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拦截来自WebView Flash插件的Web请求

webkit cocoa

J. Perkins · 技术社区 · 16 年前

我有一个桌面浏览器应用程序,它使用一个WebView来托管一个Flash插件。Flash插件定期向外部网站请求新数据,然后将其绘制成精美的图形。

我想拦截这些Web请求并获取数据(这样我可以通过咆哮来显示它,而不是保留桌面窗口)。但我能说的是,Flash的请求不会被普通的WebView代理接受。

还有别的地方可以挂钩吗?我尝试通过[nsurlcache setshareduralcache]安装自定义nsurlcache,但从未被调用。我还尝试了使用其他一些类(如nscachedurlResponse)的方法,但找不到方法。有什么想法吗?多谢!

1 回复 | 直到 15 年前

J. Perkins 15 年前

令人惊讶的是,没有人回答这个问题,其实很容易。创建nsurlprotocol的子类,然后调用registerClass开始拦截。

[NSURLProtocol registerClass:[MyCustomURLProtocol class]];

下面是子类的重要部分:

#define REQUEST_HEADER_TAG  @"x-mycustomurl-intercept"

+ (BOOL)canInitWithRequest:(NSURLRequest*)theRequest
{
    // Check for the custom header on the request to break the 
    // infinite loop created by the [startLoading] below.
    if ([theRequest valueForHTTPHeaderField:REQUEST_HEADER_TAG]) {
        return NO;
    }

    if ([theRequest.URL.scheme caseInsensitiveCompare:@"http"] == NSOrderedSame) {
        return YES;
    }
    return NO;
}

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

- (id)initWithRequest:(NSURLRequest*)theRequest
       cachedResponse:(NSCachedURLResponse*)cachedResponse
               client:(id<NSURLProtocolClient>)client
{
    // Add a custom header on the request to break the 
    // infinite loop created by the [startLoading] below.
    NSMutableURLRequest* newRequest = [theRequest mutableCopy];
    [newRequest setValue:@"" forHTTPHeaderField:REQUEST_HEADER_TAG];

    // Now continue the process with this "tagged" request
    self = [super initWithRequest:theRequest 
                   cachedResponse:cachedResponse 
                           client:client];
    if (self) {
       // capture the data received 
       [self setRequest:newRequest];
       receivedData = [[NSMutableData data] retain];
    }

    [newRequest release];
    return self;
}

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


- (void)startLoading
{
    // Load the data off the web as usual, but set myself up as the delegate 
    // so I can intercept the response data as it comes in.
    [self setConnection:[NSURLConnection connectionWithRequest:request delegate:self]];
}


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

#pragma mark NSURLConnection delegate implementation

- (void)connection:(NSURLConnection*)conn 
                   didReceiveResponse:(NSURLResponse*)response 
{
    [[self client] URLProtocol:self 
            didReceiveResponse:response 
            cacheStoragePolicy:[request cachePolicy]];
    [receivedData setLength:0];
}


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


- (void)connectionDidFinishLoading:(NSURLConnection*)conn
{
    [[self client] URLProtocolDidFinishLoading:self];
    [self setConnection:nil];
    if (requestTag != 0) {
        if (requestDelegate && 
            [requestDelegate respondsToSelector:
               @selector(finishedLoadingData:forURL:taggedWith:)]) {
            [requestDelegate finishedLoadingData:receivedData 
                                          forURL:[request URL] 
                                      taggedWith:requestTag];
        }
    }
}


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