iOS 网络通信 · 一鸣的博客

最近在研究 AFNetworking 源码，发现了一些原先没掌握好的东东，整理下…

NSURL

对于 NSURL 的理解，原先指示停留在将 NSString 转换为 NSURL。今天细看文档，发现好多好用的功能，原先还自己封装来获取 URL 后缀，现在看来是真没文化啊。

0.经典用法

1 2	NSURL url1 = [NSURL URLWithString:@"http://www.baidu.com/img/bd_logo1.png"]; NSURL url2 = [NSURL URLWithString:@"/img/bd_logo1.png" relativeToURL:[NSURL URLWithString:@"http://www.baidu.com"]];

1.加载项目中本地网页

1 2	NSString urlPath = [[NSBundle mainBundle] pathForResource:@"404" ofType:@"html"]; NSURL url = [NSURL URLWithString:urlPath];

2.获取扩展名

1 2	NSURL url = [NSURL URLWithString:@"http://www.iyiming.me/hello.png"]; NSString pathExtension = [url pathExtension];//扩展名 png

3.获取组成部分

1 2	NSURL url = [NSURL URLWithString:@"http://www.iyiming.me/index.htm"]; NSArray pathComponentsArray = [url pathComponents];//所有组成部分 [/,index.htm]

4.获取主机

1 2	NSURL url = [NSURL URLWithString:@"http://www.iyiming.me/index.htm"]; NSString host = [url host];//主机 www.iyiming.me

5.获取端口号

1 2	NSURL url = [NSURL URLWithString:@"http://www.iyiming.me:80/index.htm"]; NSNumber port = [url port];//端口号 80

6.获取查询参数

1 2	NSURL url = [NSURL URLWithString:@"http://www.iyiming.me:80/index.htm?key1=value1&key2=value2"]; NSString query = [url query];//查询参数 key1=value1&key2=value2

7.获取协议名称

1 2	NSURL url = [NSURL URLWithString:@"http://www.iyiming.me:80/index.htm?key1=value1&key2=value2"]; NSString scheme = [url scheme];//协议 http

8.获取锚定位

1 2	NSURL url = [NSURL URLWithString:@"http://www.iyiming.me:80/index.htm#jumpLocation"]; NSString fragment = [url fragment];//锚定位 jumpLocation

9.获取用户名

1 2	NSURL url = [NSURL URLWithString:@"ftp://yiming@www.iyiming.me"]; NSString user = [url user];//用户名 yiming

NSMutableURLRequest

NSURLMutableRequest 是 NSURLRequest 的子类，名如其类，它是可扩充的NSURLRequest。

0.缓存

enum
{
    NSURLRequestUseProtocolCachePolicy  = 0,
    NSURLRequestReloadIgnoringLocalCacheData  = 1,
    NSURLRequestReturnCacheDataElseLoad  = 2,
    NSURLRequestReturnCacheDataDontLoad  = 3,
};
typedef NSUInteger  NSURLRequestCachePolicy;

关于缓存的介绍，可以看看下面这篇博客，写的很是详细：

iOS 开发之缓存（一）：内存缓存

1.设置请求超时时间

设置 timeoutInterval 属性的就 OK 啦。

2.GET 请求

#pragma mark -获取参数字符串
- (NSString *) parametersStr:(NSDictionary *) parametersDic
{
    NSMutableArray *parametersArray = [[NSMutableArray alloc] init];
    for (id key in parametersDic.allKeys) {
        if ([key isKindOfClass:[NSString class]]) {
            id value = parametersDic[key];
            NSString *parameterStr = [NSString stringWithFormat:@"%@=%@",key,value];
            [parametersArray addObject:parameterStr];
        }
    }
    NSString *parametersStr = [parametersArray componentsJoinedByString:@"&"];
    return parametersStr;
}
#pragma mark -GET Request
- (NSURLRequest *) GET:(NSString *)URLString parameters:(NSDictionary *) parametersDic
{
    NSString *parametersStr = [self parametersStr:parametersDic];//请求参数字符串
    NSString *requestURLStr = [NSString stringWithFormat:@"%@?%@",URLString,parametersStr];//请求URL字符串
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:requestURLStr]];
    //设置请求头部
    ////设置ContentType
    [request addValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"];
    //设置Content-length
    [request addValue:[NSString stringWithFormat:@"%lu",(unsigned long)[parametersStr length]] forHTTPHeaderField:@"Content-Length"];
    //设置请求类型 GET
    [request setHTTPMethod:@"GET"];
    return request;
}

3.POST 请求

#pragma mark -POST Request
- (NSURLRequest *) POST:(NSString *)URLString parameters:(NSDictionary *) parametersDic
{
    NSString *parametersStr = [self parametersStr:parametersDic];//请求参数字符串
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:URLString]];
    //设置请求头部
    ////设置ContentType
    [request addValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"];
    //设置Content-length
    [request addValue:[NSString stringWithFormat:@"%lu",(unsigned long)[parametersStr length]] forHTTPHeaderField:@"Content-Length"];
    //设置请求类型 GET
    [request setHTTPMethod:@"POST"];
    //设置请求Body
    [request setHTTPBody:[parametersStr dataUsingEncoding:NSUTF8StringEncoding]];
    return request;
}

4.发送图片等多媒体数据

未完成

NSURLConnection

0.同步加载数据

    NSURLRequest *request = [self GET:urlStr parameters:parametersDic];
    NSError *error = nil;
    NSURLResponse *response = nil;
    NSData *data = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error];
    if (!error) {
        NSString *dataStr = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
        NSLog(@"获取的字符串 %@",dataStr);
}

1.异步加载数据

1.1 +connectionWithRequest:delegate:

1 2	NSURLRequest *request = [self GET:urlStr parameters:parametersDic]; [NSURLConnection connectionWithRequest:request delegate:self];

1.2 -initWithRequest:delegate:

1	[[NSURLConnection alloc] initWithRequest:request delegate:self];

1.3 -initWithRequest:delegate:startImmediately:

startImmediately 参数为 YES 时，会立刻执行。如果 startImmediately 参数为 NO 时，将不会在当前 RunLoop 中运行，需要手动调用 scheduleInRunLoop:forMode: 方法。不调用scheduleInRunLoop:forMode:方法，也可以调用 start 方法来执行,此时的RunLoop 是当时的 RunLoop。关于 RunLoop 可以参考这篇文章

1 2	NSURLConnection *connection = [[NSURLConnection alloc] initWithRequest:request delegate:self startImmediately:NO]; [connection start];

1.4 -sendAsynchronousRequest:queue:completionHandler:

queue 参数是指 completionHandler Block 执行所在的队列

[NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *connectionError) {
    if (!connectionError) {
        dispatch_async(dispatch_get_global_queue(0, 0), ^{
            NSString *dataStr = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
            dispatch_async(dispatch_get_main_queue(), ^{
                NSLog(@"获取的字符串 %@",dataStr);
            });
        });
    }else{
        NSLog(@"error:%@",connectionError.localizedDescription);
    }
}];

2.取消 Connection

调用 cancel 方法,如果取消之后，还想继续建立连接，需要重新实例化 connection 对象

1	[connection cancel];

NSURLConnectionDelegate

这个协议经常用到，但是不知道它是用来干啥的。相关资料也很少，只好查看官方文档

NSURLConnectionDelegate 是配合 NSURLConnectionDataDelegate、NSURLConnectionDownloadDelegate 协议使用的。常见的connection:didFailWithError:方法就属于 NSURLConnectionDelegate。

NSURLConnectionDelegate 中声明的方法，有些方法都已经废除了，见下图：

网络通信

0.-connection:willSendRequestForAuthenticationChallenge:

Tells the delegate that the connection will send a request for an authentication challenge.
告诉协议，连接（connection）将会为身份认证询问发送一个请求

1.- (BOOL)connectionShouldUseCredentialStorage:(NSURLConnection *)connection

URL 加载者是否使用凭证存储来认证连接
Sent to determine whether the URL loader should use the credential storage for authenticating the connection.

如何返回 NO，连接不会自动询问凭证存储，不会存储凭证，然而，在connection:didReceiveAuthenticationChallenge方法中，更具需要可以自己实现询问凭证存储，存储凭证。

在 iOS 7 和 OS X v10.9之前，实现connection:willSendRequestForAuthenticationChallenge:方法不会调用connectionShouldUseCredentialStorage:方法。也就是说，在以后的操作系统（iOS 7 和 OS X v10.9后）中，实现connection:willSendRequestForAuthenticationChallenge:方法会调用connectionShouldUseCredentialStorage:方法。

2.例子：实现访问无线路由器设置页面

一般无线路由器设置了密码，访问路由器设置页面会出现如下图页面（有的是http://192.168.0.1或者是http://192.168.1.1）：

网络通信

//步骤一  建立连接
NSURLRequest *request = [self POST:@"http://192.168.0.1" parameters:nil];
connection = [[NSURLConnection alloc] initWithRequest:request delegate:self startImmediately:NO];
[connection start];
//步骤二 实现NSURLConnectionDelegate  
#pragma mark -NSURLConnectionDataDelegate
- (void)connection:(NSURLConnection *)connection willSendRequestForAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge {
    if ([challenge previousFailureCount] == 0) {
        NSLog(@"received authentication challenge");
        NSURLCredential *newCredential = [NSURLCredential credentialWithUser:@"这个地方输入用户名"
        password:@"这个地方输入密码"
        persistence:NSURLCredentialPersistenceForSession];
        NSLog(@"credential created");
        [[challenge sender] useCredential:newCredential forAuthenticationChallenge:challenge];
        NSLog(@"responded to authentication challenge");
    }else {
        NSLog(@"previous authentication failure");
    }
}
//步骤三 实现NSURLConnectionDataDelegate
- (void) connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
    [responseData setLength:0];
    NSLog(@"接收响应");
}
- (void) connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
    [responseData  appendData:data];
    NSLog(@"接收数据...");
}
- (void) connectionDidFinishLoading:(NSURLConnection *)connection
{
    NSString *newStr = [[NSString alloc] initWithData:responseData encoding:NSUTF8StringEncoding];
    //简单测试 用于显示路由器设置页面
    UIWebView *mainWebView = [[UIWebView alloc] initWithFrame:CGRectMake(0, 0, 320, 400)];
    [mainWebView loadHTMLString:newStr baseURL:[NSURL URLWithString:@"http://192.168.0.1"]];
    [self.view addSubview:mainWebView];
    NSLog(@"完成 %@",newStr);
}

NSURLConnectionDataDelegate

未完成

参考文章

苹果官方文档：NSURL
苹果官方文档：NSMutableURLRequest
苹果官方文档：NSURLConnection
iOS 开发中级：HTTP 请求 GET POST 网络编程实现