Go-Ethereum – How to Access Geth from Node.js

I fixed it. UI front-end now works, pulling contract data through to the browser.

I was not careful with my port references between geth/cors, http-server, and the one referenced in my UI javascript as Péter Szilágyi sniffed out. I list my working steps below to help others trace similar problems:

First: start geth using: geth --rpc --rpccorsdomain="http://localhost:3000" //presuming the UI will be run on port 3000

Second: Launch the http server on the above referenced port. In my case, used the npm installed module 'http-server': http-server -p 3000 //must match the port referenced in rpccorsdomain above.

Third: Made sure web3 was installed with npm. Linked app.js to index.html and included this code at the top:

 var Web3 = require('web3');

// Initialize connection
 var web3 = new Web3(new Web3.providers.HttpProvider('http://127.0.0.1:8545'));  //may want to test for non-existence first per docs
 var ABI = [...]
 var greeterAddress = "..."
 var greeter = web3.eth.contract(ABI).at(greeterAddress);

You cannot do a init again if you have already done a init on datadir. In order to achive what you want you need to first create simply create account .... once account is created use that for pre-funding, by putting it in the genesis file, now go for the init of datadir.

so steps are
1) Creation of account in datadir

geth --datadir <path_of_data_directory> account new ( I have used command line method for account creation, which does not require invocation of geth console)

2) use the account created as pre-funded account, add entry in genesis file.

3) Init of the datadirectory with the genesis file.

geth --datadir <path_of_data_directory> init <path_of_genesis_file>

I have used bare minimum parameters, it should also work fine with the parameter you are using. Main point to note you cannot re-initialize your data directory once it is initialized.