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ios网络编程(HTTP socket)

时间:2015-02-12 12:25:24      阅读:246      评论:0      收藏:0      [点我收藏+]

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http编程综述:亦可称为soap编程。通常情况下,http编程要比socket编程相对要简单易用得多。所以用的最广广泛。

一、http编程其实就是http请求。http请求最长用的方法是 get 和 post 方法。

==》get方法和post方法相比理解起来比较简单,get方法可以直接请求一个url,也可以url后面拼接上参数作为一个新的url地址进行请求。get方法后面的value要经过unicode编码。form的enctype属性默认为application/x-www-form-urlencoded。不能发送二进制文件。 ==》post方法相对要复杂一些。首先post方法要设置key和value ,所有的key和value都会拼接成 key1=value1&key2=value2的样式的字符串,然后这个字符串转化为二进制放到 http请求的body中。当请求发送的时候,也就跟随body一起传给服务器。http请求Content-Type设置为:application/x-www-form-urlencoded。这里讲的只是简单的post请求,一般发送文件不会选择这种方式(从技术方面考虑也可以发送文件,就是把文件以 key 和 value的方式放入)。下面我们再讨论一下post发送二进制文件更加普遍的方法。

二、HTTP协议是什么? 简单来说,就是一个基于应用层的通信规范:双方要进行通信,大家都要遵守一个规范,这个规范就是HTTP协议。 HTTP协议能做什么? 很多人首先一定会想到:浏览网页。没错,浏览网页是HTTP的主要应用,但是这并不代表HTTP就只能应用于网页的浏览。HTTP是一种协议,只要通信的双方都遵守这个协议,HTTP就能有用武之地。比如咱们常用的QQ,迅雷这些软件,都会使用HTTP协议(还包括其他的协议)。 HTTP协议如何工作? 大家都知道一般的通信流程:首先客户端发送一个请求(request)给服务器,服务器在接收到这个请求后将生成一个响应(response)返回给客户端。 在这个通信的过程中HTTP协议在以下4个方面做了规定:

1.         Request和Response的格式() 2.         建立连接的方式(1、非持久连接 2、持久连接) 3.         缓存的机制 4.         响应授权激发机制

(应用场合) 5.        基于HTTP的应用(1、 HTTP代理 2、多线程下载 3、 HTTPS传输协议原理 4、开发web程序时常用的Request Methods 5、用户与服务器的交互)

常用cocoa内部类: 

1,Reachability.h 苹果demo支持网络连接诊断

2,NSConnection连接、NSMutableURLRequest URL网址的请求封装包

3,NSXMLParser XML解析

常用第三方库:

1,ASIHttprequest 库

操作步骤:

1:检查网络环境(3G/WIFI) 2:发起NSConnection请求 3:处理返回xml数据包(NSXMLParser解析xml文件),或者返回文件png、pdf之类 4:若返回数据包中含有待下载的图片下载地址。则重复2、3步骤下载下来图片。只不过3中返回的是文件。

socket编程综述:

常用cocoa内部类:

常用第三方库:1,Asyncsocket库

操作步骤:

 

一:确认网络环境3G/WIFI 

      1. 添加源文件和framework            开发Web等网络应用程序的时候,需要确认网络环境,连接情况等信息。如果没有处理它们,是不会通过Apple的审查的。      Apple 的 例程 Reachability 中介绍了取得/检测网络状态的方法。要在应用程序程序中使用Reachability,首先要完成如下两部:            1.1. 添加源文件:      在你的程序中使用 Reachability 只须将该例程中的 Reachability.h 和 Reachability.m 拷贝到你的工程中。如下图:                    1.2.添加framework:      将SystemConfiguration.framework 添加进工程。如下图:                  2. 网络状态            Reachability.h中定义了三种网络状态:      typedef enum {          NotReachable = 0,            //无连接          ReachableViaWiFi,            //使用3G/GPRS网络          ReachableViaWWAN            //使用WiFi网络      } NetworkStatus;            因此可以这样检查网络状态:        Reachability *r = [Reachability reachabilityWithHostName:@“www.apple.com”];      switch ([r currentReachabilityStatus]) {              case NotReachable:                      // 没有网络连接                      break;              case ReachableViaWWAN:                      // 使用3G网络                      break;              case ReachableViaWiFi:                      // 使用WiFi网络                      break;      }            3.检查当前网络环境      程序启动时,如果想检测可用的网络环境,可以像这样      // 是否wifi      + (BOOL) IsEnableWIFI {          return ([[Reachability reachabilityForLocalWiFi] currentReachabilityStatus] != NotReachable);      }        // 是否3G      + (BOOL) IsEnable3G {          return ([[Reachability reachabilityForInternetConnection] currentReachabilityStatus] != NotReachable);      }      例子:      - (void)viewWillAppear:(BOOL)animated {          if (([Reachability reachabilityForInternetConnection].currentReachabilityStatus == NotReachable) &&               ([Reachability reachabilityForLocalWiFi].currentReachabilityStatus == NotReachable)) {              self.navigationItem.hidesBackButton = YES;              [self.navigationItem setLeftBarButtonItem:nil animated:NO];          }      }        4. 链接状态的实时通知      网络连接状态的实时检查,通知在网络应用中也是十分必要的。接续状态发生变化时,需要及时地通知用户:            Reachability 1.5版本      // My.AppDelegate.h      #import “Reachability.h”        @interface MyAppDelegate : NSObject <UIApplicationDelegate> {          NetworkStatus remoteHostStatus;      }        @property NetworkStatus remoteHostStatus;        @end        // My.AppDelegate.m      #import “MyAppDelegate.h”        @implementation MyAppDelegate      @synthesize remoteHostStatus;        // 更新网络状态      - (void)updateStatus {          self.remoteHostStatus = [[Reachability sharedReachability] remoteHostStatus];      }        // 通知网络状态      - (void)reachabilityChanged:(NSNotification *)note {          [self updateStatus];          if (self.remoteHostStatus == NotReachable) {              UIAlertView *alert = [[UIAlertView alloc] initWithTitle:NSLocalizedString(@”AppName”, nil)                           message:NSLocalizedString (@”NotReachable”, nil)                          delegate:nil cancelButtonTitle:@”OK” otherButtonTitles: nil];              [alert show];              [alert release];          }      }        // 程序启动器,启动网络监视      - (void)applicationDidFinishLaunching:(UIApplication *)application {                // 设置网络检测的站点          [[Reachability sharedReachability] setHostName:@”www.apple.com”];          [[Reachability sharedReachability] setNetworkStatusNotificati*****Enabled:YES];          // 设置网络状态变化时的通知函数          [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(reachabilityChanged:)                                                   name:@”kNetworkReachabilityChangedNotification” object:nil];          [self updateStatus];      }        - (void)dealloc {          // 删除通知对象          [[NSNotificationCenter defaultCenter] removeObserver:self];          [window release];          [super dealloc];      }             Reachability 2.0版本              // MyAppDelegate.h      @class Reachability;            @interface MyAppDelegate : NSObject <UIApplicationDelegate> {              Reachability  *hostReach;          }        @end        // MyAppDelegate.m      - (void)reachabilityChanged:(NSNotification *)note {          Reachability* curReach = [note object];          NSParameterAssert([curReach isKindOfClass: [Reachability class]]);          NetworkStatus status = [curReach currentReachabilityStatus];                if (status == NotReachable) {              UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@”AppName”"                                message:@”NotReachable”                                delegate:nil                                cancelButtonTitle:@”YES” otherButtonTitles:nil];                                [alert show];                                [alert release];          }      }                                      - (void)applicationDidFinishLaunching:(UIApplication *)application {          // …                              // 监测网络情况          [[NSNotificationCenter defaultCenter] addObserver:self                                selector:@selector(reachabilityChanged:)                                name: kReachabilityChangedNotification                                object: nil];          hostReach = [[Reachability reachabilityWithHostName:@"www.google.com"] retain];          hostReach startNotifer];          // …      }      二:使用NSConnection下载数据            1.创建NSConnection对象,设置委托对象            NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:[self urlString]]];      [NSURLConnection connectionWithRequest:request delegate:self];            2. NSURLConnection delegate委托方法          - (void)connection:(NSURLConnection *)connection didReceiveResp*****e:(NSURLResp*****e *)resp*****e;            - (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error;            - (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data;            - (void)connectionDidFinishLoading:(NSURLConnection *)connection;          3. 实现委托方法      - (void)connection:(NSURLConnection *)connection didReceiveResp*****e:(NSURLResp*****e *)resp*****e {          // store data          [self.receivedData setLength:0];            //通常在这里先清空接受数据的缓存      }            - (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {             /* appends the new data to the received data */          [self.receivedData appendData:data];        //可能多次收到数据,把新的数据添加在现有数据最后      }        - (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {          // 错误处理      }        - (void)connectionDidFinishLoading:(NSURLConnection *)connection {          // disconnect          [UIApplication sharedApplication].networkActivityIndicatorVisible = NO;             NSString *returnString = [[NSString alloc] initWithData:self.receivedData encoding:NSUTF8StringEncoding];          NSLog(returnString);          [self urlLoaded:[self urlString] data:self.receivedData];          firstTimeDownloaded = YES;      }    三:使用NSXMLParser解析xml文件        1. 设置委托对象,开始解析      NSXMLParser *parser = [[NSXMLParser alloc] initWithData:data];   //或者也可以使用initWithContentsOfURL直接下载文件,但是有一个原因不这么做:      // It’s also possible to have NSXMLParser download the data, by passing it a URL, but this is not desirable      // because it gives less control over the network, particularly in responding to connection errors.      [parser setDelegate:self];      [parser parse];        2. 常用的委托方法      - (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName                                   namespaceURI:(NSString *)namespaceURI                                  qualifiedName:(NSString *)qName                                   attributes:(NSDictionary *)attributeDict;      - (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName                                   namespaceURI:(NSString *)namespaceURI                                   qualifiedName:(NSString *)qName;      - (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string;      - (void)parser:(NSXMLParser *)parser parseErrorOccurred:(NSError *)parseError;        static NSString *feedURLString = @”http://www.yifeiyang.net/test/test.xml”;        3.  应用举例      - (void)parseXMLFileAtURL:(NSURL *)URL parseError:(NSError **)error      {          NSXMLParser *parser = [[NSXMLParser alloc] initWithContentsOfURL:URL];          [parser setDelegate:self];          [parser setShouldProcessNamespaces:NO];          [parser setShouldReportNamespacePrefixes:NO];          [parser setShouldResolveExternalEntities:NO];          [parser parse];          NSError *parseError = [parser parserError];          if (parseError && error) {              *error = parseError;          }          [parser release];      }        - (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI                                           qualifiedName:(NSString*)qName attributes:(NSDictionary *)attributeDict{          // 元素开始句柄          if (qName) {              elementName = qName;          }          if ([elementName isEqualToString:@"user"]) {              // 输出属性值              NSLog(@”Name is %@ , Age is %@”, [attributeDict objectForKey:@"name"], [attributeDict objectForKey:@"age"]);          }      }        - (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI                                           qualifiedName:(NSString *)qName      {          // 元素终了句柄          if (qName) {                 elementName = qName;          }      }        - (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string      {          // 取得元素的text      }        NSError *parseError = nil;      [self parseXMLFileAtURL:[NSURL URLWithString:feedURLString] parseError:&parseError]; 

//实例

//

//  NLViewController.m

//  NetWorkTest

//

//  Created by Nono on 12-5-16.

//  Copyright (c) 2012年 NonoWithLilith. All rights reserved.

//

#import “NLViewController.h”

@interface NLViewController ()

@end

@implementation NLViewController

@synthesize label = _label;

@synthesize data = _data;

@synthesize connection = _connection;

- (void)dealloc{

    [self.label release];

    [self.data release];

    [super dealloc];

}

- (void)viewDidLoad

{

    [super viewDidLoad];

    UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(10.0, 10.0, 300.0, 400)];

    self.label = label;

    label.textAlignment = UITextAlignmentCenter;

    [label setNumberOfLines:0];

    label.lineBreakMode = UILineBreakModeWordWrap; 

    self.label.text = @”正在在请求数据”;

    [self.view addSubview:label];

    [label release];

    //step 1:请求地址

    NSString *urlString = @”http://www.google.com”;

    NSURL *url = [NSURL URLWithString:urlString];

    //step 2:实例化一个request

    NSURLRequest *requrst = [NSURLRequest requestWithURL:url cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:30.0];

    //step 3:创建链接

    self.connection = [[NSURLConnection alloc] initWithRequest:requrst delegate:self];

    if ( self.connection) {

        NSLog(@”链接成功”);

    }else {

        NSLog(@”链接失败”);

    }

    [url release];

    [urlString release];

    [requrst release];

// Do any additional setup after loading the view, typically from a nib.

}

- (void)viewDidUnload

{

    self.label = nil;

    self.data = nil;

    [super viewDidUnload];

    // Release any retained subviews of the main view.

}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation

{

    return (interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown);

}

#pragma mark-

#pragma NSUrlConnectionDelegate methods

- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response

{

    //接受一个服务端回话,再次一般初始化接受数据的对象

    NSLog(@”返回数据类型:%@”,[response textEncodingName]); 

    NSMutableData *d = [[NSMutableData alloc] init];

     self.data = d;

    [d release];

}

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data

{

    //接受返回数据,这个方法可能会被调用多次,因此将多次返回数据加起来

    NSUInteger datalength = [data length];

    NSLog(@”返回数据量:%d”,datalength);

    [self.data appendData:data];

}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection

{

    //连接结束

    NSLog(@”%d:”,[self.data length]);

    NSStringEncoding enc = CFStringConvertEncodingToNSStringEncoding(kCFStringEncodingGB_18030_2000);

    NSString *mystr = [[NSString alloc] initWithData:_data encoding:enc];

   // string i

    NSLog(@”最后的结果:%@”,mystr);

    self.label.text = mystr;

    [mystr release];

    [self.connection release];

}

- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error

{

    //链接错误

}

@end

ios网络编程(HTTP socket)

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原文地址:http://www.cnblogs.com/transcendent/p/4287637.html

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