Hardhat plugin for integration with OKLink's contract verification service.
This plugin helps you verify the source code for your Solidity contracts on OKLink.
It's smart and it tries to do as much as possible to facilitate the process:
- Just provide the deployment address and constructor arguments, and the plugin will detect locally which contract to verify.
- If your contract uses Solidity libraries, the plugin will detect them and deal with them automatically. You don't need to do anything about them.
- A simulation of the verification process will run locally, allowing the plugin to detect and communicate any mistakes during the process.
- Once the simulation is successful the contract will be verified using the OKLink API.
npm install --save-dev @enjinstarter/hardhat-oklink-verify
And add the following statement to your hardhat.config.js
:
require("@enjinstarter/hardhat-oklink-verify");
Or, if you are using TypeScript, add this to your hardhat.config.ts
:
import "@enjinstarter/hardhat-oklink-verify";
This plugin provides the oklink-verify
task, which allows you to verify contracts through OKLink's service.
This plugin does not extend the environment.
You need to add the following OKLink config to your hardhat.config.js
file:
module.exports = {
networks: {
mainnet: { ... }
},
oklink: {
// Your API key for OKLink
// Obtain one at https://www.oklink.com/en/
apiKey: "YOUR_OKLINK_API_KEY"
}
};
Alternatively you can specify more than one block explorer API key, by passing an object under the apiKey
property, see Multiple API keys and alternative block explorers
.
Lastly, run the oklink-verify
task, passing the address of the contract, the network where it's deployed, and the constructor arguments that were used to deploy it (if any):
npx hardhat oklink-verify --network okc DEPLOYED_CONTRACT_ADDRESS "Constructor argument 1"
When the constructor has a complex argument list, you'll need to write a javascript module that exports the argument list. The expected format is the same as a constructor list for an ethers contract. For example, if you have a contract like this:
struct Point {
uint x;
uint y;
}
contract Foo {
constructor (uint x, string s, Point memory point, bytes b) { ... }
}
then you can use an arguments.js
file like this:
module.exports = [
50,
"a string argument",
{
x: 10,
y: 5,
},
// bytes have to be 0x-prefixed
"0xabcdef",
];
Where the third argument represents the value for the point
parameter.
The module can then be loaded by the oklink-verify
task when invoked like this:
npx hardhat oklink-verify --constructor-args arguments.js DEPLOYED_CONTRACT_ADDRESS
NOTE: Libraries are unsupported as Multicontract Verify API currently does not support libraryList parameter.
Some library addresses are undetectable. If your contract uses a library only in the constructor, then its address cannot be found in the deployed bytecode.
To supply these missing addresses, you can create a javascript module that exports a library dictionary and pass it through the --libraries
parameter:
hardhat verify --libraries libraries.js OTHER_ARGS
where libraries.js
looks like this:
module.exports = {
SomeLibrary: "0x...",
};
If your project targets multiple EVM-compatible networks that have different explorers, you'll need to set multiple API keys.
To configure the API keys for the chains you are using, provide an object under oklink/apiKey
with the identifier of each chain as the key. This is not necessarily the same name that you are using to define the network. For example, if you are going to verify contracts in Ethereum mainnet, Optimism and Arbitrum, your config would look like this:
module.exports = {
networks: {
mainnet: { ... },
testnet: { ... }
},
oklink: {
apiKey: {
okc: "YOUR_OKC_MAINNET_OKLINK_API_KEY",
okcTestnet: "YOUR_OKC_TESTNET_OKLINK_API_KEY",
}
}
};
To see the full list of supported networks, run npx hardhat oklink-verify --list-networks
. The identifiers shown there are the ones that should be used as keys in the apiKey
object.
If the chain you are using is not in the list, you can manually add the necessary information to verify your contracts on it. For this you need three things: the chain id of the network, the URL of the verification endpoint, and the URL of the explorer.
For example, if Rinkeby wasn't supported, you could add it like this:
oklink: {
apiKey: {
bsc: "<bsc-api-key>"
},
customChains: [
{
network: "bsc",
chainId: 56,
urls: {
apiURL: "https://www.oklink.com/api/explorer/v1/bsc/contract/multipartVerify",
browserURL: "https://www.oklink.com/en/bsc"
}
}
]
}
Keep in mind that the name you are giving to the network in customChains
is the same one that has to be used in the apiKey
object.
To see which custom chains are supported, run npx hardhat oklink-verify --list-networks
.
To call the verification task from within a Hardhat task or script, use the "oklink-verify:verify"
subtask. Assuming the same contract as above, you can run the subtask like this:
await hre.run("oklink-verify:verify", {
address: contractAddress,
constructorArguments: [
50,
"a string argument",
{
x: 10,
y: 5,
},
"0xabcdef",
],
});
If the verification is not successful, an error will be thrown.
If your contract has libraries with undetectable addresses, you may pass the libraries parameter with a dictionary specifying them:
hre.run("oklink-verify:verify", {
// other args
libraries: {
SomeLibrary: "0x...",
}
}
The plugin works by fetching the bytecode in the given address and using it to check which contract in your project corresponds to it. Besides that, some sanity checks are performed locally to make sure that the verification won't fail.
- Adding, removing, moving or renaming new contracts to the hardhat project or reorganizing the directory structure of contracts after deployment may alter the resulting bytecode in some solc versions. See this Solidity issue for further information.