User Access Token

The User Access Token provides functionality for retrieving user access tokens and associated addresses by alias. Access tokens represent user ownership and control over specific aliases in the system.

Overview

User Access Tokens are NFTs that grant users control over their registered aliases. Each token is uniquely identified by a combination of the policy ID and a token name derived from the alias. These tokens are held in user wallets and serve as proof of alias ownership.

Methods

getUtxoByAlias(alias)

Retrieves the UTXO containing the access token for a specific alias.

Syntax:

const utxo = await sdk.provider.core.course.userAccessToken.getUtxoByAlias(alias)

Parameters:

• alias (string) - The alias name to search for

Returns:

• Promise<Utxo> - The UTXO containing the access token for the specified alias

Example:

try {
  const alias = "myalias";
  const utxo = await sdk.provider.core.course.userAccessToken.getUtxoByAlias(alias);
  console.log('Access token UTXO found:', utxo.txHash);
  console.log('Token location:', utxo.output.address);
} catch (error) {
  if (error.message.includes('No UTXOs found for alias')) {
    console.error('Access token not found for alias:', alias);
  } else {
    console.error('Error retrieving access token:', error);
  }
}

Behavior:

1. Constructs the token name by prefixing “323232” to the hexadecimal representation of the alias
2. Searches for UTXOs containing assets with the constructed token name and policy ID
3. Returns the first matching UTXO found

Throws:

• Error - When no UTXO is found for the specified alias or when the fetch operation fails

getAddressByAlias(alias)

Retrieves the Cardano address where the access token for a specific alias is currently held.

Syntax:

const address = await sdk.provider.core.course.userAccessToken.getAddressByAlias(alias)

Parameters:

• alias (string) - The alias name to search for

Returns:

• Promise<string> - The Cardano address holding the access token

Example:

try {
  const alias = "myalias";
  const address = await sdk.provider.core.course.userAccessToken.getAddressByAlias(alias);
  console.log('Access token held at address:', address);
  // Example output: addr1q9x2kw...
} catch (error) {
  console.error('Failed to get address for alias:', error);
}

Behavior:

1. Uses getUtxoByAlias() to find the UTXO containing the access token
2. Extracts and returns the address from the UTXO output

Throws:

• Error - When the alias is not found or when address extraction fails

Use Cases:

• Verifying current ownership of an alias
• Determining where to send transactions related to alias management
• Checking if an alias is currently active and held by a user