ATS设置

按照惯例写一个UIWebView，用来加载网页：

_webView = [[UIWebView alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)];
_webView.delegate = self;
[self.view addSubview:_webView];
NSURL *url = [NSURL URLWithString:@"https://github.com/"];
_request = [NSURLRequest requestWithURL:url];
[_webView loadRequest:_request];

run一下看看加载出来了吗？如果发现屏幕一片白并没有出现网页内容，不要惊讶，看看你的控制台是不是报出以下错误：

NSURLSession/NSURLConnection HTTP load failed (kCFStreamErrorDomainSSL, -9802)

这个怎么解决呢？没错ATS设置：去plist文件里添加一项App Transport Security Settings，它是个字典类型，给它增加一对键值，键：Allow Arbitrary Loads ，值设为YES。

以上，搞定ATS设置，网页成功加载了：

如果你的网页是self signed website，那么你的屏幕应该还是一片白，并且控制台又报错：

NSURLSession/NSURLConnection HTTP load failed (kCFStreamErrorDomainSSL, -9813)

注意：这两次错误并不是一样的,后面数字代码不同
（并不太清楚这个码代表的意思，有知道的朋友请留言告知，感谢。）

NSURLConnection

使用webview加载自签名https站点的时候，必须在请求的时候将该站点设置为安全的，才能继续访问。所以我们需要在webview开始加载网页的时候首先判断判断该站点是不是https站点，如果是的话，先让他暂停加载，用NSURLConnection 来访问改站点，然后再身份验证的时候，将该站点置为可信任站点。然后在用webview重新加载请求。

直接上代码：

#pragma mark - UIWebViewDelegate

// Note: This method is particularly important. As the server is using a self signed certificate,
// we cannot use just UIWebView - as it doesn't allow for using self-certs. Instead, we stop the
// request in this method below, create an NSURLConnection (which can allow self-certs via the delegate methods
// which UIWebView does not have), authenticate using NSURLConnection, then use another UIWebView to complete
// the loading and viewing of the page. See connection:didReceiveAuthenticationChallenge to see how this works.
- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType;
{
    NSLog(@"Did start loading: %@ auth:%d", [[request URL] absoluteString], _authenticated);

    if (!_authenticated) {

        _authenticated = NO;

        _urlConnection = [[NSURLConnection alloc] initWithRequest:_request delegate:self];

        [_urlConnection start];

        return NO;
    }
    return YES;
}

#pragma mark - NURLConnection delegate

- (void)connection:(NSURLConnection *)connection didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge;
{
    NSLog(@"WebController Got auth challange via NSURLConnection");

    if ([challenge previousFailureCount] == 0)
    {
        _authenticated = YES;

        NSURLCredential *credential = [NSURLCredential credentialForTrust:challenge.protectionSpace.serverTrust];

        [challenge.sender useCredential:credential forAuthenticationChallenge:challenge];

    } else
    {
        [[challenge sender] cancelAuthenticationChallenge:challenge];
    }
}

// We use this method is to accept an untrusted site which unfortunately we need to do, as our PVM servers are self signed.
- (BOOL)connection:(NSURLConnection *)connection canAuthenticateAgainstProtectionSpace:(NSURLProtectionSpace *)protectionSpace
{
    return [protectionSpace.authenticationMethod isEqualToString:NSURLAuthenticationMethodServerTrust];
}

#pragma mark - NSURLConnectionDataDelegate

- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response;
{
    NSLog(@"WebController received response via NSURLConnection");

    // remake a webview call now that authentication has passed ok.
    _authenticated = YES;
    [_web loadRequest:_request];

    // Cancel the URL connection otherwise we double up (webview + url connection, same url = no good!)
    [_urlConnection cancel];
}

以上设置，可成功加载自签名网页。

但是，虽然加载成功，但是控制台还是报了以下错误：

NSURLSession/NSURLConnection HTTP load failed (kCFStreamErrorDomainSSL, -9843)

最后

推荐参考链接:
stackoverflow Q1
stackoverflow Q2