Download all the versions of a file from a SharePoint document library

Introduction

Some days back, I submitted a code snippet named File Shunter that can be used to upload multiple files in a batch to a SharePoint (2003/2007) document library with meta data update and switching versioning On/Off. This code snippet (some of its parts I found on the net some time back) named Anti Shunter can be used to download all versions of all documents from a document library (up to any number of folders, if they exist), and it can be configured to retain the uploaded Date Created and Date Modified.

Background

Some days back, we had to upgrade from SharePoint 2003 to MOSS 2007, and we maintain a huge document library for an electronic document system (approx 200,000 files with many versions), and none of the In-Place or other methods helped to upgrade to SP 2007. We maintain a number of meta data columns which are mainly composed of file names. So, I had to write some piece of code which could download all the versions of all files into a folder structure, retaining there actual Date Created and Date Modified and composing the file name as required from meta data columns.

Using the code

The following code can be used in a number of ways to get a single required file, all files, or a few files filtered by some meta data column or the Title/Name column. I have used the SharePoint 2007 Object Model (based on Microsoft.SharePoint.dll) and used the SPFile and SPWeb classes to access a file and then its versions, and each version required meta data. Say, a file has five versions in a folder named A, then this code will create a folder "A" with four subfolders named "Revision-4" "Revision-3", "Revision 2", "Revision 1", each folder containing the file version, and the current file will be in folder "A" outside of the other revision subfolders. So now, this folder structure can be uploaded again into a new document library or used for any other purpose required. The following function can be used recursively in order to access all the folders/subfolders within a document library. The Document Library columns named Date Created and Date Modified can be accessed and stored into variables, and while saving the files, using the FileSystem class, a file's Date Created and Modified can be updated.

Private Function AccessFolder(ByVal folder As SPFolder) As Long

    Dim strPath As String = String.Empty

    Dim lFolderSize As Long = 0

    If m_strExportDir <> String.Empty Then
        strPath = folder.ServerRelativeUrl
    End If

    Dim iTotalVersions As Integer = 0
    Dim iI As Integer = 0
    Dim FinalFileName As String = ""
    Dim dt_SPFileCreated As DateTime
    Dim s_FileName As String = ""

    For Each file As SPFile In folder.Files
      iTotalVersions = file.Versions.Count
      Dim versions As SPFileVersionCollection = file.Versions  
       For iI = 0 To iTotalVersions - 1
             iTotalDocs = iTotalDocs + 1         
             Dim version As SPFileVersion = versions(iI)
            ' Dim hash As System.Collections.Hashtable = _
                          file.Versions(iI).Properties
            ' Dim keys As System.Collections.ICollection = hash.Keys
             s_FileName = file.Name
             dt_SPFileCreated = file.Versions(iI).Created 
             m_iTotalFileVersions += 1
            ' Now the above declared hash and keys can be used
            ' to acces each metadata columns
            ' as follows
            ' Dim key As Object
            'For Each key In keys
            'If key.ToString.ToLower = "Ur Custom Column Name" Then
                 ' Do whatever required
            ' End if 
           FinalFileName = file.name
           System.IO.Directory.CreateDirectory(Pathtofilesystemtosave + _
                     "\Revision-" + m_iTotalFileVersions.ToString)
           Dim sFileLoc As String = path + "\Revision-" + _
               m_iTotalFileVersions.ToString + "\\" + FinalFileName
           Dim binFile As Byte() = version.OpenBinary()
           If binFile.Length > 0 Then
           Dim fs As FileStream = New FileStream(sFileLoc, _
                     FileMode.OpenOrCreate, FileAccess.Write)
           fs.Write(binFile, 0, binFile.Length)
           fs.Close()
           End If
       Next

       ' Now for current file
       iI = iI + 1
       iTotalDocs = iTotalDocs + 1
       Dim hash As System.Collections.Hashtable = file.Properties
       Dim keys As System.Collections.ICollection = hash.Keys
       s_FileName = file.Name
       dt_SPFileCreated = file.TimeCreated

       ' In the same way as above for versions, Key ca be declared to access 
       ' hash table for meta data column collection to access(skipping)
       FinalFileName = file.Name
       System.IO.Directory.CreateDirectory(Pathtofilesystemtosave + _
                        "\Revision-" + iI.ToString)
       Dim sFileLoc As String = Path + "\Revision-" + _
                 iI.ToString + "\\" + FinalFileName
       Dim binFile As Byte() = file.OpenBinary()
       If binFile.Length >= 0 Then
         Dim fs As FileStream = New FileStream(sFileLoc, _
                   FileMode.OpenOrCreate, FileAccess.Write)
         fs.Write(binFile, 0, binFile.Length)
         fs.Close()
       end if
    Next
End Function