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xahau.js/docs/GUIDES.md
2015-07-03 00:43:46 -04:00

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#Guides
This file provides step-by-step walkthroughs for some of the most common usages of `ripple-lib`.
###In this document
1. [Connecting to the Ripple network with `Remote`](GUIDES.md#connecting-to-the-ripple-network)
2. [Using `Remote` functions and `Request` objects](GUIDES.md#sending-rippled-API-requests)
3. [Listening to the network](GUIDES.md#listening-to-the-network)
4. [Submitting a payment to the network](GUIDES.md#submitting-a-payment-to-the-network)
* [A note on transaction fees](GUIDES.md#a-note-on-transaction-fees)
5. [Submitting a trade offer to the network](GUIDES.md#submitting-a-trade-offer-to-the-network)
###Also see
1. [The ripple-lib README](../README.md)
2. [The ripple-lib API Reference](REFERENCE.md)
##Connecting to the Ripple network
1. [Get ripple-lib](../README.md#installation)
2. Load the ripple-lib module into a Node.js file or webpage:
```js
/* Loading ripple-lib with Node.js */
var Remote = require('ripple-lib').Remote;
/* Loading ripple-lib in a webpage */
// var Remote = ripple.Remote;
```
3. Create a new `Remote` and connect to the network:
```js
var options = {
trace : false,
trusted: true,
local_signing: true,
servers: [
{ host: 's-west.ripple.com', port: 443, secure: true }
]
};
var remote = new Remote(options);
remote.connect(function(err, res) {
/* remote connected, use some remote functions here */
});
```
__NOTE:__ See the API Reference for available [`Remote` options](REFERENCE.md#1-remote-options)
4. You're connected! Read on to see what to do now.
##Generating a new Ripple Wallet
```js
var ripple = require('ripple-lib');
// subscribing to a server allows for more entropy
var remote = new ripple.Remote({
servers: [
{ host: 's1.ripple.com', port: 443, secure: true }
]
});
remote.connect(function(err, res) {
/* remote connected */
});
// Wait for randomness to have been added.
// The entropy of the random generator is increased
// by random data received from a rippled
remote.once('random', function(err, info) {
var wallet = ripple.Wallet.generate();
console.log(wallet);
// { address: 'rEf4sbVobiiDGExrNj2PkNHGMA8eS6jWh3',
// secret: 'shFh4a38EZpEdZxrLifEnVPAoBRce' }
});
```
##Sending rippled API requests
`Remote` contains functions for constructing a `Request` object.
A `Request` is an `EventEmitter` so you can listen for success or failure events -- or, instead, you can provide a callback.
Here is an example, using [requestServerInfo](https://ripple.com/wiki/JSON_Messages#server_info).
+ Constructing a `Request` with event listeners
```js
var request = remote.requestServerInfo();
request.on('success', function onSuccess(res) {
//handle success
});
request.on('error', function onError(err) {
//handle error
});
request.request();
```
+ Using a callback:
```js
remote.request('server_info', function(err, res) {
if (err) {
//handle error
} else {
//handle success
}
});
```
__NOTE:__ See the API Reference for available [`Remote` functions](REFERENCE.md#2-remote-functions)
##Listening to the network
See the [wiki](https://ripple.com/wiki/JSON_Messages#subscribe) for details on subscription requests.
```js
/* Loading ripple-lib with Node.js */
var Remote = require('ripple-lib').Remote;
/* Loading ripple-lib in a webpage */
// var Remote = ripple.Remote;
var remote = new Remote({options});
remote.connect(function() {
var remote = new Remote({
// see the API Reference for available options
servers: [ 'wss://s1.ripple.com:443' ]
});
remote.connect(function() {
console.log('Remote connected');
var streams = [
'ledger',
'transactions'
];
var request = remote.requestSubscribe(streams);
request.on('error', function(error) {
console.log('request error: ', error);
});
// the `ledger_closed` and `transaction` will come in on the remote
// since the request for subscribe is finalized after the success return
// the streaming events will still come in, but not on the initial request
remote.on('ledger_closed', function(ledger) {
console.log('ledger_closed: ', JSON.stringify(ledger, null, 2));
});
remote.on('transaction', function(transaction) {
console.log('transaction: ', JSON.stringify(transaction, null, 2));
});
remote.on('error', function(error) {
console.log('remote error: ', error);
});
// fire the request
request.request();
});
});
```
* https://ripple.com/wiki/RPC_API#transactions_stream_messages
* https://ripple.com/wiki/RPC_API#ledger_stream_messages
##Submitting a payment to the network
Submitting a payment transaction to the Ripple network involves connecting to a `Remote`, creating a transaction, signing it with the user's secret, and submitting it to the `rippled` server. Note that the `Amount` module is used to convert human-readable amounts like '1 XRP' or '10.50 USD' to the type of Amount object used by the Ripple network.
```js
/* Loading ripple-lib Remote and Amount modules in Node.js */
var Remote = require('ripple-lib').Remote;
var Amount = require('ripple-lib').Amount;
/* Loading ripple-lib Remote and Amount modules in a webpage */
// var Remote = ripple.Remote;
// var Amount = ripple.Amount;
var MY_ADDRESS = 'rrrMyAddress';
var MY_SECRET = 'secret';
var RECIPIENT = 'rrrRecipient';
var AMOUNT = Amount.from_human('1 USD').set_issuer('rrrIssuer');
var remote = new Remote({ /* Remote options */ });
remote.connect(function() {
remote.setSecret(MY_ADDRESS, MY_SECRET);
var transaction = remote.createTransaction('Payment', {
account: MY_ADDRESS,
destination: RECIPIENT,
amount: AMOUNT
});
transaction.submit(function(err, res) {
/* handle submission errors / success */
});
});
```
###A note on transaction fees
A full description of network transaction fees can be found on the [Ripple Wiki](https://ripple.com/wiki/Transaction_Fee).
In short, transaction fees are very small amounts (on the order of ~10) of [XRP drops](https://ripple.com/wiki/Ripple_credits#Notes_on_drops) spent and destroyed with every transaction. They are largely used to account for network load and prevent spam. With `ripple-lib`, transaction fees are calculated locally by default and the fee you are willing to pay is submitted along with your transaction.
Since the fee required for a transaction may change between the time when the original fee was calculated and the time when the transaction is submitted, it is wise to use the [`fee_cushion`](REFERENCE.md#1-remote-options) to ensure that the transaction will go through. For example, suppose the original fee calculated for a transaction was 10 XRP drops but at the instant the transaction is submitted the server is experiencing a higher load and it has raised its minimum fee to 12 XRP drops. Without a `fee_cusion`, this transaction would not be processed by the server, but with a `fee_cusion` of, say, 1.5 it would be processed and you would just pay the 2 extra XRP drops.
The [`max_fee`](REFERENCE.md#1-remote-options) option can be used to avoid submitting a transaction to a server that is charging unreasonably high fees.
##Submitting a trade offer to the network
Submitting a trade offer to the network is similar to submitting a payment transaction. Here is an example offering to sell 1 USD in exchange for 100 XRP:
```js
/* Loading ripple-lib Remote and Amount modules in Node.js */
var Remote = require('ripple-lib').Remote;
var Amount = require('ripple-lib').Amount;
/* Loading ripple-lib Remote and Amount modules in a webpage */
// var Remote = ripple.Remote;
// var Amount = ripple.Amount;
var MY_ADDRESS = 'rrrMyAddress';
var MY_SECRET = 'secret';
var GATEWAY = 'rrrGateWay';
var remote = new Remote({ /* Remote options */ });
remote.connect(function() {
remote.setSecret(MY_ADDRESS, MY_SECRET);
var transaction = remote.createTransaction('OfferCreate', {
account: MY_ADDRESS,
taker_pays: '100',
taker_gets: '1/USD/' + GATEWAY
});
transaction.submit(function(err, res) {
/* handle submission errors / success */
});
});
```