Module Reference

The ModuleRef class provides functionality for managing and querying course module-related blockchain data. It allows clients to retrieve module addresses, module-specific UTXOs, and token policies associated with course modules.

Overview

Each module within a course is represented on-chain and has an associated validator address derived from the course’s NFT policy. This class facilitates retrieval of UTXOs linked to modules, either directly by address or through a module token name.

Methods

getAddress(courseNftPolicy)

Derives the blockchain address for a module validator using the course NFT policy.

Syntax:

const address = await sdk.provider.core.course.moduleRef.getAddress(courseNftPolicy)

Parameters:

• courseNftPolicy (string) – The policy ID of the course NFT

Returns:

• Promise<string> – The derived address for the course module validator

Example:

try {
  const address = await sdk.provider.core.course.moduleRef.getAddress("a1b2c3d4...");
  console.log("Module address:", address);
} catch (error) {
  console.error("Failed to derive module address:", error);
}

Throws:

• SdkError – When address derivation fails

getModuleReferenceTokenPolicy(courseNftPolicy)

Fetches the policy ID of the local state token associated with a course module.

Syntax:

const policyId = await sdk.provider.core.course.moduleRef.getModuleReferenceTokenPolicy(courseNftPolicy)

Parameters:

• courseNftPolicy (string) – The policy ID of the course NFT

Returns:

• Promise<string> – The token policy ID for the course module reference

Example:

try {
  const policyId = await sdk.provider.core.course.moduleRef.getModuleReferenceTokenPolicy("a1b2c3d4...");
  console.log("Module reference token policy ID:", policyId);
} catch (error) {
  console.error("Failed to get module reference token policy:", error);
}

Throws:

• SdkError – When token policy derivation fails

getUtxos(courseNftPolicy?, address?)

Retrieves UTXOs related to a course module using either a course policy or a direct address.

Syntax:

const utxos = await sdk.provider.core.course.moduleRef.getUtxos(courseNftPolicy?, address?)

Parameters:

• courseNftPolicy (string, optional) – The course NFT policy ID
• address (string, optional) – Direct module address

Returns:

• Promise<Utxo[]> – Array of module-related UTXOs

Example:

try {
  const utxos = await sdk.provider.core.course.moduleRef.getUtxos("a1b2c3d4...");
  console.log(`Found ${utxos.length} module UTXOs`);
} catch (error) {
  console.error("Error retrieving module UTXOs:", error);
}

Behavior:

• If address is not provided, derives it using the provided courseNftPolicy
• Requires at least one of the two parameters

Throws:

• SdkError – If parameters are missing or fetching fails

getUtxoByModuleTokenName(courseId, moduleTokenName)

Retrieves a specific module UTXO by its module token name.

Syntax:

const utxo = await sdk.provider.core.course.moduleRef.getUtxoByModuleTokenName(courseId, moduleTokenName)

Parameters:

• courseId (string) – The course NFT policy ID
• moduleTokenName (string) – The name of the module token (string-encoded, not hex)

Returns:

• Promise<Utxo> – The matching module UTXO

Example:

try {
  const utxo = await sdk.provider.core.course.moduleRef.getUtxoByModuleTokenName("a1b2c3d4...", "moduleA");
  console.log("Module UTXO found:", utxo.txHash);
} catch (error) {
  console.error("Failed to fetch module UTXO:", error);
}

Behavior:

1. Fetches all UTXOs for the course
2. Searches UTXOs for assets whose token name matches moduleTokenName
3. Converts asset names from hex for comparison

Throws:

• SdkError – If no matching UTXO is found or if an error occurs during search

Use Cases:

• Identifying and retrieving module data on-chain
• Verifying module presence within a course
• Extracting module-specific metadata for rendering or validation