(SQL Server) 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.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

-- Important: See this note about string length limitations for strings returned by sp_OAMethod calls.
--
CREATE PROCEDURE ChilkatSample
AS
BEGIN
    DECLARE @hr int
    DECLARE @iTmp0 int
    -- Important: Do not use nvarchar(max).  See the warning about using nvarchar(max).
    DECLARE @sTmp0 nvarchar(4000)
    -- This example requires the Chilkat API to have been previously unlocked.
    -- See Global Unlock Sample for sample code.

    DECLARE @scard int
    -- Use "Chilkat_9_5_0.SCard" for versions of Chilkat < 10.0.0
    EXEC @hr = sp_OACreate 'Chilkat.SCard', @scard OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    -- First establish a context to the PC/SC Resource Manager
    DECLARE @success int
    EXEC sp_OAMethod @scard, 'EstablishContext', @success OUT, 'user'
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @scard, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @scard
        RETURN
      END

    -- 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.
    DECLARE @json int
    -- Use "Chilkat_9_5_0.JsonObject" for versions of Chilkat < 10.0.0
    EXEC @hr = sp_OACreate 'Chilkat.JsonObject', @json OUT

    EXEC sp_OAMethod @scard, 'FindSmartcards', @success OUT, @json
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @scard, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @scard
        EXEC @hr = sp_OADestroy @json
        RETURN
      END

    -- 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"
    --     }
    --   ]
    -- }

    EXEC sp_OASetProperty @json, 'EmitCompact', 0
    EXEC sp_OAMethod @json, 'Emit', @sTmp0 OUT
    PRINT @sTmp0

    PRINT ' '

    -- We can iterate over the JSON to find the readers with a smart card already inserted..
    DECLARE @name nvarchar(4000)

    DECLARE @sbState int
    -- Use "Chilkat_9_5_0.StringBuilder" for versions of Chilkat < 10.0.0
    EXEC @hr = sp_OACreate 'Chilkat.StringBuilder', @sbState OUT

    DECLARE @i int
    SELECT @i = 0
    DECLARE @count_i int
    EXEC sp_OAMethod @json, 'SizeOfArray', @count_i OUT, 'reader'
    WHILE @i < @count_i
      BEGIN
        EXEC sp_OASetProperty @json, 'I', @i
        EXEC sp_OAMethod @json, 'StringOf', @name OUT, 'reader[i].name'

        EXEC sp_OAMethod @sbState, 'Clear', NULL
        EXEC sp_OAMethod @json, 'StringOfSb', @success OUT, 'reader[i].state', @sbState

        EXEC sp_OAMethod @sbState, 'Contains', @iTmp0 OUT, 'present', 1
        IF @iTmp0 = 1
          BEGIN

            PRINT @name + ' has a smart card inserted.'
          END
        ELSE
          BEGIN

            PRINT @name + ' does not have a smart card inserted.'
          END
        SELECT @i = @i + 1
      END

    PRINT ' '

    -- 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.
    DECLARE @stReaders int
    -- Use "Chilkat_9_5_0.StringTable" for versions of Chilkat < 10.0.0
    EXEC @hr = sp_OACreate 'Chilkat.StringTable', @stReaders OUT

    EXEC sp_OAMethod @scard, 'ListReaders', @success OUT, @stReaders
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @scard, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @scard
        EXEC @hr = sp_OADestroy @json
        EXEC @hr = sp_OADestroy @sbState
        EXEC @hr = sp_OADestroy @stReaders
        RETURN
      END

    -- Show the reader names..
    DECLARE @numReaders int
    EXEC sp_OAGetProperty @stReaders, 'Count', @numReaders OUT
    SELECT @i = 0
    WHILE @i < @numReaders
      BEGIN

        EXEC sp_OAMethod @stReaders, 'StringAt', @sTmp0 OUT, @i
        PRINT @i + ': ' + @sTmp0
        SELECT @i = @i + 1
      END

    -- 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.
    DECLARE @json2 int
    -- Use "Chilkat_9_5_0.JsonObject" for versions of Chilkat < 10.0.0
    EXEC @hr = sp_OACreate 'Chilkat.JsonObject', @json2 OUT

    EXEC sp_OAMethod @scard, 'GetStatusChange', @success OUT, 30000, @stReaders, @json2
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @scard, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @scard
        EXEC @hr = sp_OADestroy @json
        EXEC @hr = sp_OADestroy @sbState
        EXEC @hr = sp_OADestroy @stReaders
        EXEC @hr = sp_OADestroy @json2
        RETURN
      END

    PRINT ' '

    -- Let's see what happened...
    EXEC sp_OASetProperty @json2, 'EmitCompact', 0
    EXEC sp_OAMethod @json2, 'Emit', @sTmp0 OUT
    PRINT @sTmp0

    PRINT ' '

    -- 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...
    DECLARE @changed int

    DECLARE @state nvarchar(4000)

    DECLARE @atr nvarchar(4000)

    DECLARE @numChanged int
    EXEC sp_OAMethod @json2, 'IntOf', @numChanged OUT, 'numChanged'

    PRINT 'number of readers with a changed state: ' + @numChanged

    SELECT @i = 0
    EXEC sp_OAMethod @json2, 'SizeOfArray', @count_i OUT, 'reader'
    WHILE @i < @count_i
      BEGIN
        EXEC sp_OASetProperty @json2, 'I', @i
        EXEC sp_OAMethod @json2, 'BoolOf', @changed OUT, 'reader[i].changed'
        IF @changed = 1
          BEGIN
            EXEC sp_OAMethod @json2, 'StringOf', @name OUT, 'reader[i].name'
            EXEC sp_OAMethod @json2, 'StringOf', @state OUT, 'reader[i].state'


            PRINT 'Changed: '

            PRINT '    reader name: ' + @name

            PRINT '    new state: ' + @state

            -- If a card is now in this reader, we should have the ATR of the card..
            EXEC sp_OAMethod @json2, 'HasMember', @iTmp0 OUT, 'reader[i].atr'
            IF @iTmp0 = 1
              BEGIN
                EXEC sp_OAMethod @json2, 'StringOf', @atr OUT, 'reader[i].atr'

                PRINT '    ATR of card inserted into this reader: ' + @atr
              END
          END
        SELECT @i = @i + 1
      END

    -- 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.
    EXEC sp_OAMethod @scard, 'ReleaseContext', @success OUT
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @scard, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
      END

    EXEC @hr = sp_OADestroy @scard
    EXEC @hr = sp_OADestroy @json
    EXEC @hr = sp_OADestroy @sbState
    EXEC @hr = sp_OADestroy @stReaders
    EXEC @hr = sp_OADestroy @json2


END
GO