How to Upload Files to SharePoint Online Using Microsoft Graph API and PowerShell

    Param (
    $Tenant                  = "xxx",
    $ClientID                = "xxx, 
    $Secret                  = 'xxx', 
    $SharePoint_SiteID       = "xxx",  
    $SharePoint_Path         = "https://xxx.sharepoint.com/sites/TeamsRecording/Shared%20Documents",  
    $SharePoint_ExportFolder = "Recording",  
    $LocalFolder             = "C:\Users\$($env:USERNAME)\OneDrive - xxx\Recordings"
)

Function Write_Log {
    param($Message_Type, $Message)
    $MyDate = "[{0:MM/dd/yy} {0:HH:mm:ss}]" -f (Get-Date)
    Write-Host "$MyDate - $Message_Type : $Message"
}

# ─── 1️⃣ Authenticate once
$Body = @{
    client_id     = $ClientID
    client_secret = $Secret
    scope         = "https://graph.microsoft.com/.default"
    grant_type    = 'client_credentials'
}
Write_Log INFO "SharePoint connexion"
$Graph_Url = "https://login.microsoftonline.com/$Tenant.onmicrosoft.com/oauth2/v2.0/token"

Try {
    $AuthorizationRequest = Invoke-RestMethod -Uri $Graph_Url -Method Post -Body $Body
    Write_Log SUCCESS "Connected to SharePoint"
} Catch {
    Write_Log ERROR "Connexion to SharePoint failed"
    Exit 1
}

$Access_token = $AuthorizationRequest.access_token
$Header = @{
    Authorization = $Access_token
    "Content-Type" = "application/json"
}

# ─── 2️⃣ Find your DriveID once
$SharePoint_Graph_URL = "https://graph.microsoft.com/v1.0/sites/$SharePoint_SiteID/drives"
Write_Log INFO "Getting SharePoint site info"
Try {
    $Result = Invoke-RestMethod -Uri $SharePoint_Graph_URL -Method GET -Headers $Header
    Write_Log SUCCESS "Got SharePoint site info"
} Catch {
    Write_Log ERROR "Getting SharePoint site info failed"
    Exit 1
}
$DriveID = $Result.value |
    Where-Object { $_.webURL -eq $SharePoint_Path } |
    Select-Object -ExpandProperty id

# ─── 3️⃣ Loop through every file under $LocalFolder
$files = Get-ChildItem -Path $LocalFolder -File
Write_Log INFO "Found $($files.Count) files in '$LocalFolder'"

foreach ($f in $files) {
    $File_Path = $f.FullName
    $FileName  = $f.Name

    Write_Log INFO "Checking: $FileName"

    # 3.1 Check if already exists
    $checkUrl = "https://graph.microsoft.com/v1.0/sites/${SharePoint_SiteID}/drives/${DriveID}/root:/${SharePoint_ExportFolder}/${FileName}"
    try {
        Invoke-RestMethod -Uri $checkUrl -Method GET -Headers $Header -ErrorAction Stop
        Write_Log INFO "Skipping '$FileName'—already uploaded."
        continue
    }
    catch {
        # 404 means not found: proceed to upload
        if ($_.Exception.Response.StatusCode.Value__ -ne 404) {
            Write_Log ERROR "Error checking existence of '$FileName': $_"
            continue
        }
    }

    Write_Log INFO "Preparing to upload: $FileName"

    # 3.2 create upload session
    $createUploadSessionUri = 
      "https://graph.microsoft.com/v1.0/sites/${SharePoint_SiteID}/drives/${DriveID}" +
      "/root:/${SharePoint_ExportFolder}/${FileName}:/createUploadSession"

    Try {
        $uploadSession = Invoke-RestMethod `
            -Uri $createUploadSessionUri -Method POST -Headers $Header -ContentType "application/json"
        Write_Log SUCCESS "Session created for $FileName"
    } Catch {
        Write_Log ERROR "Preparing upload for $FileName failed"
        continue
    }

    # 3.3 read the file & upload in one shot
    $fileInBytes = [System.IO.File]::ReadAllBytes($File_Path)
    $fileLength  = $fileInBytes.Length
    $headers     = @{ 'Content-Range' = "bytes 0-$($fileLength-1)/$fileLength" }

    Write_Log INFO "Uploading $FileName"
    Try {
        Invoke-RestMethod `
            -Method Put `
            -Uri $uploadSession.uploadUrl `
            -Body $fileInBytes `
            -Headers $headers
        Write_Log SUCCESS "Uploaded $FileName"
    } Catch {
        Write_Log ERROR "Failed to upload $FileName"
    }
}

Write_Log SUCCESS "All file uploads completed."