141 lines
5.0 KiB
Markdown
141 lines
5.0 KiB
Markdown
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# Javascript Library
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To simplify the process of building the whisper messages, a js file `status-gas-relayer.js` was created in the test-dapp. It only requires to setup connection to geth, and required keypairs and symkeys. This file might be expanded upon in the future and converted to a npm package.
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## Use
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```
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import StatusGasRelayer, {Contracts, Functions, Messages} from 'status-gas-relayer';
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// Connecting to web3
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const web3 = new Web3('ws://localhost:8546');
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const kid = await web3js.shh.newKeyPair()
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const skid = await web3.shh.addSymKey("0xd0d905c1c62b810b787141430417caf2b3f54cffadb395b7bb39fdeb8f17266b");
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```
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#### Subscribing to messages
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General message subscription. Special handling is needed for handling relayer availability messages. The `sig` property is the relayer's public key that needs to be sent when sending a transaction message. More than 1 relayer can reply, so it's recommended to save these keys in a list/array.
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```
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StatusGasRelayer.subscribe(web3js, (error, msgObj) => {
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if(error) {
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console.error(error);
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return;
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}
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if(msgObj.message == Messages.available){
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// Relayer availability message
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console.log("Relayer available: " + msgObj.sig);
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} else {
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// Normal message
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console.log(msgObj);
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}
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}, {
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privateKeyID: kid
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});
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```
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#### Polling for relayers
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```
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const identityAddress = this.props.identityAddress; // Identity contract
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const accountAddress = web3.eth.defaultAccount;
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const gasToken = SNT.options.address;
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const gasPrice = 1000000000000; // In wei equivalent to the used token
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const s = new StatusGasRelayer.AvailableRelayers(Contracts.Identity, identityAddress, accountAddress)
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.setRelayersSymKeyID(skid)
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.setAsymmetricKeyID(kid)
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.setGas(gasToken, gasPrice);
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await s.post(web3);
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```
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#### Signing a message
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Signing a message is similar to invoking a function. Both use mostly the same functions. The difference is that when you invoke a function, you need to specify the relayer and asymmetric key Id.
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```
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try {
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const s = new StatusGasRelayer.Identity(identityAddress, accountAddress)
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.setContractFunction(Functions.Identity.call)
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.setTransaction(to, value, data)
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.setGas(gasToken, gasPrice, gasLimit);
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const signature = await s.sign(web3);
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} catch(error){
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console.log(error);
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}
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```
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#### Using Identity contract `call` function
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This functionality is used when a Identity will invoke a contract function or transfer ether without paying fees
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```
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try {
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const s = new StatusGasRelayer.Identity(identityAddress, accountAddress)
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.setContractFunction(Functions.Identity.call)
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.setTransaction(to, value, data) // 'value' is in wei, and 'data' must be a hex string
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.setGas(gasToken, gasPrice, gasLimit)
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.setRelayer(relayer)
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.setAsymmetricKeyID(kid);
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await s.post(signature, web3);
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} catch(error){
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console.log(error);
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}
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```
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#### Using Identity contract `approveAndCall` function
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This functionality is used when a Identity will invoke a contract function that requires a transfer of Tokens
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```
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try {
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const s = new StatusGasRelayer.Identity(identityAddress, accountAddress)
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.setContractFunction(Functions.Identity.approveAndCall)
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.setTransaction(to, value, data)
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.setBaseToken(baseToken)
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.setGas(gasToken, gasPrice, gasLimit)
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.setRelayer(relayer)
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.setAsymmetricKeyID(kid);
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await s.post(signature, web3);
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} catch(error){
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console.log(error);
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}
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```
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#### Using SNTController `transferSNT` function
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This functionality is used for simple wallets to perform SNT transfers without paying ETH fees
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```
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try {
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const accounts = await web3.eth.getAccounts();
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const s = new StatusGasRelayer.SNTController(SNTController.options.address, accounts[2])
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.transferSNT(to, amount)
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.setGas(gasPrice)
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.setRelayer(relayer)
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.setAsymmetricKeyID(kid);
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await s.post(signature, web3);
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} catch(error){
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console.log(error);
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}
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```
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#### Using SNTController `execute` function
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```
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try {
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const accounts = await web3.eth.getAccounts();
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const s = new StatusGasRelayer.SNTController(SNTController.options.address, accounts[2])
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.execute(allowedContract, data)
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.setGas(gasPrice, gasMinimal)
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.setRelayer(relayer)
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.setAsymmetricKeyID(kid);
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await s.post(signature, web3);
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} catch(error){
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console.log(error);
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}
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```
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