FileWebRequest クラス

[アーティクル]
03/28/2008

WebRequest クラスのファイルシステムの実装を提供します。

この型のすべてのメンバの一覧については、FileWebRequest メンバを参照してください。

System.Object
   System.MarshalByRefObject
      System.Net.WebRequest
         System.Net.FileWebRequest

<Serializable>
Public Class FileWebRequest   Inherits WebRequest
[C#]
[Serializable]
public class FileWebRequest : WebRequest
[C++]
[Serializable]
public __gc class FileWebRequest : public WebRequest
[JScript]
public
   Serializable
class FileWebRequest extends WebRequest

スレッドセーフ

この型の public static (Visual Basicでは Shared) のすべてのメンバは、マルチスレッド操作で安全に使用できます。インスタンスのメンバの場合は、スレッドセーフであるとは限りません。

解説

FileWebRequest クラスは、 file:// スキームを使用してローカルファイルを要求する URI 用に、 WebRequest 抽象 (Visual Basic では MustInherit) 基本クラスを実装します。

FileWebRequest コンストラクタは使用しないでください。 FileWebRequest クラスの新しいインスタンスを初期化するには、 WebRequest.Create メソッドを使用します。URI スキームが file:// の場合、 Create メソッドは、 FileWebRequest インスタンスを返します。

GetResponse メソッドは、 RequestUri プロパティで指定されるファイルへの同期要求を行い、応答を格納した FileWebResponse インスタンスを返します。 BeginGetResponse メソッドと EndGetResponse メソッドを使用して、ファイルへの非同期要求を可能にします。

ファイルにデータを書き込む場合、 GetRequestStream メソッドは書き込み先の Stream インスタンスを返します。 BeginGetRequestStream メソッドと EndGetRequestStream メソッドは、書き込みデータストリームへの非同期アクセスを可能にします。

FileWebRequest クラスは、エラー処理とコードアクセスセキュリティのために File クラスを使用します。

使用例

 
'
' 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


[C#] 

// 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. 

using System.Net;
using System;
using System.IO;
using System.Text;

namespace Mssc.PluggableProtocols.File
{
  class TestGetRequestStream
  {
    private static FileWebRequest myFileWebRequest;

    private static void showUsage()
    {
      Console.WriteLine("\nPlease enter file name and timeout :");
      Console.WriteLine("Usage: cs_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.");
    }

    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.Timeout = timeout;
        // Set the Method property to POST  
        myFileWebRequest.Method="POST";
      }
      catch(WebException e)
      {
        Console.WriteLine("WebException: "+e.Message);
      }
      catch(UriFormatException e)
      {
        Console.WriteLine("UriFormatWebException: "+e.Message);
      }
    }

    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();
        byte[] byteArray = encoder.GetBytes(userInput);    
        // Set the ContentLength property.
        myFileWebRequest.ContentLength=byteArray.Length;  
        string contentLength = myFileWebRequest.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.Length);

        Console.WriteLine("\nThe String you entered was successfully written to the file.");  

        readStream.Close();

      }
      catch(WebException e)
      {
        Console.WriteLine("The WebException: "+e.Message);
      }
      catch(UriFormatException e)
      {
        Console.WriteLine("The UriFormatWebException: "+e.Message);
      }
    }

    public static void Main(String[] args)
    {
      if (args.Length < 2)
        showUsage();
      else
      {
        makeFileRequest(args[0], int.Parse(args[1]));
        writeToFile();
      }
    }
  }
}

[C++] 

// This program creates or open a text file in which it stores a string.
// Both file and string are passed by the user.
// Note. In order for this program to work, the folder containing the test file
// must be shared with its permissions set to allow write access.

#using <mscorlib.dll>
#using <System.dll>

using namespace System;
using namespace System::IO;
using namespace System::Text;
using namespace System::Net;

__gc class TestGetRequestStream {
private:
   static FileWebRequest*  myFileWebRequest;

   static void showUsage() {
      Console::WriteLine(S"\nPlease enter file name and timeout :");

      Console::WriteLine(S"Usage: cs_getrequeststream <systemname>/<sharedfoldername>/<filename> timeout");
      Console::WriteLine(S"Example: cs_getrequeststream ndpue/temp/hello.txt 1000");
      Console::WriteLine(S"Small timeout values (for instance 3 or less) cause a timeout exception.");
   }

   static void makeFileRequest(String* fileName, int timeout) {
      try {
         // Create a Uri object.
         Uri* myUrl = new Uri(String::Format(S"file://{0}", fileName));
         // Create a FileWebRequest object.
         myFileWebRequest = dynamic_cast<FileWebRequest*>(WebRequest::CreateDefault(myUrl));
         // Set the timeout to the value selected by the user.
         myFileWebRequest->Timeout = timeout;
         // Set the Method property to POST
         myFileWebRequest->Method=S"POST";
      } catch (WebException* e) {
         Console::WriteLine(S"WebException: {0}", e->Message);
      } catch (UriFormatException* e) {
         Console::WriteLine(S"UriFormatWebException: {0}", e->Message);
      }
   }

   static void writeToFile() {
      try {
         // Enter the string to write into the file.
         Console::WriteLine(S"Enter the string you want to write:");
         String* userInput = Console::ReadLine();
         // Convert the string to Byte array.
         ASCIIEncoding* encoder = new ASCIIEncoding();
         Byte byteArray[] = encoder->GetBytes(userInput);
         // Set the ContentLength property.
         myFileWebRequest->ContentLength=byteArray->Length;
         String* contentLength = myFileWebRequest->ContentLength.ToString();
         Console::WriteLine(S"\nThe content length is {0}.", contentLength);
         // Get the file stream handler to write into the file.
         Stream* readStream=myFileWebRequest->GetRequestStream();

         // Write to the file stream.
         // Note. In order 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. The permissions
         // can be set so everyone can modify the file.
         // FileWebRequest::Credentials property cannot be used for this purpose.
         readStream->Write(byteArray, 0, userInput->Length);

         Console::WriteLine(S"\nThe String you entered was successfully written into the file.");

         readStream->Close();

      } catch (WebException* e) {
         Console::WriteLine(S"The WebException: {0}", e->Message);
      } catch (UriFormatException* e) {
         Console::WriteLine(S"The UriFormatWebException: {0}", e->Message);
      }
   }

public:
   static void Main() {
      String* args[] = Environment::GetCommandLineArgs();
      if (args->Length < 3)
         showUsage();
      else {
         makeFileRequest(args[1], Int32::Parse(args[2]));
         writeToFile();
      }
   }
};

int main()
{
   TestGetRequestStream::Main();
}

[JScript] JScript のサンプルはありません。Visual Basic、C#、および C++ のサンプルを表示するには、このページの左上隅にある言語のフィルタボタンをクリックします。

必要条件

名前空間: System.Net

プラットフォーム: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 ファミリ

アセンブリ: System (System.dll 内)

参照

FileWebRequest メンバ | System.Net 名前空間 | File

次の方法で共有

FileWebRequest クラス

スレッドセーフ

解説

使用例

必要条件

参照

その他のリソース