问题描述

我有一个以编程方式创建的 UIWebView，它用于浏览存储在我的服务器上的 iPhone 风格的网站.在这个网站上，有一些用户可以下载到我的应用程序中的文件链接.现在，我正在尝试通过以下方式检测到这一点:

I have a programatically crated UIWebView, and it is used to browse a iPhone-style site stored on my server. In this website, there are a few links to files users can download into my application. Right now, I'm trying to detect this with:

- (BOOL) webView:(UIWebView *) webView shouldStartLoadWithRequest:(NSURLRequest *) request navigationType:(UIWebViewNavigationType) navigationType
{
    url = [request URL];
    NSString *mimeType = [request valueForHTTPHeaderField:@"Content-Type"];
    NSLog(@"Content-type: %@", mimeType);
    if(mimeType == @"application/zip" || mimeType == @"application/x-zip" || mimeType == @"application/octet-stream")
    {
        NSLog(@"Downloading file!");
        [NSThread detachNewThreadSelector:@selector(download:) toTarget:self withObject:@"/tmp/file.ipa"];
        return NO;
    }
    return YES;
}

但是，当调用此方法时，内容类型标头几乎总是(null)，所以我永远无法下载文件.

However, when this method is called, the content-type header is almost always (null), so I never am able to download a file.

你会如何正确地做到这一点?

How would you do this correctly?

推荐答案

您正在尝试从尚未生成的 NSURLRequest 中检测 Content-Type.在使用 NSURLConnection 发出请求之前，您不会知道 Content-Type.在这种情况下，我可能只会查看 URL 路径的文件扩展名.

You're trying to detect a Content-Type from an NSURLRequest which has not yet been made. You won't know the Content-Type until after the request is made using NSURLConnection. In this case, I'd probably just look at the file extension of the URL path.

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