smart-contracts | Ethereum smart contracts for security and utility tokens | Cryptocurrency library

Don’t use a HashMap. Create real data classes:

blockchain transactions are not immediate, but must queue before being mined on the blockchain and be effective

When you add liquidity given amountADesired you have to give it amountBDesired in proportion to the existing pair (example pair: 2:1 you have to put 2 tokens A and 1 token B)

once you send the transaction, before it is mined it may happen that others make operations on that liquidity pool, changing the proportion accordingly

by entering amountAmin and amountBmin you are practically telling him: "as long as the proportion is between amountADesired:amountBDesired and amountAMin:amountBmin accepts my liquidity addition, if instead the proportion exceeds my range, cancel my transaction"

The difference is that the one with the "s" return the series of outputs resulting from a path of swaps. Whereas the ones without the "s" return the output for a single swap.

So if I swap along the path ["ETHUSDT", "USDTUSDC"] then getAmountsOut will return the USDT output amount from the ETHUSDT swap and the USDC output amount from the "USDTUSDC" swap. The returned value will look like: [usdtAmount, usdcAmount].

If I swap "ETHUSDT" then getAmountOut will return usdtAmount.

The inverse is true for getAmountsIn/getAmountIn.

It's defined here: https://github.com/pancakeswap/pancake-swap-periphery/blob/master/contracts/libraries/PancakeLibrary.sol#L63

I you are completely sure that the object inside "data" will only ever have a single key, we can take the object, convert it into a list of values, fail if the list is empty or has more than one value, and otherwise continue parsing. Like this:

Thanks for the flag. The node that was hosting this is deprecated, the article has been updated, and the docs have the latest example.

Please use:

The response basically looks like a list of dicts. So to extract names (or other keys) you can just do a list comprehension:

[d['name'] for d in data_quote]

But what about contract rewards and other funds belonging to the contract account? How would the original owner get access to that if keys are deleted?

The contract should be implemented in such a way that would allow certain operations.

Let's take a lockup contract as an example. This contract has a single owner, and the funds are locked for a certain amount of time, and the contract only provides certain methods to be called and guarded with the specific logic:

• As an owner, I can delegate (stake) my tokens to staking pools while I still cannot arbitrary transfer the tokens
• As an owner, I can withdraw the rewards from the staking pool through the lockup contract, and transfer those to an arbitrary account
• Once the lockup time is over, as an owner, I can call add_full_access_key function, and thus gain full access over the account, and even delete it after that (transferring all the tokens to some other account).

All that is explicitly implemented on the contract level, and easy to review, and given there is no other AccessKey on the lockup contract, we can be sure that there is no other way to interfere with the contract logic.

Here is rough guide

1. Get ABI for Uniswap contract

2. Create a web3.py contract object

3. You can use web3.eth.getLogs() to query events over past block range

4. You cannot query all events once, because there are so many events and Infura would time out. Instead you need to query events carefully over a block range slices.

Here is some old code which may or may not work with the latest web3.py versions

https://github.com/TokenMarketNet/sto/blob/master/sto/ethereum/scanner.py#L153

If you want a real time scanner you can listed to events over a WebSocket connection as they happen:

https://web3py.readthedocs.io/en/stable/filters.html#asynchronous-filter-polling

This is a contract created by another contract. So there's no chance for the developer to set an ABI.

You should refer to the creator contract's code.