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

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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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integer li_rc
oleobject loo_Scard
integer li_Success
oleobject loo_Json
string ls_Name
oleobject loo_SbState
integer i
integer li_Count_i
oleobject loo_StReaders
integer li_NumReaders
oleobject loo_Json2
integer li_Changed
string ls_State
string ls_Atr
integer li_NumChanged

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

loo_Scard = create oleobject
// Use "Chilkat_9_5_0.SCard" for versions of Chilkat < 10.0.0
li_rc = loo_Scard.ConnectToNewObject("Chilkat.SCard")
if li_rc < 0 then
    destroy loo_Scard
    MessageBox("Error","Connecting to COM object failed")
    return
end if

// First establish a context to the PC/SC Resource Manager
li_Success = loo_Scard.EstablishContext("user")
if li_Success = 0 then
    Write-Debug loo_Scard.LastErrorText
    destroy loo_Scard
    return
end if

// 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.
loo_Json = create oleobject
// Use "Chilkat_9_5_0.JsonObject" for versions of Chilkat < 10.0.0
li_rc = loo_Json.ConnectToNewObject("Chilkat.JsonObject")

li_Success = loo_Scard.FindSmartcards(loo_Json)
if li_Success = 0 then
    Write-Debug loo_Scard.LastErrorText
    destroy loo_Scard
    destroy loo_Json
    return
end if

// 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"
//     }
//   ]
// }

loo_Json.EmitCompact = 0
Write-Debug loo_Json.Emit()
Write-Debug " "

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

loo_SbState = create oleobject
// Use "Chilkat_9_5_0.StringBuilder" for versions of Chilkat < 10.0.0
li_rc = loo_SbState.ConnectToNewObject("Chilkat.StringBuilder")

i = 0
li_Count_i = loo_Json.SizeOfArray("reader")
do while i < li_Count_i
    loo_Json.I = i
    ls_Name = loo_Json.StringOf("reader[i].name")

    loo_SbState.Clear()
    loo_Json.StringOfSb("reader[i].state",loo_SbState)

    if loo_SbState.Contains("present",1) = 1 then
        Write-Debug ls_Name + " has a smart card inserted."
    else
        Write-Debug ls_Name + " does not have a smart card inserted."
    end if

    i = i + 1
loop
Write-Debug " "

// 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.
loo_StReaders = create oleobject
// Use "Chilkat_9_5_0.StringTable" for versions of Chilkat < 10.0.0
li_rc = loo_StReaders.ConnectToNewObject("Chilkat.StringTable")

li_Success = loo_Scard.ListReaders(loo_StReaders)
if li_Success = 0 then
    Write-Debug loo_Scard.LastErrorText
    destroy loo_Scard
    destroy loo_Json
    destroy loo_SbState
    destroy loo_StReaders
    return
end if

// Show the reader names..
li_NumReaders = loo_StReaders.Count
i = 0
do while i < li_NumReaders
    Write-Debug string(i) + ": " + loo_StReaders.StringAt(i)
    i = i + 1
loop

// 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.
loo_Json2 = create oleobject
// Use "Chilkat_9_5_0.JsonObject" for versions of Chilkat < 10.0.0
li_rc = loo_Json2.ConnectToNewObject("Chilkat.JsonObject")

li_Success = loo_Scard.GetStatusChange(30000,loo_StReaders,loo_Json2)
if li_Success = 0 then
    Write-Debug loo_Scard.LastErrorText
    destroy loo_Scard
    destroy loo_Json
    destroy loo_SbState
    destroy loo_StReaders
    destroy loo_Json2
    return
end if

Write-Debug " "

// Let's see what happened...
loo_Json2.EmitCompact = 0
Write-Debug loo_Json2.Emit()
Write-Debug " "

// 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...

li_NumChanged = loo_Json2.IntOf("numChanged")
Write-Debug "number of readers with a changed state: " + string(li_NumChanged)

i = 0
li_Count_i = loo_Json2.SizeOfArray("reader")
do while i < li_Count_i
    loo_Json2.I = i
    li_Changed = loo_Json2.BoolOf("reader[i].changed")
    if li_Changed = 1 then
        ls_Name = loo_Json2.StringOf("reader[i].name")
        ls_State = loo_Json2.StringOf("reader[i].state")

        Write-Debug "Changed: "
        Write-Debug "    reader name: " + ls_Name
        Write-Debug "    new state: " + ls_State

        // If a card is now in this reader, we should have the ATR of the card..
        if loo_Json2.HasMember("reader[i].atr") = 1 then
            ls_Atr = loo_Json2.StringOf("reader[i].atr")
            Write-Debug "    ATR of card inserted into this reader: " + ls_Atr
        end if

    end if

    i = i + 1
loop

// 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.
li_Success = loo_Scard.ReleaseContext()
if li_Success = 0 then
    Write-Debug loo_Scard.LastErrorText
end if



destroy loo_Scard
destroy loo_Json
destroy loo_SbState
destroy loo_StReaders
destroy loo_Json2