FileWebRequest Class
Assembly: System (in system.dll)
'Declaration <SerializableAttribute> _ Public Class FileWebRequest Inherits WebRequest Implements ISerializable 'Usage Dim instance As FileWebRequest
/** @attribute SerializableAttribute() */ public class FileWebRequest extends WebRequest implements ISerializable
SerializableAttribute public class FileWebRequest extends WebRequest implements ISerializable
Not applicable.
The FileWebRequest class implements the WebRequestabstract base class for Uniform Resource Identifiers (URIs) that use the file:// scheme to request local files.
Do not use the FileWebRequest constructor. Use the WebRequest.Create method to initialize new instances of the FileWebRequest class. If the URI scheme is file://, the Create method returns a FileWebRequest object.
The GetResponse method makes a synchronous request for the file specified in the RequestUri property and returns a FileWebResponse object that contains the response. You can make an asynchronous request for the file using the BeginGetResponse and EndGetResponse methods.
When you want to write data to a file, the GetRequestStream method returns a Stream instance to write to. The BeginGetRequestStream and EndGetRequestStream methods provide asynchronous access to the write data stream.
The FileWebRequest class relies on the File class for error handling and code access security.
The following code example uses the FileWebRequest class to access a file system resource.
' ' This example creates or opens a text file and stores a string in it. ' Both the file and the string are passed by the user. ' Note. For this program to work, the folder containing the test file ' must be shared, with its permissions set to allow write access. Imports System.Net Imports System Imports System.IO Imports System.Text Namespace Mssc.PluggableProtocols.File Module TestGetRequestStream Class TestGetRequestStream Private Shared myFileWebRequest As FileWebRequest ' Show how to use this program. Private Shared Sub showUsage() Console.WriteLine(ControlChars.Lf + "Please enter file name and timeout :") Console.WriteLine("Usage: vb_getrequeststream <systemname>/<sharedfoldername>/<filename> timeout") Console.WriteLine("Example: vb_getrequeststream ngetrequestrtream() ndpue/temp/hello.txt 1000") Console.WriteLine("Small time-out values (for example, 3 or less) cause a time-out exception.") End Sub Private Shared Sub makeFileRequest(ByVal fileName As String, ByVal timeout As Integer) Try ' Create a Uri object.to access the file requested by the user. Dim myUrl As New Uri("file://" + fileName) ' Create a FileWebRequest object.for the requeste file. myFileWebRequest = CType(WebRequest.CreateDefault(myUrl), FileWebRequest) ' Set the time-out to the value selected by the user. myFileWebRequest.Timeout = timeout ' Set the Method property to POST myFileWebRequest.Method = "POST" Catch e As WebException Console.WriteLine(("WebException is: " + e.Message)) Catch e As UriFormatException Console.WriteLine(("UriFormatWebException is: " + e.Message)) End Try End Sub Private Shared Sub writeToFile() Try ' Enter the string to write to the file. Console.WriteLine("Enter the string you want to write:") Dim userInput As String = Console.ReadLine() ' Convert the string to a byte array. Dim encoder As New ASCIIEncoding Dim byteArray As Byte() = encoder.GetBytes(userInput) ' Set the ContentLength property. myFileWebRequest.ContentLength = byteArray.Length Dim contentLength As String = myFileWebRequest.ContentLength.ToString() Console.WriteLine(ControlChars.Lf + "The content length is {0}.", contentLength) ' Get the file stream handler to write to the file. Dim readStream As Stream = myFileWebRequest.GetRequestStream() ' Write to the stream. ' Note. For this to work the file must be accessible ' on the network. This can be accomplished by setting the property ' sharing of the folder containg the file. ' FileWebRequest.Credentials property cannot be used for this purpose. readStream.Write(byteArray, 0, userInput.Length) Console.WriteLine(ControlChars.Lf + "The String you entered was successfully written to the file.") readStream.Close() Catch e As WebException Console.WriteLine(("WebException is: " + e.Message)) Catch e As UriFormatException Console.WriteLine(("UriFormatWebException is: " + e.Message)) End Try End Sub Public Shared Sub Main(ByVal args() As String) If args.Length < 2 Then showUsage() Else makeFileRequest(args(0), Integer.Parse(args(1))) writeToFile() End If End Sub 'Main End Class 'TestGetRequestStream End Module End Namespace
// This example creates or opens a text file and stores a string in it.
// Both the file and the string are passed by the user.
// Note. For this program to work, the folder containing the test file
// must be shared, with its permissions set to allow write access.
import System.Net.*;
import System.*;
import System.IO.*;
import System.Text.*;
class TestGetRequestStream
{
private static FileWebRequest myFileWebRequest;
private static void ShowUsage()
{
Console.WriteLine("\nPlease enter file name and timeout :");
Console.WriteLine("Usage: jsl_getrequeststream <systemname>/"
+ "<sharedfoldername>/<filename> timeout");
Console.WriteLine("Example: cs_getrequeststream ngetrequestrtream()"
+ "ndpue/temp/hello.txt 1000");
Console.WriteLine("Small time-out values (for example, 3 or less) "
+ "cause a time-out exception.");
} //ShowUsage
private static void MakeFileRequest(String fileName, int timeout)
{
try {
// Create a Uri object.
Uri myUrl = new Uri("file://" + fileName);
// Create a FileWebRequest object.
myFileWebRequest =
((FileWebRequest)(WebRequest.CreateDefault(myUrl)));
// Set the time-out to the value selected by the user.
myFileWebRequest.set_Timeout(timeout);
// Set the Method property to POST
myFileWebRequest.set_Method("POST");
}
catch (WebException e) {
Console.WriteLine(("WebException: " + e.get_Message()));
}
catch (UriFormatException e) {
Console.WriteLine(("UriFormatWebException: " + e.get_Message()));
}
} //MakeFileRequest
private static void WriteToFile()
{
try {
// Enter the string to write to the file.
Console.WriteLine("Enter the string you want to write:");
String userInput = Console.ReadLine();
// Convert the string to a byte array.
ASCIIEncoding encoder = new ASCIIEncoding();
ubyte byteArray[] = encoder.GetBytes(userInput);
// Set the ContentLength property.
myFileWebRequest.set_ContentLength(byteArray.length);
String contentLength =
(new Long(myFileWebRequest.get_ContentLength())).ToString();
Console.WriteLine("\nThe content length is {0}.", contentLength);
// Get the file stream handler to write to the file.
Stream readStream = myFileWebRequest.GetRequestStream();
// Write to the file stream.
// Note. For this to work, the file must be accessible
// on the network. This can be accomplished by setting the property
// sharing of the folder containg the file.
// FileWebRequest.Credentials property cannot be used for
// this purpose.
readStream.Write(byteArray, 0, userInput.get_Length());
Console.WriteLine("\nThe String you entered was successfully "
+ "written to the file.");
readStream.Close();
}
catch (WebException e) {
Console.WriteLine(("The WebException: " + e.get_Message()));
}
catch (UriFormatException e) {
Console.WriteLine(("The UriFormatWebException: "
+ e.get_Message()));
}
} //WriteToFile
public static void main(String[] args)
{
if (args.length < 2) {
ShowUsage();
}
else {
MakeFileRequest(args[0], Integer.parseInt(args[1]));
WriteToFile();
}
} //main
} //TestGetRequestStream
Windows 98, Windows Server 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.