c# - How to make HTTP POST web request

itemprop="text">

Canonical
How can I make an HTTP
request and send some data using the POST
method?

I
can do GET request but have no idea how to make a
POST.

class="post-text" itemprop="text">

class="normal">Answer

There are
several ways to perform HTTP GET and
POST requests:

/>

Method A: HttpClient
(Preferred)

This is a wrapper around
HttpWebRequest. href="https://stackoverflow.com/questions/20530152/deciding-between-httpclient-and-webclient/27737601#27737601">Compare
with
WebClient.

Available
in: .NET Framework 4.5+, .NET Standard
1.1+, .NET Core 1.0+
.

Currently the preferred approach.
Asynchronous. Portable version for other platforms available via href="https://www.nuget.org/packages/Microsoft.Net.Http"
rel="noreferrer">NuGet.

using
            System.Net.Http;

Setup

It
is href="https://docs.microsoft.com/en-us/azure/architecture/antipatterns/improper-instantiation/"
rel="noreferrer">recommended to instantiate one
HttpClient for your application's lifetime and share
it.

private static readonly
            HttpClient client = new
            HttpClient();

See
href="https://docs.microsoft.com/en-us/dotnet/architecture/microservices/implement-resilient-applications/use-httpclientfactory-to-implement-resilient-http-requests#what-is-httpclientfactory"
rel="noreferrer">HttpClientFactory for a
Dependency Injection solution.

/>

• POST

  
  
  

  var
              values = new Dictionary
  {
  { "thing1", "hello"
              },
  { "thing2", "world" }
  };
  
  
  var
              content = new FormUrlEncodedContent(values);
  
  var response = await
              client.PostAsync("http://www.example.com/recepticle.aspx",
              content);
  
  var responseString = await
              response.Content.ReadAsStringAsync();
  




• GET

  
  
  

  var
              responseString = await
              client.GetStringAsync("http://www.example.com/recepticle.aspx");
  

/>

Method B: 3rd-Party
Libraries

href="https://github.com/restsharp/RestSharp"
rel="noreferrer">RestSharp

• POST

  
  
  
  

  
              var client = new RestClient("http://example.com");
   // client.Authenticator =
              new HttpBasicAuthenticator(username, password);
   var request = new
              RestRequest("resource/{id}");
   request.AddParameter("thing1", "Hello");
              
   request.AddParameter("thing2", "world"); 
  
              request.AddHeader("header", "value");
   request.AddFile("file",
              path);
   var response = client.Post(request);
   var content =
              response.Content; // raw content as string
  
   var response2 =
              client.Post(request);
   var name =
              response2.Data.Name;
  

href="https://flurl.dev/"
rel="noreferrer">Flurl.Http

Newer
library sporting a fluent API and testing helpers. HttpClient under the hood. Portable.
Available via rel="noreferrer">NuGet.

            using
            Flurl.Http;

/>

• POST

  
  
  

  var
              responseString = await "http://www.example.com/recepticle.aspx"
  
              .PostUrlEncodedAsync(new { thing1 = "hello", thing2 = "world" })
  
              .ReceiveString();
  
  




• GET

  
  
  

  var
              responseString = await "http://www.example.com/recepticle.aspx"
  
              .GetStringAsync();
  

/>

Method C: HttpWebRequest (Not
recommended for new work)

Available in:
.NET Framework 1.1+, .NET Standard
2.0+, .NET Core
1.0+

using
            System.Net;
using System.Text; // for class Encoding
using
            System.IO; // for
            StreamReader

/>

• POST

  
  
  

  var
              request =
              (HttpWebRequest)WebRequest.Create("http://www.example.com/recepticle.aspx");
  
  var
              postData = "thing1=" + Uri.EscapeDataString("hello");
   postData +=
              "&thing2=" + Uri.EscapeDataString("world");
  var data =
              Encoding.ASCII.GetBytes(postData);
  
  
  request.Method =
              "POST";
  request.ContentType =
              "application/x-www-form-urlencoded";
  request.ContentLength =
              data.Length;
  
  using (var stream =
              request.GetRequestStream())
  {
   stream.Write(data, 0,
              data.Length);
  }
  
  var response =
              (HttpWebResponse)request.GetResponse();
  
  
  var
              responseString = new
              StreamReader(response.GetResponseStream()).ReadToEnd();
  




• GET

  
  
  

  var
              request =
              (HttpWebRequest)WebRequest.Create("http://www.example.com/recepticle.aspx");
  
  var
              response = (HttpWebResponse)request.GetResponse();
  
  var
              responseString = new
              StreamReader(response.GetResponseStream()).ReadToEnd();
  
  

/>

Method D: WebClient (Not recommended for new
work)

This is a wrapper around
HttpWebRequest. href="https://stackoverflow.com/questions/20530152/deciding-between-httpclient-and-webclient/27737601#27737601">Compare
with
HttpClient.

Available
in: .NET Framework 1.1+, NET Standard
2.0+, .NET Core
2.0+

using
            System.Net;
using
            System.Collections.Specialized;

/>

• POST

  
  
  
  

  using
              (var client = new WebClient())
  {
   var values = new
              NameValueCollection();
   values["thing1"] = "hello";
  
              values["thing2"] = "world";
  
   var response =
              client.UploadValues("http://www.example.com/recepticle.aspx",
              values);
  
   var responseString =
              Encoding.Default.GetString(response);
  }
  
  




• GET

  
  
  

  using
              (var client = new WebClient())
  {
   var responseString =
              client.DownloadString("http://www.example.com/recepticle.aspx");
  }