ethereum

README

chancoin

About chancoin

chancoin is an innovative solution to the scalability problem with the Ethereum blockchain. Our mission is to be a leading force in building the Internet of Value, and its infrastructure. We are working to create an alternative, scalable financial system which is more secure, transparent, efficient, inclusive, and equitable for everyone.

chancoin relies on a system of 150 Masternodes with a Proof of Stake Voting consensus that can support near-zero fee, and 2-second transaction confirmation times. Security, stability, and chain finality are guaranteed via novel techniques such as double validation, staking via smart-contracts, and "true" randomization processes.

chancoin supports all EVM-compatible smart-contracts, protocols, and atomic cross-chain token transfers. New scaling techniques such as sharding, private-chain generation, and hardware integration will be continuously researched and incorporated into chancoin's masternode architecture. This architecture will be an ideal scalable smart-contract public blockchain for decentralized apps, token issuances, and token integrations for small and big businesses.

More details can be found at our technical white paper

Read more about us on:

• our website: http://chancoin.com
• our blogs and announcements: https://medium.com/chancoin
• our documentation portal: https://docs.chancoin.com

Building the source

chancoin provides a client binary called chancoin for both running a masternode and running a full-node. Building chancoin requires both a Go (1.7+) and C compiler; install both of these.

Once the dependencies are installed, just run the below commands:

$ git clone https://github.com/chancoin/chancoin chancoin
$ cd chancoin
$ make chancoin

Alternatively, you could quickly download our pre-complied binary from our github release page

Running chancoin

Running a chancoin masternode

Please refer to the official documentation on how to run a node if your goal is to run a masternode. The recommanded ways of running a node and applying to become a masternode are explained in detail there.

Attaching to the chancoin test network

We published our test network 2.0 with full implementation of PoSV consensus at https://stats.testnet.chancoin.com. If you'd like to experiment with smart contract creation and DApps, you might be interested to give these a try on our Testnet.

In order to connect to one of the masternodes on the Testnet, just run the command below:

$ chancoin attach https://testnet.chancoin.com

This will open the JavaScript console and let you query the blockchain directly via RPC.

Running chancoin locally

Download genesis block

$GENESIS_PATH : location of genesis file you would like to put

    export GENESIS_PATH=path/to/genesis.json

• Testnet

     curl -L https://raw.githubusercontent.com/chancoin/chancoin/master/genesis/testnet.json -o $GENESIS_PATH

• Mainnet

     curl -L https://raw.githubusercontent.com/chancoin/chancoin/master/genesis/mainnet.json -o $GENESIS_PATH

Create datadir

• create a folder to store chancoin data on your machine

     export DATA_DIR=/path/to/your/data/folder
     
     mkdir -p $DATA_DIR/chancoin

Initialize the chain from genesis

    chancoin init $GENESIS_PATH --datadir $DATA_DIR

Initialize / Import accounts for the nodes's keystore

If you already had an existing account, import it. Otherwise, please initialize new accounts

    export KEYSTORE_DIR=path/to/keystore

Initialize new accounts

     
     chancoin account new \
     
       --password [YOUR_PASSWORD_FILE_TO_LOCK_YOUR_ACCOUNT] \
     
       --keystore $KEYSTORE_DIR

Import accounts

     chancoin  account import [PRIVATE_KEY_FILE_OF_YOUR_ACCOUNT] \
 
     --keystore $KEYSTORE_DIR \
 
     --password [YOUR_PASSWORD_FILE_TO_LOCK_YOUR_ACCOUNT]

List all available accounts in keystore folder

    chancoin account list --datadir ./  --keystore $KEYSTORE_DIR

Start a node

Environment variables

• $IDENTITY: the name of your node
• $PASSWORD: the password file to unlock your account
• $YOUR_COINBASE_ADDRESS: address of your account which generated in the previous step
• $NETWORK_ID: the networkId. Mainnet: 88. Testnet: 89
• $BOOTNODES: The comma separated list of bootnodes. Find them here
• $WS_SECRET: The password to send data to the stats website. Find them here
• $NETSTATS_HOST: The stats website to report to, regarding to your environment. Find them here
• $NETSTATS_PORT: The port used by the stats website (usually 443)

Let's start a node

    chancoin  --syncmode "full" \
        
        --datadir $DATA_DIR --networkid $NETWORK_ID --port 30303 \
        
        --keystore $KEYSTORE_DIR --password $PASSWORD \
        
        --rpc --rpccorsdomain "*" --rpcaddr 0.0.0.0 --rpcport 8545 --rpcvhosts "*" \
        
        --rpcapi "db,eth,net,web3,personal,debug" \
        
        --gcmode "archive" \
        
        --ws --wsaddr 0.0.0.0 --wsport 8546 --wsorigins "*" --unlock "$YOUR_COINBASE_ADDRESS" \
        
        --identity $IDENTITY \
        
        --mine --gasprice 2500 \
        
        --bootnodes $BOOTNODES \
        
        --ethstats $IDENTITY:$WS_SECRET@$NETSTATS_HOST:$NETSTATS_PORT
        
        console

Some explanations on the flags

           --verbosity: log level from 1 to 5. Here we're using 4 for debug messages
           
           --datadir: path to your data directory created above.
           
           --keystore: path to your account's keystore created above.
           
           --identity: your full-node's name.
           
           --password: your account's password.
           
           --networkid: our network ID.
           
           --chancoin-testnet: required when the networkid is testnet(89).
           
           --port: your full-node's listening port (default to 30303)
           
           --rpc, --rpccorsdomain, --rpcaddr, --rpcport, --rpcvhosts: your full-node will accept RPC requests at 8545 TCP.
           
           --ws, --wsaddr, --wsport, --wsorigins: your full-node will accept Websocket requests at 8546 TCP.
           
           --mine: your full-node wants to register to be a candidate for masternode selection.
           
           --gasprice: Minimal gas price to accept for mining a transaction.
           
           --targetgaslimit: Target gas limit sets the artificial target gas floor for the blocks to mine (default: 4712388)
           
           --bootnode: bootnode information to help to discover other nodes in the network
           
           --gcmode: blockchain garbage collection mode ("full", "archive")
           
           --synmode: blockchain sync mode ("fast", "full", or "light". More detail: https://github.com/chancoin/chancoin/blob/master/eth/downloader/modes.go#L24)
           
           --ethstats: send data to stats website

To see all flags usage

      chancoin --help

See your node on stats page

• Testnet: https://stats.testnet.chancoin.com
• Mainnet: http://stats.chancoin.com

Road map

The implementation of the following features is being studied by our research team:

• Layer 2 scalability with state sharding
• DEX integration
• Spam filtering
• Multi-chain interoperabilty

Contributing and technical discussion

Thank you for considering to try out our network and/or help out with the source code. We would love to get your help; feel free to lend a hand. Even the smallest bit of code, bug reporting, or just discussing ideas are highly appreciated.

If you would like to contribute to the chancoin source code, please refer to our Developer Guide for details on configuring development environment, managing dependencies, compiling, testing and submitting your code changes to our repo.

Please also make sure your contributions adhere to the base coding guidelines:

• Code must adhere to official Go formatting guidelines (i.e uses gofmt).
• Code comments must adhere to the official Go commentary guidelines.
• Pull requests need to be based on and opened against the master branch.
• Any code you are trying to contribute must be well-explained as an issue on our github issue page
• Commit messages should be short but clear enough and should refer to the corresponding pre-logged issue mentioned above.

For technical discussion, feel free to join our chat at Gitter.

Documentation

Overview

Package ethereum defines interfaces for interacting with Ethereum.

Index

• Variables
• type CallMsg
• type ChainReader
• type ChainStateReader
• type ChainSyncReader
• type ContractCaller
• type FilterQuery
• type GasEstimator
• type GasPricer
• type LogFilterer
• type PendingContractCaller
• type PendingStateEventer
• type PendingStateReader
• type Subscription
• type SyncProgress
• type TransactionReader
• type TransactionSender

Variables

var NotFound = errors.New("not found")

NotFound is returned by API methods if the requested item does not exist.

Types

type CallMsg

type CallMsg struct {
	From            common.Address  // the sender of the 'transaction'
	To              *common.Address // the destination contract (nil for contract creation)
	Gas             uint64          // if 0, the call executes with near-infinite gas
	GasPrice        *big.Int        // wei <-> gas exchange ratio
	Value           *big.Int        // amount of wei sent along with the call
	Data            []byte          // input data, usually an ABI-encoded contract method invocation
	BalanceTokenFee *big.Int
}

CallMsg contains parameters for contract calls.

type ChainReader

type ChainReader interface {
	BlockByHash(ctx context.Context, hash common.Hash) (*types.Block, error)
	BlockByNumber(ctx context.Context, number *big.Int) (*types.Block, error)
	HeaderByHash(ctx context.Context, hash common.Hash) (*types.Header, error)
	HeaderByNumber(ctx context.Context, number *big.Int) (*types.Header, error)
	TransactionCount(ctx context.Context, blockHash common.Hash) (uint, error)
	TransactionInBlock(ctx context.Context, blockHash common.Hash, index uint) (*types.Transaction, error)

	// This method subscribes to notifications about changes of the head block of
	// the canonical chain.
	SubscribeNewHead(ctx context.Context, ch chan<- *types.Header) (Subscription, error)
}

ChainReader provides access to the blockchain. The methods in this interface access raw data from either the canonical chain (when requesting by block number) or any blockchain fork that was previously downloaded and processed by the node. The block number argument can be nil to select the latest canonical block. Reading block headers should be preferred over full blocks whenever possible.

The returned error is NotFound if the requested item does not exist.

type ChainStateReader

type ChainStateReader interface {
	BalanceAt(ctx context.Context, account common.Address, blockNumber *big.Int) (*big.Int, error)
	StorageAt(ctx context.Context, account common.Address, key common.Hash, blockNumber *big.Int) ([]byte, error)
	CodeAt(ctx context.Context, account common.Address, blockNumber *big.Int) ([]byte, error)
	NonceAt(ctx context.Context, account common.Address, blockNumber *big.Int) (uint64, error)
}

ChainStateReader wraps access to the state trie of the canonical blockchain. Note that implementations of the interface may be unable to return state values for old blocks. In many cases, using CallContract can be preferable to reading raw contract storage.

type ChainSyncReader

type ChainSyncReader interface {
	SyncProgress(ctx context.Context) (*SyncProgress, error)
}

ChainSyncReader wraps access to the node's current sync status. If there's no sync currently running, it returns nil.

type ContractCaller

type ContractCaller interface {
	CallContract(ctx context.Context, call CallMsg, blockNumber *big.Int) ([]byte, error)
}

A ContractCaller provides contract calls, essentially transactions that are executed by the EVM but not mined into the blockchain. ContractCall is a low-level method to execute such calls. For applications which are structured around specific contracts, the abigen tool provides a nicer, properly typed way to perform calls.

type FilterQuery

type FilterQuery struct {
	FromBlock *big.Int         // beginning of the queried range, nil means genesis block
	ToBlock   *big.Int         // end of the range, nil means latest block
	Addresses []common.Address // restricts matches to events created by specific contracts

	// The Topic list restricts matches to particular event topics. Each event has a list
	// of topics. Topics matches a prefix of that list. An empty element slice matches any
	// topic. Non-empty elements represent an alternative that matches any of the
	// contained topics.
	//
	// Examples:
	// {} or nil          matches any topic list
	// {{A}}              matches topic A in first position
	// {{}, {B}}          matches any topic in first position, B in second position
	// {{A}}, {B}}        matches topic A in first position, B in second position
	// {{A, B}}, {C, D}}  matches topic (A OR B) in first position, (C OR D) in second position
	Topics [][]common.Hash
}

FilterQuery contains options for contract log filtering.

type GasEstimator

type GasEstimator interface {
	EstimateGas(ctx context.Context, call CallMsg) (uint64, error)
}

GasEstimator wraps EstimateGas, which tries to estimate the gas needed to execute a specific transaction based on the pending state. There is no guarantee that this is the true gas limit requirement as other transactions may be added or removed by miners, but it should provide a basis for setting a reasonable default.

type GasPricer

type GasPricer interface {
	SuggestGasPrice(ctx context.Context) (*big.Int, error)
}

GasPricer wraps the gas price oracle, which monitors the blockchain to determine the optimal gas price given current fee market conditions.

type LogFilterer

type LogFilterer interface {
	FilterLogs(ctx context.Context, q FilterQuery) ([]types.Log, error)
	SubscribeFilterLogs(ctx context.Context, q FilterQuery, ch chan<- types.Log) (Subscription, error)
}

LogFilterer provides access to contract log events using a one-off query or continuous event subscription.

Logs received through a streaming query subscription may have Removed set to true, indicating that the log was reverted due to a chain reorganisation.

type PendingContractCaller

type PendingContractCaller interface {
	PendingCallContract(ctx context.Context, call CallMsg) ([]byte, error)
}

PendingContractCaller can be used to perform calls against the pending state.

type PendingStateEventer

type PendingStateEventer interface {
	SubscribePendingTransactions(ctx context.Context, ch chan<- *types.Transaction) (Subscription, error)
}

A PendingStateEventer provides access to real time notifications about changes to the pending state.

type PendingStateReader

type PendingStateReader interface {
	PendingBalanceAt(ctx context.Context, account common.Address) (*big.Int, error)
	PendingStorageAt(ctx context.Context, account common.Address, key common.Hash) ([]byte, error)
	PendingCodeAt(ctx context.Context, account common.Address) ([]byte, error)
	PendingNonceAt(ctx context.Context, account common.Address) (uint64, error)
	PendingTransactionCount(ctx context.Context) (uint, error)
}

A PendingStateReader provides access to the pending state, which is the result of all known executable transactions which have not yet been included in the blockchain. It is commonly used to display the result of ’unconfirmed’ actions (e.g. wallet value transfers) initiated by the user. The PendingNonceAt operation is a good way to retrieve the next available transaction nonce for a specific account.

type Subscription

type Subscription interface {
	// Unsubscribe cancels the sending of events to the data channel
	// and closes the error channel.
	Unsubscribe()
	// Err returns the subscription error channel. The error channel receives
	// a value if there is an issue with the subscription (e.g. the network connection
	// delivering the events has been closed). Only one value will ever be sent.
	// The error channel is closed by Unsubscribe.
	Err() <-chan error
}

Subscription represents an event subscription where events are delivered on a data channel.

type SyncProgress

type SyncProgress struct {
	StartingBlock uint64 // Block number where sync began
	CurrentBlock  uint64 // Current block number where sync is at
	HighestBlock  uint64 // Highest alleged block number in the chain
	PulledStates  uint64 // Number of state trie entries already downloaded
	KnownStates   uint64 // Total number of state trie entries known about
}

SyncProgress gives progress indications when the node is synchronising with the Ethereum network.

type TransactionReader

type TransactionReader interface {
	// TransactionByHash checks the pool of pending transactions in addition to the
	// blockchain. The isPending return value indicates whether the transaction has been
	// mined yet. Note that the transaction may not be part of the canonical chain even if
	// it's not pending.
	TransactionByHash(ctx context.Context, txHash common.Hash) (tx *types.Transaction, isPending bool, err error)
	// TransactionReceipt returns the receipt of a mined transaction. Note that the
	// transaction may not be included in the current canonical chain even if a receipt
	// exists.
	TransactionReceipt(ctx context.Context, txHash common.Hash) (*types.Receipt, error)
}

TransactionReader provides access to past transactions and their receipts. Implementations may impose arbitrary restrictions on the transactions and receipts that can be retrieved. Historic transactions may not be available.

Avoid relying on this interface if possible. Contract logs (through the LogFilterer interface) are more reliable and usually safer in the presence of chain reorganisations.

The returned error is NotFound if the requested item does not exist.

type TransactionSender

type TransactionSender interface {
	SendTransaction(ctx context.Context, tx *types.Transaction) error
}

TransactionSender wraps transaction sending. The SendTransaction method injects a signed transaction into the pending transaction pool for execution. If the transaction was a contract creation, the TransactionReceipt method can be used to retrieve the contract address after the transaction has been mined.

The transaction must be signed and have a valid nonce to be included. Consumers of the API can use package accounts to maintain local private keys and need can retrieve the next available nonce using PendingNonceAt.