Ich habe unten eine Vertragsquelle zusammengestellt:
pragma solidity ^0.4.0;
////////////////////////////////////////////////////////////
// This is an example contract hacked together at a meetup.
// It is by far not complete and only used to show some
// features of Solidity.
////////////////////////////////////////////////////////////
contract queue
{
Queue requests;
event ElementPopped(uint256 _element);
event ElementPushed(uint256 _element, uint256 _index);
function queue() {
requests.data.length = 200;
}
struct Queue {
uint256[] data;
uint256 front;
uint256 back;
}
/// @dev the number of elements stored in the queue.
function length(Queue storage q) constant internal returns (uint256) {
return q.back - q.front;
}
/// @dev the number of elements this queue can hold
function capacity(Queue storage q) constant internal returns (uint256) {
return q.data.length - 1;
}
function isOverlapped(Queue storage q) internal returns (bool) {
return (q.back + 1) % q.data.length == q.front;
}
/// @dev push a new element to the back of the queue
function push(Queue storage q, uint256 data) internal {
if (isOverlapped(q)) throw;
q.data[q.back] = data;
ElementPushed(data, q.back);
q.back = (q.back + 1) % q.data.length;
}
/// @dev remove and return the element at the front of the queue
function pop(Queue storage q) internal returns (uint256 r)
{
if (q.back == q.front)
return; // throw;
r = q.data[q.front];
delete q.data[q.front];
q.front = (q.front + 1) % q.data.length;
return r;
}
function addRequest(uint256 d) {
push(requests, d);
}
function popRequest() {
ElementPopped(pop(requests));
}
function queueLength() constant returns (uint256) {
return length(requests);
}
}
Es gibt ein Ereignis, das :event ElementPopped(uint256 _element); Ich kompiliere die Quelle in https://ethereum.github.io/browser-solidity , füge dann den Inhalt von Web3 deploy in die Geth-Konsole ein.
var queue_sol_queueContract = web3.eth.contract([{"constant":false,"inputs":[{"name":"d","type":"uint256"}],"name":"addRequest","outputs":[],"payable":false,"type":"function"},{"constant":true,"inputs":[],"name":"queueLength","outputs":[{"name":"","type":"uint256"}],"payable":false,"type":"function"},{"constant":false,"inputs":[],"name":"popRequest","outputs":[],"payable":false,"type":"function"},{"inputs":[],"payable":false,"type":"constructor"},{"anonymous":false,"inputs":[{"indexed":false,"name":"_element","type":"uint256"}],"name":"ElementPopped","type":"event"},{"anonymous":false,"inputs":[{"indexed":false,"name":"_element","type":"uint256"},{"indexed":false,"name":"_index","type":"uint256"}],"name":"ElementPushed","type":"event"}]);
var queue_sol_queue = queue_sol_queueContract.new(
{
from: web3.eth.accounts[0],
data: '0x6060604052341561000c57fe5b5b60c860006000018161001f9190610026565b505b610077565b81548183558181151161004d5781836000526020600020918201910161004c9190610052565b5b505050565b61007491905b80821115610070576000816000905550600101610058565b5090565b90565b6102b0806100866000396000f30060606040526000357c0100000000000000000000000000000000000000000000000000000000900463ffffffff1680634ca1fad814610051578063ab91c7b014610071578063e4690a0b14610097575bfe5b341561005957fe5b61006f60048080359060200190919050506100a9565b005b341561007957fe5b6100816100b8565b6040518082815260200191505060405180910390f35b341561009f57fe5b6100a76100ca565b005b6100b460008261010d565b5b50565b60006100c460006101b4565b90505b90565b7fe32433683389a476fe90f93c07386d118310387cc5442554f0f6c2cc839c59426100f560006101c9565b6040518082815260200191505060405180910390a15b565b6101168261025a565b156101215760006000fd5b8082600001836002015481548110151561013757fe5b906000526020600020900160005b50819055507fef848106789acd461bcac88ec81e355ecd41e4be7d7491a567cca53a6cbcec96818360020154604051808381526020018281526020019250505060405180910390a1816000018054905060018360020154018115156101a657fe5b0682600201819055505b5050565b6000816001015482600201540390505b919050565b60008160010154826002015414156101e057610255565b8160000182600101548154811015156101f557fe5b906000526020600020900160005b5054905081600001826001015481548110151561021c57fe5b906000526020600020900160005b50600090558160000180549050600183600101540181151561024857fe5b0682600101819055508090505b919050565b600081600101548260000180549050600184600201540181151561027a57fe5b061490505b9190505600a165627a7a7230582025c3f2cf14912bcd818ae8b84356a11a18211d3aca9b44e6ade995ff784c95800029',
gas: '4700000'
}, function (e, contract){
console.log(e, contract);
if (typeof contract.address !== 'undefined') {
console.log('Contract mined! address: ' + contract.address + ' transactionHash: ' + contract.transactionHash);
}
})
Dann gebe ich diese unten in die Geth-Konsole ein:
> var event = queue_sol_queue.ElementPopped();
undefined
>event.watch(function(error, result){
// result will contain various information
// including the argumets given to the Deposit
// call.
if (!error)
console.log(result);
});
{
callbacks: [function(error, result)],
filterId: "0x41099921185e90179ba1ac1ff38a91bf",
getLogsCallbacks: [],
implementation: {
getLogs: function(),
newFilter: function(),
poll: function(),
uninstallFilter: function()
},
options: {
address: "0x8bed67280f46cc1ffd401cdb3dd5909f254c8f34",
from: undefined,
fromBlock: undefined,
to: undefined,
toBlock: undefined,
topics: ["0xe32433683389a476fe90f93c07386d118310387cc5442554f0f6c2cc839c5942 "]
},
pollFilters: [],
requestManager: {
polls: {
0x41099921185e90179ba1ac1ff38a91bf: {
data: {...},
id: "0x41099921185e90179ba1ac1ff38a91bf",
callback: function(error, messages),
uninstall: function()
}
},
provider: {
newAccount: function(),
send: function github.com/ethereum/go-ethereum/console.(*bridge).Send-fm() ,
sendAsync: function github.com/ethereum/go-ethereum/console.(*bridge).Send -fm(),
sign: function(),
unlockAccount: function()
},
timeout: {},
poll: function(),
reset: function(keepIsSyncing),
send: function(data),
sendAsync: function(data, callback),
sendBatch: function(data, callback),
setProvider: function(p),
startPolling: function(data, pollId, callback, uninstall),
stopPolling: function(pollId)
},
formatter: function(),
get: function(callback),
stopWatching: function(callback),
watch: function(callback)
}
Dann:
> queue_sol_queue.addRequest(3, { from: web3.eth.accounts[0] })
"0xe95758f98cda307dc602ff4c6e923a1c61df37a39256436129768bb0d4911d7a"
> queue_sol_queue.addRequest(3, { from: web3.eth.accounts[0] })
"0x21f70350015d0a3d8200d6fcc11534e66028e5861740d113c54e279266ee3bee"
> queue_sol_queue.addRequest(3, { from: web3.eth.accounts[0] })
"0x9f2a01aaf63d25dcd9f06b3d2edf65c14a5d44f1bc6d658777b7b68bb6697248"
> queue_sol_queue.addRequest(3, { from: web3.eth.accounts[0] })
"0x1403a55b839759cc6036790d56d8989d0966013d855bb382db03efff1e5eb5c0"
> queue_sol_queue.popRequest( { from: web3.eth.accounts[0] })
"0x78225091797345db0810e587425a9f79cb364c4cdb0af60ff2df44eed77a137d"
> [object Object]
> queue_sol_queue.popRequest( { from: web3.eth.accounts[0] })
"0xc812830b2ed2c6aedbaeb7811cef51dd662eaed1c6ad28855e57571f782648e3"
> [object Object]
warum ist es [Objekt Objekt]? und wie zeigt man das richtige Ergebnis an? Vielen Dank .
Die resultVariable in console.log(result)ist ein Objekt, das diese Felder enthält (siehe Dokumentation ):
Objekt - Ein Ereignisobjekt wie folgt:
address: String, 32 Bytes - Adresse, von der dieses Protokoll stammt.
args: Object – Die Argumente, die vom Ereignis stammen.
blockHash: String, 32 Bytes – Hash des Blocks, in dem sich dieses Protokoll befand. null, wenn es anhängig ist.
blockNumber: Number – die Blocknummer, in der sich dieses Protokoll befand. null, wenn es anhängig ist.
logIndex: Number – Ganzzahl der Log-Indexposition im Block.
event: String – Der Ereignisname.
entfernt: bool - Geben Sie an, ob die Transaktion, aus der dieses Ereignis erstellt wurde, aus der Blockchain entfernt wurde (aufgrund eines verwaisten Blocks) oder nie darauf zugegriffen wurde (aufgrund einer abgelehnten Transaktion).
transactionIndex: Number - Ganzzahl des Transaktionsindexpositionsprotokolls, aus dem erstellt wurde.
transactionHash: String, 32 Bytes – Hash der Transaktionen, aus denen dieses Protokoll erstellt wurde.
Diese können über result.address, result.args, usw. aufgerufen werden.
Sie können das Objekt in eine schöne Zeichenfolge zum Drucken verwandelnconsole.log(JSON.stringify(result))
Ja.