一、何為Cookie

Cookie是網(wǎng)站為了便是終端身份，保存在終端本地的用戶憑證信息。Cookie中的字段與意義由服務(wù)端進(jìn)行定義。例如，當(dāng)用戶在某個(gè)網(wǎng)站進(jìn)行了登錄操作后，服務(wù)端會(huì)將Cookie信息返回給終端，終端會(huì)將這些信息進(jìn)行保存，在下一次再次訪問這個(gè)網(wǎng)站時(shí)，終端會(huì)將保存的Cookie信息一并發(fā)送到服務(wù)端，服務(wù)端根據(jù)Cookie信息是否有效來判斷此用戶是否可以自動(dòng)登錄。

二、iOS中進(jìn)行Cookie管理的兩個(gè)類

iOS中進(jìn)行HTTP網(wǎng)絡(luò)請求Cookie管理主要由兩個(gè)類負(fù)責(zé)，一個(gè)類是NSHTTPCookieStorage類，一個(gè)是NSHTTPCookie類。

1.NSHTTPCookieStorage

NSHTTPCookieStorage類采用單例的設(shè)計(jì)模式，其中管理著所有HTTP請求的Cookie信息，常用方法如下：

//獲取單例對象
+ (NSHTTPCookieStorage *)sharedHTTPCookieStorage;
//所有Cookie數(shù)據(jù)數(shù)組 其中存放NSHTTPCookie對象
@property (nullable , readonly, copy) NSArray<NSHTTPCookie *> *cookies;
//手動(dòng)設(shè)置一條Cookie數(shù)據(jù)
- (void)setCookie:(NSHTTPCookie *)cookie;
//刪除某條Cookie信息
- (void)deleteCookie:(NSHTTPCookie *)cookie;
//刪除某個(gè)時(shí)間后的所有Cookie信息 iOS8后可用
- (nullable NSArray<NSHTTPCookie *> *)cookiesForURL:(NSURL *)URL;
//獲取某個(gè)特定URL的所有Cookie數(shù)據(jù)
- (void)removeCookiesSinceDate:(NSDate *)date NS_AVAILABLE(10_10, 8_0);
//為某個(gè)特定的URL設(shè)置Cookie
- (void)setCookies:(NSArray<NSHTTPCookie *> *)cookies forURL:(nullable NSURL *)URL mainDocumentURL:(nullable NSURL *)mainDocumentURL;
//Cookie數(shù)據(jù)的接收協(xié)議
/*
枚舉如下：
typedef NS_ENUM(NSUInteger, NSHTTPCookieAcceptPolicy) {
    NSHTTPCookieAcceptPolicyAlways,//接收所有Cookie信息
    NSHTTPCookieAcceptPolicyNever,//不接收所有Cookie信息
    NSHTTPCookieAcceptPolicyOnlyFromMainDocumentDomain//只接收主文檔域的Cookie信息
};
*/
@property NSHTTPCookieAcceptPolicy cookieAcceptPolicy;
系統(tǒng)下面的兩個(gè)通知與Cookie管理有關(guān)：

//Cookie數(shù)據(jù)的接收協(xié)議改變時(shí)發(fā)送的通知
FOUNDATION_EXPORT NSString * const NSHTTPCookieManagerAcceptPolicyChangedNotification;
//管理的Cookie數(shù)據(jù)發(fā)生變化時(shí)發(fā)送的通知
FOUNDATION_EXPORT NSString * const NSHTTPCookieManagerCookiesChangedNotification;

2.NSHTTPCookie

NSHTTPCookie是具體的HTTP請求Cookie數(shù)據(jù)對象，其中屬性方法如下：

//下面兩個(gè)方法用于對象的創(chuàng)建和初始化 都是通過字典進(jìn)行鍵值設(shè)置
- (nullable instancetype)initWithProperties:(NSDictionary<NSString *, id> *)properties;
+ (nullable NSHTTPCookie *)cookieWithProperties:(NSDictionary<NSString *, id> *)properties;
//返回Cookie數(shù)據(jù)中可用于添加HTTP頭字段的字典
+ (NSDictionary<NSString *, NSString *> *)requestHeaderFieldsWithCookies:(NSArray<NSHTTPCookie *> *)cookies;
//從指定的響應(yīng)頭和URL地址中解析出Cookie數(shù)據(jù)
+ (NSArray<NSHTTPCookie *> *)cookiesWithResponseHeaderFields:(NSDictionary<NSString *, NSString *> *)headerFields forURL:(NSURL *)URL;
//Cookie數(shù)據(jù)中的屬性字典
@property (nullable, readonly, copy) NSDictionary<NSString *, id> *properties;
//請求響應(yīng)的版本
@property (readonly) NSUInteger version;
//請求相應(yīng)的名稱
@property (readonly, copy) NSString *name;
//請求相應(yīng)的值
@property (readonly, copy) NSString *value;
//過期時(shí)間
@property (nullable, readonly, copy) NSDate *expiresDate;
//請求的域名
@property (readonly, copy) NSString *domain;
//請求的路徑
@property (readonly, copy) NSString *path;
//是否是安全傳輸
@property (readonly, getter=isSecure) BOOL secure;
//是否只發(fā)送HTTP的服務(wù)
@property (readonly, getter=isHTTPOnly) BOOL HTTPOnly;
//響應(yīng)的文檔
@property (nullable, readonly, copy) NSString *comment;
//相應(yīng)的文檔URL
@property (nullable, readonly, copy) NSURL *commentURL;
//服務(wù)端口列表
@property (nullable, readonly, copy) NSArray<NSNumber *> *portList;

三、清除Cookie
清除所有的cookie 方法：

NSURL *url = [NSURL URLWithString:@"http://www.baidu.com"]; 
    if (url) { 
        NSArray *cookies = [[NSHTTPCookieStorage sharedHTTPCookieStorage] cookiesForURL:url]; 
        for (int i = 0; i < [cookies count]; i++) { 
            NSHTTPCookie *cookie = (NSHTTPCookie *)[cookies objectAtIndex:i]; 
            [[NSHTTPCookieStorage sharedHTTPCookieStorage] deleteCookie:cookie]; 
             
        }  
  清除某一個(gè)特定的cookie方法：
NSArray * cookArray = [[NSHTTPCookieStorage sharedHTTPCookieStorage] cookiesForURL:[NSURL URLWithString:self.loadURL]]; NSString * successCode = @""; for (NSHTTPCookie*cookie in cookArray) { if ([cookie.name isEqualToString:@"cookiename"]) { [[NSHTTPCookieStorage sharedHTTPCookieStorage] deleteCookie:cookie]; } } 

清除某一個(gè)url緩存的方法：
[[NSURLCache sharedURLCache] removeCachedResponseForRequest:[NSURLRequest requestWithURL:url]]; 

清除所有緩存方法：       
[[NSURLCache sharedURLCache] removeAllCachedResponses];