Scanning Encoded Cards

Learn how to scan an encoded card to retrieve useful information about the card.

You can use an encoder to scan a plastic key card to read its encoded parameters. The scan result includes the card's properties, such as its card number, serial number, and other useful details. The returned payload can also reveal whether the card is up-to-date with the server. If discrepancies are detected, Seam also provides warnings to indicate that the card is out-of-date and needs re-encoding.

The scanning process consists of the following basic steps:

1. Initiate the scanning process. Use the /acs/encoders/scan_credential endpoint. Specify the acs_encoder_id of the encoder that you want to use to scan the card. This request returns an action attempt that tracks the status of the scan. See Initiate the Scanning Process.

2. Poll the returned action attempt, until its status becomes success. See Confirm Successful Scan.

3. View the scanned card payload. Once the status of the action attempt is success, view the card payload within the action attempt. Note any action_attempt.result.warnings. Warning messages show which properties are out of sync. See View the Scanned Card Payload. Also, see a list of common scanning errors.

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1. Initiate the Scanning Process

To scan a card, first, identify the acs_encoder_id of the encoder that you want to use to scan the card. Then, initiate the scan using the /acs/encoders/scan_credential endpoint.

Python

Code:

# Retrieve a list of all available encoders in a building, 
# that is, connected to a single acs_system.
seam.acs.encoders.list(
  acs_system_ids = [building_system_id]
)

# Scan the card using the desired encoder.
scanning_action_attempt = seam.acs.encoders.scan_credential(
  acs_encoder_id = encoder.acs_encoder_id
)

Output:

ActionAttempt(
  status='pending',
  action_attempt_id='11111111-2222-3333-4444-666666666666',
  action_type='SCAN_CREDENTIAL',
  result=null,
  error=null
)

cURL (bash)

JavaScript

Ruby

PHP

C#

Java

Go

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2. Confirm Successful Scan

When you make an /acs/encoders/scan_credential request, Seam returns an action attempt. To identify when the scan has completed and to confirm that the scan was successful, poll this action attempt, until its status becomes success.

Python

Code:

seam.action_attempts.get(
  action_attempt_id = scanning_action_attempt.action_attempt_id
)

Output:

ActionAttempt(
  status='success',
  action_attempt_id='11111111-2222-3333-4444-666666666666',
  action_type='SCAN_CREDENTIAL',
  result={
    ...
  },
  error=null
)

cURL (bash)

JavaScript

Ruby

PHP

C#

Java

Go

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3. View the Scanned Card Payload

Once the action attempt's status is success, view the action attempt payload to view information about the scanned card. Pay special attention to the following parts of the returned payload:

• action_attempt.result.warnings list any properties that Seam has detected are out-of-sync between the card and the encoder.

• action_attempt.result.acs_credential_on_seam lists the properties of the credential as stored on the ACS server.

• action_attempt.result.acs_credential_on_encoder lists the properties of the credential as stored on the card.

{
  "status": "success",
  "action_attempt_id": "11111111-2222-3333-4444-666666666666",
  "action_type": "SCAN_CREDENTIAL",
  "result": {
    "warnings": [
      {
        "warning_code": "acs_credential_on_encoder_out_of_sync",
        "warning_message": "The following properties are out of sync
                            between acs_credential_on_encoder and
                            acs_credential_on_seam: ends_at"
      }
    ],
    "acs_credential_on_seam": {
      "starts_at": "2024-12-01T15:00:00.000Z",
      "ends_at": "2024-12-04T12:00:00.000Z"
      "card_number": "1234abc",
      "display_name": "Card 1234abc",
      "access_method": "card",
      "acs_system_id": "11111111-1111-1111-1111-111111111111",
      "acs_credential_id": "66666666-6666-6666-6666-666666666666",
      ...      
    },
    "acs_credential_on_encoder": {
      "starts_at": "2024-12-01T15:00:00.000Z",
      "ends_at": "2024-10-30T19:00:00.000Z",
      "card_number": "1234abc",
      ...
    }
  },
  "error": null
}

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Common Scanning Errors

Error	Description
no_card_on_encoder	No card was placed on the encoder.
uncategorized_error	Any other encoding error.