(PowerShell) SharePoint -- Download Newer Files

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Demonstrates how to download all files from a SharePoint folder that are newer than the local files.

Chilkat .NET Downloads Chilkat .NET Assemblies

Add-Type -Path "C:\chilkat\ChilkatDotNet47-9.5.0-x64\ChilkatDotNet47.dll"

# This requires the Chilkat API to have been previously unlocked.
# See Global Unlock Sample for sample code.

# -------------------------------------------------------------------------
# The following comments apply to SharePoint Windows classic authentication.
# -------------------------------------------------------------------------
# For example, imagine our SharePoint endpoint is https://xyzoffice.mycompany.com/
# The SHAREPOINT_NTLM_DOMAIN would be "mycompany.com"
# The SHAREPOINT_HTTPS_DOMAIN would be "xyzoffice.mycompany.com"
# Also, the SHAREPOINT_USERNAME would be just the name, not a full email address.
# for example, "chilkat" instead of "chilkat@mycompany.com"

$http = New-Object Chilkat.Http

# If SharePoint Windows classic authentication is used, then set the 
# Login, Password, LoginDomain, and NtlmAuth properties.
$http.Login = "SHAREPOINT_USERNAME"
$http.Password = "SHAREPOINT_PASSWORD"
$http.LoginDomain = "SHAREPOINT_NTLM_DOMAIN"
$http.NtlmAuth = $true

# -------------------------------------------------------------------------
# The more common case is to use SharePoint Online authentication (via the SPOIDCRL cookie).
# If so, do not set Login, Password, LoginDomain, and NtlmAuth, and instead
# establish the cookie as shown at SharePoint Online Authentication
# -------------------------------------------------------------------------

# First we'll download a list of all the files in the /Documents folder.
# This provides the names and last-modified date/times of the files located
# on the SharePoint server.
$http.Accept = "application/json;odata=verbose"
$http.AcceptCharset = "utf-8"

$sbJson = New-Object Chilkat.StringBuilder
$success = $http.QuickGetSb("https://SHAREPOINT_HTTPS_DOMAIN/_api/web/GetFolderByServerRelativeUrl('/Documents')/Files",$sbJson)
if ($success -ne $true) {
    $($http.LastErrorText)
    exit
}

# Before proceeding, make sure the local directory where we'll be downloading files exists.
$fac = New-Object Chilkat.FileAccess
$fac.DirEnsureExists("qa_output/sharepoint/Documents")

# OK.. load the JSON and iterate over each file
$json = New-Object Chilkat.JsonObject
$json.LoadSb($sbJson)

$numFiles = $json.SizeOfArray("d.results")
$("Number of Files in the SharePoint /Documents folder = " + $numFiles)

$lastModRemote = New-Object Chilkat.CkDateTime

$localPath = New-Object Chilkat.StringBuilder
$fileUrl = New-Object Chilkat.StringBuilder

$i = 0
while ($i -lt $numFiles) {
    $json.I = $i

    $filename = $json.StringOf("d.results[i].Name")
    $sLastModified = $json.StringOf("d.results[i].TimeLastModified")

    $([string]$i + 1 + ": " + $filename + " (" + $sLastModified + ")")

    $lastModRemote.SetFromTimestamp($sLastModified)

    $bDownload = $false
    # Check to see if the local file exists.  If not, then download.
    $localPath.SetString("qa_output/sharepoint/Documents/")
    $localPath.Append($filename)
    if ($fac.FileExists($localPath.GetAsString()) -ne $true) {
        $("This file does not exist locally.")
        $bDownload = $true
    }
    else {
        # Get the local file's date time and compare with the remote file date/time.
        $lastModLocal = $fac.GetLastModified($localPath.GetAsString())
        if ($fac.LastMethodSuccess -eq $true) {
            # Get the difference in seconds between the local and remote last-modified times.
            # if the return value is negative, then the caller's time is 
            # older than the argument.  (in this case, a negative return value means
            # the local file is older than the remote file.

            # Note: The DiffSeconds method was found to be missing in the Chilkat .NET build
            # (and possibly in other builds). It will be present in the v9.5.0.67 release and later.
            $numSeconds = $lastModLocal.DiffSeconds($lastModRemote)
            if ($numSeconds -lt 0) {
                $("The local file is older than the remote file.")
                $bDownload = $true
            }

        }
        else {
            $("Unable to get the local file's last-modified date/time.")
            $($fac.LastErrorText)
        }

    }

    if ($bDownload -eq $true) {
        $fileUrl.SetString("https://SHAREPOINT_HTTPS_DOMAIN/_api/web/GetFolderByServerRelativeUrl('/Documents')/Files('")
        $fileUrl.Append($filename)
        $fileUrl.Append("')/$value")

        $("Downloading " + $filename)

        $success = $http.Download($fileUrl.GetAsString(),$localPath.GetAsString())
        if ($success -ne $true) {
            $($http.LastErrorText)
            exit
        }

        # Set the local file's last-modified date/time to that of the server's.
        $fac.SetLastModified($localPath.GetAsString(),$lastModRemote)

    }

    $i = $i + 1
}

$("All finished.")