I am porting Ethereum smart contract in Solidity to EOS platform, but I meet a problem: how to send some events to Dapp so as to update the UI? Now I have to poll the table the smart contract saved to get the status.
Is there event emitting function in EOS smart contract? Or is there another better solution to get the smart contract internal data?
Check out the demux library for listening to EOS blockchain events. As far as I know there is no event logs like in Ethereum so you have to poll the api node
Currently, an event system like on the ethereum blockchain is not really supported. There are two github issues of the eos code that mention this feature, but say that it is not directly supported
In https://github.com/EOSIO/eos/issues/4003#issuecomment-400155409 the poster says that you currently could achieve this by using a plugin on your own nodeos server.
In https://github.com/EOSIO/eos/issues/1640#issuecomment-375488939 Dan says that it is possible, but the tooling is still being developed.
You want to use require_recipient(dapp_acc) and from your node you will listen and receive it, then you can broadcast to your dapp.
require_recipient is more about relaying actions than notifying clients