iOS Web Development (3) using nsurlsession

• Nsurlsession Introduction

Nsurlsession in iOS7.0 began to introduce, in the framework of the position and nsurlconnection parallel

Nsurlsession is capable of completing all nsurlconnection functions and has a very large function extension

Starting with iOS9.0, Apple officially abandoned nsurlconnection

The main classes that are involved in the use of nsurlsession are the relationships between them

650) this.width=650; "Src=" Http://s1.51cto.com/wyfs02/M00/7C/B2/wKiom1bWdTPh9yjOAAF0FwGe7SU279.png " title= "Screen shot 2016-03-02 pm 1.08.10.png" alt= "Wkiom1bwdtph9yjoaaf0fwge7su279.png"/>

Three modes of operation:

Default session mode: Similar to nsurlconnection, using disk caching

Instantaneous session mode: Do not use disk cache

Background session mode: can also be uploaded or downloaded when the program enters the background

Nsurlsessionconfigration is used to generate the configuration for these three modes of operation, as follows

+ (Nsurlsessionconfiguration *) defaultsessionconfiguration+ (nsurlsessionconfiguration *) ephemeralsessionconfiguration+ (Nsurlsessionconfiguration *) Backgroundsessionconfigurationwithidentifier: ( NSString *) identifier

Nsurlsession the creation of the Session object:

Use the default session mode, default cache, Cookie, and credential+ (nsurlsession *) sharedsession//use the specified operating mode + (Nsurlsession *) Sessionwithconfiguration: (nsurlsessionconfiguration*) configuration//using the specified working mode, queue for Task runtime, Agent + (Nsurlsession *) Sessionwithconfiguration: (nsurlsessionconfiguration*) configuration delegate: (id<nsurlsessiondelegate>) Delegate Delegatequeue: (Nsoperationqueue *) queue

Nsurlsession to send a network request using the steps:

A. Creating a Task object

B. Controlling the execution of tasks

C. Obtaining the results of a task execution in a block or proxy method

Three types of tasks supported: (base class nsurlsessiontask for tasks)

Data tasks using Nsurlsessiondatatask description

Download tasks using Nsurlsessiondownloadtask description

Upload Task using Nsurlsessionuploadtask description

• of the Task object

Task Object Nsurlsessiontask in Nsurlsession, all created by Nsurlsession object

Emphasis: Asynchronous operations do not block execution of the current code and cannot get results by return values or parameters

Nsurlsessiontask the status of the Task object:

@property (readonly) nsurlsessiontaskstate statetypedef ns_enum (Nsinteger, nsurlsessiontaskstate) {Nsurlsessiontasks taterunning = 0,//running Status nsurlsessiontaskstatesuspended = 1,//Pending Status Nsurlsessiontaskstatecanceling = 2,//Cancel Status nsurlsessiontaskstatecompleted = 3,//completion status};

When a task object is created, the status of the task is suspended

Methods to control task execution (modify task status):

-(void) Cancel/Cancel task-(void) resume//Run task-(void) suspend//Suspend task

• Data task-block way to get results

Data Task creation:

-(Nsurlsessiondatatask *) Datataskwithurl: (nsurl *) URL Completionhandler: (void (^) (NSData *data, Nsurlresponse * Response, Nserror *error)) completionhandler-(Nsurlsessiondatatask *) Datataskwithrequest: (Nsurlrequest *) request Completionhandler: (void (^) (NSData *data, Nsurlresponse *response, nserror*error)) Completionhandler

The result of processing the request in the block (response data, Response object, Error object)

For example: Send a GET request to get JSON data for the specified game task information

nsstring *urlstr = @ "Http://localhost/lolShow.php?number=20&from=0"; nsurl * url = [nsurl urlwithstring:urlstr]; nsurlrequest * request = [nsurlrequest requestwithurl:url];//Create Data Task nsurlsession  * session = [nsurlsession sharedsession]; nsurlsessiondatatask * datatask = [session datataskwithrequest:request  completionhandler:^ (nsdata * __nullable data, nsurlresponse * __nullable  Response, nserror * __nullable error)  {    if  ( error  )  {        nslog (@ "1 %@", [error  Localizeddescription]);         return ;    }     //serializes JSON data into OC objects     nsarray * arr = [ Nsjsonserialization jsonobjectwithdata:data options:0 error:&error];    if  ( error )  {         nslog (@ "2 %@",  [error localizeddescription]);         return ;    }    //Dictionary Turn model     for  (nsdictionary * dict in arr )  {         AMHeroModel * model = [AMHeroModel  Heromodelwithdict:dict];        [self.heroinfoarray addobject: model];    }    [[nsoperationqueue mainqueue]  addoperationwithblock:^{        [self stoploading];//Refresh ui     }];}];/ /Start Task [datatask resume];

• Data task-proxy method to get results

Creation of data tasks:

-(Nsurlsessiondatatask *) Datataskwithurl: (Nsurl *) url-(Nsurlsessiondatatask *) Datataskwithrequest: (NSURLRequest *) Request

Agent Properties for Nsurlsession

@property (ReadOnly, retain) id< nsurlsessiondelegate > Delegate

Agency agreements involved: <NSURLSessionDelegate><NSURLSessionTaskDelegate>

<NSURLSessionDataDelegate><NSURLSessionDownloadDelegate>

Common proxy methods for data tasks:

Received answer Object-(void) Urlsession: (Nsurlsession *) session Datatask: (nsurlsessiondatatask*) datatask Didreceiveresponse: ( Nsurlresponse *) Response Completionhandler: (void (^) (nsurlsessionresponsedisposition disposition)) completionhandler//receiving data (may execute multiple times)-(void) Urlsession: (Nsurlsession *) session Datatask: (nsurlsessiondatatask*) Datatask didreceivedata: (NSData *) data//complete a request for the answer process-(void) Urlsession: (Nsurlsession *) session task: ( Nsurlsessiontask *) Task Didcompletewitherror: (NSERROR *) error

This article is from the "Ammon" blog, make sure to keep this source http://annmeng.blog.51cto.com/3321237/1746703

iOS Web Development (3) using nsurlsession