淺談iOS中的userAgent

 

User-Agent（用戶代理）字符串是Web瀏覽器用於聲明自身型號版本並隨HTTP請求發送給Web服務器的字符串，在Web服務器上可以獲取到該字符串。

在公司產品中，在userAgent中增加了NetType字段，用於標識客戶端當前的網絡環境。

• NetType/WIFI
• NetType/3G

web服務器端根據NetType類型加載不同分辨率的商品圖片。我們只有兩種，WIFI下高清圖，非WIFI低分辨率圖。

獲取WebView的userAgent

iOS客戶端中獲取webView的userAgent的方法:

NSMutableString *userAgent = [NSMutableString stringWithString:[[UIWebView new] stringByEvaluatingJavaScriptFromString:@"navigator.userAgent"]];

根據需要添加不同的標識到新的userAgent中,這里添加一個WMall標識。

NSString *newUagent = [NSString stringWithFormat:@"%@ WMall/%@", userAgent, [SystemInfo appShortVersion]]; NSDictionary *dictionnary = [[NSDictionary alloc] initWithObjectsAndKeys:newUagent, @"UserAgent", nil]; [[NSUserDefaults standardUserDefaults] registerDefaults:dictionnary];

newUagent 為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

根據網絡類型設置不同的NetType標識

iOS中判斷網絡狀態一般用AFNetWorking中的方法：
在appDelegate的application didFinishLaunchingWithOptions方法中啟動網絡狀態監聽：

[[AFNetworkReachabilityManager sharedManager] startMonitoring]; [[AFNetworkActivityIndicatorManager sharedManager] setEnabled:YES];

然后在基類BaseViewController中監聽網絡更新通知

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(networkReachabilityStatusDidChange:) name:AFNetworkingReachabilityDidChangeNotification object:nil];

- (void)networkReachabilityStatusDidChange:(NSNotification *)notify{ NSLog(@"網絡變化通知：%@",notify.userInfo[AFNetworkingReachabilityNotificationStatusItem]); AFNetworkReachabilityStatus status = [notify.userInfo[AFNetworkingReachabilityNotificationStatusItem] integerValue]; NSString *net = nil; switch (status) { case AFNetworkReachabilityStatusNotReachable: net = @"無網絡"; 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:@"當前網絡狀態%@",net]]; }

注意先判斷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]; }

newUagent 為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