To parse RDF data

The last chapter introduced how to acquire RDF data from the blockchain. This chapter will show how to parse these RDF data.

Data filtering

EIP6239 covers a lot more ground than the Relation Protocol does. So, we will filter the events shown in the last chapter.

Graph Indexer will parse the RDF data conforming to Schema specification.

This is to say that the address returned by the contract's schemaURI() method must exist in Schema specification for it to be parsed by the Graph Indexer.

In the EIP6239 specification, the process to acquire a Schema is defined:

interface ISemanticRDFSchema {
	/**
 	* @notice Get the URI of schema for this contract.
 	* @return The URI of the contract which points to a configuration profile.
 	*/
	function schemaURI() external view returns (string memory);
}

Procedures for parsing

Acquire the prefix definition from Schema:

PREFIX : <http://relationlabs.ai/entity/>
PREFIX p: <http://relationlabs.ai/property/>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>

Put it together with the RDF data parsed from Event:

:Soul_0x0109c8ee3151bde7b6b5d9f37e9d2c4bc16930fe p:following :Soul_0x6247123ec0fe0d25feb811e3c4d4a760c1f2e63e .

We now have a complete RDF:

PREFIX : <http://relationlabs.ai/entity/>
PREFIX p: <http://relationlabs.ai/property/>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>

:Soul_0x0109c8ee3151bde7b6b5d9f37e9d2c4bc16930fe a :Soul;
p:name "Alice" .

:Soul_0x6247123ec0fe0d25feb811e3c4d4a760c1f2e63e a :Soul;
p:name "Bob" .

:Soul_0x0109c8ee3151bde7b6b5d9f37e9d2c4bc16930fe p:following :Soul_0x6247123ec0fe0d25feb811e3c4d4a760c1f2e63e .