System.Net.HttpWebRequest Class

public class HttpWebRequest : WebRequest

Base Types

Object
  MarshalByRefObject
    WebRequest
      HttpWebRequest

Assembly

System

Library

Networking

Summary

Provides an HTTP-specific implementation of the WebRequest class.

Description

This class implements properties and methods defined in WebRequest and provides additional properties and methods that enable the user to interact directly with servers using the Hypertext Transfer Protocol (HTTP).

[Note: Instances of this class are automatically created by the WebRequest class. For example, an instance of HttpWebRequest is created when the System.Net.WebRequest.Create(System.Uri,System.Boolean) method is called and a Uniform Resource Identifier (URI) beginning with http:// is specified. It is expected that an instance of this class will be constructed for every request made to the server. For example, after a call to System.Net.HttpWebRequest.Abort cancels an asynchronous operation, a call to System.Net.HttpWebRequest.GetRequestStream causes a WebException to be thrown.

Requests can be sent synchronously or asynchronously. The System.Net.HttpWebRequest.GetResponse method sends a request to a server synchronously and returns a HttpWebResponse instance containing the response. An asynchronous request for a resource is sent using the System.Net.HttpWebRequest.BeginGetResponse(System.AsyncCallback,System.Object) and System.Net.HttpWebRequest.EndGetResponse(System.IAsyncResult) methods.

Request data is sent using a request stream. The System.Net.HttpWebRequest.GetRequestStream , System.Net.HttpWebRequest.BeginGetRequestStream(System.AsyncCallback,System.Object), and System.Net.HttpWebRequest.EndGetRequestStream(System.IAsyncResult) methods return a Stream instance used to send data.

When errors occur while accessing an Internet resource, the HttpWebRequest class throws a WebException , and the System.Net.WebException.Status property that indicates the source of the error. When System.Net.WebException.Status is System.Net.WebExceptionStatus.ProtocolError, the System.Net.WebException.Response property contains the HttpWebResponse received from the Internet resource.

Certain HTTP headers are protected; the user cannot set them directly in the header collection obtained from the System.Net.HttpWebRequest.Headers property. Instead, these headers are set using the associated properties of a HttpWebRequest instance, or are set by the system. The following table describes how each protected header is set.

Header	Set by
Accept	System.Net.HttpWebRequest.Accept
Connection	System.Net.HttpWebRequest.Connection System.Net.HttpWebRequest.KeepAlive
Content-Length	System.Net.HttpWebRequest.ContentLength
Content-Type	System.Net.HttpWebRequest.ContentType
Expect	System.Net.HttpWebRequest.Expect
Date	Set to current date by the system.
Host	Set to current host by the system.
if-Modified-since	System.Net.HttpWebRequest.IfModifiedSince
Range	System.Net.HttpWebRequest.AddRange(System.Int32,System.Int32)
Referer	System.Net.HttpWebRequest.Referer
Transfer-Encoding	System.Net.HttpWebRequest.TransferEncoding System.Net.HttpWebRequest.SendChunked
User-Agent	System.Net.HttpWebRequest.UserAgent

]

See Also

System.Net Namespace

Members

HttpWebRequest Methods

HttpWebRequest.Abort Method
HttpWebRequest.AddRange(int, int) Method
HttpWebRequest.AddRange(int) Method
HttpWebRequest.AddRange(System.String, int, int) Method
HttpWebRequest.AddRange(System.String, int) Method
HttpWebRequest.BeginGetRequestStream Method
HttpWebRequest.BeginGetResponse Method
HttpWebRequest.EndGetRequestStream Method
HttpWebRequest.EndGetResponse Method
HttpWebRequest.GetHashCode Method
HttpWebRequest.GetRequestStream Method
HttpWebRequest.GetResponse Method

HttpWebRequest Properties

HttpWebRequest.Accept Property
HttpWebRequest.Address Property
HttpWebRequest.AllowAutoRedirect Property
HttpWebRequest.AllowWriteStreamBuffering Property
HttpWebRequest.Connection Property
HttpWebRequest.ConnectionGroupName Property
HttpWebRequest.ContentLength Property
HttpWebRequest.ContentType Property
HttpWebRequest.ContinueDelegate Property
HttpWebRequest.Credentials Property
HttpWebRequest.Expect Property
HttpWebRequest.HaveResponse Property
HttpWebRequest.Headers Property
HttpWebRequest.IfModifiedSince Property
HttpWebRequest.KeepAlive Property
HttpWebRequest.MaximumAutomaticRedirections Property
HttpWebRequest.MediaType Property
HttpWebRequest.Method Property
HttpWebRequest.Pipelined Property
HttpWebRequest.PreAuthenticate Property
HttpWebRequest.ProtocolVersion Property
HttpWebRequest.Proxy Property
HttpWebRequest.Referer Property
HttpWebRequest.RequestUri Property
HttpWebRequest.SendChunked Property
HttpWebRequest.ServicePoint Property
HttpWebRequest.Timeout Property
HttpWebRequest.TransferEncoding Property
HttpWebRequest.UserAgent Property

System.Net.HttpWebRequest.Abort cancels any pending asynchronous operation. After this method is called, calling System.Net.HttpWebRequest.GetResponse, System.Net.HttpWebRequest.BeginGetResponse(System.AsyncCallback,System.Object), System.Net.HttpWebRequest.EndGetResponse(System.IAsyncResult), System.Net.HttpWebRequest.GetRequestStream, System.Net.HttpWebRequest.BeginGetRequestStream(System.AsyncCallback,System.Object), or System.Net.HttpWebRequest.EndGetRequestStream(System.IAsyncResult) will throw a WebException with System.Net.WebException.Status set to System.Net.WebExceptionStatus.RequestCanceled .

[Note: If no pending request exists, calling this method does not cause an exception to be thrown.

This method overrides System.Net.WebRequest.Abort.

]

See Also

System.Net.HttpWebRequest Class, System.Net Namespace

from

A Int32 indicating the starting byte position of the entity-body data to be returned.

to

A Int32 indicating the last byte.

Exceptions

Exception Type	Condition
ArgumentOutOfRangeException	from < 0. -or- to < 0. -or- from > to .
InvalidOperationException	The range header could not be added.

Description

This method is equivalent to System.Net.HttpWebRequest.AddRange(System.Int32,System.Int32)("bytes", from, to).

[Note: The HTTP Range header specifies either a single range of bytes or a set of byte ranges in an entity-body to be returned. If the server accessed by the current instance supports the use of this header, this allows for the partial retrieval of the entity due to, for example, the entity being particularly large or there having been a failed transfer of data.

For more information on the HTTP Range header, see Section 14.35 of RFC 2616.

]

See Also

System.Net.HttpWebRequest Class, System.Net Namespace

range

A Int32 that specifies the starting or ending point of the range. If this value is positive, the range is from the beginning of the data to range. If this value is negative, the range is from range to the end of the data.

Exceptions

Exception Type	Condition
InvalidOperationException	The range header could not be added.

Description

This method is equivalent to System.Net.HttpWebRequest.AddRange(System.Int32,System.Int32)("bytes", range).

[Note: The HTTP Range header specifies either a single range of bytes or a set of byte ranges in an entity-body to be returned. If the server accessed by the current instance supports the use of this header, this allows for the partial retrieval of the entity due to, for example, the entity being particularly large or there having been a failed transfer of data.

For more information on the HTTP Range header, see Section 14.35 of RFC 2616.

]

See Also

System.Net.HttpWebRequest Class, System.Net Namespace

rangeSpecifier

A String that contains the description of the range.

from

A Int32 designating the position at which to start sending data.

to

A Int32 designating the position at which to stop sending data.

Exceptions

Exception Type	Condition
ArgumentNullException	rangeSpecifier is null .
ArgumentOutOfRangeException	from < 0. -or- to < 0. -or- from > to .
ArgumentException	rangeSpecifier is invalid.
InvalidOperationException	The range header could not be added.

Description

[Note: The HTTP Range header specifies either a single range of bytes or a set of byte ranges in an entity-body to be returned. If the server accessed by the current instance supports the use of this header, this allows for the partial retrieval of the entity due to, for example, the entity being particularly large or there having been a failed transfer of data.

For more information on the HTTP Range header, see Section 14.35 of IETF RFC 2616.

]

See Also

System.Net.HttpWebRequest Class, System.Net Namespace

rangeSpecifier

A String that contains the description of the range.

range

A Int32 that designates the starting or ending point of the range. If this value is positive, the range is from the beginning of the data to range. If this value is negative, the range is from range to the end of the data.

Exceptions

Exception Type	Condition
ArgumentNullException	rangeSpecifier is null .
ArgumentException	rangeSpecifier is invalid.
InvalidOperationException	The range header could not be added.

Description

[Note: The HTTP Range header specifies either a single range of bytes or a set of byte ranges in an entity-body to be returned. If the server accessed by the current instance supports the use of this header, this allows for the partial retrieval of the entity due to, for example, the entity being particularly large or there having been a failed transfer of data.

For more information on the HTTP Range header, see Section 14.35 of RFC 2616.

]

See Also

System.Net.HttpWebRequest Class, System.Net Namespace

callback

A AsyncCallback delegate to be called when the stream is available. Can be null .

state

A Object containing state information for the asynchronous request. Can be null .

Return Value

A IAsyncResult that contains information about the asynchronous operation.

Exceptions

Exception Type	Condition
InvalidOperationException	The stream is being used by a previous call to System.Net.HttpWebRequest.BeginGetRequestStream(System.AsyncCallback,System.Object) . -or- No writeable stream is available.
ProtocolViolationException	The System.Net.HttpWebRequest.ContentLength property of the current instance is not set. -or- The System.Net.HttpWebRequest.Method property of the current instance is "GET" or "HEAD".
WebException	System.Net.HttpWebRequest.Abort was previously called. -or- An error occurred while processing the request.

Description

This method starts an asynchronous operation. To get the request stream, call the System.Net.HttpWebRequest.EndGetRequestStream(System.IAsyncResult) method and specify the IAsyncResult object returned by this method. [Note: The System.Net.HttpWebRequest.EndGetRequestStream(System.IAsyncResult) method should be called exactly once for each call to System.Net.HttpWebRequest.BeginGetRequestStream(System.AsyncCallback,System.Object).]

If the callback parameter is not null , the method(s) referenced by callback are invoked when the asynchronous operation completes. The IAsyncResult object returned by this method is passed as the argument to the method(s) referenced by callback .

The state parameter can be any object that the caller wishes to have available for the duration of the asynchronous operation. This object is available via the System.IAsyncResult.AsyncState property of the object returned by this method.

The value of the System.Net.HttpWebRequest.ContentLength property of the current instance is required to be set prior to calling this method.

[Note: The method(s) invoked by the callback delegate can call the System.Net.HttpWebRequest.EndGetRequestStream(System.IAsyncResult) method to retrieve the stream.

This method is the asynchronous version of the System.Net.HttpWebRequest.GetRequestStream method.

This method overrides System.Net.WebRequest.BeginGetRequestStream(System.AsyncCallback,System.Object) .

]

See Also

System.Net.HttpWebRequest Class, System.Net Namespace

callback

A AsyncCallback delegate to be called when the stream is available. Can be null .

state

A Object containing state information for the asynchronous request. Can be null .

Return Value

A IAsyncResult that contains information about the asynchronous operation.

Exceptions

Exception Type	Condition
InvalidOperationException	System.Net.HttpWebRequest.BeginGetResponse(System.AsyncCallback,System.Object) or System.Net.HttpWebRequest.GetResponse was previously called on this instance.
ProtocolViolationException	The System.Net.HttpWebRequest.ContentLength property of the current instance has not been set.
WebException	System.Net.HttpWebRequest.Abort was previously called.

Description

This method starts an asynchronous operation. To get the response, call the System.Net.HttpWebRequest.EndGetResponse(System.IAsyncResult) method and specify the IAsyncResult object returned by this method. [Note: The System.Net.HttpWebRequest.EndGetResponse(System.IAsyncResult) method should be called exactly once for each call to System.Net.HttpWebRequest.BeginGetResponse(System.AsyncCallback,System.Object).]

If the callback parameter is not null , the method referenced by callback is invoked when the asynchronous operation completes. The IAsyncResult object returned by this method is passed as the argument to the method referenced by callback.

The state parameter can be any object that the caller wishes to have available for the duration of the asynchronous operation. This object is available via the System.IAsyncResult.AsyncState property of the object returned by this method.

[Note: The method(s) invoked by the callback delegate can call the System.Net.HttpWebRequest.EndGetResponse(System.IAsyncResult) method to retrieve the response.

This method is the asynchronous version of the System.Net.HttpWebRequest.GetResponse method.

This method overrides System.Net.WebRequest.BeginGetResponse(System.AsyncCallback,System.Object).

]

See Also

System.Net.HttpWebRequest Class, System.Net Namespace

asyncResult

The IAsyncResult object that holds the state information for the asynchronous operation.

Return Value

A Stream to write request data to.

Exceptions

Exception Type	Condition
ArgumentNullException	asyncResult is null .
ArgumentException	asyncResult was not returned by the current instance from a call to System.Net.WebRequest.BeginGetRequestStream(System.AsyncCallback,System.Object).
InvalidOperationException	This method was called previously using asyncResult. -or- No stream is available.
WebException	System.Net.HttpWebRequest.Abort was previously called. -or- An error occurred while processing the request.

Description

[Note: The caller is responsible for calling the System.IO.Stream.Close method to close the stream.

This method overrides System.Net.WebRequest.EndGetRequestStream(System.IAsyncResult).

]

See Also

System.Net.HttpWebRequest Class, System.Net Namespace

Returns a WebResponse that contains a response to the specified pending Internet request.

Parameters

asyncResult

The IAsyncResult object that hold the state information for the asynchronous operation.

Return Value

A WebResponse that contains a response to the Internet request referenced by asyncResult .

Exceptions

Exception Type	Condition
ArgumentNullException	asyncResult is null .
ArgumentException	asyncResult was not returned by the current instance from a call to System.Net.WebRequest.BeginGetResponse(System.AsyncCallback,System.Object).
InvalidOperationException	This method was called previously using asyncResult. -or- The System.Net.HttpWebRequest.ContentLength property of the current instance is greater than 0 but the data has not been written to the request stream.
WebException	System.Net.HttpWebRequest.Abort was previously called. -or- An error occurred while processing the request.

Description

[Note: This method completes an asynchronous request for an Internet resource that was started by calling System.Net.HttpWebRequest.BeginGetResponse(System.AsyncCallback,System.Object).

This method overrides System.Net.WebRequest.EndGetResponse(System.IAsyncResult).

]

See Also

System.Net.HttpWebRequest Class, System.Net Namespace

A Int32 containing the hash code for the current instance.

Description

The algorithm used to generate the hash code is unspecified.

[Note: This method overrides System.Object.GetHashCode.]

See Also

System.Net.HttpWebRequest Class, System.Net Namespace

Returns a Stream for writing data to the Internet resource requested by the current instance.

Return Value

A Stream for writing data to an Internet resource requested by the current instance.

Exceptions

Exception Type	Condition
ProtocolViolationException	The System.Net.HttpWebRequest.Method property of the current instance is "GET" or "HEAD". -or- The System.Net.HttpWebRequest.ContentLength property of the current instance is not set.
InvalidOperationException	The System.Net.HttpWebRequest.GetRequestStream method was called more than once. -or- No writeable stream is available.
WebException	System.Net.HttpWebRequest.Abort was previously called. -or- The timeout period for the request expired. -or- An error occurred while processing the request.

Description

The value of the System.Net.HttpWebRequest.ContentLength property is required to be set before writing data to the stream.

[Note: This method returns a stream to use to send data for the HttpWebRequest. Once the Stream instance has been returned, data can be sent with the HttpWebRequest by using the System.IO.Stream.Write(System.Byte[],System.Int32,System.Int32) method.

Call the System.IO.Stream.Close method to close the stream and release the connection for reuse. Failure to close the stream may cause the application to run out of connections.

This method overrides System.Net.WebRequest.GetRequestStream.

]

See Also

System.Net.HttpWebRequest Class, System.Net Namespace

A WebResponse containing the response from the Internet resource requested by the current instance.

Exceptions

Exception Type	Condition
ProtocolViolationException	The System.Net.HttpWebRequest.ContentLength property of the current instance is not set.
WebException	System.Net.HttpWebRequest.Abort was previously called. -or- The timeout period for the request expired. -or- An error occurred while processing the request.

Description

[Note: This method returns a WebResponse instance containing the response from the Internet resource requested by the current instance. The actual instance returned is an instance of HttpWebResponse , and can be typecast to that class to access HTTP-specific properties.

This method overrides System.Net.WebRequest.GetResponse .

]

See Also

System.Net.HttpWebRequest Class, System.Net Namespace

Gets or sets a String containing the value of the HTTP Accept header.

Property Value

A String containing the value of the HTTP Accept header. The default value of this property is null .

Description

[Note: For additional information see section 14.1 of IETF RFC 2068 - HTTP/1.1.]

See Also

System.Net.HttpWebRequest Class, System.Net Namespace

A Uri identifying the Internet resource that responds to the current request. The default is the URI used by the System.Net.WebRequest.Create(System.Uri,System.Boolean) method to initialize the current instance.

Description

This property is read-only.

The value of this property is set to the URI that is the source of the response after all redirections are complete.

[Note: The URI of the original request is kept in the System.Net.HttpWebRequest.RequestUri property.]

See Also

System.Net.HttpWebRequest Class, System.Net Namespace

Gets or sets a Boolean value that indicates whether the current request will follow redirection responses.

Property Value

true if the current request will automatically follow redirection responses from the Internet resource; otherwise false . The default value is true .

Description

[Note: Set System.Net.HttpWebRequest.AllowAutoRedirect to true to allow the current request to automatically follow HTTP redirection headers to the new location of a resource.

The maximum number of redirections to follow is set by the System.Net.HttpWebRequest.MaximumAutomaticRedirections property.

]

See Also

System.Net.HttpWebRequest Class, System.Net Namespace

Gets or sets a Boolean value that indicates whether to buffer the data sent to the Internet resource requested by the current instance.

Property Value

true to enable buffering of the data sent to the Internet resource requested by the current instance; false to disable buffering. The default is true .

Description

[Note: When System.Net.HttpWebRequest.AllowWriteStreamBuffering is true , the data is buffered in memory so it is ready to be resent in the event of redirections or authentication requests.

Depending on available memory, setting System.Net.HttpWebRequest.AllowWriteStreamBuffering as true might impact system performance when uploading large amounts of data.

]

See Also

System.Net.HttpWebRequest Class, System.Net Namespace

A String containing the value of the Connection HTTP header. The default value is null .

Exceptions

Exception Type	Condition
ArgumentException	The value of System.Net.HttpWebRequest.Connection is set to "Keep-alive" or "Close". This value is case insensitive.

Description

The current request sends the System.Net.HttpWebRequest.Connection property to the Internet resource as the Connection HTTP header.

[Note: If System.Net.HttpWebRequest.KeepAlive is true , the value "Keep-alive" is appended to the end of the Connection header.

For additional information see section 14.10 of IETF RFC 2068 - HTTP/1.1.

]

See Also

System.Net.HttpWebRequest Class, System.Net Namespace

A String that contains the name of the connection group for the current instance. The default value is null .

Description

[Note: The System.Net.HttpWebRequest.ConnectionGroupName property enables a request to be associated with a connection group. This is useful when an application makes requests to one server for different users, such as a Web site that retrieves customer information from a database server.

Each connection group creates additional connections for a server. This may result in exceeding System.Net.ServicePoint.ConnectionLimit for that server.

This property overrides System.Net.WebRequest.ConnectionGroupName.

]

See Also

System.Net.HttpWebRequest Class, System.Net Namespace

A Int64 value that specifies the number of bytes of data to send to the Internet resource. The default is -1, which indicates that this value has not been set.

Exceptions

Exception Type	Condition
InvalidOperationException	Data has already been written to the request stream.
ArgumentOutOfRangeException	A value less than zero is specified for a set operation.

Description

The System.Net.HttpWebRequest.ContentLength property contains the value to send as the Content-length HTTP header of the request.

Any value other than -1 in the System.Net.HttpWebRequest.ContentLength property indicates that the request will upload data; only methods that upload data are allowed in the System.Net.HttpWebRequest.Method property.

This property is required to be set prior to writing data to the request data stream. Once the System.Net.HttpWebRequest.ContentLength property is set to a value, that number of bytes is required to be written to the request data stream. [Note: Get the request data stream by calling System.Net.HttpWebRequest.GetRequestStream , or System.Net.HttpWebRequest.BeginGetRequestStream(System.AsyncCallback,System.Object) and System.Net.HttpWebRequest.EndGetRequestStream(System.IAsyncResult) .]

[Note: For additional information see section 14.13 of IETF RFC 2068 - HTTP/1.1.

This property overrides System.Net.WebRequest.ContentLength.

]

See Also

System.Net.HttpWebRequest Class, System.Net Namespace

System.Net.HttpWebRequest Class, System.Net Namespace

A HttpContinueDelegate that references the methods that are invoked when an HTTP Continue response is received. The default value is null .

Description

[Note: This delegate is useful to display the status of responses received by the current instance.

]

See Also

System.Net.HttpWebRequest Class, System.Net Namespace

A ICredentials object containing the authentication credentials associated with the current instance. The default is null .

Description

[Note: The System.Net.HttpWebRequest.Credentials property contains authentication information to identify the client making the request. The System.Net.HttpWebRequest.Credentials property can be either an instance of NetworkCredential, in which case the user, password, and domain information contained in the NetworkCredential instance is used to authenticate the request, or it can be an instance of CredentialCache, in which case the uniform resource identifier (URI) of the request is used to determine the user, password, and domain information to use to authenticate the request.

This property overrides System.Net.WebRequest.Credentials .

]

See Also

System.Net.HttpWebRequest Class, System.Net Namespace

A String that contains the contents of the HTTP Expect header. The default value is null .

Exceptions

Exception Type	Condition
ArgumentException	The value specified for a set operation is "100-continue". This value is case insensitive.

Description

[Note: By default, System.Net.HttpWebRequest.Expect is null . Other values can be added to the list that System.Net.HttpWebRequest.Expect maintains, or all values except "100-continue" can be deleted from the list by setting System.Net.HttpWebRequest.Expect to null .

For additional information see section 14.20 of IETF RFC 2068 - HTTP/1.1.

]

See Also

System.Net.HttpWebRequest Class, System.Net Namespace

Gets a Boolean value indicating whether a response has been received for the current instance.

Property Value

true if a response has been received; otherwise false .

Description

This property is read-only.

See Also

System.Net.HttpWebRequest Class, System.Net Namespace

A WebHeaderCollection containing the name/value pairs of the headers for the current instance.

Exceptions

Exception Type	Condition
InvalidOperationException	A set operation was requested but data has already been written to the request data stream.

Description

The following table lists the HTTP headers that cannot be set using the collection returned by this property.

Header	Set by
Accept	System.Net.HttpWebRequest.Accept .
Connection	System.Net.HttpWebRequest.Connection . System.Net.HttpWebRequest.KeepAlive.
Content-Length	System.Net.HttpWebRequest.ContentLength.
Content-Type	System.Net.HttpWebRequest.ContentType.
Expect	System.Net.HttpWebRequest.Expect.
Date	Set by the system to the current date.
Host	Set by the system to the current host information.
Range	System.Net.HttpWebRequest.AddRange(System.Int32,System.Int32) .
Referer	System.Net.HttpWebRequest.Referer.
Transfer-Encoding	System.Net.HttpWebRequest.TransferEncoding. System.Net.HttpWebRequest.SendChunked.
User-Agent	System.Net.HttpWebRequest.UserAgent.

[Note: This property overrides System.Net.WebRequest.Headers.]

See Also

System.Net.HttpWebRequest Class, System.Net Namespace

A DateTime that contains the contents of the HTTP If-Modified-Since header. The default value is the current date and time of the system.

Description

[Note: For additional information see section 14.25 of IETF RFC 2068 - HTTP/1.1.]

See Also

System.Net.HttpWebRequest Class, System.Net Namespace

Gets or sets a Boolean value indicating whether to make a persistent connection to the server hosting the Internet resource requested by the current instance.

Property Value

true indicates that the current request will contain an HTTP Connection header with the value "Keep-alive" ; otherwise, false . The default value is true .

Description

[Note: An application uses System.Net.HttpWebRequest.KeepAlive to indicate a preference for persistent connections. When this property is true , the application makes persistent connections to the servers that support them.]

See Also

System.Net.HttpWebRequest Class, System.Net Namespace

A Int32 value that indicates the maximum number of redirection responses that the current instance will follow. The default value is implementation-defined.

Exceptions

Exception Type	Condition
ArgumentException	The value specified for a set operation is less than or equal to zero.

Description

[Note: This property sets the maximum number of redirections for the request to follow if the System.Net.HttpWebRequest.AllowAutoRedirect property is true .]

See Also

System.Net.HttpWebRequest Class, System.Net Namespace

A String that identifies the media type of the current request. The default value is null .

Description

[Note: The value of this property affects the System.Net.HttpWebResponse.CharacterSet property. When this property is set in the current instance, the corresponding media type is chosen from the list of character sets returned in the response HTTP Content-type header. ]

See Also

System.Net.HttpWebRequest Class, System.Net Namespace

A String containing an HTTP method. The default value is "GET".

Exceptions

Exception Type	Condition
ArgumentException	null , System.String.Empty, or an invalid value was specified for a set operation.

Description

If the System.Net.HttpWebRequest.ContentLength property is set to any value other than -1, the System.Net.HttpWebRequest.Method property is required to be set to a protocol method that sends request data.

The System.Net.HttpWebRequest.Method property can be set to any of the following HTTP 1.1 protocol methods:

HTTP Method	Description
GET	Retrieves in entity-body form the information identified by the System.Net.HttpWebRequest.RequestUri property of the current instance.
HEAD	Identical to GET except that the message-body is not returned in the response.
POST	Requests that the origin server accept the entity enclosed in the request as a new subordinate of the resource identified the Request-URI in the Request-Line.
PUT	Requests that the enclosed entity be stored under the supplied Request-URI.
DELETE	Requests that the origin server delete the resource identified by the Request-URI.
TRACE	Invokes a remote, application-layer loopback of the request message.
OPTIONS	Requests information about the communication options available on the request/response chain identified by the Request-URI. [Note: This allows the client to determine the options and/or requirements associated with a resource, or the capabilities of a server, without implying a resource action or initiating a resource retrieval.]

[Note: For detailed information regarding these methods, see sections 9.2 to 9.8 of RFC 2616.

This property overrides System.Net.WebRequest.Method .

]

See Also

System.Net.HttpWebRequest Class, System.Net Namespace

Gets or sets a Boolean value indicating whether to pipeline the current request to the Internet resource.

Property Value

true if the current request can be pipelined; otherwise, false . The default is true .

Description

An application uses this property to indicate a preference for pipelined connections. If System.Net.HttpWebRequest.Pipelined is true , an application makes pipelined connections to servers that support them.

[Note: Pipelined connections are made only when the System.Net.HttpWebRequest.KeepAlive property is true .]

See Also

System.Net.HttpWebRequest Class, System.Net Namespace

System.Net.HttpWebRequest Class, System.Net Namespace

A Version that represents the HTTP version to use for the request. The default is System.Net.HttpVersion.Version11.

Exceptions

Exception Type	Condition
ArgumentException	The HTTP version is set to a value other than 1.0 or 1.1.

Description

The HttpWebRequest class supports only versions 1.0 and 1.1 of HTTP. Setting System.Net.HttpWebRequest.ProtocolVersion to a different version causes a ArgumentException exception to be thrown.

[Note: To set the System.Net.HttpWebRequest.ProtocolVersion property of the current instance, specify one of the members of the use the HttpVersion class. ]

See Also

System.Net.HttpWebRequest Class, System.Net Namespace

The WebProxy instance to use as a proxy for the current instance. The default value is set by calling System.Net.GlobalProxySelection.Select .

Exceptions

Exception Type	Condition
ArgumentNullException	A set operation was requested and the specified value was null .
InvalidOperationException	A set operation was requested but data has already been sent to the request stream.
SecurityException	The caller does not have permission for the requested operation.

Description

The System.Net.HttpWebRequest.Proxy property identifies the WebProxy instance to use to communicate with the destination server.

[Note: To specify that no proxy should be used, set the System.Net.HttpWebRequest.Proxy property to the proxy instance returned by the System.Net.GlobalProxySelection.GetEmptyWebProxy method.

This property overrides System.Net.WebRequest.Proxy.

]

See Also

System.Net.HttpWebRequest Class, System.Net Namespace

A String containing the value of the HTTP Referer header. The default value is null .

Description

[Note: For additional information see section 14.36 of IETF RFC 2068 - HTTP/1.1.]

See Also

System.Net.HttpWebRequest Class, System.Net Namespace

Gets the Uri of the resource that receives requests sent by the current instance.

Property Value

The Uri of the resource that receives requests sent by the current instance.

Description

This property is read-only.

This property is the Uri instance passed to the current instance via the System.Net.WebRequest.Create(System.Uri,System.Boolean) method.

[Note: Following a redirection header does not change the System.Net.HttpWebRequest.RequestUri property. The URI of the resource that actually responded to the current instance is contained by System.Net.HttpWebRequest.Address property of the current instance.

This property overrides System.Net.WebRequest.RequestUri.

]

See Also

System.Net.HttpWebRequest Class, System.Net Namespace

System.Net.HttpWebRequest Class, System.Net Namespace

A ServicePoint that represents the network connection to the destination. The value of this property is null until the System.Net.HttpWebRequest.GetResponse method is called.

Description

This property is read-only.

See Also

System.Net.HttpWebRequest Class, System.Net Namespace

A Int32 indicating the number of milliseconds to wait for a response until the request times out, or System.Threading.Timeout.Infinite to indicate that the request does not time out.

Exceptions

Exception Type	Condition
ArgumentOutOfRangeException	A value less than zero and not equal to System.Threading.Timeout.Infinite is specified for a set operation.

Description

System.Net.HttpWebRequest.Timeout is the number of milliseconds that a synchronous request made with the System.Net.HttpWebRequest.GetResponse method waits for a response. If a resource does not respond within the time-out period, the request throws a WebException with the System.Net.WebException.Status property set to System.Net.WebExceptionStatus.Timeout.

[Note: This property overrides System.Net.WebRequest.Timeout.]

See Also

System.Net.HttpWebRequest Class, System.Net Namespace

A String that contains the value of the HTTP Transfer-encoding header. The default value is null .

Exceptions

Exception Type	Condition
InvalidOperationException	System.Net.HttpWebRequest.TransferEncoding is set when System.Net.HttpWebRequest.SendChunked is false .
ArgumentException	System.Net.HttpWebRequest.TransferEncoding is set to the value "Chunked". This value is case insensitive.

Description

This property can be set in the current instance only if the System.Net.HttpWebRequest.SendChunked property in the current instance is true .

[Note: Clearing System.Net.HttpWebRequest.TransferEncoding by setting it to null has no effect on the value of System.Net.HttpWebRequest.SendChunked.

Values assigned to the System.Net.HttpWebRequest.TransferEncoding property replace any existing contents.

For additional information see section 14.41 of IETF RFC 2068 - HTTP/1.1.

]

See Also

System.Net.HttpWebRequest Class, System.Net Namespace

A String containing the value of the HTTP User-agent header. The default value is null .

Description

[Note: For additional information see section 14.43 of IETF RFC 2068 - HTTP/1.1.]

See Also

System.Net.HttpWebRequest Class, System.Net Namespace