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gas-relayer | ||
test-dapp | ||
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README.md |
README.md
token-gas-relayer
Gas relayer mplementation for economic abstraction. This project consists of two elements:
gas-relayer
: nodejs service that listens to whisper on a symmetric key, with specific topics, and processes any transaction.test-dapp
: DApp created for testing purposes. It allows the easy creation of the messages expected by the service.
Node
Before executing this program, config/config.json
must be setup and npm install
needs to be executed. Important values to verify are related to the node configuration, just like:
- Host, port and protocol to connect to the geth node
- Host, port and protocol Ganache will use when forking the blockchain for gas estimations and other operations
- Wallet account used for processing the transactions
- Symmetric key used to receive the Whisper messages
- Symmetric key used to send the heartbeats that notify the tokens and prices accepted
- Accepted tokens information
- Contract configuration
A geth
node running whisper (via -shh
option) is required. To execute the gas-relayer, you may use any of the following three methods.
npm start
node src/service.js
nodemon src/service.js
Test DApp
To run the test dapp, use embark run
and then browse http://localhost:8000/relayer-test.html
.
The gas relayer service needs to be running, and configured correctly to process the transactions. Things to take in account are: the account used in embark, and the contract addresses.
(TODO: update testnet configuration to guarantee the contract addresses don't change)
Additional notes
How to send a message to this service (all accounts and privatekeys should be replaced by your own test data)
shh.post({symKeyID: SYM_KEY, sig: WHISPER_KEY_ID, ttl: 1000, powTarget: 1, powTime: 20, topic: TOPIC_NAME, payload: PAYLOAD_BYTES});
SYM_KEY
must contain the whisper symmetric key used. It is shown on the console when running the service withnode
. With the provided configuration you can use the value:
0xd0d905c1c62b810b787141430417caf2b3f54cffadb395b7bb39fdeb8f17266b`
WHISPER_KEY_ID
represents a keypair registered on your node, that will be used to sign the message. Can be generated withweb3W.shh.newKeyPair()
TOPIC_NAME
must contain one of the topic names generated based on converting the contract name to hex, and taking the first 8 bytes. For the provided configuration the following topics are available:-
- IdentityGasRelay:
0x4964656e
- IdentityGasRelay:
-
- SNTController:
0x534e5443
- SNTController:
PAYLOAD_BYTES
a hex string that contains the identity/contract address to invoke and the web3 encoded abi function invocation plus parameters. If we were to executecallGasRelayed(address,uint256,bytes,uint256,uint256,uint256,address,bytes)
(part of the IdentityGasRelay) in contract0x692a70d2e424a56d2c6c27aa97d1a86395877b3a
, with these values:"0x11223344556677889900998877665544332211",100,"0x00",1,10,20,"0x1122334455112233445511223344551122334455"
, "0x1122334455",PAYLOAD_BYTES
can be prepared as follows:
const whisperKeyPairID = await web3W.shh.newKeyPair();
const jsonAbi = ABIOfIdentityGasRelay.filter(x => x.name == "callGasRelayed")[0];
const funCall = web3.eth.abi.encodeFunctionCall(jsonAbi,
[
"0x11223344556677889900998877665544332211",
100,
"0x00",
1,
10,
20,
"0x1122334455112233445511223344551122334455",
"0x1122334455"
]);
const msgObj = {
symKeyID: "0xd0d905c1c62b810b787141430417caf2b3f54cffadb395b7bb39fdeb8f17266b",
sig: whisperKeyPairID,
ttl: 1000,
powTarget: 1,
powTime: 20,
topic: "0x4964656e",
payload: web3.utils.toHex({
'address': "0x692a70d2e424a56d2c6c27aa97d1a86395877b3a",
'encodedFunctionCall': funCall
})
};
web3.shh.post(msgObj)
.then((err, result) => {
console.log(result);
console.log(err);
});