# Playing with HttpClient in .NET 4.8

Creating a new HttpClient instance for every request will exhaust the number of sockets available under heavy loads. This will result in SocketException errors.

Don't use **using** statements. Because HttpClient instances should be **long-lived**. Disposing them forcibly closes the underlying TCP connection that is supposed to be pooled. If we share a single instance of HttpClient then we can reduce the waste of sockets by reusing them. Don't use ;

**.Wait()**

**.Result**

**.GetAwaiter().GetResult()** to avoid blocking.

You create a single static instance of HttpClient. In console or desktop applications, you can expose this instance just about anywhere. In an [ASP.NET](http://ASP.NET) application, you can **create it in the Global.asax.cs** file.

If you have a manageable number of configurations, create an HttpClient instance for each one. You will be slightly less efficient than a single instance, but significantly more efficient than creating and disposing each time.

In this way, you can re-use the client instances as appropriate. Just set all the headers, base URLs, and ServicePointManager connection timeouts individually.

**Global.asax.cs**:

```csharp
using System;
using System.Net;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Web;
using System.Web.Optimization;
using System.Web.Routing;

namespace WebApplicationTestHttpClient
{
    public class Global : HttpApplication
    {
        internal static HttpClient httpClientInstance1;
        //internal static HttpClient httpClientInstance2;

        void Application_Start(object sender, EventArgs e)
        {
            // Code that runs on application startup
            RouteConfig.RegisterRoutes(RouteTable.Routes);
            BundleConfig.RegisterBundles(BundleTable.Bundles);

            // 1
            Uri baseUri1 = new Uri("https://api.domain1.com");
            httpClientInstance1 = new HttpClient();
            httpClientInstance1.BaseAddress = baseUri1;
            httpClientInstance1.DefaultRequestHeaders.Clear();
            httpClientInstance1.DefaultRequestHeaders.ConnectionClose = false;
            httpClientInstance1.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/xml"));
            ServicePointManager.FindServicePoint(baseUri1).ConnectionLeaseTimeout = 60 * 1000;

            // 2
            //Uri baseUri2 = new Uri("http://api.domain2.com"); // /json_api/
            //httpClientInstance2 = new HttpClient();
            //httpClientInstance2.BaseAddress = baseUri2;
            //httpClientInstance2.DefaultRequestHeaders.Clear();
            //httpClientInstance2.DefaultRequestHeaders.ConnectionClose = false;
            //httpClientInstance2.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/x-www-form-urlencoded"));
            //ServicePointManager.FindServicePoint(baseUri2).ConnectionLeaseTimeout = 60 * 1000;
        }
    }
}
```

**Basic Usage Example**:

```csharp
public async Task<string> Post1()
{
	StringBuilder parameter = new StringBuilder();
	parameter.Append("payload");

	var content = new StringContent(parameter.ToString(), Encoding.UTF8, "application/xml");
	var response = await Global.httpClientInstance1.PostAsync("/sms/send/xml", content);
	response.EnsureSuccessStatusCode();
	string result = await response.Content.ReadAsStringAsync();

	return result;
}
```

Reference :

[https://www.codeproject.com/Articles/1194406/Using-HttpClient-As-It-Was-Intended-Because-You-re](https://www.codeproject.com/Articles/1194406/Using-HttpClient-As-It-Was-Intended-Because-You-re)

[https://www.mytechramblings.com/posts/dotnet-httpclient-basic-usage-scenarios/](https://www.mytechramblings.com/posts/dotnet-httpclient-basic-usage-scenarios/)  
[https://www.aspnetmonsters.com/2016/08/2016-08-27-httpclientwrong/](https://www.aspnetmonsters.com/2016/08/2016-08-27-httpclientwrong/)

[https://stackoverflow.com/questions/18976042/httpclientfactory-create-vs-new-httpclient](https://stackoverflow.com/questions/18976042/httpclientfactory-create-vs-new-httpclient)

[https://softwareengineering.stackexchange.com/questions/330364/should-we-create-a-new-single-instance-of-httpclient-for-all-requests/370742#370742](https://softwareengineering.stackexchange.com/questions/330364/should-we-create-a-new-single-instance-of-httpclient-for-all-requests/370742#370742)