Foreach ftp file enumerator

Case
I want to loop through all files in a FTP folder and process them. I need a Foreach ftp file enumerator, but the Foreach Loop component only loops through local files.

Solution
There are a couple of options. You could use a Script Task, a wildcard in the RemotePath Property of the FTP Task or a Third Party component to download all files to a certain folder and loop through those files with a Foreach Loop file enumerator. This is the most common approach.
This example uses a Script Task to get a list of ftp files and uses a Foreach From Variable Enumerator to loop through those files.

Update: There is now a custom Foreach FTP File Enumerator available.



1) Variables
We need a couple of variables to keep things flexible:

• FtpWorkingDirectory: String variable with the remote folder path. Example: /root/data/
• DownloadDirectory: String variable that contains the path of the download folder: Example: d:\SourceFiles\
• FtpFileURL: String variable used in the foreach loop to store the remote filename in. Example: 01-01-2011.csv
• FtpFileList: Object variable to store the remote file list in.

Variables to keep things flexible

2) Ftp Connection Manager
Create a FTP Connection Manager by right clicking in the Connection Manager pane and select New Connection... In the new window select FTP and click Add. After that fill in the FTP Connection Manager Editor. Test the connection manager and rename it to myFtpServer (this name is used in the Script Task).

New FTP connection

After closing you can rename it.

3) Script Task
Add a Script Task to the Control Flow and give it a suitable name. Edit the Script Task and add variable FtpWorkingDirectory as ReadOnly and FtpFileList as ReadWrite.

Script Task to get list of files

4) The Script
Edit the script and copy the following code.

// #C Code
using System;
using System.Collections;       // Added
using System.Data;
using System.Net;
using Microsoft.SqlServer.Dts.Runtime;
using System.Windows.Forms;

namespace ST_f20cc76ba3bc47849f70c6cbfd4701dc.csproj
{
    [System.AddIn.AddIn("ScriptMain", Version = "1.0", Publisher = "", Description = "")]
    public partial class ScriptMain : Microsoft.SqlServer.Dts.Tasks.ScriptTask.VSTARTScriptObjectModelBase
    {

        #region VSTA generated code
        enum ScriptResults
        {
            Success = Microsoft.SqlServer.Dts.Runtime.DTSExecResult.Success,
            Failure = Microsoft.SqlServer.Dts.Runtime.DTSExecResult.Failure
        };
        #endregion

        public void Main()
        {
            try
            {
                // Get the ftp connection from the Connection Managers collection
                ConnectionManager ftpServer = Dts.Connections["myFtpServer"];

                // Create a FTP connection object and us the credentials of connection manager
                FtpClientConnection myFtpConnection = new FtpClientConnection(ftpServer.AcquireConnection(null));

                // Open the connection
                myFtpConnection.Connect();

                // Set work folder with the value of the variable
                myFtpConnection.SetWorkingDirectory(Dts.Variables["FtpWorkingDirectory"].Value.ToString());

                // Create StringArrays for filenames and folders
                // The folderNames aren't used, but is mandatory
                // for the next method.
                String[] fileNames;
                String[] folderNames;

                // Get a directory listing and fill the StringArray variables
                myFtpConnection.GetListing(out folderNames, out fileNames);

                // Copy StringArray to ArrayList to fit in Object variable
                ArrayList fileNamesArray = new ArrayList(fileNames);
                
                // Optional sorter
                fileNamesArray.Sort();

                // Fill ssis object variable
                Dts.Variables["FtpFileList"].Value = fileNamesArray;

                // Close connection
                myFtpConnection.Close();

                // Close Script Task, set result to success
                Dts.TaskResult = (int)ScriptResults.Success;
            }
            catch (Exception ex)
            {
                // Fire error and set result to failure
                Dts.Events.FireError(0, "FTP Script Task", "Error: " + ex.Message, string.Empty, 0);
                Dts.TaskResult = (int)ScriptResults.Failure;
            }
        }
    }
}

Or VB.Net

' VB.Net code
Imports System
Imports System.Collections
Imports System.Data
Imports System.Math
Imports Microsoft.SqlServer.Dts.Runtime

<System.AddIn.AddIn("ScriptMain", Version:="1.0", Publisher:="", Description:="")> _
<System.CLSCompliantAttribute(False)> _
Partial Public Class ScriptMain
 Inherits Microsoft.SqlServer.Dts.Tasks.ScriptTask.VSTARTScriptObjectModelBase

 Enum ScriptResults
  Success = Microsoft.SqlServer.Dts.Runtime.DTSExecResult.Success
  Failure = Microsoft.SqlServer.Dts.Runtime.DTSExecResult.Failure
 End Enum
 
    Public Sub Main()
        Try
            ' Get the ftp connection from the Connection Managers collection
            Dim ftpServer As ConnectionManager = Dts.Connections("myFtpServer")

            ' Create a FTP connection object and us the credentials of connection manager
            Dim myFtpConnection As FtpClientConnection = New FtpClientConnection(ftpServer.AcquireConnection(Nothing))

            ' Open the connection
            myFtpConnection.Connect()

            ' Set work folder with the value of the variable
            myFtpConnection.SetWorkingDirectory(Dts.Variables("FtpWorkingDirectory").Value.ToString())

            ' Create StringArrays for filenames and folders
            ' The folderNames aren't used, but is mandatory
            ' for the next method.
            Dim fileNames() As String
            Dim folderNames() As String

            ' Get a directory listing and fill the StringArray variables
            myFtpConnection.GetListing(folderNames, fileNames)

            ' Copy StringArray to ArrayList to fit in Object variable
            Dim fileNamesArray As ArrayList = New ArrayList(fileNames)

            ' Optional sorter
            fileNamesArray.Sort()

            ' Fill ssis object variable
            Dts.Variables("FtpFileList").Value = fileNamesArray

            ' Close connection
            myFtpConnection.Close()

            ' Close Script Task, set result to success
            Dts.TaskResult = ScriptResults.Success
        Catch ex As Exception
            ' Fire error and set result to failure
            Dts.Events.FireError(0, "FTP Script Task", "Error: " + ex.Message, String.Empty, 0)
            Dts.TaskResult = ScriptResults.Failure
        End Try
    End Sub
End Class

5) Foreach Loop
Add a Foreach Loop after the Script Task. Edit the Foreach Loop and on the Collection tab select Foreach From Variable Enumerator as enumerator and select the object variable FtpFileList as the variable.

Foreach From Variable Enumerator

6) Foreach Loop Variable Mappings
On the Variable Mappings tab of the Foreach Loop select the variable FtpFileURL.

Variable Mapping

7) FTP Task General
Add a FTP task within the Foreach Loop. Edit the FTP Task and on the General tab you can select the FTP Connection which we created in step 2. And you can give it a suitable name.

General: select the ftp connection

8) FTP Task File Transfer
On the File Transfer tab you can select the DownloadDirectory variable for the local folder. In the Operation category you should select Receive files as the operation. For RemotePath you can enter a dummy value because we are overriding that value with an expression in the next step.

File Transfer

9) FTP Task Expressions
At the Expressions tab you must add an expression for the RemotePath: @[User::FtpWorkingDirectory] +  @[User::FtpFileURL] This expression combines the working folder (/root/data/) and the filename (01-01-2011.csv) into: /root/data/01-01-2011.csv.

Click at 2 to open the Expression Editor

10) Process file in Data Flow
Add a Data Flow Task within the Foreach Loop to process the downloaded files.

Process files

10) Process file in Connection Manager
Create a Data Flow like the example below. I named the connection for the csv file myDownloadedFtpFile. Go to the properties of that connection and add an expression for the ConnectionString so we can use it in the Foreach Loop: @[User::DownloadDirectory] + @[User::FtpFileURL]

A simple data flow

Expression to override the ConnectionString property

11) The result
Run the package to see the result.

The result

Download example package

Note: In the Script Task you can use the .Net variable folderNames to create some recursive function to loop through all subfolders as well.

Note: If you just want to download all files with a Script Task and use a Foreach Loop file enumerator to process all files, you can replace the C# lines 48 - 55 or the VB.Net lines 41 - 48 with the following code:

// C# Code
// Download all files at once. Don't forget to add the SSIS variable DownloadDirectory to the ReadOnlyVariables
myFtpConnection.ReceiveFiles(fileNames, Dts.Variables["DownloadDirectory"].Value.ToString(), true, false);

' VB.Net code
' Download all files at once. Don't forget to add the SSIS variable DownloadDirectory to the ReadOnlyVariables
myFtpConnection.ReceiveFiles(fileNames, Dts.Variables("DownloadDirectory").Value.ToString(), true, false)

Update: There is a custom Foreach FTP File Enumerator available.