Blockchain API Payments Integration in Ruby

How blockchain works
Blockchain is a distributed database, which consists of two records:

1. Individual transactions
2. Blocks

Individual transactions consist of “Header” and “Data” which is related to transactions. Transactions take place for a given period of time. Block is used to create alphanumeric string called as “Hash”.When the first record is created, the next block takes previous block’s Hash for creation of their own Hash. This is authenticated or validated. At this point of the Blockchain process, a majority of nodes in the network must agree the new block’s hash is correctly calculated and ensures that all copies of the distributed ledger share the same state. Once block added, cannot be changed. If we try to change or swap that block, the hashes for previous and subsequent blocks will also change. The other computers in the network will also understand that problem and they will never add new block, until the problem is resolved. When the problem is solved they will start to add the block. If a problem is found in the block it will be not accepted and the process repeats.

Integration on Blockchain API with Rails:
To integrate blockchain api to exchange bitcoin from one wallet to another wallet.
API KEY:
To get the API key we have to first signup on the link https://api.blockchain.info/customer/signup
then we will get the API key, for e.g. :
api_code: XXXXXXXX-XXX-XXXX-XXXX-XXXXXXXXXXXX
Create API:
First need to create a wallet:
I have created the wallet in the method:
http://localhost:3030/api/v2/create_wallet
Description: This api is use to create blockchain wallet
# create_wallet: http://XXX.XXX.X.XX:3030/api/v2/create_wallet
# create_wallet: https://blockchain.info/api/v2/create_wallet
Write the API method to check the wallet balance.

            wallet_address: “Address of the wallet”

            Confirmation: “Password”

address_balance: https://blockchain.info/q/addressbalance/%{wallet_address}?confirmations=%{confirmation}
Write API to send or receive bitcoin using guid.

 Guid: Uniq id of the user
 main_password: blockchain password
 second_password: blockchain second password
 to: Receiving address
 from: Sending address

make_payment_by_guid: http://localhost:3030/merchant/%{guid}/payment?password=%{main_password}&second_password=%{second_password}&to=%{address}&amount=%{amount}&from=%{from}
current_rate: https://blockchain.info/ticker
Description: “this api will use for getting bitcoin value as per the local currency.”
for ex., 1btc = ? (USD)
The following method is used to call the bitcoin exchange API using guid
# def self.transaction_by_guid(receiver_address, amount_in_btc, guid, main_pass, second_pass)
def self.receive_btc_by_guid(guid, sender_main_password, sender_second_password, to_wallet_address, amt_in_btc, from_wallet_address)
# convert btc to satoshi and add transaction fee
amount = (btc_to_satoshi(amt_in_btc))
# Prepare params
request_url = Bitcoinexchange::Application.blockchain[“api”][“make_payment_by_guid”] % {guid: guid || ”, main_password: sender_main_password || ”, second_password: sender_second_password || ”, address: to_wallet_address, amount: amount, from: from_wallet_address}
# If in response failure occurred using third party API or http client it generate error and return nil into the response
response =  begin
RestClient.get(request_url, {“Content-Type”: “application/x-www-form-urlencoded”})
rescue RestClient::ExceptionWithResponse => e
e.response
end
# If response is success(code == 200)
response_body = JSON.parse(response.body)
if response.code == 200
response_body
elsif response_body[“error”]!=””
response_body[“error”]
# it gives the the converted value in BTC
# response_body = “#{response_b[“message”]}” +” to “+”#{response_b[“to”]}”+”successfully.”
else
# To raise the error if error occured in executing blockchain api
raise Exceptions::TransactionError::ParamsError, response.body
end
end

Source: http://www.cryptextechnologies.com/blogs/blockchain-api-integration