system-credential.ps1

#
# system_credential.ps1
#

# An array to store credentaials in memory (each object contains key,username,password)
$script:credentialsStore = @()

function New-StoredCredential
{
    <#
    .SYNOPSIS
        Adds a credentials to the in memory credential store.
     
    .DESCRIPTION
        A user will be asked to provide a username and password. Credentials will be stored in memory table.
        The credentails will be stored as secure string.
        You shall call Save-Credentials to save in memory table to file.
 
    .EXAMPLE
        New-StoredCredential -Key 'SMTP Credentials' -Message 'Provide a credentials for SMTP server'
    #>

    [CmdletBinding()]
    param (
        [parameter(Mandatory=$true)]
        [string]$Key,
        [parameter()]
        [string]$Username,
        [parameter()]
        [string]$Password,
        [parameter()]
        [string]$Message="Please provide credentials:"
    )

    $credentialsItem = Get-StoredCredential($Key)
    if( $credentialsItem -ne $null )
    {
        Write-Warning "A key '$Key' already exist!"
        return
    }
    
    $user = $null
    $pwd = $null
    if( $Username -eq '' -and $Password -eq '')
    {    
        $credentials = Get-Credential -Message $Message 
        $user = $credentials.UserName | ConvertTo-SecureString -AsPlainText -Force | ConvertFrom-SecureString 
        $pwd = $credentials.Password | ConvertFrom-SecureString 
    }
    else
    {
        $user = $Username  | ConvertTo-SecureString -AsPlainText -Force | ConvertFrom-SecureString 
        $pwd =  $Password  | ConvertTo-SecureString -AsPlainText -Force | ConvertFrom-SecureString 
    }

    $credentialsItem = New-Object PSObject
    $credentialsItem | Add-Member �MemberType NoteProperty �Name Key �Value $Key
    $credentialsItem | Add-Member �MemberType NoteProperty �Name Username �Value $user
    $credentialsItem | Add-Member �MemberType NoteProperty �Name Password �Value $pwd

    $script:credentialsStore += $credentialsItem;
}


function Export-CredentialStore
{
    <#
    .SYNOPSIS
        Saves an in memory credentials table to the CSV file.
     
    .EXAMPLE
        Save-CredentialStore -Path 'C:\MyScriptsConfiguration'
    #>

    [CmdletBinding()]
    param (
        [parameter(Mandatory=$true)]
        [string]$Path
    )
    $script:credentialsStore | Export-Csv -Path $Path -NoTypeInformation
}


function Import-CredentialStore
{
    <#
    .SYNOPSIS
        Loads credentials from a CSV file and stores credentials in a memory table.
     
    .EXAMPLE
        Load-CredentialStore -Path 'C:\MyScriptsConfiguration'
    #>

    [CmdletBinding()]
    param (
        [parameter(Mandatory=$true)]
        [string]$Path
    )
    $script:credentialsStore = Import-Csv -Path $Path 
}

function Get-StoredCredential
{
    [CmdletBinding()]
    param (
        [parameter(Mandatory=$true)]
        [string]$Key
    )
    return $script:credentialsStore | Where-Object { $_.Key -eq $Key }
}


function TryGet-StoredCredential
{
    [CmdletBinding()]
    param (
        [parameter(Mandatory=$true)]
        [string]$Key
    )

    $credentialsItem = Get-StoredCredential($Key)
    if( $credentialsItem -eq $null )
    {
        New-StoredCredential($Key)
        return Get-StoredCredential($Key)
    }
}


function ConvertTo-PlainText
{
    <#
    .SYNOPSIS
        Converts a secure string to the plain text
     
    .EXAMPLE
        ConvertTo-PlainText -String 'jsjdakdajskdajsd'
    #>

    [CmdletBinding()]
    param (
        [parameter(Mandatory=$true)]
        [string]$Secret
    )
    $secureString = $Secret | ConvertTo-SecureString 
    $BSTR = [System.Runtime.InteropServices.Marshal]::SecureStringToBSTR( $secureString )            
    return [System.Runtime.InteropServices.Marshal]::PtrToStringAuto($BSTR)
}

Export-ModuleMember -Function ConvertTo-PlainText
Export-ModuleMember -Function New-StoredCredential
Export-ModuleMember -Function TryGet-StoredCredential
Export-ModuleMember -Function Get-StoredCredential
Export-ModuleMember -Function Import-CredentialStore
Export-ModuleMember -Function Export-CredentialStore