@alayanetwork/web3-provider-engine

    14.2.1 • Public • Published

    Web3 ProviderEngine

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    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. platon_call may trigger platon_getAccountBalance, platon_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,
      platon_hashrate: '0x00',
      platon_mining: false,
      platon_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
    12.0.0
    11.0.0
    • zero.js - replaced http subprovider with fetch provider (includes polyfill for node).
    10.0.0
    • renamed HookedWalletSubprovider personalRecoverSigner to recoverPersonalSignature
    9.0.0
    • pollingShouldUnref option now defaults to false

    Keywords

    none

    Install

    npm i @alayanetwork/web3-provider-engine

    DownloadsWeekly Downloads

    2

    Version

    14.2.1

    License

    MIT

    Unpacked Size

    2 MB

    Total Files

    95

    Last publish

    Collaborators

    • alayanetwork