工作遇到需要识别连接固定wifi热点，并获取该热点的BSSID的需求。记得以前搞过这个需求，于是直接用 Captive Network 来搞了。实现方法如下：
+ (NSString *)currentWifiBSSID
{
NSString *bssid = nil;
NSArray *ifs = (__bridge id)CNCopySupportedInterfaces();
for (NSString *ifname in ifs) {
NSDictionary *info = (__bridge id)CNCopyCurrentNetworkInfo((__bridge CFStringRef)ifname);
if (info[@"BSSID"])
{
bssid = info[@"BSSID"];
}
}
return bssid;
}
这个方法在ios9之前一直是work的，但郁闷的是在ios9+上 Captive Network 里面的方法全都Deprecated，瞬间有种抓狂的感觉。
后来在网上一番搜索，发现需要NEHotspotHelper APIs使用权限的entitlement。见http://stackoverflow.com/questions/31555640/how-to-get-wifi-ssid-in-ios9-after-captivenetwork-is-depracted-and-calls-for-wif。
于是跟apple 申请... 得到回复如下：
Hello,
Thank you for your interest in the Network Extension framework. Unfortunately, these APIs are not designed for the use you’ve identified. We’ll let you know if that changes.
The NEHotspotHelper APIs are meant to be used by hotspot network implementers to facilitate connections to known wireless networks that they manage. ... If your app needs to verify or retrieve information about the currently connected WiFi network, the following Captive Network APIs, while deprecated, have been re-enabled in iOS 9 instead.
CNCopySupportedInterfaces
CNCopyCurrentNetworkInfo
Please visit developer.apple.com to download the latest build.
得到提示，升级xcode到最新版本，再build，果然可以在ios9.0+ 的系统上拿到BSSID号了。
