Develop Reference

"The underlying connection was closed: An unexpected error occurred on a send.". Postman goes OK with same headers

Scenario
Win10 x64
VS2013
I'm trying to make a WebRequest, but I'm getting the following error:
The underlying connection was closed: An unexpected error occurred on a send.
Digging into the inner exception, I got:
"Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host."
The code which does the request is the following:
private static Hashtable exec (String method, String uri, Object data, String contentType) {
Hashtable response;
HttpWebRequest request = (HttpWebRequest)WebRequest.Create (API_BASE_URL + uri);
request.UserAgent = "MercadoPago .NET SDK v"+MP.version; //version resolves to 0.3.4
request.Accept = MIME_JSON; // application/json
request.Method = method; //GET
request.ContentType = contentType; //application/json
setData (request, data, contentType); //setData in this case does nothing.
String responseBody = null;
try {
HttpWebResponse apiResult = (HttpWebResponse)request.GetResponse (); //Error throws here
responseBody = new StreamReader (apiResult.GetResponseStream ()).ReadToEnd ();
response = new Hashtable();
response["status"] = (int) apiResult.StatusCode;
response["response"] = JSON.JsonDecode(responseBody);
} catch (WebException e) {
Console.WriteLine (e.Message);
}
}
What i've already done:
Made the request via Console Application and MVC Application controller. Both throws the same exception
Called the API via Postman with the exact same headers, which brings me the content correctly.
Those requests were working okay via c# about 4 days ago and I suddenly started having issues, but considering the fact that it responds okay for Postman, I can't figure out where's the problem.
Here's Postman's response
EDIT: Did both requests with Fiddler listening. The result for Postman shows a direct request to the API with HTTPS. When trying with my ConsoleApplication, it shows a HTTP request, which makes a tunnel to the API endpoint, port 443.
The TextView from Fiddler for the tunnel request says the following:
I noticed the "time" field which refers to a very old date, but i don't know what does it mean.

It is kind of bad practice to enable Tls12 like this-
ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;
In future, if you'd need to use higher version of TLS, you'll have to update your code.
If you are using an older version of .NET, you can simply switch it higher version in which Tls12 is enabled by default.
For example, this simple change in your web.config will enable Tls12 automatically-
<httpRuntime targetFramework="4.6.1"/>

You can try the code below:
string url = ""; // url of the endpoint
WebClient client = new WebClient();
ServicePointManager.Expect100Continue = true;
ServicePointManager.SecurityProtocol = SecurityProtocolType.Ssl3;
client.Encoding = Encoding.UTF8;
client.Headers.Add("content-type", "application/json"); // same as other parameters in the header
var data = client.DownloadString(url);

Figured it out. I needed to include the use of TLS1.2.
ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;

(As a reference for others who have the same issue)this also might be the result of a Double Hop issue , where you should pass the credited user along(in the pool) to the passing server or from one Environment to the other , otherwise the user is set to "ANONYMOUS/USER" and you will get a "An existing connection was forcibly closed by the remote host." Error

i found same error, just mention
request.UserAgent = "anything u want";

Using one legged OAuth1 in C#, gets error: (401) Unauthorized

I am using an one legged OAuth1 web service! which means I don't need to get a token to get my result just consumer key and secret is enough.I have used many different APIs and got the same result every time,I don't get what I'm doing wrong!
here is the latest API I've used:
https://github.com/rhargreaves/oauth-dotnetcore
the OAuth classes are pretty much straight forward,I've used those and made my request this way:
OAuthRequest client = OAuthRequest.ForRequestToken("key", "secret");
client.RequestUrl = "http://some site/?q=api/sbu_rest/user_books_returned/username";
// For HTTP header authorization
string auth = client.GetAuthorizationHeader();
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(client.RequestUrl);
request.Headers.Add("Authorization", auth);
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
but I get the error:
The remote server returned an error: (401) Unauthorized.
It's worth to mention that I have checked my URL ,key and secret in postman and they work fine(I'll get the result I want which is a list of books!)
PS: the signature method is HMAC-SHA1

Consuming REST Webservice. API Key Authentication

I have little problem that I have been trying to solve for some time. I want to connect to a REST web service and I have the API key for that web service that I want to consume. I have tried the service in the Google REST console and it works fine.
But when I try to build a c# .net project for it I dont know how to set the api key for the authentication. I took this code from other site:
string url = "http://Demo.company.com/Data/Values/1029/CarPart/id/"
HttpWebRequest GETRequest = (HttpWebRequest)WebRequest.Create(url);
GETRequest.Method = "GET";
Console.WriteLine("Sending GET Request");
HttpWebResponse GETResponse = (HttpWebResponse)GETRequest.GetResponse();
Stream GETResponseStream = GETResponse.GetResponseStream();
StreamReader sr = new StreamReader(GETResponseStream);
Console.WriteLine("Response from Server");
Console.WriteLine(sr.ReadToEnd());
How can I authenticate this service with my Api key: asdf1234. I need to add it to my header but how? Can you show me some code example?
Cheers
Thor

You should be able to do something like:
HttpWebRequest GETRequest = (HttpWebRequest)WebRequest.Create(url);
GETRequest.Method = "GET";
GETRequest.Headers.Add("api-key", "asdf1234");
Where "api-key" is the name of the header you want to set.

Grab the contents of a Drupal website that is secured with a login form

I would like to grab some content from a website that is made with Drupal.
The challenge here is that i need to login on this site before i can access the page i want to scrape. Is there a way to automate this login process in my C# code, so i can grab the secure content?

To access the secured content, you'll need to store and send cookies with every request to your server, starting with the request that sends your log in info and then saving the session cookie that the server gives you (which is your proof that you are who you say you are).
You can use the System.Windows.Forms.WebBrowser for a less control but out-of-the-box solution that will handle cookies.
My preferred method is to use System.Net.HttpWebRequest to send and receive all web data and then use the HtmlAgilityPack to parse the returned data into a Document Object Model (DOM) which can be easily read from.
The trick to getting System.Net.HttpWebRequest to work is that you must create a long-lived System.Net.CookieContainer that will keep track of your log in info (and other things the server expects you to keep track of). The good news is that the HttpWebRequest will take care of all of this for you if you provide the container.
You need a new HttpWebRequest for each call you make, so you must sets their .CookieContainer to the same object every time. Here is an example:
UNTESTED
using System.Net;
public void TestConnect()
{
CookieContainer cookieJar = new CookieContainer();
HttpWebRequest request = (HttpWebRequest)WebRequest.Create("http://www.mysite.com/login.htm");
request.CookieContainer = cookieJar;
HttpWebResponse response = (HttpWebResponse) request.GetResponse();
// do page parsing and request setting here
request = (HttpWebRequest)WebRequest.Create("http://www.mysite.com/submit_login.htm");
// add specific page parameters here
request.CookeContainer = cookieJar;
response = (HttpWebResponse) request.GetResponse();
request = (HttpWebRequest)WebRequest.Create("http://www.mysite.com/secured_page.htm");
request.CookeContainer = cookieJar;
// this will now work since you have saved your authentication cookies in 'cookieJar'
response = (HttpWebResponse) request.GetResponse();
}
http://msdn.microsoft.com/en-us/library/system.windows.forms.webbrowser.aspx
HttpWebRequest Class
http://msdn.microsoft.com/en-us/library/system.net.httpwebrequest.cookiecontainer.aspx

You'll have to use the Services module to do that. Also check out this link for a bit of explanation.

HttpWebRequest with GET: 401 unauthorized

I found some problem with httpWebRequest, I've read all the same issues on other forums, but answers don't seem to work. My code:
HttpWebRequest wr = (HttpWebRequest)WebRequest.Create(url);
HttpWebResponse resp;
wr.ContentType = "text/html; charset=UTF-8";
wr.Method = "GET";
wr.Credentials = new NetworkCredential("user", "password");
resp = (HttpWebResponse)wr.GetResponse();
The remote server returned an error: (401) Unauthorized.
Response says there's no auth token in cookies. I can receieve this token using my auth request with POST method. I even tried to put it to CookieContainer by "new Cookie ("authToken",token_value)". But the result is the same - error 401. Does anybody know the solution?
Thanx.
I use Zimbra web server, have an access to control it. .NET 4.0. My url is the path to .eml file I need to download. To specify the file I need to add some GET parameters: id and part. So the whole address looks like http://someserver.info/service/content/get?id=1&part=1

(Answered in the comments and question edits by OP. Moved here. See Question with no answers, but issue solved in the comments (or extended in chat) )
The OP wrote:
The authorization token in Zimbra called ZM_AUTH_TOKEN so you need to put your authtoken in cookies like this:
wr.CookieContainer = new CookieContainer();
wr.CookieContainer.Add(new Uri(url), new Cookie("ZM_AUTH_TOKEN", rc.AuthToken));
You don't need to put the auth headers then, the request will work