Rest Api Https Reqest (The certificate authority is invalid or incorrect)

Juressic · January 2020

Hello,

I'm trying to get simple json data from my linux SSH remote server (UWP, Android) but it refuse to respond to my App.

But i'm confused why i can get the data when i send the request with my browser(with not secure warning) or through Postman(with Settings option: SSL certificate Off) ??

I'm wonder how could i resolve this, how can i avoid certificate authority and get the data (just like in Postman), and how shall i actually have to deal with SSL certification in my HTTPS reqeust. My server support OpenSSL.

MAIN SEGMENT OF MY CODE:

    HttpClient client = new HttpClient();
    var response = await client.GetStringAsync("https://" +  ServerApiLinkConnection);
    Debug.WriteLine(response);

ERROR:

    System.Net.Http.HttpRequestException: An error occurred while sending the request. ---> System.Exception: The text associated with this error code could not be found.

    The certificate authority is invalid or incorrect

       at System.Net.Http.HttpHandlerToFilter.SendAsync(HttpRequestMessage request, CancellationToken cancel)
       at System.Net.Http.HttpClientHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
       --- End of inner exception stack trace ---
       at System.Net.Http.HttpClientHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
       at System.Net.Http.HttpClient.FinishSendAsyncUnbuffered(Task`1 sendTask, HttpRequestMessage request, CancellationTokenSource cts, Boolean disposeCts)
       at System.Net.Http.HttpClient.GetStringAsyncCore(Task`1 getTask)

Juressic · January 2020

Half of the problem is solved! I've figured out how to avoid SSL certification.

        HttpClientHandler clientHandler = new HttpClientHandler();
                clientHandler.ServerCertificateCustomValidationCallback = (sender, cert, chain, sslPolicyErrors) => { return true; };
                HttpClient client = new HttpClient(clientHandler);
        var response = await client.GetStringAsync("http://...<link>");
                Debug.WriteLine("GET DATA RESPONSE = " + response);

Now i have to deal with certification itself. What should i do?

LandLu · January 2020

Now i have to deal with certification itself

This is not a Xamarin part issue. If you want to know how to build a ssl/tls certificate, we will easily find some approaches after searching:
https://www.entrustdatacard.com/blog/2019/march/how-to-build-an-ssl-tls-certificate
https://www.linode.com/docs/security/ssl/create-a-self-signed-tls-certificate/

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Rest Api Https Reqest (The certificate authority is invalid or incorrect)

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