Flush Custom Metadata Function

This section details the flushCustomMetadata function within the Name Service. This function allows the current owner (user) of a registered identity (identity, typically a username) to remove all custom metadata entries associated with that identity in a single transaction.

To flush all custom metadata, the identity owner must authorize the action with their signature and pay a fee via the EVVM contract. This fee is calculated dynamically as 10 times the current reward amount per metadata entry via getPriceToFlushCustomMetadata(identity). An optional priority fee can also be paid to the executor. This function can be executed by any address.

Function Type: public
Function Signature: flushCustomMetadata(address,string,uint256,bytes,uint256,uint256,bool,bytes)
Function Selector: 0x3e7899a1

Parameters

Parameter Name	Type	Description
user	address	The address of the current owner of the identity who is authorizing the flush.
identity	string	The registered identity (e.g., username) from which all custom metadata entries will be flushed.
nonce	uint256	The owner's (user) nonce specific to the NameService contract (nameServiceNonce) for this flushCustomMetadata action's replay protection.
signature	bytes	The EIP-191 signature from the owner (user) authorizing this flush all metadata action.
priorityFee_EVVM	uint256	Optional fee (in principal tokens) paid by the owner (user) to the msg.sender (executor) via the EVVM contract for prioritized processing of this transaction.
nonce_EVVM	uint256	Required. The owner's (user) nonce for the EVVM payment call used to pay the total calculated Flush Fee + Priority Fee.
priorityFlag_EVVM	bool	Required. Priority flag (sync/async) for the EVVM payment call paying the fees.
signature_EVVM	bytes	Required. The owner's (user) signature authorizing the EVVM payment call.

Signature Links & EVVM Payment

• The EVVM payment signature (signature_EVVM) covers the total amount (calculated Flush Fee + priorityFee_EVVM) and is paid by the identity owner (user). It uses the Single Payment Signature Structure. Since a flush fee is always required, these EVVM parameters are mandatory.
• The NameService flush custom metadata signature (signature) must be generated by the current owner (user) and follows the Flush Custom Metadata Signature Structure.
• The flush fee is calculated dynamically as 10 times the current EVVM reward amount per metadata entry via getPriceToFlushCustomMetadata(identity).

Metadata Pricing

The cost to flush all custom metadata is calculated dynamically based on the current EVVM reward amount and the number of metadata entries:

Flush Fee = (10 * getRewardAmount()) * customMetadataMaxSlots

This ensures the pricing scales with both the network's current reward structure and the amount of work required to flush all entries.

Workflow

Failure at validation steps typically reverts the transaction. The steps execute in the specified order.

1. Identity Ownership Verification: Checks if the provided user address is the registered owner of the identity. Reverts if user is not the owner.
2. NameService Nonce Verification: Checks if the provided nonce is unused for the user using the verifyIfNonceIsAvailable modifier. Reverts if the nonce is already used.
3. Flush Custom Metadata Signature Validation: Verifies the signature provided by user (the owner) against the reconstructed message hash using verifyMessageSignedForFlushCustomMetadata. Reverts if the signature is invalid according to the Flush Custom Metadata Signature Structure.
4. Empty Metadata Validation: Checks that the identity has at least one metadata entry (identityDetails[identity].customMetadataMaxSlots > 0). Reverts if there are no metadata entries to flush.
5. Payment Execution: Calls makePay to transfer the payment using getPriceToFlushCustomMetadata(identity) and priorityFee_EVVM of principal tokens from user to the service via the EVVM contract. Reverts if the payment fails.
6. Custom Metadata Removal (Flush): Iterates through all metadata entries and deletes them:
   • Loops from i = 0 to customMetadataMaxSlots - 1
   • Deletes each entry: delete identityCustomMetadata[identity][i]
7. Reward Distribution (to Executor): If the executor (msg.sender) is an sMATE staker, calls an internal helper function (makeCaPay) to distribute rewards in principal tokens directly to msg.sender. The rewards consist of:
   • 5 times the base reward amount multiplied by the number of metadata entries ((5 * getRewardAmount()) * customMetadataMaxSlots).
   • The full priorityFee_EVVM, if it was greater than zero and successfully paid in Step 5.
8. Reset Metadata Counter: Sets identityDetails[identity].customMetadataMaxSlots = 0 to reflect that all metadata has been removed.
9. Nonce Management: Marks the NameService nonce as used for the user address within the nameServiceNonce mapping.