iOS NSURLSession 详解

一：NSURLSession

• 类似之前的NSURLConnection, 可配置每个session的 cookie,证书等网络连接配置信息 

  NSURLSessionConfiguration

• 包含三大任务 ：NSURLSessionTask--(NSURLSessionDataTask,NSURLSessionUploadTask,NSURLSessionDownloadTask)
• 常用api

    

@interface NSURLSession : NSObject// 单例+ (NSURLSession *)sharedSession;//配置 Session+ (NSURLSession *)sessionWithConfiguration:(NSURLSessionConfiguration *)configuration;+ (NSURLSession *)sessionWithConfiguration:(NSURLSessionConfiguration *)configuration delegate:(id <NSURLSessionDelegate>)delegate delegateQueue:(NSOperationQueue *)queue;

/*Data 请求 request */- (NSURLSessionDataTask *)dataTaskWithRequest:(NSURLRequest *)request;/* Data 请求 url. */- (NSURLSessionDataTask *)dataTaskWithURL:(NSURL *)url;/* 上传文件请求 fileUrl */- (NSURLSessionUploadTask *)uploadTaskWithRequest:(NSURLRequest *)request fromFile:(NSURL *)fileURL;/* 上传Data请求 NSData */- (NSURLSessionUploadTask *)uploadTaskWithRequest:(NSURLRequest *)request fromData:(NSData *)bodyData;/* 上传数据流请求 request */- (NSURLSessionUploadTask *)uploadTaskWithStreamedRequest:(NSURLRequest *)request;/* 下载文件.request */- (NSURLSessionDownloadTask *)downloadTaskWithRequest:(NSURLRequest *)request;/* 下载文件 url */- (NSURLSessionDownloadTask *)downloadTaskWithURL:(NSURL *)url;/* 断点下载请求 ， */- (NSURLSessionDownloadTask *)downloadTaskWithResumeData:(NSData *)resumeData;

异步请求操作

@interface NSURLSession (NSURLSessionAsynchronousConvenience)/* 异步数据请求 NSData */- (NSURLSessionDataTask *)dataTaskWithRequest:(NSURLRequest *)request completionHandler:(void (^)(NSData *data, NSURLResponse *response, NSError *error))completionHandler;- (NSURLSessionDataTask *)dataTaskWithURL:(NSURL *)url completionHandler:(void (^)(NSData *data, NSURLResponse *response, NSError *error))completionHandler;/* * 异步文件上传请求 file,NSData */- (NSURLSessionUploadTask *)uploadTaskWithRequest:(NSURLRequest *)request fromFile:(NSURL *)fileURL completionHandler:(void (^)(NSData *data, NSURLResponse *response, NSError *error))completionHandler;- (NSURLSessionUploadTask *)uploadTaskWithRequest:(NSURLRequest *)request fromData:(NSData *)bodyData completionHandler:(void (^)(NSData *data, NSURLResponse *response, NSError *error))completionHandler;/* 异步下载请求 */- (NSURLSessionDownloadTask *)downloadTaskWithRequest:(NSURLRequest *)request completionHandler:(void (^)(NSURL *location, NSURLResponse *response, NSError *error))completionHandler;- (NSURLSessionDownloadTask *)downloadTaskWithURL:(NSURL *)url completionHandler:(void (^)(NSURL *location, NSURLResponse *response, NSError *error))completionHandler;- (NSURLSessionDownloadTask *)downloadTaskWithResumeData:(NSData *)resumeData completionHandler:(void (^)(NSURL *location, NSURLResponse *response, NSError *error))completionHandler;@end

二：NSURLSessionTask 任务

• 包含三大任务 ：NSURLSessionTask--(NSURLSessionDataTask,NSURLSessionUploadTask,NSURLSessionDownloadTask)
• 关系图

    

     系统定义的 常用api，如，对 网络任务的暂停，继续

@interface NSURLSessionTask : NSObject <NSCopying>   ......../* 取消任务*/- (void)cancel;/* 任务状态*/@property (readonly) NSURLSessionTaskState state;/*任务暂停和继续 */- (void)suspend;- (void)resume;  ........@end

 任务状态：

typedef NS_ENUM(NSInteger, NSURLSessionTaskState) {    NSURLSessionTaskStateRunning = 0,                     /* The task is currently being serviced by the session */    NSURLSessionTaskStateSuspended = 1,    NSURLSessionTaskStateCanceling = 2,                   /* The task has been told to cancel.  The session will receive a URLSession:task:didCompleteWithError: message. */    NSURLSessionTaskStateCompleted = 3,                   /* The task has completed and the session will receive no more delegate notifications */} NS_ENUM_AVAILABLE(10_9, 7_0);

 三大子类，Data,Upload，Download操作 ，都是抽象类，基本不提供任何操作

@interface NSURLSessionDataTask : NSURLSessionTask@end/* * An NSURLSessionUploadTask does not currently provide any additional*/@interface NSURLSessionUploadTask : NSURLSessionDataTask@end@interface NSURLSessionDownloadTask : NSURLSessionTask/*断点续传  */- (void)cancelByProducingResumeData:(void (^)(NSData *resumeData))completionHandler;@end

 

三：演示代码

1:异步的GET 请求 Data 数据

    NSURL *url = [NSURL URLWithString:@"http://httpbin.org/get"];    NSURLSession *session = [NSURLSession sharedSession];    NSURLSessionDataTask *dataTask = [session dataTaskWithURL:url completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {                NSLog(@"%@",[[NSString alloc]initWithData:data encoding:NSUTF8StringEncoding]);            }];        //任务创建后，不会立即执行，调用resume 立即执行;    [dataTask resume];

2：异步 下载文件

    NSURL *url = [NSURL URLWithString:@"http://dl.360safe.com/360zip_setup_3.1.0.2061.exe"];    NSURLRequest *request = [NSURLRequest requestWithURL:url];    NSURLSession *session = [NSURLSession sharedSession];    NSURLSessionDownloadTask *downTask = [session downloadTaskWithRequest:request completionHandler:^(NSURL *location, NSURLResponse *response, NSError *error) {                //文件下载会被先写入到一个 临时路径 location,我们需要将下载的文件移动到我们需要地方保存        NSURL *savePath = [NSURL fileURLWithPath:@"/Users/user/Desktop/360zip.exe"];        [[NSFileManager defaultManager] moveItemAtURL:location toURL:savePath error:nil];            }];        [downTask resume];

3: 异步上传文件

 NSURL *URL = [NSURL URLWithString:@"http://example.com/upload"]; NSURLRequest *request = [NSURLRequest requestWithURL:URL]; NSData *data = ...; NSURLSession *session = [NSURLSession sharedSession]; NSURLSessionUploadTask *uploadTask = [session uploadTaskWithRequest:request                                                            fromData:data                                                   completionHandler:     ^(NSData *data, NSURLResponse *response, NSError *error) {         // ...     }]; [uploadTask resume];