IndexerModule

The IndexerModule provides efficient on-chain indexing of attestations by various parameters (subject, schema, attester, portal). It allows for quick retrieval of attestation IDs without relying solel

Link to the code

When to use this module?

Use this module when you need:

• On-chain queryability of attestations by subject, schema, attester, or portal

• Fast lookup of all attestations for a specific address or entity

• To build on-chain logic that depends on finding related attestations

• A backup indexing mechanism in case off-chain indexers are unavailable

The IndexerModule is particularly useful for smart contracts that need to query attestations on-chain, such as reputation systems or access control mechanisms.

When not to use this module?

Don't use this module if:

• You only need off-chain querying (use the subgraph instead - it's more efficient and cost-effective)

• You're creating many attestations and want to minimize gas costs (indexing adds gas overhead)

• You need to track revoked attestations separately (this module doesn't un-index revoked attestations)

Important disclaimers

This module has several limitations:

1. Does not un-index revoked attestations - Revoked attestations remain in the index

2. Does not work as intended with bulk attestations - The attestation ID prediction may be incorrect during bulk operations

3. Does not consider chain prefix - The indexed attestation ID doesn't include the chain prefix used by the registry

How to use this module?

1. Include the module when registering your portal

Add the IndexerModule address to your portal's modules array. The module will automatically index attestations as they are created.

2. Query attestations

The IndexerModule provides several public view functions to retrieve attestation IDs:

Get attestations by subject

function getAttestationIdsBySubject(bytes calldata subject) 
  external view returns (bytes32[] memory);

Returns all attestation IDs for a given subject.

Get attestations by subject and schema

function getAttestationIdsBySubjectBySchema(
  bytes calldata subject,
  bytes32 schemaId
) external view returns (bytes32[] memory);

Returns all attestation IDs for a specific subject and schema combination.

Get attestations by attester

function getAttestationIdsByAttester(address attester) 
  external view returns (bytes32[] memory);

Returns all attestation IDs created by a specific attester.

Get attestations by schema

function getAttestationIdsBySchema(bytes32 schema) 
  external view returns (bytes32[] memory);

Returns all attestation IDs using a specific schema.

Get attestations by portal

function getAttestationIdsByPortal(address portal) 
  external view returns (bytes32[] memory);

Returns all attestation IDs created through a specific portal.

Get attestations by portal and subject

function getAttestationIdsByPortalBySubject(
  address portal,
  bytes calldata subject
) external view returns (bytes32[] memory);

Returns all attestation IDs for a specific portal and subject combination.

3. Manually index existing attestations

If you want to index attestations that were created before the module was added, you can use:

function indexAttestation(bytes32 attestationId) public;

function indexAttestations(bytes32[] calldata attestationIds) external;

These functions allow anyone to index existing attestations by providing their IDs.

How to check if an attestation is indexed?

function getIndexedAttestationStatus(bytes32 attestationId) 
  external view returns (bool);

Returns true if the attestation has been indexed, false otherwise.

Gas considerations

Indexing attestations adds gas overhead to each attestation creation. Consider this trade-off between on-chain queryability and gas costs when deciding whether to use this module.