Change User Agent in UIWebView (iPhone SDK)

Question

I have a business need to be able to customize the UserAgent for an embedded UIWebView. (For instance, I'd like the server to respond differently if, say, a user is using one version of the app versus another.)

Is it possible to customize the UserAgent in the existing iPhone SDK's UIWebView control the way it is, say, for an embedded IE browser in a Windows app?

Answer 1

Actually adding any header field to the NSURLRequest argument in shouldStartLoadWithRequest seems to work, because the request responds to setValue:ForHTTPHeaderField - but it doesn't actually work - the request is sent out without the header.

So I used this workaround in shouldStartLoadWithRequest which just copies the given request to a new mutable request, and re-loads it. This does in fact modify the header which is sent out.

if ( [request valueForHTTPHeaderField:@"MyUserAgent"] == nil )
{
    NSMutableURLRequest *modRequest = [request mutableCopyWithZone:NULL];
    [modRequest setValue:@"myagent" forHTTPHeaderField:@"MyUserAgent"];
    [webViewArgument loadRequest:modRequest];
    return NO;
}

Unfortunately, this still doesn't allow overriding the user-agent http header, which is apparently overwritten by Apple. I guess for overriding it you would have to manage a NSURLConnection by yourself.

Answer 2

The only problem I have found was change user agent only

- (BOOL)application:(UIApplication *)application
        didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    NSDictionary *dictionary = [NSDictionary 
        dictionaryWithObjectsAndKeys:
        @"Mozilla/5.0 (iPod; U; CPU iPhone OS 4_3_3 like Mac OS X; ja-jp) AppleWebKit/533.17.9 (KHTML, like Gecko) Version/5.0.2 Mobile/8J2 Safari/6533.18.5", 
        @"UserAgent", nil];
    [[NSUserDefaults standardUserDefaults] registerDefaults:dictionary];
}

Answer 3

Taking everything this is how it was solved for me:

- (void)viewDidLoad {
    NSURL *url = [NSURL URLWithString: @"http://www.amazon.com"];
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
    [request setValue:@"Foobar/1.0" forHTTPHeaderField:@"User-Agent"];
    [webView loadRequest:request];
}

Thanks Everyone.

Answer 4

By pooling the answer by Louis St-Amour and the NSUserDefaults+UnRegisterDefaults category from this question/answer, you can use the following methods to start and stop user-agent spoofing at any time while your app is running:

#define kUserAgentKey @"UserAgent"

- (void)startSpoofingUserAgent:(NSString *)userAgent {
    [[NSUserDefaults standardUserDefaults] registerDefaults:@{ kUserAgentKey : userAgent }];
}

- (void)stopSpoofingUserAgent {
    [[NSUserDefaults standardUserDefaults] unregisterDefaultForKey:kUserAgentKey];
}

Answer 5

I faced the same question. I want to add some info to the user-agent, also need to keep the original user-agent of webview. I solved it by using the code below:

    //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:@" Jiecao/2.4.7 ch_appstore"];
NSLog(@"new agent :%@", newAgent);

//regist the new agent
NSDictionary *dictionnary = [[NSDictionary alloc] initWithObjectsAndKeys:newAgent, @"UserAgent", nil];
[[NSUserDefaults standardUserDefaults] registerDefaults:dictionnary];

Use it before you instancing webview.

Answer 6

Modern Swift

Here's a suggestion for Swift 3+ projects from StackOverflow users PassKit and Kheldar:

UserDefaults.standard.register(defaults: ["UserAgent" : "Custom Agent"])

Source: https://stackoverflow.com/a/27330998/128579

Earlier Objective-C Answer

With iOS 5 changes, I recommend the following approach, originally from this StackOverflow question: UIWebView iOS5 changing user-agent as pointed out in an answer below. In comments on that page, it appears to work in 4.3 and earlier also.

Change the "UserAgent" default value by running this code once when your app starts:

NSDictionary *dictionary = @{@"UserAgent": @"Your user agent"};
[[NSUserDefaults standardUserDefaults] registerDefaults:dictionary];
[[NSUserDefaults standardUserDefaults] synchronize];

See previous edits on this post if you need methods that work in versions of iOS before 4.3/5.0. Note that because of the extensive edits, the following comments / other answers on this page may not make sense. This is a four year old question, after all. ;-)