NSURLSession获取间歇性SSLHandshake失败(-9810)错误

Question

从安全墙后面的安全URL下载图像。类似的URLhttps://foo.com/bar.png

有时我会出现SSLHandshake错误。有时错误会发生一次，但有时错误是持续的，我无法下载文件。

DownloadImageApp[2914] <Warning>: CHALLENGE!!! (NSURLAuthenticationMethodServerTrust)
DownloadImageApp[2914] <Warning>:    server = foo.com
DownloadImageApp[2914] <Warning>: CFNetwork SSLHandshake failed (-9810)
DownloadImageApp[2914] <Warning>: CHALLENGE!!! (NSURLAuthenticationMethodServerTrust)
DownloadImageApp[2914] <Warning>:    server = foo.com
DownloadImageApp[2914] <Warning>: CHALLENGE!!! (NSURLAuthenticationMethodNTLM)
DownloadImageApp[2914] <Warning>:    NSURLAuthenticationMethodNTLM

我使用以下代码来处理挑战

- (void)URLSession:(NSURLSession *)session didReceiveChallenge:(NSURLAuthenticationChallenge *)challenge completionHandler:(void (^)(NSURLSessionAuthChallengeDisposition, NSURLCredential *))completionHandler {
NSLog(@"CHALLENGE!!! (%@)", challenge.protectionSpace.authenticationMethod);
if (challenge.error)
NSLog(@"  -- error: %@", challenge.error.description);
if (challenge.previousFailureCount > 0)
NSLog(@"  -- previous failure count = %d", challenge.previousFailureCount);
if (challenge.proposedCredential)
NSLog(@"  -- proposed credential user: %@", challenge.proposedCredential.user);
if ([challenge.protectionSpace.authenticationMethod isEqualToString:NSURLAuthenticationMethodServerTrust]) {
NSLog(@"   server = %@", challenge.protectionSpace.host);
completionHandler(NSURLSessionAuthChallengeUseCredential, [NSURLCredential credentialForTrust:challenge.protectionSpace.serverTrust]);
} else if ([challenge.protectionSpace.authenticationMethod isEqualToString:NSURLAuthenticationMethodNTLM]) {
NSLog(@"   NSURLAuthenticationMethodNTLM");
NSURLCredential *credential = [NSURLCredential credentialWithUser:@"username" password:@"passwordIsSecretShhh" persistence:NSURLCredentialPersistenceForSession];
completionHandler(NSURLSessionAuthChallengeUseCredential, credential);
} else {
NSLog(@"   ????");
}
}

即使它完全失败，无法加载，我仍然可以跳到Safari，输入URL并加载它。所以我正在寻找除了糟糕的网络问题或托管网络服务器的不稳定问题之外会导致这个问题的想法。

Answer 1

我终于解决了这个问题。这与我的代码无关。

问题是由服务器中安装的Trend SSL监控软件引起的。一旦软件被禁用，错误立即消失。

这不是一个很好的答案，但希望它能帮助其他人。