Metadata Registry is an event driven registry that builds the metadata database using theGraph and the Poster contract (see EIP-3722).
Anyone can register a new metadata, the owner or authorized accounts can update or delete a metadata.
Any dApp can query and consume the metadata using the subgraph API. For example, the clr.fund app will use the metadata to populate the project page while adding a new project or viewing the project details.
The metadata registry depends on the Poster contract being deployed on the network that subgraph is indexing. If it's not deployed, use this script to deploy it.
To register a new metadata, simply call the Poster.post() function to log an event. The Poster contract has been deployed at the same address, 0x000000000000cd17345801aa8147b8D3950260FF, on multiple EVM compatible networks using the Singleton Factory.
function post(string calldata content, string calldata tag) public {
emit NewPost(msg.sender, content, tag);
}
The inputs to the Poster.post() function should be:
- tag: "METADATA"
- content: a JSON formatted string with a content field that is an array of instruction objects for managing metadata and metadata permissions. See Content Layout for more details.
Subgraph is used to track the state of metadata by indexing events logged through the Poster contract. When a new metadata is registered, it will be assigned a unique ID generated as network-transactionHash-logIndex). This ID will be used for updating or deleting the metadata as well as setting the metadata permissions.
Content of the metadata will not be verified as the registry is designed to be generic and can accept any metadata. It is the Dapp's responsibility to verify metadata.
See subgraph entity definitions: /packages/subgraph/schema.graphql.
See subgraph UML: /packages/subgraph/subgraphUML.png
A library that merges subgraph results from different networks. See /packages/composer/README.md for more details.