PowerShell API Wrapper Tutorial

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Important notice: The PowerShell API wrapper for the MailStore Server Administration API provided on this website, represents an example implementation of an API client. This wrapper should help system administrators and developers to quickly understand how the Administration API of MailStore Server works and how to use it in own scripts. Please understand that beyond this documentation no further support for the Python API wrapper is provided.

This tutorial aims to explain the usage of the Administration API through simple Windows PowerShell example scripts. Basic knowledge of MailStore Server, Windows and PowerShell is a necessary precondition. In order to prevent loss of data, service interruption or other problems, it is highly recommended to use a non-productive test environment for this tutorial as well as for script development in general. The 30-day-trial version of MailStore Server is perfectly suited for this.

Installation of Necessary Components

The examples demonstrated here use the MailStore PowerShell API Wrapper and are compatible with Windows PowerShell 3.0 and higher. Depending on your version of Windows it might be necessary to download and install a compatible version of PowerShell first. You can find the components necessary for this tutorial here:

Please take note of the system requirements and further notices for the respective version of the Windows Management Framework.

Important Notice: Installation of a Windows Management Framework on systems that require a specific version of Windows PowerShell, such as Microsoft Exchange Servers, is not supported and may lead to massive system failures and data loss.

After downloading and installing Windows PowerShell (if necessary) please unzip the MailStore PowerShell API Wrapper and the example scripts (to C:\MailStore Server Scripting Tutorial\PowerShell\ by default).

Neither the MailStore PowerShell API Wrapper nor the example scripts are digitally signed, therefore execution of such scripts has to be enabled in an administrative PowerShell session using

  Set-ExecutionPolicy -ExecutionPolicy Unrestricted

Importing the MailStore PowerShell API Wrapper

The MailStore PowerShell API Wrapper is implemented as a PowerShell Script Module (MS.PS.Lib.psm1) and can thus be imported in a PowerShell session via its manifest (MS.PS.Lib.psd1) by using Import-Module.

Please open a PowerShell session and import the API wrapper module using this command:

  Import-Module "C:\MailStore Server Scripting Tutorial\PowerShell\API-Wrapper\MS.PS.Lib.psd1"

Getting Information about the MailStore PowerShell API Wrapper

The MailStore PowerShell API Wrapper provides several functions and variables to access the MailStore Server Administration API, following PowerShell conventions. Enter the following command to get information about these features:

  Get-Module MS.PS.Lib | fl

More detailed information is available through the module's properties. For example,

  (Get-Module MS.PS.Lib).ExportedFunctions

returns the functions provided by the module. Via

  Get-Help *MSApi*

the MailStore PowerShell API Wrapper returns inline help for all its functions.

Calling API Wrapper Functions

The following example script (Example1.ps1 in the tutorial package) explains the basic usage of MailStore PowerShell API Wrapper functions.

  Import-Module '..\API-Wrapper\MS.PS.Lib.psd1'
  $mssapiclient = New-MSApiClient -Username admin -Password admin -MailStoreServer localhost -Port 8463 -IgnoreInvalidSSLCerts
  $return = Invoke-MSApiCall $mssapiclient "GetServerInfo"
  $return | fl

The function New-MSApiClient creates a new API client object which the Invoke-MSApiCall function uses for API calls. The values for -Username, -Password, -MailStoreServer and -Port used in the script are the function's defaults, only the switch -IgnoreInvalidSSLCerts has to be set if untrusted certificates are used; otherwise an error occurs.

Apart from the API client object, Invoke-MSApiCall needs an API command and its parameters if applicable. The command GetServerInfo in the script does not have any parameters and returns an object as follows:

 Type  : JSON
 Token : 
 Data  : @{error=; token=; statusVersion=2; statusCode=succeeded; percentProgress=; statusText=; result=; logOutput=}

The Type property characterizes the type of the object contained in the Data property. If the result has been returned immediately by the server, the object's Type property has the value "JSON". If the server needs some time to answer the request (mostly for asynchronous API commands, see below), the value is "JOB". The Token property is only relevant in the latter case.

The Data property contains the status of the API call returned by MailStore Server as a JSON object:

 PS C:\MailStore Server Scripting Tutorial\PowerShell\Scripts>$return.Data | fl
 error           : 
 token           : 
 statusVersion   : 2
 statusCode      : succeeded
 percentProgress : 
 statusText      : 
 result          : @{version=9.0.3.9845; machineName=PC001}
 logOutput       : 

If the call has succeeded, the status object's result property contains another JSON object with the data returned by the function:

 PS C:\MailStore Server Scripting Tutorial\PowerShell\Scripts> $return.data.result | fl
 version     : 9.0.3.9845
 machineName : PC001
 

Providing Parameters

For most MailStore Server Administration API commands you need to provide parameters. Of course, the MailStore PowerShell API Wrapper's Invoke-MSApiCall function can submit these parameters, as demonstrated by the following script (Example2.ps1 in the tutorial package):

  Import-Module '..\API-Wrapper\MS.PS.Lib.psd1'
  $msapiclient = New-MSApiClient -Username admin -Password admin -MailStoreServer localhost -Port 8463 -IgnoreInvalidSSLCerts
  $users = (Invoke-MSApiCall $msapiclient "GetUsers").Data.result
  foreach ($user in $users) {(Invoke-MSApiCall $msapiclient "GetUserInfo" @{userName = $user.userName}).Data.result | fl}

The scripts lists details about the users created in MailStore Server. Because the MailStore PowerShell API Wrapper converts MailStore Server Management API responses into objects, their properties can be used directly in the script's workflow.

The API command GetUserInfo used in the script requires a parameter userName. The function Invoke-MSApiCall expects parameters as a hashtable, e.g. @{parametername1 = value1; parametername2 = value2;...}. Parameter names are case sensitive.

First, MailStore Server's user list is requested with the API command GetUsers which returns an array of user entries as follows:

 userName          : abby.hernandez
 fullName          : Abby Hernandez
 distinguishedName : CN=Abby Hernandez,OU=tutorial,DC=example,DC=com

The script now iterates over this array using the userName property of each entry as a parameter for the API command GetUserInfo. For the entry listed above the result could be as follows:

 userName            : abby.hernandez
 fullName            : Abby Hernandez
 distinguishedName   : CN=Abby Hernandez,OU=tutorial,DC=example,DC=com
 authentication      : directoryServices
 emailAddresses      : {abby.hernandez@example.com}
 pop3UserNames       : {}
 privileges          : {login}
 privilegesOnFolders : {@{folder=abby.hernandez; privileges=System.Object[]}}

As can be seen in the privilegesOnFolders property, returned objects may be nested and may also contain further objects.

Handling Asynchronous API Calls

The server may decide to execute Administration API commands asynchronously if their execution may take more time. The MailStore PowerShell API Wrapper identifies calls of such asynchronously executed API commands and executes them as PowerShell Jobs in the background.

Processing API Wrapper PowerShell Jobs Synchronously

A script's execution can be interrupted until a PowerShell Job created by the API wrapper terminates as demonstrated by the following script (Example3.ps1 in the tutorial package):

  Import-Module '..\API-Wrapper\MS.PS.Lib.psd1'
  $msapiclient = New-MSApiClient -Username "admin" -Password "admin" -Server "localhost" -Port 8463 -IgnoreInvalidSSLCerts
  $return = Invoke-MSApiCall $msapiclient "VerifyStore" @{id = "1"}
  $return | fl
  if ($return.Type -eq "JOB") {
      $null = Wait-Job $return.Data
      (Receive-Job $return.Data).Data
  } else {
      $return.Data
  }

If an API command is executed asynchronously by the MailStore Server, an object with the Type property "JOB" is returned.

 Type  : JOB
 Token : sa9e8d780329f1e0c59503a2e041f7c72b
 Data  : System.Management.Automation.PSRemotingJob

The Token property now contains a unique ID returned by the server that identifies the server process; it is important for event handling (see below). The Data property contains the PowerShell Job which processes the status objects returned by the server in the background.

This PowerShell Job monitors the status of its corresponding server process and is terminated when that process is finished. Through the PowerShell cmdlet Wait-Job the scripts waits until the job has been completed, getting the job's results through Receive-Job:

 Type       : JSON
 Token      : 
 Data       : @{error=; token=sa9e8d780329f1e0c59503a2e041f7c72b; statusVersion=85; statusCode=succeeded; percentProgress=100; statusText=; result=; logOutput=}
 RunspaceId : 4851b10d-ee88-46a0-a7f4-6214aa0a4c3f


Please note: The RunspaceId is generated by the PowerShell automatically and can be ignored here.

Processing API Wrapper PowerShell Jobs Asynchronously

Instead of interrupting a script's execution, the PowerShell Jobs created by the API wrapper can be reacted to while they are running in the background. These jobs trigger a PowerShell EngineEvent with each status request that the script can subscribe to execute further code on each occurrence. To demonstrate this, the previous script needs to be adapted only a bit (Example4.ps1 in the tutorial package):

  Import-Module '..\API-Wrapper\MS.PS.Lib.psd1'
  $msapiclient = New-MSApiClient -Username "admin" -Password "admin" -Server "localhost" -Port 8463 -IgnoreInvalidSSLCerts
  $return = Invoke-MSApiCall $msapiclient "VerifyStore" @{id = "1"}
  $return | fl
  if ($return.Type -eq "JOB") {
    $mssevent = Register-EngineEvent -SourceIdentifier $return.Token -Action {write-host $event.MessageData.Data}
  } else {
    $return.Data
  }

Here the script subscribes to the event that is triggered by the background job via Register-EngineEvent, using the return object's Token property as SourceIdentifier. By that property the event relates to the triggering PowerShell Job and thus to the server process. The Action script block is itself created as a PowerShell Job that is executed with each triggering of the event. Through the MessageData property of the $event automatic variable the script block can access the return object provided by the background job. That object's Data property contains the status of the server process:

 @{error=; token=e2b7c58ff37df64e2b62bb02bde9bbfd; statusVersion=77; statusCode=running; percentProgress=95; statusText=; result=; logOutput=  1400 messages verified...}

Via these mechanisms the script can execute further tasks while monitoring the server process in the background. Execution and handling of multiple asynchronous API commands is also possible this way.

Cancelling Asynchronous API Wrapper PowerShell Jobs

To cancel the execution of an asynchronous API command, use Stop-MSApiCall with either the token or the "JOB" return object. For the example above the call would be:

  Stop-MSApiCall $MSApiclient -AsyncReturnObject $return
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About MailStore

  • MailStore Server is one of the leading email archiving solutions for SMB.
  • For private use there is a free tool for email archiving furthermore: MailStore Home.