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AssetsFacet
smart-contractsfacetserc1155assetstokenisation

AssetsFacet

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AssetsFacet.sol is the full ERC-1155 implementation embedded inside the Aurellion Diamond. It handles all token operations — minting, transferring, custody — for real-world asset tokens. It mirrors the standalone AuraAsset.sol contract but operates within the shared Diamond storage.

Overview

Property Value
File contracts/diamond/facets/AssetsFacet.sol
Implements IERC1155, IERC1155MetadataURI
Storage Smart Contracts/Libraries/DiamondStorage AppStorage
Access Control validNode modifier, onlyOwner

Core Concepts

Token ID Generation

Token IDs are deterministically generated from asset definition data:

tokenID = uint256(keccak256(abi.encode(asset)));

This means the same physical asset definition always produces the same token ID, enabling idempotent minting.

Mint Hash

Each mint event produces a unique hash per account+asset combination:

hash = keccak256(abi.encode(account, asset));

This hash is used as the key for IPFS metadata, custody tracking, and event indexing.

Multi-Custodian Custody

Assets are held in custody by the minting node. Multiple nodes can mint the same tokenId; each tracks their custody independently:

tokenCustodianAmounts[tokenId][account] += amount;  // Per-custodian
tokenCustodyAmount[tokenId] += amount;               // Global total

Functions

ERC-1155 Standard Functions

`balanceOf(address account, uint256 id) → uint256`

Returns the balance of account for token id. Reads from erc1155Balances[id][account].

`balanceOfBatch(address[] accounts, uint256[] ids) → uint256[]`

Batch version of balanceOf. Reverts with ERC1155InvalidArrayLength if arrays differ in length.

`setApprovalForAll(address operator, bool approved)`

Sets operator as approved/revoked for all of msg.sender's tokens. Emits: ApprovalForAll(msg.sender, operator, approved)

`isApprovedForAll(address account, address operator) → bool`

Returns approval status for operator over account's tokens.

`safeTransferFrom(address from, address to, uint256 id, uint256 amount, bytes data)`

Transfers amount of token id from from to to. Requires caller is from or approved operator.

`safeBatchTransferFrom(address from, address to, uint256[] ids, uint256[] amounts, bytes data)`

Batch transfer. Same approval requirements.

`uri(uint256 id) → string`

Returns the base metadata URI (erc1155URI). Token-specific metadata at {uri}{id}.

`setURI(string newuri)`

Owner-only. Sets the base URI.

`totalSupply(uint256 id) → uint256`

Returns total minted supply for token id.

`exists(uint256 id) → bool`

Returns totalSupply(id) > 0.

Node Minting

`nodeMint(address account, AssetDefinition asset, uint256 amount, string className, bytes data) → (bytes32 hash, uint256 tokenID)`

The primary entry point for tokenising physical assets. Only callable by verified node operators.

Modifiers: validNode(msg.sender)

Process:

  1. Validates class is active: isClassActive[keccak256(abi.encode(className))]
  2. Generates deterministic token ID: uint256(keccak256(abi.encode(asset)))
  3. Generates mint hash: keccak256(abi.encode(account, asset))
  4. Stores hash → class and hash → tokenId mappings
  5. Appends hash to ipfsID array
  6. Calls internal _mint(account, tokenID, amount, data)
  7. Updates custody: tokenCustodianAmounts[tokenId][account] += amount
  8. Updates global: tokenCustodyAmount[tokenId] += amount

Emits:

  • MintedAsset(account, hash, tokenId, name, assetClass, className)
  • CustodyEstablished(tokenId, account, amount)

Reverts:

  • InvalidNode() — caller has no active valid node
  • ClassInactive() — asset class is not active
  • AssetAlreadyExists() — duplicate mint attempt

Class Management

`addSupportedClass(string className)`

Owner-only. Activates a new asset class (e.g., "GOAT", "WHEAT", "DIAMOND"). Emits: SupportedClassAdded(classNameHash, className)

`removeSupportedClass(string className)`

Owner-only. Deactivates a class using tombstoning — the class is marked inactive but not removed from the array (preserves array indices for existing assets). Emits: SupportedClassRemoved(classNameHash, className)

`getSupportedClasses() → string[]`

Returns all class names including tombstoned ones. Filter by isClassActive for active-only.

Custody Functions

`redeemCustody(uint256 tokenId, uint256 amount, address custodian)`

Releases tokens from a custodian's escrow to the redeemer. Validates the redeemer is not the custodian themselves. Emits: CustodyReleased(tokenId, custodian, amount, redeemer)

Events

Event Parameters When
MintedAsset account, hash, tokenId, name, assetClass, className Successful node mint
AssetAttributeAdded hash, attributeIndex, name, values, description Attribute added to asset
CustodyEstablished tokenId, custodian, amount Tokens minted into custody
CustodyReleased tokenId, custodian, amount, redeemer Custody released
SupportedClassAdded classNameHash, className New class activated
SupportedClassRemoved classNameHash, className Class deactivated
ApprovalForAll account, operator, approved Operator approval changed
TransferSingle operator, from, to, id, value Single token transfer
TransferBatch operator, from, to, ids, values Batch token transfer

Errors

Error Condition
InvalidNode() msg.sender has no active valid node
ClassInactive() Asset class is deactivated
ClassAlreadyExists() Adding a class that already exists
ClassNotFound() Removing a class that doesn't exist
AssetAlreadyExists() Minting a duplicate asset
InsufficientBalance() Transfer amount exceeds balance
ExceedsCustodyAmount() Redemption exceeds custody
NoCustodian() No custodian found for tokenId
CannotRedeemOwnCustody() Custodian attempting to redeem own custody
ERC1155InvalidReceiver Recipient cannot receive ERC-1155
ERC1155InsufficientBalance Standard ERC-1155 balance error
ERC1155MissingApprovalForAll Not approved to transfer
ERC1155InvalidArrayLength Batch arrays differ in length

Security

  • The validNode modifier iterates ownerNodes[msg.sender] to find any active+valid node. Nodes must be registered and marked validNode=true by an admin.
  • Custody tracking prevents double-spending: tokens can only be transferred after custody is properly established.
  • ERC-1155 transfer callbacks (onERC1155Received) are called for contract recipients.

Integration

Node Dashboard uses nodeMint when a node operator registers a new asset. See Roles/Node Operator and Frontend/Pages Reference.

Indexer listens to MintedAsset events to populate the assets table. See Indexer/Schema and Queries.

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