Question

我正在根据this other question中的说明为我的应用中的网页浏览设置自定义UserAgent。具体来说，我正在设置

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

在应用启动时。（只需为UIWebView设置NSMutableURLRequest的相应标头 - UserAgent，User-Agent，User_Agent - 不起作用。）

这会导致我的嵌入式Web视图使用正确的用户代理。但是，它还打破了Facebook SDK用于对话框的嵌入式Web视图 - 例如，在我发布到我的墙上之后，FB对话框webview的内容被替换为类似于{{1}的 text 并且webview不像通常那样关闭（用户必须手动关闭它）。仅当我设置了自定义用户代理时才会出现此情况。

我认为我可以通过在Facebook调用之前取消设置用户代理并在之后重置它来解决问题，但似乎我无法取消设置默认默认值;我尝试在每次Facebook调用之前调用window.location.href="fbconnect:\/\/success?post_id=100002469633196_43677789308119...和[[NSUserDefaults standardUserDefaults] removeObjectForKey:@"UserAgent"]并在调用的结果处理程序中再次设置它们，但我仍然看到相同的错误行为。

我尝试将初始设置切换为[[NSUserDefaults standardUserDefaults] removePersistentDomainForName:NSRegistrationDomain]，但我的网页视图不会选择用户代理。

当然，有人之前在使用非Facebook嵌入式网页浏览的应用中使用过Facebook SDK。我错过了什么？我已经在这方面进行了多次轮次，每次都似乎几乎没有完全解决所有问题。

Answer 1

我最终必须通过实现NSURLProtocol子类来完成此操作。虽然我的实现很混乱，但我在下面包含了一个清理版本，因为我很惊讶不能在StackOverflow上找到一个例子。

#import <Foundation/Foundation.h>

@interface MyProtocol : NSURLProtocol {
    NSURLConnection *connection;
}

@property (nonatomic, retain) NSURLConnection *connection;

@end

@implementation MyProtocol

@synthesize connection;

#pragma mark -
#pragma mark custom methods

+ (NSString *)myUA {
    return [[NSUserDefaults standardUserDefaults] stringForKey:@"MyCustomUserAgent"];
}
+ (BOOL)canInitWithRequest:(NSURLRequest *)request
{
    NSString *scheme = [request.URL.scheme stringByAppendingString:@"://"];
    NSString *baseRequestString = [[[request.URL absoluteString] stringByReplacingOccurrencesOfString:request.URL.path withString:@""]
                                   stringByReplacingOccurrencesOfString:scheme withString:@""];
    if (request.URL.query != nil) {
        NSString *query = [@"?" stringByAppendingString:request.URL.query];
        baseRequestString = [baseRequestString stringByReplacingOccurrencesOfString:query withString:@""];
    }

    BOOL shouldIntercept = [baseRequestString isEqualToString:myWebHost];
    BOOL alreadyIntercepted = [[NSURLProtocol propertyForKey:@"UserAgent" inRequest:request] isEqualToString:[self myUA]];
    return shouldIntercept && !alreadyIntercepted;
}

+ (NSURLRequest *) canonicalRequestForRequest:(NSURLRequest *)request
{
    return request;
}

- (id)initWithRequest:(NSURLRequest *)request cachedResponse:(NSCachedURLResponse *)cachedResponse client:(id<NSURLProtocolClient>)client
{
    NSMutableURLRequest *mutableRequest = [NSMutableURLRequest requestWithURL:request.URL
                                                       cachePolicy:request.cachePolicy
                                                   timeoutInterval:request.timeoutInterval];
    [mutableRequest setAllHTTPHeaderFields:[request allHTTPHeaderFields]];
    [mutableRequest setHTTPMethod:[request HTTPMethod]];
    if ([request HTTPBody] != nil)
        [mutableRequest setHTTPBody:[request HTTPBody]];
    if ([request HTTPBodyStream] != nil)
        [mutableRequest setHTTPBodyStream:[request HTTPBodyStream]];
    [NSURLProtocol setProperty:[[self class] myUA] forKey:@"UserAgent" inRequest:mutableRequest];
    [mutableRequest setValue:[[self class] myUA] forHTTPHeaderField:@"User-Agent"];
    [mutableRequest setValue:[[self class] myUA] forHTTPHeaderField:@"User_Agent"];

    self = [super initWithRequest:mutableRequest cachedResponse:cachedResponse client:client];
    return self;
}

- (void) dealloc
{
    [connection release];
}

#pragma mark -
#pragma mark boilerplate NSURLProtocol subclass requirements

- (void) startLoading
{
    self.connection = [[NSURLConnection connectionWithRequest:[self request] delegate:self] retain];
}

- (void)stopLoading
{
    [self.connection cancel];
}

- (void)connection:(NSURLConnection*)conn didReceiveResponse:(NSURLResponse*)response
{
    [[self client] URLProtocol:self didReceiveResponse:response cacheStoragePolicy:[[self request] cachePolicy]];
}

- (void)connection:(NSURLConnection*)connection didReceiveData:(NSData*)data
{
    [[self client] URLProtocol:self didLoadData:data];
}

- (void)connectionDidFinishLoading:(NSURLConnection*)conn
{
    [[self client] URLProtocolDidFinishLoading:self];
}

- (NSURLRequest*)connection:(NSURLConnection*)connection willSendRequest:(NSURLRequest*)theRequest redirectResponse:(NSURLResponse*)redirectResponse
{
    return theRequest;
}

- (void)connection:(NSURLConnection*)conn didFailWithError:(NSError*)error
{
    [[self client] URLProtocol:self didFailWithError:error];
}

@end

请注意，在您提出要应用的任何网络请求之前，协议必须在[NSURLProtocol registerClass:[MyProtocol class]];注册 - 例如，在applicationDidFinishLaunchingWithOptions:中。

覆盖UIWebView用户代理 - 但不适用于Facebook SDK

1 个答案: