CFNetwork编程1

本文主要是介绍CFNetwork编程1，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

学习ASIHTTPRequest的使用，是对apple提供的sdk 中CFNetwork的封装，实现了很多的功能。简单总结CFNetwork编程的基本内容。

包括 CFSocket类，CFStream类，CFHTTP类，CFFTP类。

CFStream：

CFReadStreamOpen(CFReadStreamRef ref);打开一个CFRedStream，就可以对其进行读，写等操作，这些操作会block，会suspend。可以通过在run loop中注册该stream可读、可写事件以及相应的callback函数，实现异步的读写。

CFStream内置支持SSL协议。

例：

CFWriteStreamRef myWriteStream =CFWriteStreamCreateWithFile(kCFAllocatorDefault, fileURL);
CFWriteStreamOpen(myWriteStream);
CFIndex numBytesRead;
UInt8 buf[myReadBufferSize];
numBytesRead = CFReadStreamRead(myReadStream, buf, sizeof(buf));
CFReadStreamClose(myReadStream);
CFRelease(myReadStream);
myReadStream = NULL;

实现异步的收发：

CFStreamCreatePairWithSocketToCFHost(kCFAllocatorDefault, host, port, &myReadStream, NULL);//创建连接，myReadStream和指定Host
//创建该流的context
CFStreamClientContext myContext = {0, myPtr, myRetain, myRelease, myCopyDesc};

// 注册读写该流相关的事件

CFOptionFlags registeredEvents = kCFStreamEventHasBytesAvailable | kCFStreamEventErrorOccurred | kCFStreamEventEndEncountered;
if (CFReadStreamSetClient(myReadStream, registeredEvents, myCallBack, &myContext))
{CFReadStreamScheduleWithRunLoop(myReadStream, CFRunLoopGetCurrent(),kCFRunLoopCommonModes);
}

// 发起连接，open。。。。

if (!CFReadStreamOpen(myReadStream)) {CFStreamError myErr = CFReadStreamGetError(myReadStream);if (myErr.error != 0) {    // An error has occurred.if (myErr.domain == kCFStreamErrorDomainPOSIX) {// Interpret myErr.error as a UNIX errno.strerror(myErr.error);} else if (myErr.domain == kCFStreamErrorDomainMacOSStatus) {OSStatus macError = (OSStatus)myErr.error;}// Check other domains.} else// start the run loopCFRunLoopRun();
}

callback的定义

void myCallBack (CFReadStreamRef stream, CFStreamEventType event, void *myPtr) {switch(event) {case kCFStreamEventHasBytesAvailable:.....UInt8 buf[BUFSIZE];CFIndex bytesRead = CFReadStreamRead(stream, buf, BUFSIZE);.....break;case kCFStreamEventErrorOccurred:CFStreamError error = CFReadStreamGetError(stream);reportError(error);CFReadStreamUnscheduleFromRunLoop(stream, CFRunLoopGetCurrent(),kCFRunLoopCommonModes);CFReadStreamClose(stream);CFRelease(stream);break;case kCFStreamEventEndEncountered:reportCompletion();CFReadStreamUnscheduleFromRunLoop(stream, CFRunLoopGetCurrent(),kCFRunLoopCommonModes);CFReadStreamClose(stream);CFRelease(stream);break;}
}

还有的方法是POLL，轮询

// 详细可参照

http://developer.apple.com/LIBRARY/IOS/#documentation/Networking/Conceptual/CFNetwork/CFStreamTasks/CFStreamTasks.html#//apple_ref/doc/uid/TP30001132-CH6-DontLinkElementID_12

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