CODEWITHSUNDEEP
asp.netiis-7.5isolatedstorage
ChrisC
ChrisC

Reputation: 1171

Can't share isolated storage file between applications in different app pools

I've got various web apps (containing WCF services) in IIS under the default website. As long as they are all running in the same app pool they can access a shared isolated storage file no problem.

However, once I move them to different app pools I get "System.IO.IsolatedStorage.IsolatedStorageException: Unable to create mutex" when one tries to access a file created by another. They are all running under NetworkService user. I tried GetUserStoreForAssembly and GetMachineStoreForAssembly all with the same result. Any ideas why they couldn't use a shared file?

I made sure to close the stream and even dispose it in case one was holding onto it, but I am running a simple test where one service writes it, then another tries to read from it later, and it always fails.

Also, I am accessing the isolated store from a signed assembly.

Does anybody have any ideas?

Here is the code:

Private Sub LoadData()
    Dim filename = FullFilePath(_fileName)

    Dim isoStorage As IsolatedStorageFile = IsolatedStorageFile.GetUserStoreForAssembly()
    ' Tried GetMachineStoreForAssembly, same failure
    isoStorage.CreateDirectory(ROOT_DIRECTORY)

    If (isoStorage.GetFileNames(filename).Length = 0) Then
        Return
    End If

    Dim stream As Stream = New IsolatedStorageFileStream(filename, FileMode.OpenOrCreate, isoStorage)
    If stream IsNot Nothing Then
        Try

            Dim formatter As IFormatter = New BinaryFormatter()
            Dim appData As Hashtable = DirectCast(formatter.Deserialize(stream), Hashtable)

            Dim enumerator As IDictionaryEnumerator = appData.GetEnumerator()
            While enumerator.MoveNext()
                Me(enumerator.Key) = enumerator.Value
            End While
        Finally
            stream.Close()
            stream.Dispose()
            stream = Nothing
        End Try
    End If

End Sub

Public Sub Save()
    Dim filename = FullFilePath(_fileName)

    ' Open the stream from the IsolatedStorage.
    Dim isoFile As IsolatedStorageFile = IsolatedStorageFile.GetUserStoreForAssembly()
    ' Tried GetMachineStoreForAssembly, same failure
    Dim stream As Stream = New IsolatedStorageFileStream(filename, FileMode.Create, isoFile)
    If stream IsNot Nothing Then
        Try
            Dim formatter As IFormatter = New BinaryFormatter()
            formatter.Serialize(stream, DirectCast(Me, Hashtable))
        Finally
            stream.Close()
            stream.Dispose()
            stream = Nothing
        End Try
    End If

End Sub

Upvotes: 2

Views: 683

Answers (1)

ChrisC
ChrisC

Reputation: 1171

Looks like it was a trust issue.

After adding the assembly accessing the isolated storage file to the gac it magically worked as everything in the gac has full trust set automatically.

This works for me, but it might not always be an option to do this for other solutions. Check out the .NET Framework caspol utility if this is the case.

Hope this helps somebody! It was a huge pitafor me.

Upvotes: 2

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