I have an .Net Core 2.1 Web API running on our server. Now I have a .NET 4.0 application where I want to consume the webservice.
I managed to get Data from the api when i ran it locally on localhost. After deploying the api to the server and modifiyng the url in the application, it does not work.
When I call WebRequest.GetRepsonse() nothing happens, till it gets to timeout and throws an Exception with the timoeout message.
The Web API runs on the IIS and I already Enabled TLS 1.0, TLS 1.1, TLS 1.2 on the server.
When I make the POST request from Postman ist works fine. We are using a proxy for internet-connections but since both client and server are in the same network, I think it could not be the proxy settings. I also tried to set proxy settings but I still not getting it to work.
I'm now running out of ideas. Can anyone help?
Here is my code:
Client-App C#.NET 4.0:
var resultDt = new DataTable();
var url = "https://myServer:5100/api/Service/Execute";
var request = (HttpWebRequest)WebRequest.Create(url);
request.Credentials = CredentialCache.DefaultCredentials;
request.UseDefaultCredentials = true;
request.ContentType = "application/json";
request.Method = "POST";
ServicePointManager.SecurityProtocol = SecurityProtocolType.Ssl3 | SecurityProtocolType.Tls | (SecurityProtocolType)3072;
try
{
using (var streamWriter = new StreamWriter(request.GetRequestStream()))
{
string json = string.Format("{{\"CommandText\":\"{0}\"}}", query);
streamWriter.Write(json);
}
using(var response = (HttpWebResponse)request.GetResponse())
{
using (var reader = new StreamReader(response.GetResponseStream()))
{
var result = reader.ReadToEnd();
if (!string.IsNullOrEmpty(result))
{
var rows = JArray.Parse(result);
foreach (var row in rows.Children())
{
var columns = row.Children<JProperty>();
if (resultDt.Columns.Count == 0)
{
foreach (var column in columns)
{
resultDt.Columns.Add(new DataColumn()
{
ColumnName = column.Name,
DataType = typeof(string)
});
}
}
var newRow = resultDt.NewRow();
foreach (var column in columns)
{
newRow[column.Name] = column.Value;
}
resultDt.Rows.Add(newRow);
}
}
}
}
}
catch (Exception ex)
{
Logger.Instance().Fatal(ex.Message, ex);
}
return resultDt;
Note:
When I use HTTPS, the programm hangs in request.GetRequestStream().
When I use HTTP, the programm hangs in request.GetResponse().
It's very strange
I finally found the solution: I just needed to set the proxy to an empty instance:
request.Proxy = new WebProxy();
I found that in wireshark, the request from the .NET 4.0 app was going to the proxy port while postman was using the correct port.
Thanks anyway
Related
In our Outlook COM add-in, we're making an API call to our server using the .NET HTTPWebRequest method. One of our customers is running into a System.Net.WebException with the message The remote name could not be resolved: 'mydomain.com' and WebExceptionStatus.NameResolutionFailure as the status. All the users from this particular customer's company are using outlook/the addin from behind a VPN so we are piggy-backing proxy configuration from IE in order to make the request.
Our API calls work for a period of time but then it randomly disconnects and then does not allow future requests to go through either. Once the users close and restart Outlook though, it seems to work just fine again without changing any network configuration or reconnecting to wifi etc.
Other posts like this suggested retrying with a sleep in between. We have added a retry mechanism with 3 attempts, each with a sleep in between but that has not resolved the intermitent issue.
Our domain is hooked up to an AWS Classic Load Balancer so mydomain.com actually resolves a CNAME record to an AWS static domain, pointing to the ELB. I'm not sure if that would have any impact on the request or routing it.
The strange part is we also have a web browser component that loads a web page in a sidebar from the exact same domain as the API calls. It works perfectly and loads a URL from the same domain. The users can also load the URL in their browsers without any issues. It just appears that the HTTPWebRequest is running into the domain resolution issue. We've checked that it's not just a matter of a weak wifi signal. Since they are able to use IE which has the same proxy config to access the site just fine, I don't think it's that.
We're at a loss for how to gracefully recover and have the request try again. I've looked into suggestions from this answer and this other answer, we'll be trying those next. Unfortunately, we are not able to make the requests use direct IP addresses as some of the other answers suggest. That also eliminates the ability to edit the hosts file to point straight to it. The reason is we can't assign a static IP on a classic ELB.
We're considering trying to set the host to use the CNAME record from AWS directly but this is going to cause SSL errors as it doesn't have a valid cert for the CNAME entry. Is there a way to get around that by masking it via a header, similar to the IP approach?
Feel free to ask for more information, I will do my best to provide it.
Any suggestions on what to try / troubleshoot are welcome!
Update: We’re targeting .NET v4.5
Here's the code
var result = string.Empty;
bool retrying = false;
int retries = 0;
HttpWebRequest webRequest = null;
try
{
ServicePointManager.ServerCertificateValidationCallback =
CertificateCheck;
ServicePointManager.MaxServicePoints = 4;
ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;
retry:
webRequest = (HttpWebRequest)WebRequest.Create(uriParam);
webRequest.Timeout = 120000;
webRequest.Method = "POST";
webRequest.ContentType = "application/x-www-form-urlencoded";
webRequest.Accept = acceptParam;
webRequest.Headers.Add("Cookie", cookieParam);
webRequest.UseDefaultCredentials = true;
webRequest.Proxy = null;
webRequest.KeepAlive = true; //default
webRequest.ServicePoint.ConnectionLeaseTimeout = webRequest.Timeout;
webRequest.ServicePoint.MaxIdleTime = webRequest.Timeout;
webRequest.ContentLength = dataParam.Length;
using (var reqStream = webRequest.GetRequestStream())
{
reqStream.Write(dataParam, 0, dataParam.Length);
reqStream.Flush();
reqStream.Close();
}
try
{
using (WebResponse webResponse = webRequest.GetResponse())
{
using (var responseStream = webResponse.GetResponseStream())
{
if (responseStream != null)
{
using (var reader = new StreamReader(responseStream))
{
result = reader.ReadToEnd();
}
}
}
webResponse.Close();
}
}
catch (WebException)
{
if (retrying && retries == 3)
{
//don't retry any more
return string.Empty;
}
retrying = true;
retries++;
webRequest.Abort();
System.Threading.Thread.Sleep(2000);
goto retry;
}
}
catch (Exception ex)
{
Log.Error(ex);
result = string.Empty;
}
finally
{
webRequest?.Abort();
}
return result;
I've created a ASP.Net Core 2.1 web application which gathers data from two sources. One is a SQL-database which supplies data via Entity Framework to my application. This one works fine. The other source is a REST API. I'm having troubles connecting to this.
I'm calling this Task which should return a user via his/hers e-mail address:
public async Task<PersonsModel> ReturnPersonByEmail(string email)
{
const string apiKey = "xxx";
using (var client = new HttpClient())
{
client.BaseAddress = new Uri("https://xx.xxx.xxxx.xx:xxx/xxxx/xxx/xx/xx/person/?email={email}");
client.DefaultRequestHeaders.Accept.Clear();
client.DefaultRequestHeaders.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("x-api-key", "123456");
var url = new Uri(client.BaseAddress.ToString());
string json = "";
try
{
ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;
var response = await client.GetAsync(url);
using (var content = response.Content)
{
json = await content.ReadAsStringAsync();
}
}
catch (Exception e)
{
var exception = e;
}
return JsonConvert.DeserializeObject<PersonsModel>(json);
}
}
}
When I try calling it via Postman client.GetAsync(url) always returns an exception:
Message = "The remote certificate is invalid according to the validation procedure."
Message = "The SSL connection could not be established, see inner exception."
I tried adding the following codesegment to launchSettings.json(as per a reply to a similar question posted here: HttpClient client.GetAsync works in full .Net framework but not in .Net core 2.1? ) "DOTNET_SYSTEM_NET_HTTP_USESOCKETSHTTPHANDLER": "0" and then I get another error:
Message = "Error 12175 calling WINHTTP_CALLBACK_STATUS_REQUEST_ERROR, 'A security error has occurred'."
If you have any idea on what might cause this problem I would be very grateful for any help. Thanks!
I want check the http traffic with Fiddler, but no any http traffic captured, my testing codes:
private static void ByRestSharp()
{
var restClient = new RestClient("https://jsonplaceholder.typicode.com");
var request = new RestRequest("posts", Method.GET);
var response = restClient.Get<List<Post>>(request);
Console.WriteLine("{0} posts return by RestSharp.", response.Data.Count);
}
But after I changed to use HttpClient, Fiddler can capture the http traffic, sample codes:
private static void ByHttpClient()
{
var httpClient = new HttpClient();
using (var req = new HttpRequestMessage(HttpMethod.Get, "https://jsonplaceholder.typicode.com/posts"))
using (var resp = httpClient.SendAsync(req).Result)
{
var json = resp.Content.ReadAsStringAsync().Result;
var users = SimpleJson.SimpleJson.DeserializeObject<List<Post>>(json);
Console.WriteLine("{0} posts return by HttpClient.", users.Count);
}
}
Is this a issue of RestSharp or Fiddler?
RestSharp supported system proxy until we moved to .NET Standard. Then, we got issues with proxy on .NET Core and then using the system proxy was removed entirely. We have an issue opened on Github and you can check the progress there.
However, explicitly setting the proxy should work for full .NET Framework, check this issue.
Code from the issue, which is confirmed to be working:
var client = new RestClient("http://www.google.com");
client.Proxy = new WebProxy("127.0.0.1", 8888);
var req = new RestRequest("/", Method.GET);
var resp = client.Execute(req);
Update 2018-05-31: RestSharp 106.3 is using the default proxy on .NET Core also, automatically. Tested with Fiddler.
Update 2022-02-23: RestSharp 107 has the Proxy property moved to RestClientOptions:
var options = new RestClientOptions("http://www.google.com") {
Proxy = new WebProxy("127.0.0.1", 8888)
};
var client = new RestClient(options);
var req = new RestRequest("/");
var resp = await client.ExecuteAsync(req);
I need to communicate with a third party which has a .asmx web service. This web service is using https. I have the required certificate (.pfx).
When first trying to add this service using Add Service Reference in Visual Studio, I got an error. I got passed this error by importing the certificate into the Personal store. After I did that, I tried to add the Service Reference again and it works. So now I can create an instance of the web service. Nice.
But now I want to invoke the service. And when I do that I get this error:
302 Notification: Digital Certificate Missing
So how can I tell my service to use the right certificate?
I finally managed to fix my problem as follows:
var service = new Service1SoapClient();
service.ClientCredentials.ClientCertificate.SetCertificate(StoreLocation.CurrentUser, StoreName.TrustedPublisher, X509FindType.FindByIssuerName, "name_of_issuer");
((BasicHttpBinding)service.Endpoint.Binding).Security.Mode = BasicHttpSecurityMode.Transport;
((BasicHttpBinding)service.Endpoint.Binding).Security.Transport.ClientCredentialType = HttpClientCredentialType.Certificate;
Please use Certificate.pfx and install it with password.
Try adding this before getting the request stream:
ServicePointManager.Expect100Continue = true;
ServicePointManager.SecurityProtocol = SecurityProtocolType.Ssl3;
request.ProtocolVersion = HttpVersion.Version10;
request.ClientCertificates.Add(new X509Certificate2("YourPfxFile(full path).pfx", "password for your pfx file");
Depending on your security requirements and environment, you may need to use a different SecurityProrocolType value.
I was also facing "The request was aborted: Could not create SSL/TLS secure channel" while requesting a web service.
Fixed issue with below code, hope this will help someone and save time.
HttpWebRequest web_request = (HttpWebRequest)WebRequest.Create("https://yourservices/test.asmx");
web_request.ContentType = "text/xml;charset=\"utf-8\"";
ServicePointManager.Expect100Continue = true;
ServicePointManager.SecurityProtocol = SecurityProtocolType.Ssl3;
web_request.ProtocolVersion = HttpVersion.Version10;
X509Certificate2Collection certificates = new X509Certificate2Collection();
certificates.Import(certName, password, X509KeyStorageFlags.MachineKeySet | X509KeyStorageFlags.PersistKeySet);
web_request.ClientCertificates = certificates;
web_request.Accept = "text/xml";
web_request.Method = "POST";
using (Stream stm = web_request.GetRequestStream())
{
using (StreamWriter stmw = new StreamWriter(stm))
{
stmw.Write(soap);
}
}
WebResponse web_response = null;
StreamReader reader = null;
try
{
web_response = web_request.GetResponse();
Stream responseStream = web_response.GetResponseStream();
XmlDocument xml = new XmlDocument();
reader = new StreamReader(responseStream);
xml.LoadXml(reader.ReadToEnd());
}
catch (Exception webExp) {
string exMessage = webExp.Message;
}
I am attempting to access an api which they had me install a local cert via mmc I have done so on my local windows 7 machine so I could test out the service. I'm using a simple winforms app to test. I'm assuming this is a self signed cert server side so I'm hoping to bypass the exception for dev purposes.
HttpWebRequest req = (HttpWebRequest)WebRequest.Create(postData);
req.Method = "POST";
req.ContentType = "application/x-www-form-uriencoded";
req.KeepAlive = true;
req.AllowAutoRedirect = false;
X509Store store = new X509Store(StoreName.Root,StoreLocation.LocalMachine);
store.Open(OpenFlags.ReadOnly);
X509Certificate cert = new X509Certificate();
for (int i = 0; i < store.Certificates.Count; i++)
{
if (store.Certificates[i].SerialNumber == "XXXX")
{
cert = store.Certificates[i];
}
}
req.ClientCertificates.Add(cert);
req.PreAuthenticate = true;
try
{
using (WebResponse resp = req.GetResponse())
{
Stream responseStream = resp.GetResponseStream();
using (StreamReader responseStreamReader = new
StreamReader(responseStream, new ASCIIEncoding()))
{
respString = responseStreamReader.ReadToEnd();
}
}
}
catch (Exception ex)
{
// there is a problem
}
I'm getting the following exception in the try catch:
The underlying connection was closed: Could not establish trust relationship for the SSL/TLS secure channel.
I do have a certificate object in the variable "cert"
When I go to the api url in my browser I get the caution warning but then can proceed and get data.
I have tried the other fixes recommended on stackoverflow such as suppressing the exception.
ServicePointManager.ServerCertificateValidationCallback = new
RemoteCertificateValidationCallback
(
delegate { return true; }
);
I realize there are quite a few of these questions similar to this and trust me I have read through them all. Thanks for any suggestions they are appreciated.
Hey the following finally fixed it for me. I went to the api server address in my browser and exported their certificate to a file on my desktop. I then opened mmc and installed the certificate like in the following link:
http://support.esri.com/en/knowledgebase/techarticles/detail/38408
After I installed I had no issues calling the webservice and the exception went away.