apla-blockchain-tools/transactions_filter/index.js

Module contains a number of tools to work with Apla Blockchain

"use strict";

// MIT License
//
// Copyright (c) 2016-2018 AplaProject
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.

/*
 * Package: apla-blockchain-tools
 * Author: Anton Zuev
 * mail: a.zuev@apla.io
 * Company: apla.io
 */


const Session = require("../session/index");
const _ = require("underscore");


class TransactionsFilter{
    /**
     *
     * @param apiUrl
     * @param options
     * @param options.numberOfBlocksToFetch - number of blocks to fetch at a time.
     */
    constructor(apiUrl, options){
        options = options || {};
        this.session = new Session(apiUrl);
        this.numberOfBlocksToFetch = options.numberOfBlocksToFetch || 50;
    }


    /**
     * returns a list of transactions
     * @param filters
     * @return {Promise.<void>}
     */
    async getTransactionsBy(filters){
        let from = 0;
        let response = await this.session.getDetailedBlocks(from, this.numberOfBlocksToFetch);
        let blocks = await response.json();
        let result = [];

        while(!blocks.error){
            result.push(TransactionsFilter.processBlocks(blocks, filters));
            from += this.numberOfBlocksToFetch;
            response = await this.session.getDetailedBlocks(from, this.numberOfBlocksToFetch);
            blocks = await response.json()
        }
        return _.flatten(result);
    }

    /**
     * processes blocks. Returns a list of transactions filtered by filters from blocks
     * @param blocks
     * @param filters
     */
    static processBlocks(blocks, filters){
        let result = [];
        for (let blockId in blocks){
            result.push(TransactionsFilter.processBlock(blocks[blockId], filters));
        }
        return _.flatten(result);
    }

    /**
     * processes one block. Returns a list of transactions filtered by filters from block
     * @param block
     * @param filters
     * @return {Array}
     */
    static processBlock(block, filters) {
        let result = [];
        for (let transaction of block.transactions) {
            if (TransactionsFilter.processTransaction(transaction, filters)) {
                transaction.blockId = block.header.block_id;
                result.push(transaction)
            }
        }
        return result;
    }


    /**
     * processes one transaction and returns whether transaction correspond to at least one of the conditions or not
     * @param transaction
     * @param filters
     * @return {boolean}
     */
    static processTransaction(transaction, filters) {
        for (let filter of filters){
            if(TransactionsFilter.applyFilter(transaction, filter)){
                return true;
            }
        }
        return false;
    }

    /**
     * checks whether transaction corresponds to the filter passed
     * @param transaction
     * @param filter
     * @return {boolean}
     */
    static applyFilter(transaction, filter) {
        if(transaction.contract_name.toString() !== filter.contractName.toString()){
            return false;
        }

        for (let key in filter.params){
            if(filter.params[key].toString() !== transaction.params[key].toString()){
                return false;
            }
        }
        return true;
    }

}

module.exports = TransactionsFilter;