scaffold-eth | 🏗 forkable Ethereum dev stack focused on fast product iterations | Cryptocurrency library
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forkable Ethereum dev stack focused on fast product iterations
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Trending Discussions on Cryptocurrency
QUESTION
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 02:43After 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.
QUESTION
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 03:03I 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.
Here is a sample code for UI (JavaScript and HTML):
QUESTION
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 20:14tickSize
for SCRTBUSD
is: 0.001.
Therefore, you have to round the quantity to the next 0.001. For example:
QUESTION
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 03:45The 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
QUESTION
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 20:23You have to use the request.security()
function in global scope, and only then use it.
You can do something like this:
QUESTION
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 14:37Try this:-
QUESTION
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 10:55Opensea 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-
QUESTION
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 06:32trc20 address features:
An encoded Mainnet address begins with T and is 34 bytes in length.
QUESTION
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 09:02Could 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).
QUESTION
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 12:35The 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:
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