User-Agent（用户代理）字符串是Web浏览器用于声明自身型号版本并随HTTP请求发送给Web服务器的字符串，在Web服务器上可以获取到该字符串。
在公司产品中，在userAgent中增加了NetType字段，用于标识客户端当前的网络环境。
- NetType/WIFI
- NetType/3G
web服务器端根据NetType类型加载不同分辨率的商品图片。我们只有两种，WIFI下高清图，非WIFI低分辨率图。
1、获取WebView的userAgent
iOS客户端中获取webView的userAgent的方法:
UIWebView * webView = [[UIWebView alloc] initWithFrame:CGRectZero];
NSString * userAgent = [webView stringByEvaluatingJavaScriptFromString:@"navigator.userAgent"];
根据需要添加不同的标识到新的userAgent中,这里添加一个WMall标识。
NSString *newUagent = [NSString stringWithFormat:@"%@ WMall/%@", userAgent, [SystemInfo appShortVersion]];
NSDictionary *dictionnary = [[NSDictionary alloc] initWithObjectsAndKeys:newUagent, @"UserAgent", nil];
[[NSUserDefaults standardUserDefaults] registerDefaults:dictionnary];
// 打印出来的newUagent是
// Mozilla/5.0 (iPhone; CPU iPhone OS 9_3 like Mac OS X) AppleWebKit/601.1.46 (KHTML, like Gecko) Mobile/13E230 WMall/3.0
2、根据网络类型设置不同的NetType标识
iOS中判断网络状态一般用AFNetWorking中的方法：
在appDelegate的application didFinishLaunchingWithOptions方法中启动网络状态监听：
[[AFNetworkReachabilityManager sharedManager] startMonitoring];
[[AFNetworkActivityIndicatorManager sharedManager] setEnabled:YES];
然后在基类BaseViewController中监听网络更新通知
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(networkReachabilityStatusDidChange:) name:AFNetworkingReachabilityDidChangeNotification object:nil];
- (void)networkReachabilityStatusDidChange:(NSNotification *)notify{
NSLog(@"网络变化通知：%@",notify.userInfo[AFNetworkingReachabilityNotificationStatusItem]);
AFNetworkReachabilityStatus status = [notify.userInfo[AFNetworkingReachabilityNotificationStatusItem] integerValue];
NSString *net = nil;
switch (status) {
case AFNetworkReachabilityStatusNotReachable:
net = @"无网络";
break;
case AFNetworkReachabilityStatusReachableViaWiFi:
net = @"WIFI";
[self changeUserAgentWithType:@"WIFI"];
break;
case AFNetworkReachabilityStatusReachableViaWWAN:
net = @"2G/3G/4G";
[self changeUserAgentWithType:@"3G"];
break;
default:
net = @"xxx";
break;
}
[Error showError:[NSString stringWithFormat:@"当前网络状态%@",net]];
}
注意先判断userAgent中是否存在NetType
//更新NetType
- (void)changeUserAgentWithType:(NSString *)type{
NSMutableString *userAgent = [NSMutableString stringWithString:[[UIWebView new] stringByEvaluatingJavaScriptFromString:@"navigator.userAgent"]];
NSString *newUagent = nil;
NSString *temp = nil;
if ([userAgent containsString:@"NetType"]) {
if ([userAgent containsString:@"WIFI"]) {
temp = @"WIFI";
}else if([userAgent containsString:@"3G"]){
temp = @"3G";
}
newUagent = [userAgent stringByReplacingOccurrencesOfString:temp withString:type];
}else{
newUagent = [NSString stringWithFormat:@"%@ NetType/%@", userAgent, type];
}
NSDictionary *dictionnary = [[NSDictionary alloc] initWithObjectsAndKeys:newUagent, @"UserAgent", nil];
NSLog(@"new useragent:%@",newUagent);
[[NSUserDefaults standardUserDefaults] registerDefaults:dictionnary];
}
// 打印 newUagent 为
// Mozilla/5.0 (iPhone; CPU iPhone OS 9_3 like Mac OS X) AppleWebKit/601.1.46 (KHTML, like Gecko) Mobile/13E230 WMall/3.0 NetType/WIFI
