fanxiong

README

GM-Chain

这是国美开发部署的一份区块链应用项目，一期应用在延保业务之上，用以简化产品供应商、销售渠道、承保公司、维修商、以及用户之间的工作流程，实现数据安全、可信、高效协同。

Official golang implementation of the GM-Fun Chain protocol.

Automated builds are available for stable releases and the unstable master branch. Binary archives will be published on official website soon..

Building the source

For prerequisites and detailed build instructions please read the Installation Instructions

Building mit requires both a Go (version 1.9 or later) and a C compiler. You can install them using your favourite package manager. https://golang.org/doc/install

Once the dependencies are installed, run

cd gm-chain
make mit

or, to build the full suite of utilities:

make all

Running Mit

Going through all the possible command line flags is out of scope here,but we've enumerated a few common parameter combos to get you up to speed quickly on how you can run your own gm-chain instance.

Full node on the main gm-chain network

By far the most common scenario is people wanting to simply interact with the gm-chain network: create accounts; transfer funds; deploy and interact with contracts. For this particular use-case the user doesn't care about years-old historical data, so we can full-sync quickly to the current state of the network. To do so:

$ mit console

Running a miner

Currently our main network is based on POW+POS.

This command will:

• Start mit in full sync mode (default), causing it to download more data in exchange for avoiding processing the entire history of the gm-chain network, which is very CPU intensive.
• Start up Mit's built-in interactive JavaScript console, (via the trailing console subcommand) through which you can invoke all official web3 methods as well as Mit's own management APIs. This too is optional and if you leave it out you can always attach to an already running gm-chain instance with mit attach.

Running mit testnet

Going through all the possible command line flags is out of scope here , but we've enumerated a few common parameter combos to get you up to speed quickly on how you can run your own gm-chain instance.

Full node on the gm-chain testnet

By far the most common scenario is people wanting to simply interact with the gm-chain network: create accounts; transfer funds; deploy and interact with contracts. For this particular use-case the user doesn't care about years-old historical data, so we can fast-sync quickly to the current state of the network. To do so:

$ mit console

This command will:

• Start mit in fast sync mode (default, can be changed with the --syncmode flag), causing it to download more data in exchange for avoiding processing the entire history of the gm-chain network, which is very CPU intensive.
• Start up Mit's built-in interactive JavaScript console, (via the trailing console subcommand) through which you can invoke all official web3 methods as well as Mit's own management APIs. This too is optional and if you leave it out you can always attach to an already running gm-chain instance with mit attach.

Full node on the gm-chain test network

Transitioning towards developers, if you'd like to play around with creating gm-chain time contracts, you almost certainly would like to do that without any real money involved until you get the hang of the entire system.

$ mit --testnet console

Specifying the --testnet flag however will reconfigure your gm-chain instance a bit:

• Instead of using the default data directory (~/.fanxiong on Linux for example), gm-chain will nest itself one level deeper into a testnet subfolder (~/.fanxiong/testnet on Linux). Note, on OSX and Linux this also means that attaching to a running testnet node requires the use of a custom endpoint since mit attach will try to attach to a production node endpoint by default. E.g. mit attach <datadir>/testnet/mit.ipc. Windows users are not affected by this.

Note: Now we have provided the testnet for you. The mainnet will be launched in the near future. Please make sure that you always using two separate accounts for play-money and real-money respectively.

Starting up your member nodes

With the bootnode operational and externally reachable (you can try telnet <ip> <port> to ensure it's indeed reachable), start every subsequent gm-chain node pointed to the bootnode for peer discovery via the --bootnodes flag.

$ mit --datadir=path/to/custom/data/folder --bootnodes=<bootnode-enode-url-from-above>

Note: Since your network will be completely cut off from the main and test networks, you'll also need to configure a miner to process transactions and create new blocks for you.

Running a miner

Currently our testnest is based on POA(Proof-of-Authority). So the miners can only mining after getting permission from us.

Contribution

Thank you for considering to help out with the source code! We welcome contributions from anyone on the internet, and are grateful for even the smallest of fixes!

If you'd like to contribute to gm-chain, please fork, fix, commit and send a pull request for the maintainers to review and merge into the main code base.

to ensure those changes are in line with the general philosophy of the project and/or get some early feedback which can make both your efforts much lighter as well as our review and merge procedures quick and simple.

License

未一(北京)科技有限公司授权国美金控使用

The gm-chain library (i.e. all code outside of the cmd directory) is licensed under the GNU Lesser General Public License v3.0, also included in our repository in the COPYING.LESSER file.

The gm-chain binaries (i.e. all code inside of the cmd directory) is licensed under the GNU General Public License v3.0, also included in our repository in the COPYING file.

Documentation

Overview

Package fanxiong defines interfaces for interacting with M.I.T chain.

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
}

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 gm-chain 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.