Snapcard Challenge

This code is to generate a bitcoin invoice without depending on the central payment processors.

I. Programing Language General

• Node.JS: The backend server
• MySQL: Database >> No need in this challenge
• Sencha Extjs: The front end UI
• ExtDirect: To communicate between front-end and back-end

II. Installation & Run A. Back-end:

• Run server by moving to the folder /BitMe/node-server/bdn then enter node server.js (assume that you got installation of nodejs on your localhost already
• Notes: o Folder ./direct stores API for front-end to call back-end using ExtDirect. The file DXConnectDB.js got function getWallet() to create the bitcoin wallet address randomly and return newly created address to the front-end. o Folder./lib stores library. The file task.js got functions to get exchange rate tickers from BitStamp and Balance from Blockchain. o Socket.IO is used to updates exchange rates and send invoice payment status to front-end

B. Frone-End

• On the browser type: http://127.0.0.1:3000/bdn/app.html to go to the website.
• On render of the Invoice, the socket shall update the exchange rate to calculate the USD equivalent real-time and up-to-date. Users can enter different amount to textbox “Amount To Send” to see the USD update.
• When user click on the Pay Now button, the front-end shall request back-end to return bitcoin wallet address and show to QR code in the new pop-up window.
• Within 1 minute, if user does not pay to the address, the invoice shall expire. Otherwise the invoice status shall become Paid or Partially Paid.

C. Communication

• ExtDirect Remote API
• Web-socket (using socket.io V0.9) to support real time update and 2-way communications for the future features.

D. Dependencies

• The following package need to be install with nodejs: o Express o Bitcoinjs-lib o Cron o Extdirect o Nconf o Request o Socket.io

III. Full Usage

Seller: who wants to receive payment in Bitcoin for his/her product.

• Step 1: Signup account with BitMe to collect bitcoin-payment. A seller then have URL such as: https:/snapcard.com/pay/bit2Le

• Step 2: Add an icon that lead to the above URL next to his product on any websites or forums, Ex: facebook.

• Step 3: That's it!

Buyer: who wants to pay bitcoin to a seller

• Step 1: Click on the icon next to product. The invoice shows up. The status of invoice is now waiting.

• Step 2: Enter or accept the amount on the invoice, then click the button "Pay Now"

• Step 3: The newly created bitcoin wallet address and its QR Code shows up on the invoice.

• Step 4: Buyer use any bitcoin wallet to scan QR code and pay for the invoice.

• Step 5: The invoice status is updated. Payment is confirmed or expired.

To collect money, a seller just sign in to the BitMe sign and check for newly-created wallets and collect bitcoins (The security can be improved here to protect from unauthorized collection)