Note

This documentation is under construction and documents the 2.x alpha versions of web3.js. The current stable version of web3.js is 1.0 and should get preferred for production use cases.

Core Method Module

The Core Method Module does provide all method classes and the abstract method factory which will be used in the AbstractWeb3Module.

AbstractMethodFactory

Source: AbstractMethodFactory

The AbstractMethodFactory does have the following constructor parameters:

  • utils - Utils The Utils object from the web3-utils module.
  • formatters - Object The formatters object from the web3-core-helpers module.

Example

import {
    AbstractMethodFactory,
    GetBlockByNumberMethod,
    ListeningMethod,
    PeerCountMethod,
    VersionMethod
} from 'web3-core-method';

class MethodFactory extends AbstractMethodFactory {
    /**
     * @param {Utils} utils
     * @param {Object} formatters
     *
     * @constructor
     */
    constructor(utils, formatters) {
        super(utils, formatters);

        this.methods = {
            getId: VersionMethod,
            getBlockByNumber: GetBlockByNumberMethod,
            isListening: ListeningMethod,
            getPeerCount: PeerCountMethod
        };
    }
}

AbstractMethod

Source: AbstractMethod

Because we are always adding new JSON-RPC methods do we just link the methods folder as resource.

Source: Methods

The provided method classes do have the following interface:

The AbstractMethod class does have the following constructor parameters:

  • rpcMethod - String The JSON-RPC method name.
  • parametersAmount - Number The amount of parameters this JSON-RPC method has.
  • utils - Utils
  • formatters - Object The formatters object.
  • moduleInstance - AbstractWeb3Module

The AbstractMethod class is the base JSON-RPC method class and does provide the basic methods and properties for creating a Web3.js compatible JSON-RPC method.

You’re able to overwrite these methods:

This example will show the usage of the setArguments(arguments: IArguments) method.

It’s also possible to set the parameters and callback method directly over the parameters and callback property of the method class.

Example

class Example extends AbstractWeb3Module {
    constructor(...) {
        // ...
    }

    sign() {
        const method = new AbstractMethod('eth_sign', 2, utils, formatters, this);
        method.setArguments(arguments)

        return method.execute();
    }
}

const example = new Example(...);

const response = await example.sign('0x0', 'message').
// > "response"


example.sign('0x0', 'message', (error, response) => {
    console.log(response);
};
// > "response"

The AbstractMethod class interface:


Type

The static readonly property Type will be used in the AbstractMethodFactory class to determine how the class should get initiated.

Reserved types:

  • observed-transaction-method - AbstractObservedTransactionMethod
  • eth-send-transaction-method - EthSendTransactionMethod

Returns

string - Example: observed-transaction-method


beforeExecution

method.beforeExecution(moduleInstance)

This method will be executed before the JSON-RPC request. It provides the possibility to customize the given parameters or other properties of the current method.

Parameters

  • moduleInstance - AbstractWeb3Module The current AbstractWeb3Module.

afterExecution

method.afterExecution(response)

This method will get executed when the provider returns with the response. The afterExecution method does provide us the possibility to map the response to the desired value.

Parameters

  • response - any The response from the provider.

Returns

any


execute

method.execute()

This method will execute the current method.

Returns

Promise<Object|string>|PromiEvent|string


rpcMethod

method.rpcMethod

This property will return the rpcMethod string. It will be used for the creation of the JSON-RPC payload object.

Returns

string


parametersAmount

method.parametersAmount

This property will return the parametersAmount. It will be used for validating the given parameters length and for the detection of the callback method.

Returns

number


parameters

method.parameters

This property does contain the given parameters.

Use the setArguments() method for setting the parameters and the callback method with the given IArguments object.

Returns

any[]


callback

method.callback

This property does contain the given callback.

Use the setArguments() method for setting the parameters and the callback method with the given IArguments object.

Returns

undefined


setArguments

method.setArguments(arguments)

This method will be used to set the given method arguments. The setArguments method will set the parameters and callback property.

Parameters

  • arguments - Array: The arguments of the function call.

Returns

Object


getArguments

method.getArguments()

This method will be used to get the method arguments. The getArguments method will return a object with the properties parameters and callback.

Returns

Object


isHash

method.isHash(value)

This method will check if the given value is a string and starts with 0x. It will be used in several methods for deciding which JSON-RPC method should get executed.

Parameters

  • value - string

Returns

boolean


AbstractObservedTransactionMethod

Source: AbstractObservedTransactionMethod

The AbstractObservedTransactionMethod extends from the AbstractMethod <web3-module-abstract-method and does have the following constructor parameters:

  • rpcMethod - String The JSON-RPC method name.
  • parametersAmount - Number The amount of parameters this JSON-RPC method has.
  • utils - Object The Utils object.
  • formatters - Object The formatters object.
  • transactionObserver - TransactionObserver The TransactionObserver class which defines the confirmation process of the transaction.

The AbstractObservedTransactionMethod is the base method class for all “send transaction” methods.

Abstract methods:

Type

The static readonly property Type will be used in the AbstractMethodFactory class to determine how the class should get initiated.

Reserved types:

  • observed-transaction-method - AbstractObservedTransactionMethod
  • eth-send-transaction-method - EthSendTransactionMethod

Returns

string - Example: observed-transaction-method


beforeExecution

method.beforeExecution(moduleInstance)

This method will be executed before the JSON-RPC request. It provides the possibility to customize the given parameters or other properties of the current method.

Parameters

  • moduleInstance - AbstractWeb3Module The current AbstractWeb3Module.

afterExecution

method.afterExecution(response)

This method will get executed when the provider returns with the response. The afterExecution method does provide us the possibility to map the response to the desired value.

Parameters

  • response - any The response from the provider.

Returns

any


execute

method.execute()

This method will execute the current method.

Returns

Promise<Object|string>|PromiEvent|string


rpcMethod

method.rpcMethod

This property will return the rpcMethod string. It will be used for the creation of the JSON-RPC payload object.

Returns

string


parametersAmount

method.parametersAmount

This property will return the parametersAmount. It will be used for validating the given parameters length and for the detection of the callback method.

Returns

number


parameters

method.parameters

This property does contain the given parameters.

Use the setArguments() method for setting the parameters and the callback method with the given IArguments object.

Returns

any[]


callback

method.callback

This property does contain the given callback.

Use the setArguments() method for setting the parameters and the callback method with the given IArguments object.

Returns

undefined


setArguments

method.setArguments(arguments)

This method will be used to set the given method arguments. The setArguments method will set the parameters and callback property.

Parameters

  • arguments - Array: The arguments of the function call.

Returns

Object


getArguments

method.getArguments()

This method will be used to get the method arguments. The getArguments method will return a object with the properties parameters and callback.

Returns

Object


isHash

method.isHash(value)

This method will check if the given value is a string and starts with 0x. It will be used in several methods for deciding which JSON-RPC method should get executed.

Parameters

  • value - string

Returns

boolean