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:_postButton];
}

/* get 請求 */
-(void)getClick{
    //請求 URL
    NSString* urlStr = [NSString stringWithFormat:@"https://m.che168.com/beijing/?pvareaid=%d",110100];
    //封裝成 NSURL
    NSURL* url = [NSURL URLWithString:urlStr];

    //初始化 請求對象
    NSURLRequest* request = [[NSURLRequest alloc] initWithURL:url];
    //也可以這樣初始化對象
    //NSURLRequest* request = [NSURLRequest requestWithURL:url];
    
    //發送請求  預設為 GET 請求
    //1 、獲得會話對象
    NSURLSession *session = [NSURLSession sharedSession];
    // 2、第一個參數：請求對象
    //      第二個參數：completionHandler回調（請求完成【成功|失敗】的回調）
    //      data：響應體信息（期望的數據）
    //      response：響應頭信息，主要是對伺服器端的描述
    //      error：錯誤信息，如果請求失敗，則error有值
    NSURLSessionDataTask *dataTask = [session dataTaskWithRequest:request completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
        if(!error){
            NSLog(@"請求載入成功。。。");
            //說明：（此處返回的數據是JSON格式的，因此使用NSJSONSerialization進行反序列化處理）
            // NSDictionary *dict = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:nil];
            //如果是字元串則直接取出
            NSString *str = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
            NSLog(@"GET 請求返回的結果是：%@",[str substringToIndex: 300]);
        }
    }];
    //執行任務
    [dataTask resume];
    
    /* ------------ ios9 之前請求方法，之後改成 NSURLSession 請求  --------------
    [NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse * _Nullable response, NSData * _Nullable data, NSError * _Nullable connectionError) {
        if(!connectionError){
            NSLog(@"載入成功。。。");
            NSString *str = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
            NSLog(@"載入的內容是：%@",[str substringToIndex:200]);
        }else{
            NSLog(@"載入失敗");
        }
    }];
    */
}


/* POST 請求 */
-(void)postClick{
    NSString *urlStr = [NSString stringWithFormat:@"https://m.che168.com/"];
    //轉碼
    // stringByAddingPercentEscapesUsingEncoding 只對 `#%^{}[]|\"<> 加空格共14個字元編碼，不包括”&?”等符號), ios9將淘汰
    // ios9 以後要換成 stringByAddingPercentEncodingWithAllowedCharacters 這個方法進行轉碼
    urlStr = [urlStr stringByAddingPercentEncodingWithAllowedCharacters:[[NSCharacterSet characterSetWithCharactersInString:@"?!@#$^&%*+,:;='\"`<>()[]{}/\\| "] invertedSet]];
    NSURL *url = [NSURL URLWithString:urlStr];
    
    //創建會話對象
    NSURLSession *session = [NSURLSession sharedSession];
    
    //創建請求對象
    NSMutableURLRequest *request =[[NSMutableURLRequest alloc] initWithURL:url];
    [request setHTTPMethod:@"POST"];
    [request setHTTPBody:[@"a=1&b=2&c=3&type=json" dataUsingEncoding:NSUTF8StringEncoding]];
    
    //根據會話對象創建一個 Task（發送請求）
    NSURLSessionDataTask* dataTask = [session dataTaskWithRequest:request completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
        if(!error){
            //8.解析數據
            // NSDictionary *dict = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:nil];
            // NSLog(@"%@",dict);
            NSString *str = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
            NSLog(@"POST 載入的內容是：%@",[str substringToIndex:200]);
        }else{
            NSLog(@"請求發生錯誤：%@", [error description]);
        }
    }];
    [dataTask resume]; //執行任務
}