Unable to run method multiple times - ruby

Question

I'm using the WiringPi gem. This block of code works as expected:
pinNumber = 7
io = WiringPi::GPIO.new do |gpio|
gpio.pin_mode(pinNumber, WiringPi::INPUT)
end
pin_state = io.digital_read(pinNumber)
return pin_state
However, when I enclose this in a method so I can make a call using Sinatra, I get the following error when I try to refresh:
wiringPiSetup*: You must only call this once per program run. This is
a fatal error. Please fix your code.
Why must this be run only once, and what is the best solution? Ultimately pin_state needs to be retrieved every time I navigate to the root url.
Here's the full code:
require 'wiringpi'
require 'sinatra'
def getstate()
pinNumber = 7
io = WiringPi::GPIO.new do |gpio|
gpio.pin_mode(pinNumber, WiringPi::INPUT)
end
pin_state = io.digital_read(pinNumber)
return pin_state
end
get '/' do
getstate()
end

Answer 1

After creating your GPIO instance, you can make repeated calls to read pins from it. Your code is creating a new instance on each call, however.
require 'wiringpi'
require 'sinatra/base'
class MyApp < Sinatra::Base
InputPin = 7
IO = WiringPi::GPIO.new do |gpio|
gpio.pin_mode(InputPin, WiringPi::INPUT)
end
def get_state(pin_number = MyApp::InputPin)
MyApp::IO.digital_read(pin_number)
end
get '/' do
get_state
end
end

Answer 2

pinNumber = 7
def io
#io ||= begin
WiringPi::GPIO.new do |gpio|
gpio.pin_mode(pinNumber, WiringPi::INPUT)
end
end
end
def getstate()
pin_state = io.digital_read(pinNumber)
return pin_state
end
get '/' do
getstate() end
Initialize the API once when your application starts (outside getState() method). You're initializing the API multiple times, thus the error.