James O'Neill's Blog

June 30, 2012

Using the Windows index to search from PowerShell: Part three. Better function output

Filed under: Powershell — jamesone111 @ 10:53 am

Note: this was originally written for the Hey,Scripting guy blog where it appeared as the 27 June 2012 episode. The code is available for download . I have some more index related posts coming up so I wanted to make sure everything was in one place


In part one, I introduced a function which queries the Windows Index using filter parameters like
  • "Contains(*,’Stingray’)"
  • "System.Keywords = ‘Portfolio’ "
  • "System.Photo.CameraManufacturer LIKE ‘CAN%’ "
  • "System.image.horizontalSize > 1024"

In part two, I showed how these parameters could be simplified to

  • Stingray (A word on its own becomes a contains term)
  • Keyword=Portfolio (Keyword, without the S is an alias for System.Keywords and quotes will be added automatically))
  • CameraManufacturer=CAN* (* will become %, and = will become LIKE, quotes will be added and CameraManufacturer will be prefixed with System.Photo)
  • Width > 1024 (Width is an alias or System.image.horizontalsize, and quotes are not added around numbers).

There is one remaining issue. PowerShell is designed so that one command’s output becomes another’s input. This function isn’t going to do much with Piped input: I can’t see another command spitting out search terms for this one, nor can I multiple paths being piped in. But the majority of items found by a search will be files: and so it should be possible to treat them like files, piping them into copy-item or whatever.
The following was my first attempt at transforming the data rows into something more helpful

$Provider= "Provider=Search.CollatorDSO; Extended Properties=’Application=Windows’;"
$adapter = new-object system.data.oledb.oleDBDataadapter -argument $SQL, $Provider
$ds      = new-object system.data.dataset
if ($adapter.Fill($ds))
    
{ foreach ($row in $ds.Tables[0])
            {if ($row."System.ItemUrl" -match "^file:")
                  {$obj = New-Object psobject -Property @{
                                Path = (($row."System.ItemUrl" -replace "^file:","") -replace "\/","\")}}
             Else {$obj = New-Object psobject -Property @{Path = $row."System.ItemUrl"}
}
             Add-Member -force -Input $obj -Name "ToString" -MemberType "scriptmethod" -Value {$this.path}
             foreach ($prop in (Get-Member -InputObject $row -MemberType property |
                                    where-object {$row."$($_.name)" -isnot [system.dbnull] }))
                  { Add-Member -ErrorAction "SilentlyContinue" -InputObject $obj -MemberType NoteProperty `
                               -Name (($prop.name -split "\." )[-1]) -Value $row."$($prop.name)"
                 
}
             foreach ($prop in ($PropertyAliases.Keys |
                                    Where-Object {$row."$($propertyAliases.$_)" -isnot [system.dbnull] }))
                  { Add-Member -ErrorAction "SilentlyContinue" -InputObject $obj ` -MemberType AliasProperty ` 
                               -Name $prop ` -Value ($propertyAliases.$prop -split "\." )[-1]
                  }
             $obj
            }
      }
This is where the function spends most of its time, looping through the data creating a custom object for each row; non-file items are given a path property which holds the System.ItemURL property; for files the ItemUrl is processed into normal format (rather than file:c/users/james format) – in many cases the item can be piped into another command successfully if it just has a Path property.

Then, for each property (database column) in the row a member is added to the custom object with a shortened version of the property name and the value (assuming the column isn’t empty).
Next, alias properties are added using the definitions in $PropertyAliases.
Finally some standard members get added. In this version I’ve pared it down to a single method, because several things expect to be able to get the path for a file by calling its tostring() method.

When I had all of this working I tried to get clever. I added aliases for all the properties which normally appear on a System.IO.FileInfo object and even tried fooling PowerShell’s formatting system into treating my file items as a file object, something that only needs one extra line of code
$Obj.psobject.typenames.insert(0, "SYSTEM.IO.FILEINFO")
Pretending a custom object is actually another type seems dangerous, but everything I tried seemed happy provided the right properties were present. The formatting worked except for the "Mode" column. I found the method which that calculates .Mode for FILEINFO objects, but it needs a real FILEINFO object. It was easy enough to get one – I had the path and it only needs a call to Get‑Item but I realized that if I was getting a FILEINFO object anywhere in the process, then it made more sense to add extra properties to that object and dispense with the custom object. I added an extra switch -NoFiles to supress this behaviour
So the code then became
$Provider ="Provider=Search.CollatorDSO; Extended Properties=’Application=Windows’;"
$adapter  = new-object system.data.oledb.oleDBDataadapter -argument $SQL, $Provider
$ds       = new-object system.data.dataset
if ($adapter.Fill($ds))
     { foreach ($row in $ds.Tables[0])
        
 { if (($row."System.ItemUrl" -match "^file:") -and (-not $NoFiles)) 
                 {$obj = Get-item -Path (($row."System.ItemUrl" -replace "^file:","") -replace "\/","\")}
            Else {$obj = New-Object psobject -Property @{Path = $row."System.ItemUrl"}
                  Add-Member -force -Input $obj -Name "ToString" -MemberType "scriptmethod" -Value {$this.path} 
          }
         
ForEach...
 
The initial code was 36 lines, making the user input more friendly took it to 60 lines, and the output added about another 35 lines, bring the total to 95.
There were 4 other kinds of output I wanted to produce:

  • Help. I added comment-based-help with plenty of examples. It runs to 75 lines making it the biggest constituent in the finished product.
    In addition I have 50 lines that are comments or blank for readability as insurance against trying to understand what those regular expressions do in a few months’ time – but there are only 100 lines of actual code.
  • A –list switch which lists the long and short names for the fields (including aliases)
  • Support for the –Debug switch – because so many things might go wrong, I have write‑debug $SQL immediately before I carry out the query, and to enable it that I have
    [CmdletBinding()] before I declare the parameters.
  • A –Value switch which uses the GROUP ON… OVER… search syntax so I can see what the possible values are in a column.
    GROUP ON queries are unusual because they fill the dataset with TWO tables.
    GROUP ON System.kind OVER ( SELECT STATEMENT) will produce a something like this as the first table.

SYSTEM.KIND   Chapter
-----------   -------
communication 0
document      1
email         2
folder        3
link          4
music         5
picture       6
program       7
recordedtv    8

The second table is the normal data suitably sorted. In this case it has all the requested fields grouped by kind plus one named "Chapter", which ties into the first table. I’m not really interested in the second table but the first helps me know if I should enter "Kind=image", "Kind=Photo" or "Kind=Picture"

I have a Select-List function which I use in my configurator and Hyper-V library, and with this I can choose which recorded TV program to watch, first selecting by title, and then if there is more than one episode, by episode.
$t=(Get-IndexedItem -Value "title" -filter "kind=recordedtv" -recurse |
            Select-List -Property title).title
start (Get-IndexedItem -filter "kind=recordedtv","title='$t'" -path |
           
 Select-List -Property ORIGINALBROADCASTDATE,PROGRAMDESCRIPTION)


In a couple of follow up posts I’ll show some of the places I use Get-IndexedItem. But for now feel free to download the code and experiment with it.

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