brynwaldwick/eve-js

A readable wrapper for using ethereum in the browser

eve-js

Build apps with ethereum in the browser. A collection of helpers to build more readable webapps with ethereum.

Intended for use alongside browser plugins like (the amazing) Metamask that load web3 onto the window.

Methods

parseProtocolUrl(url)

Build a raw ethereum transaction by parsing an ethereum "protocol url" and query, according to this discussion here.

The transaction is encoded like ethereum:[to_address]?[params,...]

Put value, and gas in params to pass these options into the transaction, along with (optionally) one of the following to encode a function call

• function: a string of the raw function signature like functionImCalling(arg_1_value, arg_2_value)

• fn: the name of the function you'd like to call (as specified in the Contract's ABI), and a query-encoded abi like

  fn=functionImCalling&
  input.arg_1.type=string&
  input.arg_1=arg_1_value&
  input.arg_2.type=address&
  input.arg_2=arg_2_value

• data: encoded bytecode of the transaction inputs as described here

buildAPIWithABI(abi)

Build an associative array (object) of javascript functions to call a Contract's functions from your application code. Call the function by name with the normal arguments from the Contract, a parameter options to optionally configure from, value, and gas, and a callback for the web3 provider.

eve = require 'eve-js'

# A hypothetical ethereum call that pays an
# invoice keyed off a unique string.

my_abi = [{
    constant: false,
    inputs: [{
        name: "purchaser",
        type: "string"}
    ],
    name: "payInvoice",
    outputs: [],
    payable: true,
    type: "function"
}]

# Build a function to use in your code
{payInvoice} = eve.buildAPIWithABI my_abi

# now call the function like...
invoice_address = 'my_invoice_address'
purchaser_key = window.user.my_unique_key
options = {}
payInvoice invoice_address, purchaser_key, options, (err, txid) ->
    # handle response here...

The functions will be called by passing them to window.web3, like Metamask provides.

execWithABI(abi, address, fn, args..., options, cb)

Call a function by name from a raw ABI and a Contract address. Optionally configure from, value, and to in options. Using the same example from above...

eve.execWithABI my_abi, invoice_address, 'PayInvoice', purchaser_key, {}, (err, txid) ->
    # handle response here...

send({to, from, gas, value}, cb)

Convenience function to send ether from raw transaction json. from and gas are optional.

eve = require 'eve-js'

bill_payer = '0x0'

my_accounts = {
    utilities: '0x0'
    dinner: '0x0'
    girlfriend: '0x0'
}

sendTransaction = (reason) ->
    eve.send {to: bill_payer, from: my_accounts[reason], value: 1000000000000000}