@dexon-foundation/web3-provider-engine
v14.1.1
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Web3 ProviderEngine
Web3 ProviderEngine is a tool for composing your own web3 providers.
Composable
Built to be modular - works via a stack of 'sub-providers' which are like normal web3 providers but only handle a subset of rpc methods.
The subproviders can emit new rpc requests in order to handle their own; e.g. eth_call
may trigger eth_getAccountBalance
, eth_getCode
, and others.
The provider engine also handles caching of rpc request results.
const ProviderEngine = require('web3-provider-engine')
const CacheSubprovider = require('web3-provider-engine/subproviders/cache.js')
const FixtureSubprovider = require('web3-provider-engine/subproviders/fixture.js')
const FilterSubprovider = require('web3-provider-engine/subproviders/filters.js')
const VmSubprovider = require('web3-provider-engine/subproviders/vm.js')
const HookedWalletSubprovider = require('web3-provider-engine/subproviders/hooked-wallet.js')
const NonceSubprovider = require('web3-provider-engine/subproviders/nonce-tracker.js')
const RpcSubprovider = require('web3-provider-engine/subproviders/rpc.js')
var engine = new ProviderEngine()
var web3 = new Web3(engine)
// static results
engine.addProvider(new FixtureSubprovider({
web3_clientVersion: 'ProviderEngine/v0.0.0/javascript',
net_listening: true,
eth_hashrate: '0x00',
eth_mining: false,
eth_syncing: true,
}))
// cache layer
engine.addProvider(new CacheSubprovider())
// filters
engine.addProvider(new FilterSubprovider())
// pending nonce
engine.addProvider(new NonceSubprovider())
// vm
engine.addProvider(new VmSubprovider())
// id mgmt
engine.addProvider(new HookedWalletSubprovider({
getAccounts: function(cb){ ... },
approveTransaction: function(cb){ ... },
signTransaction: function(cb){ ... },
}))
// data source
engine.addProvider(new RpcSubprovider({
rpcUrl: 'https://testrpc.metamask.io/',
}))
// log new blocks
engine.on('block', function(block){
console.log('================================')
console.log('BLOCK CHANGED:', '#'+block.number.toString('hex'), '0x'+block.hash.toString('hex'))
console.log('================================')
})
// network connectivity error
engine.on('error', function(err){
// report connectivity errors
console.error(err.stack)
})
// start polling for blocks
engine.start()
When importing in webpack:
import * as Web3ProviderEngine from 'web3-provider-engine';
import * as RpcSource from 'web3-provider-engine/subproviders/rpc';
import * as HookedWalletSubprovider from 'web3-provider-engine/subproviders/hooked-wallet';
Built For Zero-Clients
The Ethereum JSON RPC was not designed to have one node service many clients. However a smaller, lighter subset of the JSON RPC can be used to provide the blockchain data that an Ethereum 'zero-client' node would need to function. We handle as many types of requests locally as possible, and just let data lookups fallback to some data source ( hosted rpc, blockchain api, etc ). Categorically, we don’t want / can’t have the following types of RPC calls go to the network:
- id mgmt + tx signing (requires private data)
- filters (requires a stateful data api)
- vm (expensive, hard to scale)
Change Log
14.0.0
- default dataProvider for zero is Infura mainnet REST api
- websocket support
- subscriptions support
- remove solc subprovider
- removed
dist
from git (but published in npm module) - es5 builds in
dist/es5
- zero + ProviderEngine bundles are es5
- web3 subprovider renamed to provider subprovider
- error if provider subprovider is missing a proper provider
- removed need to supply getAccounts hook
- fixed
hooked-wallet-ethtx
message signing - fixed
hooked-wallet
default txParams
13.0.0
- txs included in blocks via
eth-block-tracker
@2.0.0
12.0.0
- moved block polling to
eth-block-tracker
.
11.0.0
- zero.js - replaced http subprovider with fetch provider (includes polyfill for node).
10.0.0
- renamed HookedWalletSubprovider
personalRecoverSigner
torecoverPersonalSignature
9.0.0
pollingShouldUnref
option now defaults to false
Current RPC method support:
static
- [x] web3_clientVersion
- [x] net_version
- [x] net_listening
- [x] net_peerCount
- [x] eth_protocolVersion
- [x] eth_hashrate
- [x] eth_mining
- [x] eth_syncing
filters
- [x] eth_newBlockFilter
- [x] eth_newPendingTransactionFilter
- [x] eth_newFilter
- [x] eth_uninstallFilter
- [x] eth_getFilterLogs
- [x] eth_getFilterChanges
accounts manager
- [x] eth_coinbase
- [x] eth_accounts
- [x] eth_sendTransaction
- [x] eth_sign
- [x] eth_signTypedData
vm
- [x] eth_call
- [x] eth_estimateGas
db source
- [ ] db_putString
- [ ] db_getString
- [ ] db_putHex
- [ ] db_getHex
compiler
- [ ] eth_getCompilers
- [ ] eth_compileLLL
- [ ] eth_compileSerpent
- [ ] eth_compileSolidity
shh gateway
- [ ] shh_version
- [ ] shh_post
- [ ] shh_newIdentity
- [ ] shh_hasIdentity
- [ ] shh_newGroup
- [ ] shh_addToGroup
data source ( fallback to rpc )
- eth_gasPrice
- eth_blockNumber
- eth_getBalance
- eth_getBlockByHash
- eth_getBlockByNumber
- eth_getBlockTransactionCountByHash
- eth_getBlockTransactionCountByNumber
- eth_getCode
- eth_getStorageAt
- eth_getTransactionByBlockHashAndIndex
- eth_getTransactionByBlockNumberAndIndex
- eth_getTransactionByHash
- eth_getTransactionCount
- eth_getTransactionReceipt
- eth_getUncleByBlockHashAndIndex
- eth_getUncleByBlockNumberAndIndex
- eth_getUncleCountByBlockHash
- eth_getUncleCountByBlockNumber
- eth_sendRawTransaction
- eth_getLogs ( not used in web3.js )
( not supported )
- eth_getWork
- eth_submitWork
- eth_submitHashrate ( not used in web3.js )