Functions/Get-MicrosoftGraphAuthenticationToken.ps1
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<#
.SYNOPSIS This function contacts the Microsoft Graph authentication servers to obtain an authentication token. #> function Get-MicrosoftGraphAuthenticationToken { [CmdletBinding(PositionalBinding=$false)] [OutputType([String])] param ( # The application ID of the Microsoft Graph web application. [Parameter(Mandatory=$true, ParameterSetName="values")] [ValidateNotNullOrEmpty()] [String]$applicationId, # The client secret of the Microsoft Graph web application. [Parameter(Mandatory=$true, ParameterSetName="values")] [ValidateNotNullOrEmpty()] [String]$clientSecret, # The name of the organization in Office 365. # Example: if the onmicrosoft domain is contoso.onmicrosoft.com, the organization name is 'contoso' [Parameter(Mandatory=$true, ParameterSetName="values")] [ValidateNotNullOrEmpty()] [String]$organizationName, # The MSPComplete endpoint containing the application ID and client secret in the credential. [Parameter(Mandatory=$true, ParameterSetName="endpoint", ValueFromPipeline=$true)] [ValidateNotNull()] $endpoint ) # Retrieve the properties from the endpoint if ($PSCmdlet.ParameterSetName -eq "endpoint") { $applicationId = $endpoint.Credential.Username $clientSecret = $endpoint.Credential.GetNetworkCredential().Password if ([String]::IsNullOrWhiteSpace((Search-HashTable $endpoint.ExtendedProperties "OrganizationName"))) { Write-Error "The endpoint does not have an 'OrganizationName' extended property." return } $organizationName = $endpoint.ExtendedProperties.OrganizationName } # Construct the REST call $url = "https://login.microsoftonline.com/$($organizationName).onmicrosoft.com/oauth2/v2.0/token" $body = @{ client_id = $applicationId grant_type = "client_credentials" client_secret = $clientSecret scope = "https://graph.microsoft.com/.default" } # Create hash table for params $invokeRestMethodParams = @{ Uri = $url ContentType = "application/x-www-form-urlencoded" Body = $body Method = "POST" } # Invoke the REST call try { $response = Invoke-RestMethod @invokeRestMethodParams } catch { Write-Error "Exception occurred while invoking REST call.`r`n$($_.Exception.Message)" return } # Verify the response if ($null -eq $response -or $response.expires_in -le 0 -or [String]::IsNullOrWhiteSpace($response.access_token)) { Write-Error "Failed to retrieve the access token." return } # Return the access token return $response.access_token } |