Macro ethcontract_derive::contract

contract!() { /* proc-macro */ }

Proc macro to generate type-safe bindings to a contract. This macro accepts a path to a Truffle artifact JSON file. Note that this path is rooted in the crate’s root CARGO_MANIFEST_DIR.

ethcontract::contract!("build/contracts/MyContract.json");

Alternatively, other sources may be used, for full details consult the ethcontract-generate::source documentation. Some basic examples:

// HTTP(S) source
ethcontract::contract!("https://my.domain.local/path/to/contract.json")
// Etherscan.io
ethcontract::contract!("etherscan:0x0001020304050607080910111213141516171819");
ethcontract::contract!("https://etherscan.io/address/0x0001020304050607080910111213141516171819");
// npmjs
ethcontract::contract!("npm:@org/package@1.0.0/path/to/contract.json")

Note that Etherscan rate-limits requests to their API, to avoid this an ETHERSCAN_API_KEY environment variable can be set. If it is, it will use that API key when retrieving the contract ABI.

Currently the proc macro accepts additional parameters to configure some aspects of the code generation. Specifically it accepts:

• crate: The name of the ethcontract crate. This is useful if the crate was renamed in the Cargo.toml for whatever reason.
• contract: Override the contract name that is used for the generated type. This is required when using sources that do not provide the contract name in the artifact JSON such as Etherscan.
• mod: The name of the contract module to place generated code in. Note that the root contract type gets re-exported in the context where the macro was invoked. This defaults to the contract name converted into snake case.
• deployments: A list of additional addresses of deployed contract for specified network IDs. This mapping allows MyContract::deployed to work for networks that are not included in the Truffle artifact’s networks property. Note that deployments defined this way take precedence over the ones defined in the Truffle artifact. This parameter is intended to be used to manually specify contract addresses for test environments, be it testnet addresses that may defer from the originally published artifact or deterministic contract addresses on local development nodes.
• methods: A list of mappings from method signatures to method names allowing methods names to be explicitely set for contract methods. This also provides a workaround for generating code for contracts with multiple methods with the same name.
• event_derives: A list of additional derives that should be added to contract event structs and enums.

Additionally, the ABI source can be preceeded by a visibility modifier such as pub or pub(crate). This visibility modifier is applied to both the generated module and contract re-export. If no visibility modifier is provided, then none is used for the generated code as well, making the module and contract private to the scope where the macro was invoked.

ethcontract::contract!(
    pub(crate) "build/contracts/MyContract.json",
    crate = ethcontract_rename,
    mod = my_contract_instance,
    contract = MyContractInstance,
    deployments {
        4 => "0x000102030405060708090a0b0c0d0e0f10111213",
        5777 => "0x0123456789012345678901234567890123456789",
    },
    methods {
        myMethod(uint256,bool) as my_renamed_method;
    },
    event_derives (serde::Deserialize, serde::Serialize),
);

See ethcontract module level documentation for additional information.