(PowerShell) PC/SC Wait for Smart Card Status Change (Inserted, Removed from Reader, etc.)

See more SCard Examples

Demonstrates how to synchronously wait for a status change, such as for a smart card to be inserted into a reader, or removed from a reader.

Note: This functionality was introduced in Chilkat v9.5.0.87.

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Add-Type -Path "C:\chilkat\ChilkatDotNet47-9.5.0-x64\ChilkatDotNet47.dll"

# This example requires the Chilkat API to have been previously unlocked.
# See Global Unlock Sample for sample code.

$scard = New-Object Chilkat.SCard

# First establish a context to the PC/SC Resource Manager
$success = $scard.EstablishContext("user")
if ($success -eq $false) {
    $($scard.LastErrorText)
    exit
}

# First we'll examine the state of all connected readers to see which have smartcards already inserted..
# Get JSON containing information about the smartcards currently inserted into readers.
# This also includes information about USB security tokens.
$json = New-Object Chilkat.JsonObject
$success = $scard.FindSmartcards($json)
if ($success -eq $false) {
    $($scard.LastErrorText)
    exit
}

# When writing this example, I have 3 smart card readers plugged into my system.
# One of them has a smart card inserted.
# Here's the JSON returned by FindSmartcards...

# {
#   "reader": [
#     {
#       "name": "Alcor Micro USB Smart Card Reader 0",
#       "state": "empty"
#     },
#     {
#       "name": "Generic Smart Card Reader Interface 0",
#       "state": "present",
#       "vendorName": "Generic",
#       "serialNumber": "3230303730383138303030303030303030",
#       "systemName": "Generic Smart Card Reader Interface 0",
#       "card": {
#         "atr": "3BFC180000813180459067464A00641606F2727E00E0",
#         "windows": {
#           "miniDriver": "tagliov70px.dll",
#           "cryptoProvider": "Microsoft Base Smart Card Crypto Provider",
#           "keyStorageProvider": "Microsoft Smart Card Key Storage Provider"
#         }
#       }
#     },
#     {
#       "name": "SCM Microsystems Inc. SCR33x USB Smart Card Reader 0",
#       "state": "empty"
#     }
#   ]
# }

$json.EmitCompact = $false
$($json.Emit())
$(" ")

# We can iterate over the JSON to find the readers with a smart card already inserted..

$sbState = New-Object Chilkat.StringBuilder

$i = 0
$count_i = $json.SizeOfArray("reader")
while ($i -lt $count_i) {
    $json.I = $i
    $name = $json.StringOf("reader[i].name")

    $sbState.Clear()
    $json.StringOfSb("reader[i].state",$sbState)

    if ($sbState.Contains("present",$true) -eq $true) {
        $($name + " has a smart card inserted.")
    }
    else {
        $($name + " does not have a smart card inserted.")
    }

    $i = $i + 1
}

$(" ")

# Now let's begin the code to wait for a change (where a smart card gets inserted or removed)

# Get the list of all readers.
$stReaders = New-Object Chilkat.StringTable
$success = $scard.ListReaders($stReaders)
if ($success -eq $false) {
    $($scard.LastErrorText)
    exit
}

# Show the reader names..
$numReaders = $stReaders.Count
$i = 0
while ($i -lt $numReaders) {
    $([string]$i + ": " + $stReaders.StringAt($i))
    $i = $i + 1
}

# Sample output from the above loop.
# 0: Alcor Micro USB Smart Card Reader 0
# 1: Generic Smart Card Reader Interface 0
# 2: SCM Microsystems Inc. SCR33x USB Smart Card Reader 0
# 

# Synchronously wait 30 seconds for a card to be inserted or removed from any of the above readers.
$json2 = New-Object Chilkat.JsonObject
$success = $scard.GetStatusChange(30000,$stReaders,$json2)
if ($success -eq $false) {
    $($scard.LastErrorText)
    exit
}

$(" ")

# Let's see what happened...
$json2.EmitCompact = $false
$($json2.Emit())
$(" ")

# This is what json2 contains.
# A card was inserted into the reader named "SCM Microsystems Inc. SCR33x USB Smart Card Reader 0"
# The "numChanged" indicates that one reader's status changed.  
# The "changed":true indicates the reader that changed.   The state is now "present".

# {
#   "numChanged": 1,
#   "reader": [
#     {
#       "name": "Alcor Micro USB Smart Card Reader 0",
#       "changed": false,
#       "state": "empty"
#     },
#     {
#       "name": "Generic Smart Card Reader Interface 0",
#       "changed": false,
#       "state": "present",
#       "atr": "3BFC180000813180459067464A00641606F2727E00E0"
#     },
#     {
#       "name": "SCM Microsystems Inc. SCR33x USB Smart Card Reader 0",
#       "changed": true,
#       "state": "present",
#       "atr": "3BDF96FF8131FE455A018048494443313158587300011B09"
#     }
#   ]
# }

# Find the reader that changed...

$numChanged = $json2.IntOf("numChanged")
$("number of readers with a changed state: " + $numChanged)

$i = 0
$count_i = $json2.SizeOfArray("reader")
while ($i -lt $count_i) {
    $json2.I = $i
    $changed = $json2.BoolOf("reader[i].changed")
    if ($changed -eq $true) {
        $name = $json2.StringOf("reader[i].name")
        $state = $json2.StringOf("reader[i].state")

        $("Changed: ")
        $("    reader name: " + $name)
        $("    new state: " + $state)

        # If a card is now in this reader, we should have the ATR of the card..
        if ($json2.HasMember("reader[i].atr") -eq $true) {
            $atr = $json2.StringOf("reader[i].atr")
            $("    ATR of card inserted into this reader: " + $atr)
        }

    }

    $i = $i + 1
}

# The output from the above loop:

# number of readers with a changed state: 1
# Changed: 
#     reader name: SCM Microsystems Inc. SCR33x USB Smart Card Reader 0
#     new state: present
#     ATR of card inserted into this reader: 3BDF96FF8131FE455A018048494443313158587300011B09

# Applications should always release the context when finished.
$success = $scard.ReleaseContext()
if ($success -eq $false) {
    $($scard.LastErrorText)
}