HttpClient

Summary

A HttpClient class represents an abstraction over HTTP. It's a modern and recommended way to make HTTP requests in .NET applications, offering better performance, flexibility, and control compared to older methods. It supports asynchronous operations for non-blocking network calls.

Remarks

It is recommended that you instantiate a single HttpClient object and reuse it throughout the life of an application. Creating an HttpClient object is also relatively expensive and reusing an instance will benefit performance. See the remarks for HttpClient.Create for more details.

The HttpClient class supports the following features:

• Asynchronous operations (async/await) for non-blocking requests.
• Request and response message encapsulation via HttpRequestMessage and HttpResponseMessage.
• Customizable request headers and content.
• Support for various HTTP methods (GET, POST, PUT, DELETE, etc.).
• Connection pooling and management for efficiency.
• Cancellation tokens for aborting ongoing requests.

Constructors

• public HttpClient()
  Initializes a new instance of the HttpClient class.
• public HttpClient(HttpMessageHandler handler)
  Initializes a new instance of the HttpClient class with a specific HttpMessageHandler.
• public HttpClient(HttpMessageHandler handler, bool disposeHandler)
  Initializes a new instance of the HttpClient class with a specific HttpMessageHandler and a value indicating whether the handler should be disposed.

Methods

• public Task GetAsync(string requestUri)
  Send a GET request to the specified Uri as an asynchronous operation.
  Parameters

  Returns

  Example

  Parameters

  • string requestUri: The Uri to request; this can be an absolute or relative Uri.

  Returns

  The task object representing the asynchronous operation.

  The Result property of the task object contains a HttpResponseMessage describing the response to the request.

  Example

  
  using System;
  using System.Net.Http;
  using System.Threading.Tasks;
  
  public class Example
  {
      public static async Task Main(string[] args)
      {
          using (HttpClient client = new HttpClient())
          {
              try
              {
                  HttpResponseMessage response = await client.GetAsync("https://jsonplaceholder.typicode.com/todos/1");
                  response.EnsureSuccessStatusCode(); // Throw if HTTP status is 4xx or 5xx
                  string responseBody = await response.Content.ReadAsStringAsync();
                  Console.WriteLine(responseBody);
              }
              catch (HttpRequestException e)
              {
                  Console.WriteLine($"\nException Caught!");
                  Console.WriteLine($"Message :{e.Message} ");
              }
          }
      }
  }
                              

• public Task PostAsync(string requestUri, HttpContent content)
  Send a POST request to the specified Uri as an asynchronous operation.
  Parameters

  Returns

  Parameters

  • string requestUri: The Uri to send the POST request to.
  • HttpContent content: The HTTP content to send with the request.

  Returns

  The task object representing the asynchronous operation. The Result property of the task object contains a HttpResponseMessage.

• public async Task GetStringAsync(string requestUri)
  Send a GET request to the specified Uri and return the response body as a string as an asynchronous operation.
  Parameters

  Returns

  Parameters

  • string requestUri: The Uri to request.

  Returns

  The task object representing the asynchronous operation. The Result property of the task object contains the response body as a string.

• public void Dispose()
  Releases the unmanaged resources that are used by the current instance of the HttpClient class and optionally releases the managed resources.

Properties

• public HttpCompletionOption CompletionOption { get; set; }
  Gets or sets the way to complete an asynchronous operation.
• public HttpHeaders DefaultRequestHeaders { get; }
  Gets or sets the HTTP headers sent with every request.
• public Uri BaseAddress { get; set; }
  Gets or sets the base address of Uniform Resource Identifiers (URIs) for requests made by this instance.

See Also

• HttpResponseMessage
• HttpRequestMessage
• HttpClientHandler
• System.Net.Http