The meterify.eth.Contract object makes it easy to interact with smart contracts on the Meter blockchain. When you create a new contract object, you give it the json interface of the respective smart contract and web3 will auto convert all calls into low level ABI calls over RPC for you.
This allows you to interact with smart contracts as if they were JavaScript objects.
To use it standalone:
import {Contract} from 'web3-eth-contract';
import {Accounts} from 'web3-eth-accounts';
const contract = new Contract(
'ws://localhost:8546',
new Accounts('ws://localhost:8546', options),
abi,
address,
options
);
contract.methods.somFunc().send({from: ....}).on('receipt', () => {
...
});
meterify.eth.Contract
new meterify.eth.Contract(jsonInterface, address, options);
Example:
const myContract = new meterify.eth.Contract([...], '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe', {
defaultAccount: '0x1234567890123456789012345678901234567891', // default from address
defaultGasPrice: '20000000000' // default gas price in wei, 20 gwei in this case
});
Parameters:
jsonInterface - Array: The json interface for the contract to instantiate
address - String (optional): This address is necessary for transactions and call requests and can also be added later using myContract.options.address = '0x1234..'.
options - Object (optional): The options of the contract. Some are used as fallbacks for calls and transactions:
Returns:
Object: The contract instance with all its methods and events.
Properties
options
The contract options object has the following properties:
data - String: The contract bytecode.
address - String (deprecated use contract.address): The address of the contract.
address
myContract.address
The address used for this contract instance.
Example:
myContract.address;
> '0xde0b295669a9fd93d5f28d9ec85e40f4cb697bae'
// set a new address
myContract.address = '0x1234FFDD...';
All transactions generated by web3.js from this contract will contain this address as the "to".
The address will be stored in lowercase.
Property:
address - String or null: The address for this contract, or null if it is not yet set.
Call this function to deploy the contract to the blockchain.
Example:
myContract.deploy({
data: '0x12345...',
arguments: [123, 'My String']
})
.send({
from: '0x1234567890123456789012345678901234567891',
gas: 1500000,
gasPrice: '30000000000000'
}, (error, transactionHash) => { ... })
.on('error', (error) => { ... })
.on('transactionHash', (transactionHash) => { ... })
.on('receipt', (receipt) => {
console.log(receipt.contractAddress) // contains the new contract address
})
.on('confirmation', (confirmationNumber, receipt) => { ... })
.then((newContractInstance) => {
console.log(newContractInstance.options.address) // instance with the new contract address
});
// When the data is already set as an option to the contract itself
myContract.options.data = '0x12345...';
myContract.deploy({
arguments: [123, 'My String']
})
.send({
from: '0x1234567890123456789012345678901234567891',
gas: 1500000,
gasPrice: '30000000000000'
})
.then((newContractInstance) => {
console.log(newContractInstance.options.address) // instance with the new contract address
});
// Simply encoding
myContract.deploy({
data: '0x12345...',
arguments: [123, 'My String']
})
.encodeABI();
> '0x12345...0000012345678765432'
// Gas estimation
myContract.deploy({
data: '0x12345...',
arguments: [123, 'My String']
})
.estimateGas((err, gas) => {
console.log(gas);
});
After successful deployment the promise will resolve with a new contract instance.
Parameters:
options - Object: The options used for deployment.
data - String: The byte code of the contract.
arguments - Array (optional): The arguments which get passed to the constructor on deployment.
Returns:
Object: The transaction object:
Array - arguments: The arguments passed to the method before. They can be changed.Function - send(#contract-send): Will deploy the contract. The promise will resolve with the new contract instance, instead of the receipt!
For details to the methods see the documentation below.
The methods of this smart contract are available through:
The name: myContract.methods.myMethod(123)
The name with parameters: myContract.methods['myMethod(uint256)'](123)
The signature: myContract.methods['0x58cf5f10'](123)
This allows calling functions with same name but different parameters from the JavaScript contract object.
Example:
// calling a method
myContract.methods.myMethod(123).call({from: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'}, (error, result) => {
...
});
// or sending and using a promise
myContract.methods.myMethod(123).send({from: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'})
.then((receipt) => {
// receipt can also be a new contract instance, when coming from a "contract.deploy({...}).send()"
});
// or sending and using the events
myContract.methods.myMethod(123).send({from: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'})
.on('transactionHash', (hash) => {
...
})
.on('receipt', (receipt) => {
...
})
.on('confirmation', (confirmationNumber, receipt) => {
...
})
.on('error', console.error);
Parameters:
Returns:
Object: The Transaction Object:
Array - arguments: The arguments passed to the method before. They can be changed.
For details to the methods see the documentation below.
Will call a "constant" method and execute its smart contract method in the EVM without sending any transaction. Note calling can not alter the smart contract state.
Example:
// using the callback
myContract.methods.myMethod(123).call({from: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'}, (error, result) => {
...
});
// using the promise
myContract.methods.myMethod(123).call({from: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'})
.then((result) => {
...
});
// MULTI-ARGUMENT RETURN:
// Solidity
contract MyContract {
function myFunction() returns(uint256 myNumber, string myString) {
return (23456, "Hello!%");
}
}
// meterify
const MyContract = new meterify.eth.Contract(abi, address);
MyContract.methods.myFunction().call()
.then(console.log);
> Result {
myNumber: '23456',
myString: 'Hello!%',
0: '23456', // these are here as fallbacks if the name is not know or given
1: 'Hello!%'
}
// SINGLE-ARGUMENT RETURN:
// Solidity
contract MyContract {
function myFunction() returns(string myString) {
return "Hello!%";
}
}
// meterify
const MyContract = new meterify.eth.Contract(abi, address);
MyContract.methods.myFunction().call()
.then(console.log);
> "Hello!%"
Parameters:
options - Object (optional): The options used for calling.
transactionObject * from - String (optional): The address the call "transaction" should be made from.
gasPrice - String (optional): The gas price in wei to use for this call "transaction". It is the wei per unit of gas.
gas - Number (optional): The maximum gas provided for this call "transaction" (gas limit).
blockNumber - Number: The block number this log was created in. null when still pending.
callback - Function (optional): This callback will be fired with the result of the smart contract method execution as the second argument, or with an error object as the first argument.
Returns:
Promise<any> - The return value(s) of the smart contract method. If it returns a single value, it's returned as is. If it has multiple return values they are returned as an object with properties and indices.
Will send a transaction to the smart contract and execute its method. Note this can alter the smart contract state.
Example:
// using the callback
myContract.methods.myMethod(123).send({from: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'}, (error, transactionHash) => {
...
});
// using the promise
myContract.methods.myMethod(123).send({from: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'})
.then((receipt) => {
// receipt can also be a new contract instance, when coming from a "contract.deploy({...}).send()"
});
// using the event emitter
myContract.methods.myMethod(123).send({from: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'})
.on('transactionHash', (hash) => {
...
})
.on('confirmation', (confirmationNumber, receipt) => {
...
})
.on('receipt', (receipt) => {
// receipt example
console.log(receipt);
> {
"transactionHash": "0x9fc76417374aa880d4449a1f7f31ec597f00b1f6f3dd2d66f4c9c6c445836d8b",
"transactionIndex": 0,
"blockHash": "0xef95f2f1ed3ca60b048b4bf67cde2195961e0bba6f70bcbea9a2c4e133e34b46",
"blockNumber": 3,
"contractAddress": "0x11f4d0A3c12e86B4b5F39B213F7E19D048276DAe",
"cumulativeGasUsed": 314159,
"gasUsed": 30234,
"events": {
"MyEvent": {
returnValues: {
myIndexedParam: 20,
myOtherIndexedParam: '0x123456789...',
myNonIndexParam: 'My String'
},
raw: {
data: '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385',
topics: ['0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7', '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385']
},
event: 'MyEvent',
signature: '0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7',
logIndex: 0,
transactionIndex: 0,
transactionHash: '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385',
blockHash: '0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7',
blockNumber: 1234,
address: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'
},
"MyOtherEvent": {
...
},
"MyMultipleEvent":[{...}, {...}] // If there are multiple of the same event, they will be in an array
}
}
})
.on('error', console.error); // If there's an out of gas error the second parameter is the receipt.
Parameters:
options - Object: The options used for sending.
from - String: The address the transaction should be sent from.
gasPrice - String (optional): The gas price in wei to use for this transaction.It is the wei per unit of gas.
gas - Number (optional): The maximum gas provided for this transaction (gas limit).
value - Number|String|BN|BigNumber(optional): The value transferred for the transaction in wei.
callback - Function (optional): This callback will be fired first with the "transactionHash", or with an error object as the first argument.
Returns:
The callback will return the 32 bytes transaction hash.
"transactionHash" returns String: is fired right after the transaction is sent and a transaction hash is available.
"confirmation" returns Number, Object: is fired for every confirmation up to the 24th confirmation. Receives the confirmation number as the first and the receipt as the second argument. Fired from confirmation 1 on, which is the block where it's mined.
"error" returns Error: is fired if an error occurs during sending. If an out of gas error, the second parameter is the receipt.
Will call estimate the gas a method execution will take when executed in the EVM without sending a transaction.
Example:
// using the callback
myContract.methods.myMethod(123).estimateGas({gas: 5000000}, function(error, gasAmount){
if(gasAmount == 5000000)
console.log('Method ran out of gas');
});
// using the promise
myContract.methods.myMethod(123).estimateGas({from: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'})
.then(function(gasAmount){
...
})
.catch(function(error){
...
});
Parameters:
options - Object (optional): The options used for calling.
from - String (optional): The address the call "transaction" should be made from.
gas - Number (optional): The maximum gas provided for this call "transaction" (gas limit). Setting a specific value helps to detect out of gas errors. If all gas is used it will return the same number.
value - Number|String|BN|BigNumber(optional): The value transferred for the call "transaction" in wei.
callback - Function (optional): This callback will be fired with the result of the gas estimation as the second argument, or with an error object as the first argument.
event - String: The name of the event in the contract, or "allEvents" to get all events.options - Object (optional): The options used for deployment.filter - Object (optional): Lets you filter events by indexed parameters, e.g. {filter: {myNumber: [12,13]}} means all events where "myNumber" is 12 or 13.topics - Array (optional): This allows you to manually set the topics for the event filter. If given the filter property and event signature, (topic[0]) will not be set automatically.
Returns:
undefined
events
myContract.events.MyEvent([options][, callback])
Subscribe to an event.
Example:
myContract.events.MyEvent({
filter: {myIndexedParam: [20,23], myOtherIndexedParam: '0x123456789...'}, // Using an array means OR: e.g. 20 or 23
fromBlock: 0
}, (error, event) => { console.log(event); })
.on('data', (event) => {
console.log(event); // same results as the optional callback above
})
.on('changed', (event) => {
// remove event from local database
})
.on('error', console.error);
// event output example
> {
returnValues: {
myIndexedParam: 20,
myOtherIndexedParam: '0x123456789...',
myNonIndexParam: 'My String'
},
raw: {
data: '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385',
topics: ['0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7', '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385']
},
event: 'MyEvent',
signature: '0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7',
logIndex: 0,
transactionIndex: 0,
transactionHash: '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385',
blockHash: '0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7',
blockNumber: 1234,
address: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'
}
Parameters:
options - Object (optional): The options used for deployment.
filter - Object (optional): Let you filter events by indexed parameters, e.g. {filter: {myNumber: [12,13]}} means all events where "myNumber" is 12 or 13.
fromBlock - Number (optional): The block number from which to get events on.
topics - Array (optional): This allows to manually set the topics for the event filter. If given the filter property and event signature, (topic[0]) will not be set automatically.
callback - Function (optional): This callback will be fired for each event as the second argument, or an error as the first argument.
Returns:
EventEmitter: The event emitter has the following events:
"data" returns Object: Fires on each incoming event with the event object as argument.
"changed" returns Object: Fires on each event which was removed from the blockchain. The event will have the additional property "removed: true".
"error" returns Object: Fires when an error in the subscription occurs.
The structure of the returned event Object looks as follows:
event - String: The event name.
signature - String|Null: The event signature, null if it's an anonymous event.
address - String: Address this event originated from.returnValues - Object: The return values coming from the event, e.g. {myVar: 1, myVar2: '0x234...'}.
logIndex - Number: Integer of the event index position in the block.
transactionIndex - Number: Integer of the transaction's index position the event was created in.
transactionHash 32 Bytes - String: Hash of the transaction this event was created in.
blockHash 32 Bytes - String: Hash of the block this event was created in. null when it's still pending.
blockNumber - Number: The block number this log was created in. null when still pending.
raw.data - String: The data containing non-indexed log parameter.
raw.topics - Array: An array with max 4 32 Byte topics, topic 1-3 contains indexed parameters of the event.events.
myContract.getPastEvents('MyEvent', {
filter: {myIndexedParam: [20,23], myOtherIndexedParam: '0x123456789...'}, // Using an array means OR: e.g. 20 or 23
fromBlock: 0,
toBlock: 'latest'
}, (error, events) => { console.log(events); })
.then((events) => {
console.log(events) // same results as the optional callback above
});
> [{
returnValues: {
myIndexedParam: 20,
myOtherIndexedParam: '0x123456789...',
myNonIndexParam: 'My String'
},
raw: {
data: '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385',
topics: ['0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7', '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385']
},
event: 'MyEvent',
signature: '0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7',
logIndex: 0,
transactionIndex: 0,
transactionHash: '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385',
blockHash: '0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7',
blockNumber: 1234,
address: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'
},{
...
}]
Parameters:
event - String: The name of the event in the contract, or "allEvents" to get all events.
options - Object (optional): The options used for deployment.
filter - Object (optional): Lets you filter events by indexed parameters, e.g. {filter: {myNumber: [12,13]}} means all events where "myNumber" is 12 or 13.
fromBlock - Number (optional): The block number from which to get events on.
toBlock - Number (optional): The block number to get events up to (Defaults to "latest").
topics - Array (optional): This allows manually setting the topics for the event filter. If given the filter property and event signature, (topic[0]) will not be set automatically.
callback - Function (optional): This callback will be fired with an array of event logs as the second argument, or an error as the first argument.
Returns:
Promise returns Array: An array with the past event Objects, matching the given event name and filter.
Creates a new contract instance with all its methods and events defined in its object.
data - String: The byte code of the contract. Used when the contract gets .
address - String: The address where the contract is deployed. See .
The object derived from the of this contract.
jsonInterface - AbiModel: The for this contract. Re-setting this will regenerate the methods and events of the contract instance.
Function - : Will estimate the gas used for deploying.
Function - : Encodes the ABI of the deployment, which is contract data + constructor parameters
Creates a transaction object for that method, which then can be , , or .
Parameters of any method depend on the smart contracts methods, defined in the .
Function - : Will call the "constant" method and execute its smart contract method in the EVM without sending a transaction (Can't alter the smart contract state).
Function - : Will send a transaction to the smart contract and execute its method (Can alter the smart contract state).
Function - : Will estimate the gas used when the method would be executed on chain.
Function - : Encodes the ABI for this method. This can be send using a transaction, call the method or passing into another smart contracts method as argument.
PromiEvent: A . Will be resolved when the transaction receipt is available, OR if this send() is called from a someContract.deploy(), then the promise will resolve with the new contract instance. Additionally the following events are available:
"receipt" returns Object: is fired when the transaction receipt is available. Receipts from contracts will have no logs property, but instead an events property with event names as keys and events as properties. See for details about the returned event object.
callback - Function: This callback will be fired for the first event as the second argument, or an error as the first argument. See for details about the event structure.
Same as but receives all events from this smart contract. Optionally the filter property can filter those events.
For the structure of a returned event Object see .
