scalachain | Blockchain implemented using the Scala programming language | Cryptocurrency library

by elleFlorio Scala Version: v.2.0 License: MIT

X-Ray Key Features Code Snippets Community Discussions(10)Vulnerabilities Install Support

kandi X-RAY | scalachain Summary

scalachain is a Scala library typically used in Blockchain, Cryptocurrency, Ethereum, Bitcoin applications. scalachain has no bugs, it has no vulnerabilities, it has a Permissive License and it has low support. You can download it from GitHub.

There a lot of good articles that explain how a blockchain works, so I will do a high level introduction just to provide some context to this project. The blockchain is a distributed ledger: it registers some transaction of values (e.g., coins) between a sender and a receiver. What makes a blockchain different from a traditional database is the decentralized nature of the blockchain: it is distributed among several communicating nodes that guarantee the validity of the transactions registered. To accomplish this goal, the blockchain stores transactions in blocks, that are created (mined) by nodes investing some computational power. Every block is created by solving a cryptographic puzzle that is hard to solve, but easy to verify. In this way, every block represents a certain amount of work - the work needed to solve the cryptographic puzzle. This is the reason why the cryptographic puzzle is called the Proof of Work: The solution of the puzzle is the proof that a node spent a certain amount of work to solve it and mine the block. The reason why nodes invest computational power to mine a block, is that the creation of a new block is rewarded by a predefined amount of coins. In this way nodes are encouraged to mine new blocks, contributing in the growth and strength of the blockchain. The solution of the cryptographic puzzle depends on the values stored in the last block mined, chaining every new block to the previous one, so to change a previously mined block a node should mine again all the blocks above the the modified one. Since every block represents an amount of work, this operation would be unfeasible once several blocks are mined upon the modified one. This is the foundation of the distributed consensus, The agreement of all the nodes on the validity of the blocks (i.e, the transactions) stored in the blockchain. It may happen that different nodes mine a block at the same time, creating different "branches" from the same blockchain - this is called a fork in the blockchain. when this happens, sets of nodes will continue mining starting from the different blocks of the new branches, that will grow in different ways. This situation is solved automatically when a branch becomes longer than the others: the longest chain always wins, so the winning branch becomes the new blockchain.

Support

Quality

Security

License

Reuse

Support

scalachain has a low active ecosystem.

It has 65 star(s) with 20 fork(s). There are 7 watchers for this library.

It had no major release in the last 12 months.

There are 0 open issues and 11 have been closed. On average issues are closed in 724 days. There are 1 open pull requests and 0 closed requests.

It has a neutral sentiment in the developer community.

The latest version of scalachain is v.2.0

Quality

scalachain has no bugs reported.

Security

scalachain has no vulnerabilities reported, and its dependent libraries have no vulnerabilities reported.

License

scalachain is licensed under the MIT License. This license is Permissive.

Permissive licenses have the least restrictions, and you can use them in most projects.

Reuse

scalachain releases are available to install and integrate.

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scalachain Key Features

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scalachain Examples and Code Snippets

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Community Discussions

Trending Discussions on Cryptocurrency

Why on printing I get value of null from API call in Loop

How to connect Metamask to Web3J (java)

Binance API: status: 400, error code: -1013, error message: Filter failure: PRICE_FILTER

Solana: Parse Token Data

Pinescript security function for colour boolean with mutable variable

How do you close a websocket connection if the API page is invalid

What token type is ETH on the Polygon network?

How to programmatically validate Tether (TRC20) Wallet Addresses in PHP?

Multiple NFTs from the same source

`ValueError: x and y must be the same size` when calling mplfinance

QUESTION

Why on printing I get value of null from API call in Loop

Asked 2022-Apr-16 at 03:06

COIN LIST is an array of crypto coins(["BTCUSDT",...]). I try to get the price using getPriceAction and RSI from getRSI and these two functions are working when I try to console DATA. But when I try to print the response after the completion of the loop. It prints the empty array and the length is 0 of this array. I want to store the DATA object (consisting of SYMBOL, closing price and RSI) as an element in the response array

...

ANSWER

Answered 2022-Apr-16 at 02:43

After the completion of the loop, the promises didn't get resolved yet, that's why it print an empty array. One way to achieve what you need is using await for(...), or wait for all promises to be resolved, and then print the results.

Source https://stackoverflow.com/questions/71890607

QUESTION

How to connect Metamask to Web3J (java)

Asked 2022-Apr-03 at 03:03

I am trying to connect my Metamask wallet to my Java Spring-Boot backend. I was trying to follow the example here. I am able to autogenerate the nonce and receive the wallet ID without a problem. I am trying to verify the signed nonce from the Wallet on the server to make sure that the sender is indeed who they say they are. However, I am unable to find any documentation on Web3J to do this.

Is web3j not the right package to use for this? The example shows how to do the verification on NodeJS based on javascript but I don't find any example on how to do this on Java.

My understanding is that the public key is the wallet ID itself and that the message is the nonce signed by the private key of the wallet which is not shared for obvious reasons. According to this, I would need to "decrypt" the message using the public key and see if the decrypted message is same as the nonce that the backend sent to Metamask to sign. Is this correct?

Here is my code to create and send the nonce to UI:

...

ANSWER

Answered 2022-Apr-03 at 03:03

I was able to figure this out finally. My initial understanding was incorrect. I was not supposed to attempt to decrypt the message to retrieve the nonce. Rather I needed to use the nonce to see if I can retrieve the public key of the private key used to sign the message and see if that public key retrieved matches the wallet ID.

The algorithm:

Receive the signed message and the wallet ID from the client
Retrieve the nonce sent to the client with the same wallet ID
Generate the hash of the nonce
Generate the signature data from the message. This basically retrieves the V, R and S and. R and S are the outputs of the ECDSA Signature and V is the Recovery ID.
Using the ECDSA Signature and Hash of the Nonce, generate the possible public Key that was used to sign the message. At max, one will be able to generate 4 possible public keys for this message.
Check if any of the generated keys match public wallet ID that the client sent. If it matches, then we have a positive match. Generate the JWT and respond to the client. If not, we know that the nonce was not signed by the Metamask wallet we expected.

The Code:

Here is a sample code for UI (JavaScript and HTML):

Source https://stackoverflow.com/questions/71630833

QUESTION

Binance API: status: 400, error code: -1013, error message: Filter failure: PRICE_FILTER

Asked 2022-Mar-16 at 20:14

status: 400, error code: -1013, error message: Filter failure: PRICE_FILTER

I am trying to create a new order to sell all SCRT that are on my account and I cannot figure out what is the problem.

The filters for SCRTBUSD are:

...

ANSWER

Answered 2022-Mar-16 at 20:14

tickSize for SCRTBUSD is: 0.001.

Therefore, you have to round the quantity to the next 0.001. For example:

Source https://stackoverflow.com/questions/71499941

QUESTION

Solana: Parse Token Data

Asked 2022-Mar-15 at 03:45

How does one parse the data in an SPL token account? It contains a binary blob and I'd like to get the token type and number of tokens.

An acceptable language is solana-cli, web3.js, or solana.py. I'm looking for any solution.

...

ANSWER

Answered 2022-Mar-15 at 03:45

The RPC give a great way to parse the data by default. You can use getParsedAccountInfo in web3.js.

Let's take the token account at 9xqnnfeonbsEGSPgF5Wd7bf9RqXy4KP22bdaGmZbHGwp

Source https://stackoverflow.com/questions/71471948

QUESTION

Pinescript security function for colour boolean with mutable variable

Asked 2022-Mar-14 at 12:47

I'm having issues with plotting the Coral Trend indicator colour code, into my 15min 21EMA security function. Since the Coral Trend indicator colour code has a mutable variable, I cannot resolve it. This is next level coding for me, haha.

I will post

the code
a screenshot
the problem
the solution I tried

The code:

...

ANSWER

Answered 2022-Feb-28 at 20:23

You have to use the request.security() function in global scope, and only then use it.

You can do something like this:

Source https://stackoverflow.com/questions/71299052

QUESTION

How do you close a websocket connection if the API page is invalid

Asked 2022-Feb-26 at 21:50

I am working with the Binance API. I am connecting to their API and trying to assess if Binance has a list of assets on their platform or not. The list of assets is seen below:

...

ANSWER

Answered 2021-Sep-21 at 14:37

Try this:-

Source https://stackoverflow.com/questions/69267777

QUESTION

What token type is ETH on the Polygon network?

Asked 2022-Feb-11 at 10:55

I am looking to work with ETH tokens on the Polygon network. My aim is to build a simple payment splitting application. Primarily to split royalties from Opensea. The issue I have come across is that Opensea doesn't seem to pay royalties in Matic token, instead, royalties are paid in ETH (plus other tokens).

I understand how to handle the network native, Matic, as well as ERC20 tokens. My main question is, what token type is ETH on the Polygon network? Is it an ERC20 (or similar) used to represent ETH on Polygon or does it have a special token type and privileges by virtue of Polygon being a layer two solution for Ethereum?

I'm sorry if this is a basic question, I tried to find answers online but because of the keywords all of the results were about bridging ETH to Polygon.

...

ANSWER

Answered 2022-Feb-11 at 10:55

Opensea uses WETH token on Polygon, which is an ERC-20 token representing the Ethereum mainnet ETH.

Please note, the "purple" Polygon ETH you see on OpenSea, is actually WETH (Wrapped Ether) on the blockchain level of Polygon.

Source: https://support.opensea.io/hc/en-us/articles/4403264773523-How-do-I-find-my-funds-on-Polygon-

Source https://stackoverflow.com/questions/71078280

QUESTION

How to programmatically validate Tether (TRC20) Wallet Addresses in PHP?

Asked 2022-Feb-09 at 10:38

I am having an issue related to validating cryptocurrency wallet addresses, specifically USDT.

USDT can be validated either as a BTC or ETH address, depending on the network type.

Basically it goes like that:

If cryptocurrency is USDT and chain type is ERC20, validate the address against ETH address format.
If cryptocurrency is USDT and wallet type is OMNI, validate the address against BTC address format.

I haven't managed to find a specific validation for USDT:TRC20 addresses and I am not sure how to validate them.

...

ANSWER

Answered 2021-Oct-15 at 06:32

trc20 address features:

An encoded Mainnet address begins with T and is 34 bytes in length.

Source https://stackoverflow.com/questions/69465635

QUESTION

Multiple NFTs from the same source

Asked 2022-Feb-06 at 09:02

General NFT question, but don't flame me, I really tried to find the answer.

Could NFT be created from the same image or copy of this image?

For example, take this NFT Lion Cat that I created: https://rarible.com/token/0x60f80121c31a0d46b5279700f9df786054aa5ee5:1200950?

Can someone download the image and create an NFT from it?

I mean, isn't it part of the idea that this is original content by me and I have the copyrights for it?

In the Image area, you got the RAW image that proves you took this picture, nobody but the photographer has this RAW image. But to create this image NFT I didn't have to provide it.

...

ANSWER

Answered 2022-Feb-06 at 09:02

Could NFT be created from the same image or copy of this image?

Can someone download the image and create an NFT from it?

Yes to both questions. It is technically possible to create multiple NFTs that all represent the same image. They can be placed in the same collection, as well as across multiple collections.

As NFTs basically contain links to this image, it's not possible to prevent someone from creating a link to a public resource, i.e. from creating another NFT representing the same image.

I mean, isn't it part of the idea that this is original content by me and I have the copyrights for it?

The ERC-721 standard mostly defines just the technical specifications. But it doesn't really cover the licensing, ownership/authorship of the underlying resource, and other non-technical topics.

An NFT only proves ownership of the token - not copyrights of the image. Also, it proves ownership by an address - not by a person. Because there can be zero to multiple people holding a private key to the same address (holding the NFT representing the image).

Source https://stackoverflow.com/questions/68816228

QUESTION

`ValueError: x and y must be the same size` when calling mplfinance

Asked 2022-Jan-30 at 14:48

import mplfinance as mpf
import talib as ta
import matplotlib.pyplot as plt
import numpy as np
%matplotlib notebook
test=df
WMA20 = ta.WMA(test['close'], timeperiod=20)
WMA60 = ta.WMA(test['close'], timeperiod=60)
WMA100 = ta.WMA(test['close'], timeperiod=100)
WMA200 = ta.WMA(test['close'], timeperiod=200)

# Set buy signals if current price is higher than 50-day MA
test['Buy'] = (test['close'] > WMA20) & (test['close'].shift(1) <= WMA20)

#plot
tcdf =test[['close']]
tcdf=tcdf.reset_index()
tcdf['date'] = tcdf['date'].apply(lambda x: x.value)

for i in range(len(test['Buy'])):
    if test['Buy'][i]==True:
       
        apd = mpf.make_addplot(tcdf.iloc[i],type='scatter',markersize=20,marker='o')


mpf.plot(test,addplot=apd, type='candle',volume=True)

...

ANSWER

Answered 2022-Jan-28 at 12:35

The problem is you are calling make_addplot() with only one data point at a time. There is also no need for the date index in the make_addplot() call; only the data.

Also, the length of data (number of rows) passed into make_addplot() must be the same as the length (number of rows) pass into plot().

make_addplot() should not be within the loop.

Try replacing this part of the code:

Source https://stackoverflow.com/questions/70893025

Community Discussions, Code Snippets contain sources that include Stack Exchange Network

Vulnerabilities

No vulnerabilities reported

Install scalachain

You can download it from GitHub.

Support

For any new features, suggestions and bugs create an issue on GitHub. If you have any questions check and ask questions on community page Stack Overflow .

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