USURLConnection 的同步 异步 与SSL certificate

通常在IPhone里用网络访问会用到NSURLConnection来做url链接请求,下面简单介绍一下:

1、同步请求
             NSURL *url=[[NSURL alloc]initWithString:urlString];

NSMutableURLRequest  *request=[[NSMutableURLRequest alloc]init];

NSError *err=nil;

NSData *data=[NSURLConnection sendSynchronousRequest:request

returningResponse:nil

error:&err];

if(data==nil)

{

 

//if([err code])

 

 

 

NSLog(@”Code:%d,domain:%@,localizedDesc:%@”,[err code],

 

[err domain],[err localizedDescription]);

 

}

 

else

 

{

 

}

 

这种情况,通过一个静态方法,请求request,这种情况下,会一直阻塞,等到返回结果,简单易用

 

 

 

2、异步请求

 

 

 

NSURL *url=[[NSURL alloc]initWithString:urlString];

 

NSMutableURLRequest  *request=[[NSMutableURLRequest alloc]init];

 

 

 

NSURLConnection *connection = [[NSURLConnection alloc] initWithRequest:requestdelegate:self];

[url release];

[request release];

if(connection)

{

receivedData = [[NSMutableData data] retain];

NSLog(@”intial done!”);

}

else

{

NSLog(@”sorry”);

}

通过一个delegate来做数据的下载以及Request的接受等等消息,此处delegate:self,所以需要本类实现一些方法,并且定义receivedData做数据的接受

基本上要实现下面节歌方法

 

 

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

{

NSLog(@”get the whole response”);

[receivedData setLength:0];

}

 

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

{

NSLog(@”get some data”);

[receivedData appendData:data];

}

 

– (void)connectionDidFinishLoading:(NSURLConnection *)connection

{

[connection release];

 

}

 

 

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

{

 

[connection release];

NSLog(@”Connection failed! Error – %@ %@”,

[error localizedDescription],

[[error userInfo] objectForKey:NSErrorFailingURLStringKey]);

}

 

 

基本上这样就搞定了!!!
但是异步模式下带来了一个新的问题,很多情况下,网络请求不在主线程,或者界面等待网络结果,不在主线程的时候,调用线程如果生命周期over,下面这些可能都没有调用到,导致得不到想要得效果,所以需要在NSURLConnection请求后面加点东西来阻塞

while(!finished) {

 

[[NSRunLoop currentRunLoop] runMode:NSDefaultRunLoopMode beforeDate:[NSDatedistantFuture]];

 

}

 

 

好了,现在我们看看SSL的问题,在NSURLConnnection本来有方法可以跳过ssl检查,可惜被apple无情的私有了,所以同步的数据请求肯定不行了,看看文档,只能通过异步delegate的方式了

 

– (BOOL)connection:(NSURLConnection *)connection canAuthenticateAgainstProtectionSpace:(NSURLProtectionSpace *)protectionSpace

{

return [protectionSpace.authenticationMethodisEqualToString:NSURLAuthenticationMethodServerTrust];

}

 

– (void)connection:(NSURLConnection *)connection didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge

{

if ([challenge.protectionSpace.authenticationMethodisEqualToString:NSURLAuthenticationMethodServerTrust])

if ([trustedHosts containsObject:challenge.protectionSpace.host])

[challenge.sender useCredential:[NSURLCredentialcredentialForTrust:challenge.protectionSpace.serverTrust]forAuthenticationChallenge:challenge];

 

[challenge.sender continueWithoutCredentialForAuthenticationChallenge:challenge];

}

 

第一个方法会根据你的URL来判断是否需要做认证

第二个方法是认证的过程,if ([trustedHosts containsObject:challenge.protectionSpace.host]),这行代码注释掉,就可以自动所有SSL通过,否则,你可以加一些Trust的hosts,其他的不通过就行了!!!

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