如何将curl命令移植到RestSharp？ 如何排除故障？

Question

I have some working curl commands, to a web service, and now I want to move them to a C# program. I am using RestSharp, and trying with the simplest of the web service calls, but just keep getting a generic error message, and I am a bit stumped how to troubleshoot it.

Is there a way to see the headers, and exact URL, that is being sent, and the headers being received?

The curl example is basically this:

curl --user user:pw https://example.com/api/version

And my C# code is:

var client = new RestClient("https://example.com");
client.Authenticator = new HttpBasicAuthenticator("user", "pw");
var request = new RestRequest ("api/version");
var response = client.Execute(request);
Console.WriteLine (response.Content);   
Console.WriteLine (response.StatusCode);    
Console.WriteLine (response.ErrorMessage);  

This gives me:

RestSharp.RestRequest

0
Error getting response stream (Write: The authentication or decryption has failed.): SendFailure

I am using Mono, on Linux. Would that be related? But I could find a few (more advanced) questions with the mono tag on StackOverflow, so it should work. (?)

If it was actually a problem with the username/password, I would get a 403 status, instead of a zero status, I assume?

PS In case it matters, the rest of my script is:

using System;
using System.Net;
using RestSharp;

namespace webtest
{
    class MainClass
    {
        public static void Main (string[] args)
        {
        ...(above code)
        }
    }
}

Answer 1

Regarding troubleshooting

So far I can suggest:

• Try commenting out the Authenticator line to see if anything changes (in my case it did not)
• Try http://google.com
• Try https://google.com

That was enough for me to see that http URLs work, https URLs fail.

(If you need more troubleshooting, and are using https, the sender parameter shown below contains various fields about the request being sent to the remote server.)

Regarding porting curl commands

By default curl on linux uses the certificates it finds in /etc/ssl/certs . The blanket equivalent for Mono is to do mozroots --import --ask-remove , which will import all certificates (see Mono security FAQ ).

Another way to do it is by putting this at the very top of your program:

ServicePointManager.ServerCertificateValidationCallback +=
    (sender, certificate, chain, sslPolicyErrors) => {
    //Console.WriteLine(certificate.ToString());
    return true;
    };

The commented line can be used to report the certificate to the user, interactively get their approval, or to check the certificate fingerprint against the expected one. By simply returning true it means all certificates are trusted and unchecked.

Bonus: Cert checks

Here is one way to check for a specific certificate:

ServicePointManager.ServerCertificateValidationCallback +=
    (sender,certificate,chain,sslPolicyErrors) => {
    if(((System.Net.HttpWebRequest)sender).Host.EndsWith("google.com") ){
        if(certificate.GetCertHashString() == "83BD2426329B0B69892D227B27FD7FBFB08E3B5E"){
            return true;
        }
        Console.WriteLine("Uh-oh, google.com cert fingerprint ({0}) is unexpected. Cannot continue.",certificate.GetCertHashString());
        return false;
    }
Console.WriteLine("Unexpected SSL host, not continuing.");
return false;
}