System.Net.Http Namespace

The System.Net.Http namespace provides a programming interface for modern HTTP applications.

Classes

ByteArrayContent

Provides HTTP content based on a byte array.

CFNetworkHandler
DelegatingHandler

A type for HTTP handlers that delegate the processing of HTTP response messages to another handler, called the inner handler.

FormUrlEncodedContent

A container for name/value tuples encoded using application/x-www-form-urlencoded MIME type.

HttpClient

Provides a base class for sending HTTP requests and receiving HTTP responses from a resource identified by a URI.

HttpClientHandler

The default message handler used by HttpClient.

HttpContent

A base class representing an HTTP entity body and content headers.

HttpMessageHandler

A base type for HTTP message handlers.

HttpMessageInvoker

A specialty class that allows applications to call the SendAsync(HttpRequestMessage, CancellationToken) method on an HTTP handler chain.

HttpMethod

A helper class for retrieving and comparing standard HTTP methods and for creating new HTTP methods.

HttpRequestException

A base class for exceptions thrown by the HttpClient and HttpMessageHandler classes.

HttpRequestMessage

Represents a HTTP request message.

HttpResponseMessage

Represents a HTTP response message including the status code and data.

MessageProcessingHandler

A base type for handlers which only do some small processing of request and/or response messages.

MultipartContent

Provides a collection of HttpContent objects that get serialized using the multipart/* content type specification.

MultipartFormDataContent

Provides a container for content encoded using multipart/form-data MIME type.

NSUrlSessionHandler
ReadOnlyMemoryContent
SocketsHttpHandler
StreamContent

Provides HTTP content based on a stream.

StringContent

Provides HTTP content based on a string.

WebRequestHandler

Provides desktop-specific features not available to Windows Store apps or other environments.

WinHttpHandler

WinHttpHandler is a specialty message handler based on the WinHTTP interface of Windows and is intended for use in server environments. This class is also available for use in Desktop apps by installing it as a NuGet package. For more information about installing this class for use in Desktop apps, see System.Net.Http.WinHttpHandler.

Enums

ClientCertificateOption

Specifies how client certificates are provided.

CookieUsePolicy

This enumeration allows control of HTTP cookies when communicating with the server.

HttpCompletionOption

Indicates if HttpClient operations should be considered completed either as soon as a response is available, or after reading the entire response message including the content.

WindowsProxyUsePolicy

This enumeration provides available options for the proxy settings used by an HttpClient when running on Windows.

Remarks

The System.Net.Http namespace is designed to provide the following:

  1. HTTP client components that allow users to consume modern web services over HTTP.

  2. HTTP components that can be used by both clients and servers (HTTP headers and messages, for example). This provides a consistent programming model on both the client and the server side for modern web services over HTTP.

The System.Net.Http namespace and the related System.Net.Http.Headers namespace provide the following set of components:

  1. HttpClient - the primary class used to send and receive requests over HTTP.

  2. HttpRequestMessage and HttpResponseMessage - HTTP messages as defined in RFC 2616 by the IETF.

  3. HttpHeaders - HTTP headers as defined in RFC 2616 by the IETF.

  4. HttpClientHandler - HTTP handlers responsible for producing HTTP response messages.

There are various HTTP message handles that can be used. These include the following.

  1. DelegatingHandler - A class used to plug a handler into a handler chain.

  2. HttpMessageHandler - A simple to class to derive from that supports the most common requirements for most applications.

  3. HttpClientHandler - A class that operates at the bottom of the handler chain that actually handles the HTTP transport operations.

  4. WebRequestHandler - A specialty class that operates at the bottom of the handler chain class that handles HTTP transport operations with options that are specific to the System.Net.HttpWebRequest object.

The contents of an HTTP message corresponds to the entity body defined in RFC 2616.

A number of classes can be used for HTTP content. These include the following.

  1. ByteArrayContent - HTTP content based on a byte array.

  2. FormUrlEncodedContent - HTTP content of name/value tuples encoded using application/x-www-form-urlencoded MIME type.

  3. MultipartContent - HTTP content that gets serialized using the multipart/* content type specification.

  4. MultipartFormDataContent - HTTP content encoded using the multipart/form-data MIME type.

  5. StreamContent - HTTP content based on a stream.

  6. StringContent - HTTP content based on a string.

If an app using the System.Net.Http and System.Net.Http.Headers namespaces 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.

Classes in the System.Net.Http and System.Net.Http.Headers namespaces can be used to develop Windows Store apps or desktop apps. When used in a Windows Store app, classes in the System.Net.Http and System.Net.Http.Headers namespaces are affected by network isolation feature, part of the application security model used by the Windows 8. The appropriate network capabilities must be enabled in the app manifest for a Windows Store app for the system to allow network access by a Windows store app. For more information, see the Network Isolation for Windows Store Apps.