ios - 从 NSURLConnectionDataDelegate 设置内容时 UIWebView 重新加载 baseUrl

Question

我正在尝试创建一个基于 UIWebView 的应用程序。其主要目的是为一些使用 NTLM 或 Basic 身份验证的网站提供身份验证，而无需用户在更改密码时为每个网站输入用户名/密码(网站共享用户/密码数据库)。

为了做到这一点，我“覆盖”了 UIWebView 的页面数据加载，这样我就可以拦截 HTTP 响应代码并在每次我访问时询问用户密码检测到 401 Unauthorized 响应。

我设置了一个 NSURLConnectionDataDelegate 来处理这样的请求:

@interface LPURLConnectionDelegate : NSObject<NSURLConnectionDataDelegate>
{
    UIWebView* _webView;
    NSMutableURLRequest* _request;
    NSURLConnection* _connection;
    NSString* _encoding;
    NSString* _mimeType;
    NSMutableData* _data;
}

- (LPURLConnectionDelegate*) initWithWebView:(UIWebView *)webView;

- (void) loadPageWithRequest: (NSURLRequest*)request;

- (void)connection:(NSURLConnection *)connection willSendRequestForAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge;
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error;
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response;
- (BOOL)connectionShouldUseCredentialStorage:(NSURLConnection *)connection;
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data;
- (void)connectionDidFinishLoading:(NSURLConnection *)connection;

@end

@implementation LPURLConnectionDelegate
- (void) loadPageWithRequest: (NSURLRequest*)request
{
    _request = [request mutableCopy];
    if(!_data)
    {
        _data = [NSMutableData dataWithCapacity:0];
        [_data retain];
    }
    [_data setLength:0];
    if(_connection)
    {
        [_connection cancel];
        [_connection release];
        _connection = nil;
    }
    _connection = [[NSURLConnection alloc] initWithRequest:_request delegate:self startImmediately:YES];
}

- (void)connection:(NSURLConnection *)connection willSendRequestForAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge
{
    LPAppDelegate* delegate = [LPAppDelegate getInstance];
    NSURLCredential* credential = [NSURLCredential credentialWithUser:[delegate getUsername] password:[delegate getPassword] persistence:NSURLCredentialPersistenceForSession];
    [[challenge sender] useCredential:credential forAuthenticationChallenge:challenge];
}

- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
    //handle connection failed
}

- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
    NSLog(@"Connection did receive response");
    NSHTTPURLResponse* httpResponse = (NSHTTPURLResponse*)response;
    _mimeType = [httpResponse MIMEType];
    _encoding = [httpResponse textEncodingName];
    //handle status - if the status is 401, the connection is canceled and the user is asked for his new password
}

- (BOOL)connectionShouldUseCredentialStorage:(NSURLConnection *)connection
{
    return YES;
}

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
    [_data appendData:data];
}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{    
    [_webView loadData:_data MIMEType:_mimeType textEncodingName:_encoding baseURL:[_request URL]];
}

@end

我的 UIWebViewDelegate 看起来像这样:

@interface LPWebViewDelegate : NSObject<UIWebViewDelegate>

- (void)webViewDidStartLoad:(UIWebView *)webView;
- (void)webViewDidFinishLoad:(UIWebView *)webView;
- (void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error;
- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType;

@end


@implementation LPWebViewDelegate

- (void) webViewDidStartLoad:(UIWebView *)webView
{
}

- (void) webViewDidFinishLoad:(UIWebView *)webView
{
    //handle success
}

- (BOOL) webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType
{
     LPURLConnectionDelegate* connectionDelegate = [[LPURLConnectionDelegate alloc] initWithWebView:webView];
     [connectionDelegate loadPageWithRequest:request];
     return NO;
}

- (void) webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error
{
    //handle fail
}

@end

基本上，我要做的是告诉 UIWebView 不要自行加载任何页面，让我处理加载页面的请求。当请求完成并且用户通过身份验证时，我尝试使用 UIWebView::loadData:MIMEType:textEncodingName:baseUrl 方法设置数据。

这里的问题是，在从 NSURLConnectionDataDelegate 设置 UIWebView 的数据后，UIWebView 重新加载设置为 的页面baseURL(至少在模拟器中 - 我还没有在实际设备上尝试过代码)。

有谁知道一种方法可以将数据设置到 UIWebView 而不会重新加载页面 (*)？

*) 我知道我可以让 UIWebView 在我让 NSURLConnection 检查身份验证(或并行)后加载页面，但我尽量避免为每个页面请求两次页眉。

注意:代码不完整，我已经提取了我认为与此问题最相关的部分。

Answer 1

实现NSURLProtocol类(class)。它本质上是一个抽象类，允许子类定义HTTP schemes的URL加载行为

查看本教程 here