My goal is to have a PHP script be invoked whenever a transaction is received by a given address.
I know Javascript but this is my first sally into Node.js. I think the right approach is to run a node.js webserver in parallel to Apache, and for that to be running a script which uses web3.eth.filter to trigger a javascript which makes a HTTP request to Apache.
Is that right? If so, I don't know how to use web3.eth.filter, the documentation isn't great.
Some hints, please?
If you are not familiar with node.js but with PHP and the ethereum architecture, I recommend you to have a look on the RPC API: https://github.com/ethereum/wiki/wiki/JSON-RPC#eth_newfilter
In particular at eth_newFilter and eth_getFilterChanges which you can simply call via rest API
e.g.
# This will install a new filter with your desired address curl -X POST --data '{"jsonrpc":"2.0","method":"eth_newFilter","params":[{"address": "0x8888f1f195afa192cfee860698584c030f4c9db1"}],"id":73}' <address:port> # Polling this will return updates - your received transactions curl -X POST --data '{"jsonrpc":"2.0","method":"eth_getFilterChanges","params":["0x16"],"id":73}' <address:port> You should check out the Ethereum-php Listener and Indexer
As opposed to above it will also work with clients who don't support EthFilter like Infura.
1) Extend a Ethereum\SmartContract and add event handlers with "onEventName"
class CallableEvents extends SmartContract { public function onCalledTrigger1 (EthEvent $event) { echo '### ' . substr(__FUNCTION__, 2) . "(\Ethereum\EmittedEvent)\n"; var_dump($event); } public function onCalledTrigger2 (EthEvent $event) { echo '### ' . substr(__FUNCTION__, 2) . "(\Ethereum\EmittedEvent)\n"; var_dump($event); } } 2) Initialize your Contracts (in this Example from Truffle builds)
$web3 = new Ethereum('http://192.168.99.100:8545'); $networkId = '5777'; // Contract Classes must have same name as the solidity classes for this to work. $contracts = SmartContract::createFromTruffleBuildDirectory( 'YOUR/truffle/build/contracts', $web3, $networkId ); 3) Create a Event processor
// process any Transaction from current Block to the future. new ContractEventProcessor( $web3, $contracts, 'latest', 'latest' ); Code is based on reactPHP.
You'll find more examples for Block or Event processing here.
