设置User Agent

　　公司的前端要给项目的webview加一个区分，用来区别是iOS端访问、android访问还是在浏览器访问的，说是要加一个User Agent ，前端根据不同信息做适配，和我说来一头雾水，后来经过开发同事的指导和在网上查阅资料，才有了点头绪，在这里和大家分享一下。

一、获取UserAgent

UIWebView方式：

UIWebView* tempWebView = [[UIWebView alloc] initWithFrame:CGRectZero];
NSString* userAgent = [tempWebView stringByEvaluatingJavaScriptFromString:@"navigator.userAgent"];
NSLog(@"UIWebView默认的userAgent = %@", userAgent);

默认UserAgent输出：

UIWebView默认的userAgent = Mozilla/5.0 (iPhone; CPU iPhone OS 10_3_1 like Mac OS X) AppleWebKit/603.1. (KHTML, like Gecko) Mobile/14E304

二、修改UserAgent

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
   UIWebView* tempWebView = [[UIWebView alloc] initWithFrame:CGRectZero];
   NSString* userAgent = [tempWebView stringByEvaluatingJavaScriptFromString:@"navigator.userAgent"];
   NSLog(@"UIWebView默认的userAgent = %@", userAgent);
   NSString *versionsss = [[[NSBundle mainBundle] infoDictionary] objectForKey:@"CFBundleShortVersionString"];;
   NSString *ua = [NSString stringWithFormat:@"%@/XYWY_YIMAI/iOS/%@", userAgent, versionsss];//自定义需要拼接的字符串
   [[NSUserDefaults standardUserDefaults] registerDefaults:@{@"UserAgent" : ua, @"User-Agent" : ua}];
}

获取UserAgent输出：

NSMutableURLRequest *request = .....

/** 获取系统的UA */
NSString *sysUA = request.allHTTPHeaderFields[@"User-Agent"];

最终得到修改后的：

Mozilla/5.0 (iPhone; CPU iPhone OS 10_3_1 like Mac OS X) AppleWebKit/603.1. (KHTML, like Gecko) Mobile/14E304/XYWY_YIMAI/iOS/5.5