iOS UIWebView通过附加字符串设置UserAgent无效

Question

Here's my code:

- (void)viewDidLoad {
[super viewDidLoad];
NSURL *url = [NSURL URLWithString:urlString];
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
//    NSString *tagString = @"Mozilla/5.0 (iPhone; CPU iPhone OS 9_3_2 like Mac OS X) AppleWebKit/601.1.46 (KHTML, like Gecko) Mobile/13F69/YoyaOrg-iOS";
//    NSString *tag = @"YoyaOrg-iOS";
NSString *defaultUserAgent = [self.mainWebView stringByEvaluatingJavaScriptFromString:@"navigator.userAgent"];
NSString *newUserAgent = [NSString stringWithFormat:@"%@ YoyaOrg-iOS",defaultUserAgent];
NSDictionary *dictionary = [NSDictionary dictionaryWithObjectsAndKeys:newUserAgent, @"UserAgent", nil];
[[NSUserDefaults standardUserDefaults] registerDefaults:dictionary];
self.mainWebView.scrollView.bounces = NO;
[self.mainWebView loadRequest:request];
}
 NSLog(@"webUserAgent:%@",defaultUserAgent);

After append string "YoyaOrg-iOS",but the log output still does not contain "YoyaOrg-iOS".if i replace UserAgent as:

 NSString *tagString = @"Mozilla/5.0 (iPhone; CPU iPhone OS 9_3_2 like Mac OS X) AppleWebKit/601.1.46 (KHTML, like Gecko) Mobile/13F69/YoyaOrg-iOS";
 NSDictionary *dictionary = [NSDictionary dictionaryWithObjectsAndKeys:tagString, @"UserAgent", nil];
[[NSUserDefaults standardUserDefaults] registerDefaults:dictionary];

then the userAgent i get is what i want;I can't make it and had wasted much time; TKS for any answers. TKS for any help!

Answer 1

Just for putting the postfix to your user-agent do the following in the didFinishLaunchingWithOptions function in your AppDelegate.swift

    /* changing User Agent system-wide */
    UserDefaults.standard.register(
        defaults: [
            "UserAgent" : "\(UIWebView().stringByEvaluatingJavaScript(from: "navigator.userAgent;")) YOUR_POSTFIX_TO_USER_AGENT"
        ]
    )

For brand new user agent you should get rid from UIWebView().stringByEvaluatingJavaScript(from: "navigator.userAgent;") call.

Answer 2

I am also looking for a way to change user agent. I learnt that I should change user agent when instantiating the webview using code like [[NSUserDefaults standardUserDefaults] registerDefaults:@{@"UserAgent":customUserAgent}]; and print the user Agent in the method webViewDidFinishLoad: using code NSLog(@"UserAgent = %@", [webView stringByEvaluatingJavaScriptFromString:@"navigator.userAgent"]); to see if the user agent is changed or not.

then I found if I put the code [webView stringByEvaluatingJavaScriptFromString:@"navigator.userAgent"] before the webview loads URL request, like this

     NSString *userAgent = [_webView stringByEvaluatingJavaScriptFromString:@"navigator.userAgent"];
    NSString *mystring = @" mystring";
    NSString *customUserAgent = [userAgent stringByAppendingString:mystring];

    [[NSUserDefaults standardUserDefaults] registerDefaults:@{@"UserAgent":customUserAgent}];

the result is not only the user agent is unchanged but also the OC-JS interaction codes I wrote using JavaScriptCore is disabled!

I found a way to fix this: init a second UIWebView which does nothing, only to get the default user agent. here's my final solution to append the default user agent string:

    _webView = [[UIWebView alloc] initWithFrame:self.view.bounds];
    _webView.scalesPageToFit = YES;

    //init another webView to get the default user agent
    NSString *userAgent = [[[UIWebView alloc] init] stringByEvaluatingJavaScriptFromString:@"navigator.userAgent"];
    NSString *mystring = @" mystring";
    NSString *customUserAgent = [userAgent stringByAppendingString:mystring];

    [[NSUserDefaults standardUserDefaults] registerDefaults:@{@"UserAgent":customUserAgent}];

this works smoothly :)