HttpClient Class
Provides a base class for sending HTTP requests and receiving HTTP responses from a resource identified by a URI.
Namespace: System.Net.Http
Assembly: System.Net.Http (in System.Net.Http.dll)
The HttpClient type exposes the following members.
| Name | Description | |
|---|---|---|
.gif?cs-save-lang=1&cs-lang=fsharp "Public method") .png?cs-save-lang=1&cs-lang=fsharp "Supported in .NET for Windows Store apps") | HttpClient() | Initializes a new instance of the HttpClient class. |
| HttpClient(HttpMessageHandler) | Initializes a new instance of the HttpClient class with a specific handler. |
| HttpClient(HttpMessageHandler, Boolean) | Initializes a new instance of the HttpClient class with a specific handler. |
| Name | Description | |
|---|---|---|
.gif?cs-save-lang=1&cs-lang=fsharp "Public property") | BaseAddress | Gets or sets the base address of Uniform Resource Identifier (URI) of the Internet resource used when sending requests. |
| DefaultRequestHeaders | Gets the headers which should be sent with each request. |
| MaxResponseContentBufferSize | Gets or sets the maximum number of bytes to buffer when reading the response content. |
| Timeout | Gets or sets the number of milliseconds to wait before the request times out. |
| Name | Description | |
|---|---|---|
| CancelPendingRequests | Cancel all pending requests on this instance. |
| DeleteAsync(String) | Send a DELETE request to the specified Uri as an asynchronous operation. |
| DeleteAsync(Uri) | Send a DELETE request to the specified Uri as an asynchronous operation. |
| DeleteAsync(String, CancellationToken) | Send a DELETE request to the specified Uri with a cancellation token as an asynchronous operation. |
| DeleteAsync(Uri, CancellationToken) | Send a DELETE request to the specified Uri with a cancellation token as an asynchronous operation. |
| Dispose() | Releases the unmanaged resources and disposes of the managed resources used by the HttpMessageInvoker. (Inherited from HttpMessageInvoker.) |
.gif?cs-save-lang=1&cs-lang=fsharp "Protected method") | Dispose(Boolean) | Releases the unmanaged resources used by the HttpClient and optionally disposes of the managed resources. (Overrides HttpMessageInvoker.Dispose(Boolean).) |
| Equals(Object) | Determines whether the specified object is equal to the current object. (Inherited from Object.) |
| Finalize | Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.) |
| GetAsync(String) | Send a GET request to the specified Uri as an asynchronous operation. |
| GetAsync(Uri) | Send a GET request to the specified Uri as an asynchronous operation. |
| GetAsync(String, HttpCompletionOption) | Send a GET request to the specified Uri with an HTTP completion option as an asynchronous operation. |
| GetAsync(String, CancellationToken) | Send a GET request to the specified Uri with a cancellation token as an asynchronous operation. |
| GetAsync(Uri, HttpCompletionOption) | Send a GET request to the specified Uri with an HTTP completion option as an asynchronous operation. |
| GetAsync(Uri, CancellationToken) | Send a GET request to the specified Uri with a cancellation token as an asynchronous operation. |
| GetAsync(String, HttpCompletionOption, CancellationToken) | Send a GET request to the specified Uri with an HTTP completion option and a cancellation token as an asynchronous operation. |
| GetAsync(Uri, HttpCompletionOption, CancellationToken) | Send a GET request to the specified Uri with an HTTP completion option and a cancellation token as an asynchronous operation. |
| GetByteArrayAsync(String) | Send a GET request to the specified Uri and return the response body as a byte array in an asynchronous operation. |
| GetByteArrayAsync(Uri) | Send a GET request to the specified Uri and return the response body as a byte array in an asynchronous operation. |
| GetHashCode | Serves as a hash function for a particular type. (Inherited from Object.) |
| GetStreamAsync(String) | Send a GET request to the specified Uri and return the response body as a stream in an asynchronous operation. |
| GetStreamAsync(Uri) | Send a GET request to the specified Uri and return the response body as a stream in an asynchronous operation. |
| GetStringAsync(String) | Send a GET request to the specified Uri and return the response body as a string in an asynchronous operation. |
| GetStringAsync(Uri) | Send a GET request to the specified Uri and return the response body as a string in an asynchronous operation. |
| GetType | Gets the Type of the current instance. (Inherited from Object.) |
| MemberwiseClone | Creates a shallow copy of the current Object. (Inherited from Object.) |
| PostAsync(String, HttpContent) | Send a POST request to the specified Uri as an asynchronous operation. |
| PostAsync(Uri, HttpContent) | Send a POST request to the specified Uri as an asynchronous operation. |
| PostAsync(String, HttpContent, CancellationToken) | Send a POST request with a cancellation token as an asynchronous operation. |
| PostAsync(Uri, HttpContent, CancellationToken) | Send a POST request with a cancellation token as an asynchronous operation. |
| PutAsync(String, HttpContent) | Send a PUT request to the specified Uri as an asynchronous operation. |
| PutAsync(Uri, HttpContent) | Send a PUT request to the specified Uri as an asynchronous operation. |
| PutAsync(String, HttpContent, CancellationToken) | Send a PUT request with a cancellation token as an asynchronous operation. |
| PutAsync(Uri, HttpContent, CancellationToken) | Send a PUT request with a cancellation token as an asynchronous operation. |
| SendAsync(HttpRequestMessage) | Send an HTTP request as an asynchronous operation. |
| SendAsync(HttpRequestMessage, HttpCompletionOption) | Send an HTTP request as an asynchronous operation. |
| SendAsync(HttpRequestMessage, CancellationToken) | Send an HTTP request as an asynchronous operation. (Overrides HttpMessageInvoker.SendAsync(HttpRequestMessage, CancellationToken).) |
| SendAsync(HttpRequestMessage, HttpCompletionOption, CancellationToken) | Send an HTTP request as an asynchronous operation. |
| ToString | Returns a string that represents the current object. (Inherited from Object.) |
The HttpClient class instance acts as a session to send HTTP requests. An HttpClient instance is a collection of settings applied to all requests executed by that instance. In addition, every HttpClient instance uses its own connection pool, isolating its requests from requests executed by other HttpClient instances.
The HttpClient also acts as a base class for more specific HTTP clients. An example would be a FacebookHttpClient providing additional methods specific to a Facebook web service (a GetFriends method, for instance).
By default, HttpWebRequest will be used to send requests to the server. This behavior can be modified by specifying a different channel in one of the constructor overloads taking a HttpMessageHandler instance as parameter. If features like authentication or caching are required, WebRequestHandler can be used to configure settings and the instance can be passed to the constructor. The returned handler can be passed to one of the constructor overloads taking a HttpMessageHandler parameter.
If an app using HttpClient and related classes in the System.Net.Http namespace intends to download large amounts of data (50 megabytes or more), then the app should stream those downloads and not use the default buffering. If the default buffering is used the client memory usage will get very large, potentially resulting in substantially reduced performance.
The following methods are thread safe:
static async void Main() { try { // Create a New HttpClient object. HttpClient client = new HttpClient(); HttpResponseMessage response = await client.GetAsync("http://www.contoso.com/"); response.EnsureSuccessStatusCode(); string responseBody = await response.Content.ReadAsStringAsync(); // Above three lines can be replaced with new helper method in following line // string body = await client.GetStringAsync(uri); Console.WriteLine(responseBody); } catch(HttpRequestException e) { Console.WriteLine("\nException Caught!"); Console.WriteLine("Message :{0} ",e.Message); } }
Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
