Ethereum send transaction by connecting geth in another server using Javascript API

Question

I started using Geth. and make a shell script which will end txn to another ETH address.

Step 1: Run command 'geth --fast --cache=1024' in one terminal and wait for full blockchain update. Step 2: Run below code as send.sh in another shell. Command: sh send.sh 'ETH address to send ETH' 'Amount'

Code for send.sh: #!/bin/sh

geth attach << EOF | grep "RESULT:" | sed "s/RESULT: //"
personal.unlockAccount("My ETH Address", "password")
var txnid = web3.eth.sendTransaction({from: "My ETH Address", to: "$1", value: web3.toWei($2, "ether")});
console.log("RESULT: " + txnid);

EOF

Output: Txn id [This works perfectly, no issues but want to send transaction from another server using javascript API by connecting this server geth]

All looks fine to me. But I want to use same functionality in https://github.com/ethereum/wiki/wiki/JavaScript-API

when I try to connect localhost:8545 not working and run Javascript API call. Not sure how to convert this code to Javascript. I am new hers any help will be great to my start up with Ethereum Javascript API.

Answer 1

8545 is an rpc endpoint
to access all the functions from a browser, you will have to serve the application to an http endpoint and have a .js and a .html file

1. install web3
   
2. https://www.npmjs.com/package/web3
   
3. https://github.com/ethereum/wiki/wiki/JavaScript-API

use http framework like express https://expressjs.com/

then in your js write

http.listen(3000, function(){
     console.log('listening on *:3000');
   });<br>
var Web3 = require('web3');
var web3 = new Web3();

use your object to invoke the methods and ping to localhost:3000 in the browser

Answer 2

You can use web3 or web3_extended for connection to your geth from remote.

var web3_extended = require('web3_extended');

var options = {
  host: 'http://localhost:8545',
  personal: true,
  ipc : false,
  admin: true,
  debug: false
};
var web3 = web3_extended.create(options);

to connect to your geth via RPC. You can use web3 in the same way.

Note: You can even connect to geth instance with IPC using web3_extended with ipc= true parameter. IPC is more secure than RPC.