iOS HTTP网络请求Cookie的读取与写入(NSHTTPCookieStorage)

当你访问一个网站时，NSURLRequest都会帮你主动记录下来你访问的站点设置的Cookie，如果 Cookie 存在的话，会把这些信息放在 NSHTTPCookieStorage 容器中共享，当你下次再访问这个站点时，NSURLRequest会拿着上次保存下来了的Cookie继续去请求。
同样适用于ASIHTTPRequest,AFNetworking, Webview等,Cookie常用于一些基于认证的网络请求

认识下NSHTTPCookieStorage
NSHTTPCookieStorage 实现了一个管理cookie的单例对象(只有一个实例)，每个Cookie都是NSHTTPCookie类的实例，作为为一个规则，Cookie在（macOS）所有应用之间共享并在不同进程之间保持同步，在iOS中不会多应用共享。Session Cookie(一个isSessionOnly方法返回YES的Cookie)只能在单一进程中使用。

Cookie
Cookie是由服务器端生成，发送给User-Agent（一般是浏览器或者客户端），浏览器会将Cookie的key/value保存到某个目录下的文本文件内，下次请求同一网站地址时就发送该Cookie给服务器

HTTP header
HTTP header中包含HTTP请求与响应的操作参数. header属性定义了所传输数据的各种特性. header属性以属性名开始,以冒号结尾,最后是属性值.属性名及值会因应用的不同

一.iOS htttp网络请求Cookie的读取与写入:
Cookie必然会通过HTTP的Respone传过来，并且Cookie在Respone中的HTTP header中。不管是什么请求框架，必然会存在Respone对象，比如AFNetworking2.x的operation.response，AFNetworking3.x的task.response等等。。。。

1.原生NSURLConnection写法

一.获取cookie
- (IBAction)cookieTouched:(id)sender {
    NSURL *url = [NSURL URLWithString:@"http://api.skyfox.org/api-test.php"];
    NSURLRequest *request = [NSURLRequest requestWithURL:url]
                                             cachePolicy:NSURLRequestReloadIgnoringLocalAndRemoteCacheData
                                         timeoutInterval:3];
    NSOperationQueue *queue = [[NSOperationQueue alloc]init];
    [NSURLConnection sendAsynchronousRequest:request
                                       queue:queue
                           completionHandler:^(NSURLResponse *response, NSData *data, NSError *error){
                              
                               //转换NSURLResponse成为HTTPResponse
                               NSHTTPURLResponse *HTTPResponse = (NSHTTPURLResponse *)response;
                               //获取headerfields
                               NSDictionary *fields = [HTTPResponse allHeaderFields];//原生NSURLConnection写法
                               // NSDictionary *fields = [operation.response allHeaderFields]; //afnetworking写法
                               NSLog(@"fields = %@",[fields description]);

                               //获取cookie方法1
                               // NSArray *cookies = [NSHTTPCookie cookiesWithResponseHeaderFields:fields forURL:url];
                               //获取cookie方法2
                               //NSString *cookieString = [[HTTPResponse allHeaderFields] valueForKey:@"Set-Cookie"];
                               //获取cookie方法3
                               NSHTTPCookieStorage *cookieJar = [NSHTTPCookieStorage sharedHTTPCookieStorage];
                               for (NSHTTPCookie *cookie in [cookieJar cookies]) {
                                   NSLog(@"cookie%@", cookie);
                               }
                           }];
    
}

2.AFNetworking 写法

 AFHTTPSessionManager *manager = [AFHTTPSessionManager manager];
    manager.responseSerializer = [AFCompoundResponseSerializer serializer];
    //demo中的api返回的是html数据，不是json
    [manager POST:@"http://dev.skyfox.org/cookie.php" parameters:nil progress:^(NSProgress * _Nonnull uploadProgress) {
        
    } success:^(NSURLSessionDataTask * _Nonnull task, id  _Nullable responseObject) {
        NSLog(@"\n======================================\n");
        NSDictionary *fields = ((NSHTTPURLResponse*)task.response).allHeaderFields;
        NSLog(@"fields = %@",[fields description]);
        NSURL *url = [NSURL URLWithString:@"http://dev.skyfox.org/cookie.php"];
        NSLog(@"\n======================================\n");
        //获取cookie方法1
        NSArray *cookies = [NSHTTPCookie cookiesWithResponseHeaderFields:fields forURL:url];
        for (NSHTTPCookie *cookie in cookies) {
            NSLog(@"cookie,name:= %@,valuie = %@",cookie.name,cookie.value);
        }
        NSLog(@"\n======================================\n");
//        //获取cookie方法2
//        NSString *cookies2 = [((NSHTTPURLResponse*)task.response) valueForKey:@"Set-Cookie"];
//        NSLog(@"cookies2 = %@",[cookies2 description]);

    } failure:^(NSURLSessionDataTask * _Nullable task, NSError * _Nonnull error) {
        
    }];

二.清空Cookie

NSHTTPCookieStorage *cookieJar = [NSHTTPCookieStorage sharedHTTPCookieStorage];
  NSArray *cookieArray = [NSArray arrayWithArray:[cookieJar cookies]];
  for (NSHTTPCookie *obj in cookieArray) {
    [cookieJar deleteCookie:obj];
  }

三.手动设置Cookie 手动设置的Cookie不会自动持久化到沙盒

第一次请求手动设置个cookie
-(void)test1:(NSString*)urlString{
    NSURL *url = [NSURL URLWithString:@"http://dev.skyfox.org/cookie.php"];
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
    
    NSMutableDictionary *cookieProperties = [NSMutableDictionary dictionary];
    [cookieProperties setObject:@"username" forKey:NSHTTPCookieName];
    [cookieProperties setObject:@"my ios cookie" forKey:NSHTTPCookieValue];
    [cookieProperties setObject:@"dev.skyfox.org" forKey:NSHTTPCookieDomain];
    [cookieProperties setObject:@"dev.skyfox.org" forKey:NSHTTPCookieOriginURL];
    [cookieProperties setObject:@"/" forKey:NSHTTPCookiePath];
    [cookieProperties setObject:@"0" forKey:NSHTTPCookieVersion];
    [cookieProperties setObject:[NSDate dateWithTimeIntervalSinceNow:60*60] forKey:NSHTTPCookieExpires];//设置失效时间
    [cookieProperties setObject:@"0" forKey:NSHTTPCookieDiscard]; //设置sessionOnly

    NSHTTPCookie *cookie = [NSHTTPCookie cookieWithProperties:cookieProperties];
    [[NSHTTPCookieStorage sharedHTTPCookieStorage] setCookie:cookie];
    [self.myWebView loadRequest:request];
}
//第二次请求会自动带上Cookie
- (IBAction)test2:(id)sender {
    NSURL *url = [NSURL URLWithString:@"http://dev.skyfox.org/cookie.php"];
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
    [self.mywebview2 loadRequest:request];
}

request还可以这样设置个Cookie

[request setHTTPShouldHandleCookies:YES];
[request setValue:[NSString stringWithFormat:@"%@=%@", [cookie name], [cookie value]] forHTTPHeaderField:@"Cookie"];

四.Cookie的本地缓存策略

//NSHTTPCookieAcceptPolicyAlways:保存所有cookie，这个是默认值
//NSHTTPCookieAcceptPolicyNever:不保存任何响应头中的cookie
//NSHTTPCookieAcceptPolicyOnlyFromMainDocumentDomain:只保存域请求匹配的cookie

[[NSHTTPCookieStorage sharedHTTPCookieStorage]setCookieAcceptPolicy:NSHTTPCookieAcceptPolicyNever];

PS:本文转载：http://www.skyfox.org/ios-url-request-cookie.html