VB6 dll calls from WCF

Emanuela Meraglia

Hi everyone, I created a library of the WCF service, which recalls a VB6 dll. The problem is this: in the procedures of the VB6 dll (not my owner) strange errors occur (especially with dates), if the initial process that hosts it is the WCF service. Everything works correctly if the initial process is a VB6 executable, a VB.NET executable, or if I run the VB6 project in debug. Among the many attempts I set all my projects with CPUs targeting x86, and although I had no problems compiling the WCF service, I also tried to replace WcfSvcHost.exe with the same in 32-bit mode (with the command "corflags / 32BIT + / FORCE WcfSvcHost.exe "), but the problem persists. Actually I don't think it's even necessary, as the hosting of the WCF library is an application console. I have no idea how to solve ... can anyone help me?

Lost User

Emanuela Meraglia wrote:

strange errors occur

Please don't keep them secret.

Richard Deeming

You're going to need to provide more details on the errors you're getting. My guess would be something to do with the regional settings for the session that's hosting your WCF service. But without any details, it's just a guess.

"These people looked deep within my soul and assigned me a number based on the order in which I joined." - Homer

Lost User

Does it run under the same user credentials as a normal executable?

Bastard Programmer from Hell :suss: If you can't read my code, try converting it here[^] "If you just follow the bacon Eddy, wherever it leads you, then you won't have to think about politics." -- Some Bell.

Emanuela Meraglia

I don't have the error because the VB6 dll is not mine, but with SQL profiler I found errors in the queries due to lack or incorrect formatting of dates.

Emanuela Meraglia

I don't have the error because the VB6 dll is not mine, but with SQL profiler I found errors in the queries due to lack or incorrect formatting of dates.

Emanuela Meraglia

The error also occurs on my development PC, on which everything is executed. So I don't think it's a problem of regional settings.

Emanuela Meraglia

I start the service without credentials:

Private Sub AvviaServizio(ByVal t As Type, ByVal uri As String, ByVal classe As String)
Dim binding As New BasicHttpBinding
binding.OpenTimeout = New TimeSpan(0, 10, 0)
binding.CloseTimeout = New TimeSpan(0, 10, 0)
binding.SendTimeout = New TimeSpan(0, 10, 0
'binding.ReceiveTimeout = New TimeSpan(0, 10, 0)
'binding.Security.Mode = SecurityMode.Transport
'binding.Security.Transport.ClientCredentialType = HttpClientCredentialType.None
'binding.Security.Transport.ProxyCredentialType = HttpProxyCredentialType.None
binding.MaxBufferPoolSize = 2147483647
binding.MaxBufferSize = 2147483647
binding.MaxReceivedMessageSize = 2147483647
binding.MessageEncoding = WSMessageEncoding.Text

    Dim host As New ServiceModel.ServiceHost(t)
    host.AddServiceEndpoint(classe, binding, New Uri(uri & classe))
    Try
        host.Description.Behaviors.Add(New ServiceMetadataBehavior With {
            .HttpGetEnabled = True,
            .HttpGetUrl = New Uri(uri & classe)
        })
        host.Open()

        \_service.Add(host)
    Catch ex As Exception
        host.Abort()
        Throw
    End Try
End Sub

Lost User

That doesn't answer my question; write the name of the current user to a logfile or similar to check.

Bastard Programmer from Hell :suss: If you can't read my code, try converting it here[^] "If you just follow the bacon Eddy, wherever it leads you, then you won't have to think about politics." -- Some Bell.

Emanuela Meraglia

I don't understand which user you're referring to

Dave Kreskowiak

VB6 can only make COM-exposed .DLL's. I don't know if that means or affects anything, but there it is. Without seeing the code that's calling the functions in the .DLL, and the error messages coming back from SQL Server, it's going to be impossible to tell you anything useful. The biggest problem is we can see the code in the VB6 .DLL, so we don't know what it expects in the function calls.

Asking questions is a skill CodeProject Forum Guidelines Google: C# How to debug code Seriously, go read these articles.
Dave Kreskowiak

Lost User

Environment.UserName All the code runs under specific credentials. Your hosted service may not be running as a default user.

Bastard Programmer from Hell :suss: If you can't read my code, try converting it here[^] "If you just follow the bacon Eddy, wherever it leads you, then you won't have to think about politics." -- Some Bell.

Emanuela Meraglia

I do not have the VB6 dll source from my provider, so I have no way of getting the error.
I am attaching images of errors captured by SQL Profiler, but I don't think they can help.
The 1.png, 2.png and 3.png files are screenshots of the SQL profiler traces captured at Runtime, while the 1_Debug.png, 2_Debug.png and 3_Debug.png files are screenshots of the SQL profiler traces captured in Debug (so working).

Since the errors do not occur by calling the VB6 dll from VB6 or VB.NET applications, or by debugging my VB6 project which instantiates the external dll, I thought the problem lies in the process that hosts it.

https://drive.google.com/open?id=1Wziux18JvKzx-7DtBMTSfrOT5TuANVVF

Emanuela Meraglia

I wrote the current user in my log file, and it matches with the Windows credentials I logged in with ... so it's ok.

Lost User

Your link points to this page.

Emanuela Meraglia

Errori.zip - Google Drive[^]

Richard Deeming

Emanuela Meraglia wrote:

errors in the queries due to lack or incorrect formatting of dates

That would suggest that the VB6 code is vulnerable to SQL Injection[^]. It it was using properly parameterized queries, date formatting wouldn't be an issue. This is a serious security vulnerability. You should either get the author to rewrite the VB6 code, or find some way to replace it.

"These people looked deep within my soul and assigned me a number based on the order in which I joined." - Homer

Lost User

:thumbsup:

Bastard Programmer from Hell :suss: If you can't read my code, try converting it here[^] "If you just follow the bacon Eddy, wherever it leads you, then you won't have to think about politics." -- Some Bell.

Emanuela Meraglia

They are rewriting it, but in the meantime I have to use their dll VB6! :(

Lost User

All the messages seem to be complaining about the syntax of the SELECT clauses (assuming my innterpretation of the Italian is coorect), and suggesting that it has something to do with the Date values. I think the only way to resolve this is to talk to the owners of the DLL.