Update list items remotely via Powershell

Question

From the server itself this works:

Add-PSSnapin "Microsoft.SharePoint.PowerShell"


$SPWeb = Get-SPWeb http://mysharepoint.org
$SPList = $SPWeb.Lists["My List"]
$SPListItem = $SPList.GetItemByUniqueId("<my unique id>")
$SPListItem["Name"] = "stuff"
$SPListItem["Title"] = "stuff"
$SPListItem.Update()

But remotely doing this:

$s = New-PSSession -ComputerName mysharepoint.org
Invoke-Command -Session $s {
Add-PSSnapin "Microsoft.SharePoint.PowerShell"
$SPWeb = Get-SPWeb http://mysharepoint.org
$SPList = $SPWeb.Lists["My List"]
$SPListItem = $SPList.GetItemByUniqueId("<my unique id>")
$SPListItem["Name"] = "stuff"
$SPListItem["Title"] = "stuff"
$SPListItem.Update()
}

Gets me:

You cannot call a method on a null-valued expression. + CategoryInfo : InvalidOperation: (:) [], RuntimeException + FullyQualifiedErrorId : InvokeMethodOnNull + PSComputerName : mysharepoint.org

Cannot index into a null array. + CategoryInfo : InvalidOperation: (:) [], RuntimeException + FullyQualifiedErrorId : NullArray + PSComputerName : mysharepoint.org

Cannot index into a null array. + CategoryInfo : InvalidOperation: (:) [], RuntimeException + FullyQualifiedErrorId : NullArray + PSComputerName : mysharepoint.org

You cannot call a method on a null-valued expression. + CategoryInfo : InvalidOperation: (:) [], RuntimeException + FullyQualifiedErrorId : InvokeMethodOnNull + PSComputerName : mysharepoint.org

Now clearly this is because I am getting a null list returned. But I can't understand why. Powershell Remoting is something I am just getting in to. How can I remotely update a list via powershell?

Answer 1

I finally found the answer!

adding these two lines to the top of my script worked.

$w = Get-SPWebApplication -Identity https://mysharepoint.org
$w.GrantAccessToProcessIdentity("domain\my_username")

Full script:

$s = New-PSSession -ComputerName mysharepoint.org
Invoke-Command -Session $s {
    Add-PSSnapin "Microsoft.SharePoint.PowerShell"

    $w = Get-SPWebApplication -Identity https://mysharepoint.org
    $w.GrantAccessToProcessIdentity("domain\my_username")

    $SPWeb = Get-SPWeb http://mysharepoint.org
    $SPList = $SPWeb.Lists["My List"]
    $SPListItem = $SPList.GetItemByUniqueId("<my unique id>")
    $SPListItem["Name"] = "stuff"
    $SPListItem["Title"] = "stuff"
    $SPListItem.Update()
}

Answer 2

If the stand alone web application and SharePoint are not in the same domain, the simple answer is that you cannot update an item in SharePoint list unless you are using Apps.

The more complex answer is that you would need to have a proxy of some sort to do this. You could write a simple layer 7 proxy inside the non-SharePoint web app that forwards the requests and the authentication or use something like Squid or even IIS itself to do this.

If both applications are in the same network and wouldn't need to make calls across the firewall. than yes it can be done via REST API

Another consideration might be hosting the non-SharePoint site in the same domain as SharePoint.

You can update the list item using REST API. Please find the answer here.

SharePoint 2013 REST api to update list item

SharePoint 2013 – CRUD on List Items Using REST Services & jQuery

UPDATED

Update list item example using powershell

$SPAssignment = Start-SPAssignment
$SPWeb = Get-SPWeb http://SP -AssignmentCollection $spAssignment

# Next step is to get the list:

$SPList = $SPWeb.Lists["Announcements"]

# When we have located the list we can retrieve the item. The quickest way is to use the GetItemByID() method:

$SPItem = $SPList.GetItemById("1")

# The example above requires that you know the ID of the item. If you don’t know the items ID you can use the Where-Object cmdlet instead:

$SPItem = $SPList.Items | Where { $_["Title"] -eq "New Announcement" }

# When you’ve retrieved the item you can modify the item information.

$SPItem["Title"] = "MyTitle"
$SPItem["Body"] = "MyBody"

# After modifying an item you have to call the Update() method to set the changes.

$SPItem.Update()

# When you’re done, use the Stop-SPAssignment cmdlet to dispose the SPWeb object.

Stop-SPAssignment $SPAssignment