Jeremy found this VB.Net code. It has a simple job: return a file back to the client, but with a twist: they don't know what the correct file extension is. So this was their solution for that problem:

Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

        If Application("PointsWhere") = "DEV" Then
            Dim strFile As String
            strFile = Application("UploadPODs").ToString.Trim & Session("PODClaim") & ".pdf"
            If System.IO.File.Exists(strFile) Then
                Response.ContentType = "Application/pdf"
            Else
                strFile = Application("UploadPODs").ToString.Trim & Session("PODClaim") & ".jpeg"
                If System.IO.File.Exists(strFile) Then
                    Response.ContentType = "image/jpeg"
                Else
                    strFile = Application("UploadPODs").ToString.Trim & Session("PODClaim") & ".jpg"
                    If System.IO.File.Exists(strFile) Then
                        Response.ContentType = "image/jpeg"
                    Else
                        strFile = Application("UploadPODs").ToString.Trim & Session("PODClaim") & ".gif"
                        If System.IO.File.Exists(strFile) Then
                            Response.ContentType = "image/gif"
                        Else
                            strFile = Application("UploadPODs").ToString.Trim & Session("PODClaim") & ".bmp"
                            If System.IO.File.Exists(strFile) Then
                                Response.ContentType = "image/bmp"
                            Else
                                strFile = Application("UploadPODs").ToString.Trim & Session("PODClaim") & ".png"
                                If System.IO.File.Exists(strFile) Then
                                    Response.ContentType = "image/png"
                                Else
                                    strFile = Application("UploadPODs").ToString.Trim & Session("PODClaim") & ".tiff"
                                    If System.IO.File.Exists(strFile) Then
                                        Response.ContentType = "image/tiff"
                                    Else
                                        strFile = Application("UploadPODs").ToString.Trim & Session("PODClaim") & ".tif"
                                        If System.IO.File.Exists(strFile) Then
                                            Response.ContentType = "image/tiff"
                                        End If
                                    End If
                                End If
                            End If
                        End If
                    End If
                End If
            End If
            Response.WriteFile(strFile)
            Response.End()
        Else
            'This is for Production
            Dim strFile As String
            strFile = Server.MapPath(Application("UploadPODs")) & Session("PODClaim") & ".pdf"
            If System.IO.File.Exists(strFile) Then
                Response.ContentType = "Application/pdf"
            Else
                strFile = Server.MapPath(Application("UploadPODs")) & Session("PODClaim") & ".jpeg"
                If System.IO.File.Exists(strFile) Then
                    Response.ContentType = "image/jpeg"
                Else
                    strFile = Server.MapPath(Application("UploadPODs")) & Session("PODClaim") & ".jpg"
                    If System.IO.File.Exists(strFile) Then
                        Response.ContentType = "image/jpeg"
                    Else
                        strFile = Server.MapPath(Application("UploadPODs")) & Session("PODClaim") & ".gif"
                        If System.IO.File.Exists(strFile) Then
                            Response.ContentType = "image/gif"
                        Else
                            strFile = Server.MapPath(Application("UploadPODs")) & Session("PODClaim") & ".bmp"
                            If System.IO.File.Exists(strFile) Then
                                Response.ContentType = "image/bmp"
                            Else
                                strFile = Server.MapPath(Application("UploadPODs")) & Session("PODClaim") & ".png"
                                If System.IO.File.Exists(strFile) Then
                                    Response.ContentType = "image/png"
                                Else
                                    strFile = Server.MapPath(Application("UploadPODs")) & Session("PODClaim") & ".tiff"
                                    If System.IO.File.Exists(strFile) Then
                                        Response.ContentType = "image/tiff"
                                    Else
                                        strFile = Server.MapPath(Application("UploadPODs")) & Session("PODClaim") & ".tif"
                                        If System.IO.File.Exists(strFile) Then
                                            Response.ContentType = "image/tiff"
                                        End If
                                    End If
                                End If
                            End If
                        End If
                    End If
                End If
            End If
            Response.WriteFile(strFile)
            Response.End()

        End If


    End Sub

I love the condition around whether they're in "DEV" or in "PROD", despite the code doing the exact same thing. The real magic, though, is the nested ifs for something that doesn't need to be nested. I can see the programmer's brain leaking smoke as they try and figure out the right way to check files and write a response, and the idea of iterating across an array of allowed extensions never occurred to them.

What I really wonder about: how many places do they branch on "DEV" and "PROD". It's like the world's worst implementation of feature flags, though marginally better than the solution an old workplace of mine had: store a text file on the server in a known location that contains the word "DEV", "TEST", or "PROD" so your code can check that file every time it needs to know what behavior it should use.

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