[Ethereum] watching all the events of a contract (geth): ‘cannot find event for log undefined: undefined’

contract-developmenteventsgo-ethereum

I am trying to watch all events of a contract with many events. The following code is supposed to do just that:

var events = myContract.allEvents();
events.watch(function(error, event){
    if (error) {
        console.log("Error: " + error);
    } else {
        console.log('some event occured');
    }
});

But if I try it in geth, and trigger an event, this is what the console tells me:

cannot find event for log
undefined: undefined

Can someone please tell me what s wrong with this code?
(I run mist at the same time, I just geth attached)

Note that I have no difficulty watching individual events. I am instead trying to watch them all with the code above.

Best Answer

How is myContract defined? Is there an allEvents() event type?

I will assume that you have defined the myContract variable but you are trying to use allEvents to retrieve all events.

See How do I retrieve the Voted events from The DAO for an example of how to retrieve specific events generated by a contract.

See web3.eth.filter to use the filter(...) function to retrieve all events.


Update Responding To Comments Below

Here's a bit of code you to check out web3.eth.filter(...) with:

var filter = web3.eth.filter({ address: ["0xc4af56cd5254aef959d4bce2f75874007808b701"], fromBlock: 2615848, toBlock: "latest" });
var i = 0;
filter.watch(function (error, result) {
  console.log("RESULT: Filter " + i++ + ": " + JSON.stringify(result));
});
filter.stopWatching();

The results produce include:

RESULT: Filter 0: {"address":"0xc4af56cd5254aef959d4bce2f75874007808b701","blockHash":"0x201154027d3c69cca298fab9983848269eee04cc26a9e1e7f2d06c9e1529b8f5","blockNumber":2615921,"data":"0x2fd64880bc17977672b2e25fff32b433975c4004b4fbd094936429e92f58d39f000000000000000000000000a74476443119a942de498590fe1f2454d7d4ac0d00000000000000000000000000000000000000000000000000000000000186a0","logIndex":2,"removed":false,"topics":["0x242ddf37c1721f450a35afdb783ef36e84d032a300600da464ff17d600cceed7"],"transactionHash":"0x6a7f83c93837f4ab11e1bc9dae2a34df4b4610b0d87512e451a36b5f53fb9661","transactionIndex":17}
RESULT: Filter 1: {"address":"0xc4af56cd5254aef959d4bce2f75874007808b701","blockHash":"0x201154027d3c69cca298fab9983848269eee04cc26a9e1e7f2d06c9e1529b8f5","blockNumber":2615921,"data":"0x2fd64880bc17977672b2e25fff32b433975c4004b4fbd094936429e92f58d39f0000000000000000000000000020dba1d308339182239056a00fcc146d2e26e0000000000000000000000000399156ee3339f4b29a53e307b98cce09fda3bac7","logIndex":3,"removed":false,"topics":["0x2d6a3482be690073d89f3c5420f70aca9f53be93321c5f45b5be55907b5f2b5b"],"transactionHash":"0x6a7f83c93837f4ab11e1bc9dae2a34df4b4610b0d87512e451a36b5f53fb9661","transactionIndex":17}
RESULT: Filter 2: {"address":"0xc4af56cd5254aef959d4bce2f75874007808b701","blockHash":"0x58fd992519b8bb06b8a8cddac850efad4f2b3b8dd5069a0d0d8f4deb15616b81","blockNumber":2617375,"data":"0x2fd64880bc17977672b2e25fff32b433975c4004b4fbd094936429e92f58d39f0000000000000000000000000020dba1d308339182239056a00fcc146d2e26e0000000000000000000000000b362bba1c7c5c857e3ac74d740c0007c48db7362","logIndex":5,"removed":false,"topics":["0x2d6a3482be690073d89f3c5420f70aca9f53be93321c5f45b5be55907b5f2b5b"],"transactionHash":"0xb7ef581cd0e6597525e254add6f820ac6ecf860d89d01656035dfd880dac2747","transactionIndex":6}
...

The events above are the Golem Network Token (GNT) TokenTraderFactory with source code available from 0xc4af56cd5254aef959d4bce2f75874007808b701. You can find further information on this TokenTraderFactory at Trustless Golem Network Token (GNT) Selling Contract.

Note that the topics in the events above include the hex strings below:

  • 0x242ddf37c1721f450a35afdb783ef36e84d032a300600da464ff17d600cceed7
  • 0x2d6a3482be690073d89f3c5420f70aca9f53be93321c5f45b5be55907b5f2b5b

Here are the events declared in the TokenTraderFactory contract:

  • event TradeListing(bytes32 bookid, address owner, address addr);
  • event NewBook(bytes32 bookid, address asset, uint256 units);

In geth:

> web3.sha3('NewBook(bytes32,address,uint256)')
"0x242ddf37c1721f450a35afdb783ef36e84d032a300600da464ff17d600cceed7"
> web3.sha3('TradeListing(bytes32,address,address)')
"0x2d6a3482be690073d89f3c5420f70aca9f53be93321c5f45b5be55907b5f2b5b"

You will have to interpret the data fields by yourself. From the second listing above, the data is 0x2fd64880bc17977672b2e25fff32b433975c4004b4fbd094936429e92f58d39f0000000000000000000000000020dba1d308339182239056a00fcc146d2e26e0000000000000000000000000399156ee3339f4b29a53e307b98cce09fda3bac7

This can be separated into:

0x
2fd64880bc17977672b2e25fff32b433975c4004b4fbd094936429e92f58d39f
0000000000000000000000000020dba1d308339182239056a00fcc146d2e26e0
000000000000000000000000399156ee3339f4b29a53e307b98cce09fda3bac7

In the TokenTraderFactory event TradeListing(bytes32 bookid, address owner, address addr) event,

bookid = 0x2fd64880bc17977672b2e25fff32b433975c4004b4fbd094936429e92f58d39f
owner  = 0x0020dba1d308339182239056a00fcc146d2e26e0
addr   = 0x399156ee3339f4b29a53e307b98cce09fda3bac7
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