HttpWebRequest Class
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HttpWebRequest Class

 

Provides an HTTP-specific implementation of the WebRequest class.

Namespace:   System.Net
Assembly:  System (in System.dll)

System::Object
  System::MarshalByRefObject
    System.Net::WebRequest
      System.Net::HttpWebRequest

[SerializableAttribute]
public ref class HttpWebRequest : WebRequest, ISerializable

NameDescription
System_CAPS_pubmethodHttpWebRequest()

Obsolete.Initializes a new instance of the HttpWebRequest class.

System_CAPS_protmethodHttpWebRequest(SerializationInfo^, StreamingContext)

Obsolete.Initializes a new instance of the HttpWebRequest class from the specified instances of the SerializationInfo and StreamingContext classes.

NameDescription
System_CAPS_pubpropertyAccept

Gets or sets the value of the Accept HTTP header.

System_CAPS_pubpropertyAddress

Gets the Uniform Resource Identifier (URI) of the Internet resource that actually responds to the request.

System_CAPS_pubpropertyAllowAutoRedirect

Gets or sets a value that indicates whether the request should follow redirection responses.

System_CAPS_pubpropertyAllowReadStreamBuffering

Gets or sets a value that indicates whether to buffer the received from the Internet resource.

System_CAPS_pubpropertyAllowWriteStreamBuffering

Gets or sets a value that indicates whether to buffer the data sent to the Internet resource.

System_CAPS_pubpropertyAuthenticationLevel

Gets or sets values indicating the level of authentication and impersonation used for this request.(Inherited from WebRequest.)

System_CAPS_pubpropertyAutomaticDecompression

Gets or sets the type of decompression that is used.

System_CAPS_pubpropertyCachePolicy

Gets or sets the cache policy for this request.(Inherited from WebRequest.)

System_CAPS_pubpropertyClientCertificates

Gets or sets the collection of security certificates that are associated with this request.

System_CAPS_pubpropertyConnection

Gets or sets the value of the Connection HTTP header.

System_CAPS_pubpropertyConnectionGroupName

Gets or sets the name of the connection group for the request.(Overrides WebRequest::ConnectionGroupName.)

System_CAPS_pubpropertyContentLength

Gets or sets the Content-length HTTP header.(Overrides WebRequest::ContentLength.)

System_CAPS_pubpropertyContentType

Gets or sets the value of the Content-type HTTP header.(Overrides WebRequest::ContentType.)

System_CAPS_pubpropertyContinueDelegate

Gets or sets the delegate method called when an HTTP 100-continue response is received from the Internet resource.

System_CAPS_pubpropertyContinueTimeout

Gets or sets a timeout, in milliseconds, to wait until the 100-Continue is received from the server.

System_CAPS_pubpropertyCookieContainer

Gets or sets the cookies associated with the request.

System_CAPS_pubpropertyCreatorInstance

Obsolete.When overridden in a descendant class, gets the factory object derived from the IWebRequestCreate class used to create the WebRequest instantiated for making the request to the specified URI.(Inherited from WebRequest.)

System_CAPS_pubpropertyCredentials

Gets or sets authentication information for the request.(Overrides WebRequest::Credentials.)

System_CAPS_pubpropertyDate

Get or set the Date HTTP header value to use in an HTTP request.

System_CAPS_pubpropertySystem_CAPS_staticDefaultCachePolicy

Gets or sets the default cache policy for this request.

System_CAPS_pubpropertySystem_CAPS_staticDefaultMaximumErrorResponseLength

Gets or sets the default maximum length of an HTTP error response.

System_CAPS_pubpropertySystem_CAPS_staticDefaultMaximumResponseHeadersLength

Gets or sets the default for the MaximumResponseHeadersLength property.

System_CAPS_pubpropertyExpect

Gets or sets the value of the Expect HTTP header.

System_CAPS_pubpropertyHaveResponse

Gets a value that indicates whether a response has been received from an Internet resource.

System_CAPS_pubpropertyHeaders

Specifies a collection of the name/value pairs that make up the HTTP headers.(Overrides WebRequest::Headers.)

System_CAPS_pubpropertyHost

Get or set the Host header value to use in an HTTP request independent from the request URI.

System_CAPS_pubpropertyIfModifiedSince

Gets or sets the value of the If-Modified-Since HTTP header.

System_CAPS_pubpropertyImpersonationLevel

Gets or sets the impersonation level for the current request.(Inherited from WebRequest.)

System_CAPS_pubpropertyKeepAlive

Gets or sets a value that indicates whether to make a persistent connection to the Internet resource.

System_CAPS_pubpropertyMaximumAutomaticRedirections

Gets or sets the maximum number of redirects that the request follows.

System_CAPS_pubpropertyMaximumResponseHeadersLength

Gets or sets the maximum allowed length of the response headers.

System_CAPS_pubpropertyMediaType

Gets or sets the media type of the request.

System_CAPS_pubpropertyMethod

Gets or sets the method for the request.(Overrides WebRequest::Method.)

System_CAPS_pubpropertyPipelined

Gets or sets a value that indicates whether to pipeline the request to the Internet resource.

System_CAPS_pubpropertyPreAuthenticate

Gets or sets a value that indicates whether to send an Authorization header with the request.(Overrides WebRequest::PreAuthenticate.)

System_CAPS_pubpropertyProtocolVersion

Gets or sets the version of HTTP to use for the request.

System_CAPS_pubpropertyProxy

Gets or sets proxy information for the request.(Overrides WebRequest::Proxy.)

System_CAPS_pubpropertyReadWriteTimeout

Gets or sets a time-out in milliseconds when writing to or reading from a stream.

System_CAPS_pubpropertyReferer

Gets or sets the value of the Referer HTTP header.

System_CAPS_pubpropertyRequestUri

Gets the original Uniform Resource Identifier (URI) of the request.(Overrides WebRequest::RequestUri.)

System_CAPS_pubpropertySendChunked

Gets or sets a value that indicates whether to send data in segments to the Internet resource.

System_CAPS_pubpropertyServerCertificateValidationCallback

Gets or sets a callback function to validate the server certificate.

System_CAPS_pubpropertyServicePoint

Gets the service point to use for the request.

System_CAPS_pubpropertySupportsCookieContainer

Gets a value that indicates whether the request provides support for a CookieContainer.

System_CAPS_pubpropertyTimeout

Gets or sets the time-out value in milliseconds for the GetResponse and GetRequestStream methods.(Overrides WebRequest::Timeout.)

System_CAPS_pubpropertyTransferEncoding

Gets or sets the value of the Transfer-encoding HTTP header.

System_CAPS_pubpropertyUnsafeAuthenticatedConnectionSharing

Gets or sets a value that indicates whether to allow high-speed NTLM-authenticated connection sharing.

System_CAPS_pubpropertyUseDefaultCredentials

Gets or sets a Boolean value that controls whether default credentials are sent with requests.(Overrides WebRequest::UseDefaultCredentials.)

System_CAPS_pubpropertyUserAgent

Gets or sets the value of the User-agent HTTP header.

NameDescription
System_CAPS_pubmethodAbort()

Cancels a request to an Internet resource.(Overrides WebRequest::Abort().)

System_CAPS_pubmethodAddRange(Int32)

Adds a byte range header to a request for a specific range from the beginning or end of the requested data.

System_CAPS_pubmethodAddRange(Int32, Int32)

Adds a byte range header to the request for a specified range.

System_CAPS_pubmethodAddRange(Int64)

Adds a byte range header to a request for a specific range from the beginning or end of the requested data.

System_CAPS_pubmethodAddRange(Int64, Int64)

Adds a byte range header to the request for a specified range.

System_CAPS_pubmethodAddRange(String^, Int32)

Adds a Range header to a request for a specific range from the beginning or end of the requested data.

System_CAPS_pubmethodAddRange(String^, Int32, Int32)

Adds a range header to a request for a specified range.

System_CAPS_pubmethodAddRange(String^, Int64)

Adds a Range header to a request for a specific range from the beginning or end of the requested data.

System_CAPS_pubmethodAddRange(String^, Int64, Int64)

Adds a range header to a request for a specified range.

System_CAPS_pubmethodBeginGetRequestStream(AsyncCallback^, Object^)

Begins an asynchronous request for a Stream object to use to write data.(Overrides WebRequest::BeginGetRequestStream(AsyncCallback^, Object^).)

System_CAPS_pubmethodBeginGetResponse(AsyncCallback^, Object^)

Begins an asynchronous request to an Internet resource.(Overrides WebRequest::BeginGetResponse(AsyncCallback^, Object^).)

System_CAPS_pubmethodCreateObjRef(Type^)

Creates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object.(Inherited from MarshalByRefObject.)

System_CAPS_pubmethodEndGetRequestStream(IAsyncResult^)

Ends an asynchronous request for a Stream object to use to write data.(Overrides WebRequest::EndGetRequestStream(IAsyncResult^).)

System_CAPS_pubmethodEndGetRequestStream(IAsyncResult^, TransportContext^%)

Ends an asynchronous request for a Stream object to use to write data and outputs the TransportContext associated with the stream.

System_CAPS_pubmethodEndGetResponse(IAsyncResult^)

Ends an asynchronous request to an Internet resource.(Overrides WebRequest::EndGetResponse(IAsyncResult^).)

System_CAPS_pubmethodEquals(Object^)

Determines whether the specified object is equal to the current object.(Inherited from Object.)

System_CAPS_protmethodFinalize()

Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection.(Inherited from Object.)

System_CAPS_pubmethodGetHashCode()

Serves as the default hash function. (Inherited from Object.)

System_CAPS_pubmethodGetLifetimeService()

Retrieves the current lifetime service object that controls the lifetime policy for this instance.(Inherited from MarshalByRefObject.)

System_CAPS_protmethodGetObjectData(SerializationInfo^, StreamingContext)

This API supports the product infrastructure and is not intended to be used directly from your code. Populates a SerializationInfo with the data required to serialize the target object.(Overrides WebRequest::GetObjectData(SerializationInfo^, StreamingContext).)

System_CAPS_pubmethodGetRequestStream()

Gets a Stream object to use to write request data.(Overrides WebRequest::GetRequestStream().)

System_CAPS_pubmethodGetRequestStream(TransportContext^%)

Gets a Stream object to use to write request data and outputs the TransportContext associated with the stream.

System_CAPS_pubmethodGetRequestStreamAsync()

When overridden in a descendant class, returns a Stream for writing data to the Internet resource as an asynchronous operation.(Inherited from WebRequest.)

System_CAPS_pubmethodGetResponse()

Returns a response from an Internet resource.(Overrides WebRequest::GetResponse().)

System_CAPS_pubmethodGetResponseAsync()

When overridden in a descendant class, returns a response to an Internet request as an asynchronous operation.(Inherited from WebRequest.)

System_CAPS_pubmethodGetType()

Gets the Type of the current instance.(Inherited from Object.)

System_CAPS_pubmethodInitializeLifetimeService()

Obtains a lifetime service object to control the lifetime policy for this instance.(Inherited from MarshalByRefObject.)

System_CAPS_protmethodMemberwiseClone()

Creates a shallow copy of the current Object.(Inherited from Object.)

System_CAPS_protmethodMemberwiseClone(Boolean)

Creates a shallow copy of the current MarshalByRefObject object.(Inherited from MarshalByRefObject.)

System_CAPS_pubmethodToString()

Returns a string that represents the current object.(Inherited from Object.)

NameDescription
System_CAPS_pubinterfaceSystem_CAPS_privmethodISerializable::GetObjectData(SerializationInfo^, StreamingContext)

This API supports the product infrastructure and is not intended to be used directly from your code. Populates a SerializationInfo with the data needed to serialize the target object.

The HttpWebRequest class provides support for the properties and methods defined in WebRequest and for additional properties and methods that enable the user to interact directly with servers using HTTP.

Do not use the HttpWebRequest constructor. Use the WebRequest::Create method to initialize new HttpWebRequest objects. If the scheme for the Uniform Resource Identifier (URI) is http:// or https://, Create returns an HttpWebRequest object.

The GetResponse method makes a synchronous request to the resource specified in the RequestUri property and returns an HttpWebResponse that contains the response object. The response data can be received by using the stream returned by GetResponseStream. If the response object or the response stream is closed, remaining data will be forfeited. The remaining data will be drained and the socket will be re-used for subsequent requests when closing the response object or stream if the following conditions hold: it's a keep-alive or pipelined request, only a small amount of data needs to be received, or the remaining data is received in a small time interval. If none of the mentioned conditions hold or the drain time is exceeded, the socket will be closed. For keep-alive or pipelined connections, we strongly recommend that the application reads the streams until EOF. This ensures that the socket will be re-used for subsequent requests resulting in better performance and less resources used.

When you want to send data to the resource, the GetRequestStream method returns a Stream object to use to send data. The BeginGetRequestStream and EndGetRequestStream methods provide asynchronous access to the send data stream.

For client authentication with HttpWebRequest, the client certificate must be installed in the My certificate store of the current user.

The HttpWebRequest class throws a WebException when errors occur while accessing a resource. The WebException::Status property contains a WebExceptionStatus value that indicates the source of the error. When WebException::Status is WebExceptionStatus::ProtocolError, the Response property contains the HttpWebResponse received from the resource.

HttpWebRequest exposes common HTTP header values sent to the Internet resource as properties, set by methods, or set by the system; the following table contains a complete list. You can set other headers in the Headers property as name/value pairs. Note that servers and caches may change or add headers during the request.

The following table lists the HTTP headers that are set either by properties or methods or the system.

Header

Set by

Accept

Set by the Accept property.

Connection

Set by the Connection property, KeepAlive property.

Content-Length

Set by the ContentLength property.

Content-Type

Set by the ContentType property.

Expect

Set by the Expect property.

Date

Set by the system to current date.

Host

Set by the system to current host information.

If-Modified-Since

Set by the IfModifiedSince property.

Range

Set by the AddRange method.

Referer

Set by the Referer property.

Transfer-Encoding

Set by the TransferEncoding property (the SendChunked property must be true).

User-Agent

Set by the UserAgent property.

System_CAPS_noteNote

HttpWebRequest is registered automatically. You do not need to call the RegisterPrefix method to register System.Net::HttpWebRequest before using URIs beginning with http:// or https://.

The local computer or application config file may specify that a default proxy be used. If the Proxy property is specified, then the proxy settings from the Proxy property override the local computer or application config file and the HttpWebRequest instance will use the proxy settings specified. If no proxy is specified in a config file and the Proxy property is unspecified, the HttpWebRequest class uses the proxy settings inherited from Internet Explorer on the local computer. If there are no proxy settings in Internet Explorer, the request is sent directly to the server.

The HttpWebRequest class parses a proxy bypass list with wildcard characters inherited from Internet Explorer differently than the bypass list is parsed directly by Internet Explorer. For example, the HttpWebRequest class will parse a bypass list of "nt*" from Internet Explorer as a regular expression of "nt.$". This differs from the native behavior of Internet Explorer. So a URL of "http://intxxxxx" would bypass the proxy using the HttpWebRequest class, but would not bypass the proxy using Internet Explorer.

System_CAPS_noteNote

The Framework caches SSL sessions as they are created and attempts to reuse a cached session for a new request, if possible. When attempting to reuse an SSL session, the Framework uses the first element of ClientCertificates (if there is one), or tries to reuse an anonymous sessions if ClientCertificates is empty.

System_CAPS_noteNote

For security reasons, cookies are disabled by default. If you want to use cookies, use the CookieContainer property to enable cookies.

The .NET Framework 4.6 includes a new security feature that blocks insecure cipher and hashing algorithms for connections. Applications using TLS/SSL through APIs such as HttpClient, HttpWebRequest, FTPClient, SmtpClient, SslStream, etc. and targeting .NET Framework 4.6 get the more-secure behavior by default.

Developers may want to opt out of this behavior in order to maintain interoperability with their existing SSL3 services OR TLS w/ RC4 services. This article explains how to modify your code so that the new behavior is disabled.

The following code example creates an HttpWebRequest for the URI http://www.contoso.com/.

HttpWebRequest^ myReq = dynamic_cast<HttpWebRequest^>(WebRequest::Create( "http://www.contoso.com/" ));

WebPermission

to access the requested URI or any URI that the request is redirected to. Associated enumeration: Connect

Universal Windows Platform
Available since 8
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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