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erc20

README.md

Apecoin Substreams

Although this substreams is tracking the Apecoin Contract, you can use this as a template for any ERC20 token. You will need to update the CONTRACT_ADDRESS, START_BLOCK and the contract metadata in the store_token function to match your token.

Quickstart

Make sure you have the latest versions of the following installed:

1. Update the CONTRACT_ADDRESS & START_BLOCK variables in src/utils/constants.rs

pub const CONTRACT_ADDRESS: &str = "0xBC4CA0EdA7647A8aB7C2061c2E118A18a936f13D";
pub const START_BLOCK: u64 = 14204532;

2. Update the contract metadata in the store_token handler function

#[substreams::handlers::store]
pub fn store_token(block: eth::v2::Block, o: StoreSetProto<apecoin::Token>) {
    if block.number == START_BLOCK {
        let token = &apecoin::Token {
            name: "Apecoin".to_string(),
            address: append_0x(Hex(CONTRACT_ADDRESS).to_string().as_str()),
            decimal: "18".to_string(),
            symbol: "Ape".to_string(),
        };
        o.set(0, format!("Token: {}", token.address), &token);
    };
}

3. Update the initialBlock params for all modules within substreams.yaml

  - name: map_transfer
    kind: map
    initialBlock: 14204533
    inputs:
      - source: sf.ethereum.type.v2.Block
    output:
      type: proto:apecoin.Transfers

4. Compile the Project with make build

We now need to recompile our WASM binary with the new changes we made to the rust files.

5. Pack the spkg with make package

We need to bundle the protobuf definitions and the WASM binary into a single file. This is what we will deploy the subgraph.

6. Deploy the subgraph with graph deploy

Modify the package.json to point to your subgraph. The deploy script will change if you are deploying to the hosted service or decentralized network, but replace this with the command that is appropriate for your setup.

7. Schema

type Account @entity {
  id: ID!
  holdings: BigDecimal!
  sent: [Transfer!]! @derivedFrom(field: "sender")
  received: [Transfer!]! @derivedFrom(field: "receiver")
  approvals: [Approval!]! @derivedFrom(field: "owner")
}

type Transfer @entity(immutable: true) {
  id: ID!
  sender: Account
  receiver: Account!
  amount: String!
  token: Token!
  timestamp: BigInt!
  txHash: String!
  blockNumber: BigInt!
  logIndex: BigInt!
}

type Approval @entity(immutable: true) {
  id: ID!
  spender: String!
  owner: Account!
  amount: String!
  timestamp: BigInt!
  token: Token!
  txHash: String!
  blockNumber: BigInt!
  logIndex: BigInt!
}

type Token @entity {
  id: ID!
  name: String!
  address: String!
  symbol: String!
  decimals: String!
  transfers: [Transfer!]! @derivedFrom(field: "token")
  approvals: [Approval!]! @derivedFrom(field: "token")
}

8. Data Flow

graph TD;
  map_transfer[map: map_transfer];
  sf.ethereum.type.v2.Block[source: sf.ethereum.type.v2.Block] --> map_transfer;
  map_approval[map: map_approval];
  sf.ethereum.type.v2.Block[source: sf.ethereum.type.v2.Block] --> map_approval;
  store_account_holdings[store: store_account_holdings];
  map_transfer --> store_account_holdings;
  store_token[store: store_token];
  sf.ethereum.type.v2.Block[source: sf.ethereum.type.v2.Block] --> store_token;
  graph_out[map: graph_out];
  map_transfer --> graph_out;
  map_approval --> graph_out;
  store_account_holdings -- deltas --> graph_out;
  store_token -- deltas --> graph_out;
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