How to use the ETS to handle complex .Net types in a CmdLet?

Let say that I have a pre-defined class

public class Book
{
public string Title { get; set; }
public string Author { get; set; }
public string ISBN { get; set; }
}

Let say that I am writing a CmdLet named Get-BookPrice that takes a Book as
input pipeline parameter and output the price (thanks a DB, whatever).

How I am supposed to do that with PowerShell?

The naive option consists in creating a CmdLet taking 3 string parameters.
This approach does not look very smart considering the ETS.

Yet with the documentation available at
http://windowssdk.msdn.microsoft.com.../ms714419.aspx
I am a bit at a loss, and do not know what to do.

Am-I supposed to
- Write a CmdLet that takes a PSObject as parameter? or is-it directly a
Book?
- Write a PsTypeConverter? From string to Book? From PSObject to Book?

Thanks in advance,
Joannes
http://www.peoplewords.com

I don't know what ETS is, but CmdLets can just take an object of type
Book. All the normal PowerShell type conversions apply, so if the book
has a static Parse(string) method, PowerShell will use it to convert
from string to Book...

Joannes Vermorel wrote:
> Let say that I have a pre-defined class
>
> public class Book
> {
> public string Title { get; set; }
> public string Author { get; set; }
> public string ISBN { get; set; }
> }
>
> Let say that I am writing a CmdLet named Get-BookPrice that takes a Book as
> input pipeline parameter and output the price (thanks a DB, whatever).
>
> How I am supposed to do that with PowerShell?
>
> The naive option consists in creating a CmdLet taking 3 string parameters.
> This approach does not look very smart considering the ETS.
>
> Yet with the documentation available at
> http://windowssdk.msdn.microsoft.com.../ms714419.aspx
> I am a bit at a loss, and do not know what to do.
>
> Am-I supposed to
> - Write a CmdLet that takes a PSObject as parameter? or is-it directly a
> Book?
> - Write a PsTypeConverter? From string to Book? From PSObject to Book?
>
> Thanks in advance,
> Joannes
> http://www.peoplewords.com

> I don't know what ETS is, but CmdLets can just take an object of type
> Book. All the normal PowerShell type conversions apply, so if the book
> has a static Parse(string) method, PowerShell will use it to convert
> from string to Book...

Yes, but precisely, I was focusing on *complex* (multiple properties)
objects. Thus, straightforward conversion string==>MyObject is not really
practical (you end-up with connection-string like custom syntax and loose the
benefits of strong typing).

Joannes

Hi Joannes,

> Let say that I have a pre-defined class
>
> public class Book
> {
> public string Title { get; set; }
> public string Author { get; set; }
> public string ISBN { get; set; }
> }
>
> Let say that I am writing a CmdLet named Get-BookPrice that takes a Book as
> input pipeline parameter and output the price (thanks a DB, whatever).
>
> How I am supposed to do that with PowerShell?

I haven't written a CmdLet but what about creating a cmdlet Create-Book
so you can write something like this:

$book=Create-Book -Title "Powershell" -Author "Unknown" -ISBN "Whatever"
Get-BookPrice $book

or like this

Create-Book -Title "Powershell" -Author "Unknown" -ISBN "Whatever" |
Get-BookPrice

and so on..

cu

Max

"Adam Milazzo" wrote:

> I don't know what ETS is, <snip>

Just in case you're interested: ETS = Extended Type System

http://msdn2.microsoft.com/en-us/library/ms714419.aspx
http://msdn2.microsoft.com/en-us/library/ms714665.aspx

--
greetings
dreeschkind

> I haven't written a CmdLet but what about creating a cmdlet Create-Book
> so you can write something like this:
>
> $book=Create-Book -Title "Powershell" -Author "Unknown" -ISBN "Whatever"
> Get-BookPrice $book

Yes, this is indeed a good approach. Thanks.

Joannes

Ps1: the common verb would be 'New' here :-)
Ps2: it seems that I am not the only one having little insights on ETS.

Hi Joannes,

> Yes, this is indeed a good approach. Thanks.

You're welcome!

> Ps1: the common verb would be 'New' here :-)

According to Bob Ross:
"We don't make mistakes here, we just have happy accidents" ;-)

cu

Max