iOS修改UserAgent信息

UserAgent可以做什么？

1. 检查浏览器或设备的功能，并根据结果加载不同的CSS;
2. 将自定义JavaScript与另一个设备相比较;
3. 与桌面计算机相比，向手机发送完全不同的页面布局;
4. 根据用户代理语言偏好自动发送文档的正确翻译;
5. 根据用户的设备类型或其他因素向特定用户推送特惠优惠;
6. 收集有关访问者的统计信息，以告知我们的网页设计和内容制作流程，或者仅仅衡量谁访问我们的网站，以及来自哪些引荐来源。

UIWebView的UA设置

在使用UIWebView时，更改user-agent，只能在原来系统UA后面添加一些东西

 //get the original user-agent of webview
UIWebView *webView = [[UIWebView alloc] initWithFrame:CGRectZero];
NSString *oldAgent = [webView stringByEvaluatingJavaScriptFromString:@"navigator.userAgent"];
NSLog(@"old agent :%@", oldAgent);
//add my info to the new agent
NSString *newAgent = [oldAgent stringByAppendingString:@"Bobo_Ma"];
NSLog(@"new agent :%@", newAgent);
//regist the new agent
NSDictionary *dictionnary = [[NSDictionary alloc] initWithObjectsAndKeys:newAgent, @"UserAgent", nil];
[[NSUserDefaults standardUserDefaults] registerDefaults:dictionnary];

WKWebView的UA设置

@property(nonatomic, strong) WKWebView *webView;

 [self.webView evaluateJavaScript:@"navigator.userAgent" completionHandler:^(id result, NSError *error) {
        __strong typeof(weakSelf) strongSelf = weakSelf;

        NSString *userAgent = result;
        NSString *newUserAgent = [userAgent stringByAppendingString:@"Bobo_Ma"];

        NSDictionary *dictionary = [NSDictionary dictionaryWithObjectsAndKeys:newUserAgent, @"UserAgent", nil];
        [[NSUserDefaults standardUserDefaults] registerDefaults:dictionary];

        strongSelf.webView = [[WKWebView alloc] initWithFrame:strongSelf.view.bounds];
        strongSelf.webView.allowsBackForwardNavigationGestures = YES;
        strongSelf.webView.UIDelegate = self;
        strongSelf.webView.navigationDelegate = self;

        if (nil != self.urlString) {
            NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:self.urlString]];
            [request setTimeoutInterval:15];
            [request setCachePolicy:NSURLRequestReloadIgnoringLocalCacheData];
            [strongSelf.webView loadRequest:request];
        }

        [strongSelf.view addSubview:self.webView];

        // After this point the web view will use a custom appended user agent
        [strongSelf.webView evaluateJavaScript:@"navigator.userAgent" completionHandler:^(id result, NSError *error) {
            NSLog(@"%@", result);
        }];
    }];