NSURLSession 学习笔记

NSURLSession 学习笔记

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 = ,                     /* The task is currently being serviced by the session */
    NSURLSessionTaskStateSuspended = ,
    NSURLSessionTaskStateCanceling = ,                   /* The task has been told to cancel.  The session will receive a URLSession:task:didCompleteWithError: message. */
    NSURLSessionTaskStateCompleted = ,                   /* 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];

参考：http://objccn.io/issue-5-4/