Develop Reference

Using events to read solidity struct

My smart contract has a struct and a function that populates it:
struct voter {
uint ID;
string firstName;
string lastName;
uint phone;
string addy;
//add picture
}
contract Poll {
uint public numVoters;
event VoterAdded(
voter newVoter
);
function AddVoter(string memory _firstName, string memory _lastName, uint _phone, string
memory _addy) public returns (voter memory){
numVoters++;
voter memory _voter = voter(numVoters, _firstName, _lastName, _phone, _addy);
_voter.ID = numVoters;
_voter.firstName = _firstName;
_voter.lastName = _lastName;
_voter.phone = _phone;
_voter.addy = _addy;
emit VoterAdded(_voter);
return _voter;
}
}
I am using truffle to test this struct, and Im trying to populate a struct and then storing a struct variable in a javascript variable.
const Poll = artifacts.require('Poll.sol');
it('Poll 1 : create voter and candidate objects2', async () =>
const tx = await poll.AddVoter('Jack', 'Jackson', 0, '');
const results = await poll.getPastEvents(
'VoterAdded',
{
fromBlock: 0, toBlock: 'latest'
});
console.log("Results", results, '${results.length} results');
const JJ = results[0];
assert.equal(JJ.firstName, 'Jack');
});
I think there is a problem with the lines after getPastEvents().
Heres the error I get:
Poll 1 : create voter and candidate objects2:
AssertionError: expected undefined to equal 'Jack'

I don't know if it's going to be of use or not, but I always used queryFilter to get the past events, using etherjs.
const eventFilter = poll.filters.VoterAdded();
const events = await poll.queryFilter(eventFilter);
console.log(events);

Requesting and reading JSON from Yahoo Finance with a generic function

My knowledge of javascript is limited. However, with much reading I was able to hack together the functions below. The goal is to define a generic function with which I can extract certain data from Yahoo finance.
In the example below, I'm pulling in A LOT of JSON data for any ticker (example link at the bottom). From the returned JSON, I select which values I'm interested in (here only dividendRate and paypoutRatio. If you call this function in a cell (I use Google Sheets), it will return 2 cells with the requested information:
=yFinance("KO")
+------+
| 1.76 |
+------+
| 0.75 |
+------+
Link used: Yahoo Finance JSON for Coca Cola
What I need, however, is to have the data formatted not in 2 cells BELOW each other, but NEXT TO each other:
=yFinance("KO")
+------+------+
| 1.76 | 0.75 |
+------+------+
I have two questions:
How can the code (probably in getMatchingValues()?) be updated to make this happen?
Is there any way to simplify these functions?
Any help is greatly appreciated, also because I feel that a generic function like this would benefit many people in the future. I have seen many posts about extracting a single value from Yahoo Finance, mostly by parsing the HTML (tables) using Google Sheets INDEX() function, but I believe via the JSON is faster and more resistent to future front-end changes at Yahoo.
function yFinance(symbol) {
const url = 'https://query2.finance.yahoo.com/v10/finance/quoteSummary/' + encodeURI(symbol)
+ '?modules=price,assetProfile,summaryDetail,incomeStatementHistory,'
+ 'balanceSheetHistory,defaultKeyStatistics,financialData,calendarEvents,'
+ 'recommendationTrend,upgradeDowngradeHistory,majorHoldersBreakdown'
;
const response = UrlFetchApp.fetch(url, {muteHttpExceptions: true});
const responseCode = response.getResponseCode();
if (responseCode === 200) {
const quote = JSON.parse(response.getContentText());
const paths = [
'summaryDetail/dividendRate/raw',
'summaryDetail/payoutRatio/raw'
];
return getMatchingValues(getPath(quote, 'quoteSummary/result/0'), paths);
}
else
{
return -1;
}
}
function getPath( obj, path ) {
if (!path || !obj) {
return null;
}
const parts = path.split('/');
const currentPath = parts[0];
const nextPath = parts.slice(1).join('/');
const currentObj = obj[currentPath];
// final path, exit here
if (nextPath.length === 0) {
return currentObj;
}
if (Array.isArray( currentObj )) {
// does an element exit at the next level
if ( currentObj[parts[1]] ) {
// will continue reading for 1 element
return getPath( currentObj, nextPath );
}
// return all the subpaths, skip the ones that are falsy
return currentObj.map( item => getPath( item, nextPath ) ).filter( v => v );
}
// get the next part of the object
return getPath( currentObj, nextPath );
}
function getMatchingValues( obj, paths ) {
return paths.flatMap( path => getPath( obj, path ));
}

If you want to get side by side values, modify by adding brackets as follows
return [getMatchingValues(getPath(quote, 'quoteSummary/result/0'), paths)];
You can simplify the code as follows
function yFinance_new(symbol) {
const url = 'https://query2.finance.yahoo.com/v10/finance/quoteSummary/' + encodeURI(symbol)
+ '?modules=price,assetProfile,summaryDetail,incomeStatementHistory,'
+ 'balanceSheetHistory,defaultKeyStatistics,financialData,calendarEvents,'
+ 'recommendationTrend,upgradeDowngradeHistory,majorHoldersBreakdown'
;
const response = UrlFetchApp.fetch(url, { muteHttpExceptions: true });
const responseCode = response.getResponseCode();
if (responseCode === 200) {
const quote = JSON.parse(response.getContentText());
return [[
quote.quoteSummary.result[0].summaryDetail.dividendRate.raw,
quote.quoteSummary.result[0].summaryDetail.payoutRatio.raw
]];
}
else {
return -1;
}
}

Solidity: Error: Please pass numbers as strings or BN objects to avoid precision errors

Have a simple contract in solidity:
contract SellStuff{
address seller;
string name;
string description;
uint256 price;
function sellStuff(string memory _name, string memory _description, uint256 _price) public{
seller = msg.sender;
name = _name;
description = _description;
price = _price;
}
function getStuff() public view returns (
address _seller,
string memory _name,
string memory _description,
uint256 _price){
return(seller, name, description, price);
}
}
And running a javascript test as follows:
var SellStuff= artifacts.require("./SellStuff.sol");
// Testing
contract('SellStuff', function(accounts){
var sellStuffInstance;
var seller = accounts[1];
var stuffName = "stuff 1";
var stuffDescription = "Description for stuff 1";
var stuffPrice = 10;
it("should sell stuff", function(){
return SellStuff.deployed().then(function(instance){
sellStuffInstance= instance;
return sellStuffInstance.sellStuff(stuffName, stuffDescription, web3.utils.toWei(stuffPrice,'ether'), {from: seller});
}).then(function(){
//the state of the block should be updated from the last promise
return sellStuffInstance.getStuff();
}).then(function(data){
assert.equal(data[0], seller, "seller must be " + seller);
assert.equal(data[1], stuffName, "stuff name must be " + stuffName);
assert.equal(data[2], stuffDescription, "stuff description must be " + stuffDescription);
assert.equal(data[3].toNumber(), web3.utils.toWei(stuffPrice,"ether"), "stuff price must be " + web3.utils.toWei(stuffPrice,"ether"));
});
});
});
But I am getting the following error:
Error: Please pass numbers as string or BN objects to avoid precision errors.
This seems to look like it pertains to the return type from the web3.utils.toWei call, so I have tried to cast it to a string:web3.utils.toWei(stuffPrice.toString(),"ether"); but this gives the Error: Number can only safely store up to 53 bits.
Not sure if I need to simply change the var in the class from uint256 or if there is a better way to cast the toWei return variable?

The error is here:
web3.utils.toWei(stuffPrice,'ether')
stuffPrice should be string.
web3.utils.toWei(String(stuffPrice),'ether')

The toWei() method accepts String|BN as the first argument. You're passing it the stuffPrice as a Number.
A quick fix is to define the stuffPrice as String:
var stuffPrice = '10'; // corrected code, String
instead of
var stuffPrice = 10; // original code, Number
Another way is to pass it a BN object.
var stuffPrice = 10; // original code, Number
web3.utils.toWei(
web3.utils.toBN(stuffPrice), // converts Number to BN, which is accepted by `toWei()`
'ether'
);

You need to declare the state variable as a string which will work in this case.
In React:
state = { playerEthervalue: ''};
const accounts = await web3.eth.getAccounts();
// Send the ethers to transaction, initiate the transaction
await lottery.methods.getPlayersAddress().send({ from: accounts[0],
value: web3.utils.toWei(this.state.playerEthervalue, 'ether') });
In solidity(.sol):
function getPlayersAddress() public payable {
require(msg.value >= 0.00000001 ether);
players.push(msg.sender);
}

Truffle test failed with "invalid opcode"

I am writing a unit test for my smart contract using truffle and when I run the test using "truffle test" the test failed with this error "Error: Returned error: VM Exception while processing transaction: invalid opcode".
smart contract code:
pragma solidity ^0.4.3;
contract owned {
address public owner;
/* Initialise contract creator as owner */
function owned() public {
owner = msg.sender;
}
/* Function to dictate that only the designated owner can call a function */
modifier onlyOwner {
require(owner == msg.sender);
_;
}
/* Transfer ownership of this contract to someone else */
function transferOwnership(address newOwner) public onlyOwner() {
owner = newOwner;
}
}
/*
* #title AsnScRegistry
* Open Vote Network
* A self-talling protocol that supports voter privacy.
*
* Author: Shahrul Sharudin
*/
contract AsnScRegistry is owned{
struct IPAddress {
uint128 ip;
uint8 mask;
}
struct MemberAddresses {
address contractAddress;
address walletAddress;
uint index;
}
mapping (uint => IPAddress[]) managedIps;
mapping (uint => MemberAddresses) ethAddresses;
uint[] private registeredAsn;
function getManagedIpByAsn(uint _asn) view public returns (uint128[] _ip, uint8[] _mask){
IPAddress[] memory addresses = managedIps[_asn];
uint128[] memory ips = new uint128[](addresses.length);
uint8[] memory mask = new uint8[](addresses.length);
for (uint i = 0; i < addresses.length; i++) {
ips[i] = addresses[i].ip;
mask[i] = addresses[i].mask;
}
return (ips, mask);
}
function getMemberAddressesByAsn(uint _asn) view public returns (address _contractAddress, address _walletAddress){
MemberAddresses memory memberAddresses = ethAddresses[_asn];
return (memberAddresses.contractAddress, memberAddresses.walletAddress);
}
function addMember(uint _asn, uint128[] _ip, uint8[] _mask, address _contractAddress, address _walletAddress) public {
MemberAddresses memory member = ethAddresses[_asn];
//throw error if member already exist
assert(member.contractAddress != 0);
for(uint i=0; i<_ip.length; i++){
managedIps[_asn].push(IPAddress({ip:_ip[i], mask:_mask[i]}));
}
uint idx = registeredAsn.push(_asn)-1;
ethAddresses[_asn] = MemberAddresses({contractAddress:_contractAddress, walletAddress:_walletAddress, index:idx});
}
function removeMember(uint _asn) public returns (uint[] _registeredAsn){
//uint memory index = ethAddresses[_asn].index;
if (ethAddresses[_asn].index >= registeredAsn.length) return;
for (uint i = ethAddresses[_asn].index; i<registeredAsn.length - 1; i++){
registeredAsn[i] = registeredAsn[i+1];
}
registeredAsn.length--;
delete managedIps[_asn];
delete ethAddresses[_asn];
return registeredAsn;
}
function getTotalMembers() view public returns (uint _totalMembers) {
return (registeredAsn.length);
}
function getRegisteredAsn() view public returns (uint[] _asn){
return (registeredAsn);
}
}
javascript unit test:
const AsnScRegistry = artifacts.require('./AsnScRegistry.sol')
const assert = require('assert')
const ip = [3524503734,3232235776];
const mask = [255,255];
const contractAddress = '0x1234567890123456789012345678901234567891';
const walletAddress = '0x1234567890123456789012345678901234567891';
const asn = 123;
let registryInstance;
contract("AsnScRegistry", accounts => {
it("Should add a new member", () =>
AsnScRegistry.deployed()
.then(instance => {
registryInstance = instance;
return instance.addMember(asn, ip, mask, contractAddress, walletAddress);
})
.then(() => registryInstance.getTotalMembers())
.then(total => assert.equal(total.toNumber(), 1, "xxxxx"))
);
});
the full source is available here: https://github.com/shaza4061/electioncommissioner
I expect the addMember() function to store the information in the smart contract and getTotalMembers() to return the number of record in registeredAsn[] array and the assertion in the unit test to pass.

The following error message:
"Error: Returned error: VM Exception while processing transaction: invalid opcode"
indicates a failed assert statement in solidity.
In your code, you have an assert which causes this error.
//throw error if member already exist
assert(member.contractAddress != 0);
Here is a manual for Solidity Smart contract debugging using Truffle.

Converting a JavaScript code using callbacks and RegEx method to equivalent code in C#

I've the below JavaScript code, that returned a function callback related to the user command, the user command could be used in different ways, hence RegEx is required:
(function (undefined) {
"use strict";
var root = this;
var commandsList = [];
var debugStyle = 'font-weight: bold; color: #00f;';
// The command matching code is a modified version of Backbone.Router by Jeremy Ashkenas, under the MIT license.
var optionalParam = /\s*\((.*?)\)\s*/g;
var optionalRegex = /(\(\?:[^)]+\))\?/g;
var namedParam = /(\(\?)?:\w+/g;
var splatParam = /\*\w+/g;
var escapeRegExp = /[\-{}\[\]+?.,\\\^$|#]/g;
var commandToRegExp = function(command) {
command = command.replace(escapeRegExp, '\\$&')
.replace(optionalParam, '(?:$1)?')
.replace(namedParam, function(match, optional) {
return optional ? match : '([^\\s]+)';
})
.replace(splatParam, '(.*?)')
.replace(optionalRegex, '\\s*$1?\\s*');
return new RegExp('^' + command + '$', 'i');
};
var registerCommand = function(command, cb, phrase) {
commandsList.push({ command: command, callback: cb, originalPhrase: phrase });
root.console.log('Command successfully loaded: %c'+phrase, debugStyle);
};
root.fonixListen = {
addCommands: function(commands) {
var cb;
for (var phrase in commands) {
if (commands.hasOwnProperty(phrase)) {
cb = root[commands[phrase]] || commands[phrase];
if (typeof cb === 'function') {
// convert command to regex then register the command
registerCommand(commandToRegExp(phrase), cb, phrase);
} else if (typeof cb === 'object' && cb.regexp instanceof RegExp) {
// register the command
registerCommand(new RegExp(cb.regexp.source, 'i'), cb.callback, phrase);
}
}
}
},
executeCommand: function(commandText) {
for (var j = 0, l = commandsList.length; j < l; j++) {
var result = commandsList[j].command.exec(commandText);
if (result) {
var parameters = result.slice(1);
// execute the matched command
commandsList[j].callback.apply(this, parameters);
return true;
}
}
}
};
}).call(this)
Below are some commands:
var commands = {
'hello :name *term': function(name) {
alert('hello '+name+''); // i.e. consider *term as optional input
},
'items identification': {
'regexp': /^(What is|What's|Could you please tell me|Could you please give me) the meaning of (TF|FFS|SF|SHF|FF|Tube Film|Shrink Film|Stretch Hood|Stretch Hood Film|Flat Film)$/,
'callback': itemsIdentification,
},
'ML SoH': {
'regexp': /^(What is|What's|Could you please tell me|Could you please give me) the (stock|inventory) of ML$/,
'callback': mlSOH,
},
'Report stock on hand': {
'regexp': /^(What is|What's) (our|the) (stock|inventory|SoH) of (TF|FFS|SF|SHF|FF|Tube Film|Shrink Film|Stretch Hood|Stretch Hood Film|Flat Film)$/,
'callback': SoH,
},
'Basic Mathematical Opertions': {
// ?\s? can be used instead of space, also could use /i instead of $/,
'regexp': /^(What is|What's|Calculate|How much is) ([\w.]+) (\+|and|plus|\-|less|minus|\*|\x|by|multiplied by|\/|over|divided by) ([\w.]+)$/,
'callback': math,
},
};
At running the app, the addCommands command is executed, and based on the input command from the user, the executeCommand command is executed.
The above works very fine with me, but I'm moving to C#, and very new to it, so looking for help, at least guiding of some functionalities and tools in C# that can help me write something similar to the above.
UPDATE
More details about what I try to do, actually I've a form, where the user input his command by voice using HTL5 voice API, the API convert this voice into text, then this text i submitted to my app, where my app work start by looking into this text, trying to find the required command using the ReqEx, then execute the programmed function/callback that is mapped with this input command.

I found the solution using Dictionary at using System.Collections.Generic; and using RegEx at using System.Text.RegularExpressions; along with the need of a function called FirstOrDefault availabe at using System.Linq;
I used Action instead of function Func as the callbacks in my case are do not return anything, i.e. they are a void functions, and because no input parameters provided, I used Action-delegate, and did not use Action<string[]>.
The working code is:
using System;
using System.Collections.Generic; // for Dictionary
using System.Linq; // for FirstOrDefault
using System.Text.RegularExpressions; // for RegEx
namespace ConsoleApplication
{
public class Program
{
public static void Main(string[] args)
{
Console.WriteLine("Hello World!");
var input = "What's the meaning of Stretch Hood";
var functions = new Dictionary<Regex, Action>
{
{new Regex("/^(What is|What's|Could you please tell me|Could you please give me) the meaning of (TF|FFS|SF|SHF|FF|Tube Film|Shrink Film|Stretch Hood|Stretch Hood Film|Flat Film)$/"),
itemsIdentification},
{new Regex("/^(What is|What's|Could you please tell me|Could you please give me) the (stock|inventory) of ML$/"),
mlSOH},
{new Regex("/^(What is|What's) (our|the) (stock|inventory|SoH) of (TF|FFS|SF|SHF|FF|Tube Film|Shrink Film|Stretch Hood|Stretch Hood Film|Flat Film)$/"),
SoH},
{new Regex("/^(What is|What's|Calculate|How much is) ([\w.]+) (\+|and|plus|\-|less|minus|\*|\x|by|multiplied by|\/|over|divided by) ([\w.]+)$/"),
math},
};
functions.FirstOrDefault(f => f.Key.IsMatch(input)).Value?.Invoke(); // This will execute the first Action found wherever the input matching the RegEx, the ?. means if not null ([Null-conditional Operators][1])
// or
Action action;
action = functions.FirstOrDefault(f => f.Key.IsMatch(input)).Value;
if (action != null)
{
action.Invoke();
}
else
{
// No function with that name
}
}
public static void itemsIdentification()
{
Console.WriteLine("Fn 1");
}
public static void mlSOH()
{
Console.WriteLine("Fn 2");
}
public static void SoH()
{
}
public static void math()
{
}
}
}