NSCachedURLResponse 返回对象，但 UIWebView 不解释内容

问题描述

我正在向 UIWebView 发送请求.加载的网页上有 AJAX 调用.我需要分析 AJAX 流量以确定用户是否登录.为此，我在 AppDelegate 中安装了一个 NSURLCache:

I am sending a request to a UIWebView. There are AJAX-calls on the loaded webpage. I need to analyze the AJAX-traffic in order to determinate, if the user is logged in or not. For doing this I installed a NSURLCache in the AppDelegate:

MYURLCache *cache = [[MYURLCache alloc] init];
[NSURLCache setSharedURLCache:cache];

这个 MYURLCache 类正确接收通过 webview 运行的流量.我只能终止 AJAX 调用.然后我产生一个自己的 AJAX 调用请求.这个返回来自网络服务器的完美响应.所以现在要做的最后一步是构造 NSCachedURLResponse 返回对象.我也管理了这个，但是 webview 在返回对象时根本不做任何事情.如果我只返回 nil，WebView 加载一切正常(nil 是 NSURLCache 的消息，没有缓存，所以 webview 应该开始自己加载它).

This MYURLCache-class correctly receives the traffic that runs through the webview. I can terminate the AJAX-calls only. I then spawn an own request of the AJAX-calls. This one returns the perfectly fine response from the webserver. So the last step to do now is constructing the NSCachedURLResponse return object. I also managed this, but the webview simply does nothing when returning the objects. If I return just nil, the WebView loads everything fine (nil is the message for the NSURLCache, that nothing is cached, so the webview should start to load it on its own).

- (NSCachedURLResponse *)cachedResponseForRequest:(NSURLRequest *)request {
    if ([[[request URL] absoluteString] rangeOfString:@"/ajax/"].location == NSNotFound) {
        return nil;
    } else {

    ASIHTTPRequest *asirequest = [ASIHTTPRequest requestWithURL:[request URL]];
    [asirequest setValidatesSecureCertificate:NO];
    [asirequest startSynchronous];
    NSError *error = [asirequest error];
    NSData* data = [[asirequest responseString] dataUsingEncoding:NSUTF8StringEncoding];

    // Create the cacheable response
    NSURLResponse *urlresponse = [[NSURLResponse alloc] initWithURL:[request URL] MIMEType:@"application/json" expectedContentLength:[data length] textEncodingName:@"UTF-8"];
    NSCachedURLResponse *cachedResponse = [[NSCachedURLResponse alloc] initWithResponse:urlresponse data:data];

    NSLog(@"cachedResponse %@", cachedResponse);
    NSLog(@"cachedResponse data %@", [[NSString alloc] initWithData:[cachedResponse data] encoding:NSUTF8StringEncoding]);

    return cachedResponse;
}  

return nil;
}

推荐答案

我找到了解决这个问题的方法...我认为这与缺少的标题有关.

I found one solution to this problem... I think it has got something to do with the headers that were missing.

如果我替换

NSURLResponse *urlresponse = [[NSURLResponse alloc] initWithURL:[request URL] MIMEType:@"application/json" expectedContentLength:[data length] textEncodingName:@"UTF-8"];
NSCachedURLResponse *cachedResponse = [[NSCachedURLResponse alloc] initWithResponse:urlresponse data:data];

有

NSHTTPURLResponse *urlresponse = [[NSHTTPURLResponse alloc] initWithURL:request.URL statusCode:200 HTTPVersion:@"1.1" headerFields:nil];
NSCachedURLResponse *cachedResponse = [[NSCachedURLResponse alloc] initWithResponse:urlresponse data:data];

整个事情都有效.该答案还建议了请求的附加自定义标头.https://stackoverflow.com/a/15234850/274518

The whole thing works. This answer in addition suggested the additional custom header of the request. https://stackoverflow.com/a/15234850/274518

NSDictionary *headers = @{@"Access-Control-Allow-Origin" : @"*", @"Access-Control-Allow-Headers" : @"Content-Type"};
NSHTTPURLResponse *urlresponse = [[NSHTTPURLResponse alloc] initWithURL:request.URL statusCode:200 HTTPVersion:@"1.1" headerFields:headers];

就我而言，我不需要它.

In my case I did not needed it.

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