Great question — answering as the UphillTech team:
The first thing I would recommend is looking at the Shopify API libraries available. For example the Shopify API Gem in Ruby. to get your app connected you need to do the following: 1) Get a developer's account on Shopify (partner account) and create an app. 2) Grab your API and secret key 3) follow the instruction on the API libraries like in the link provided (steps 1-7) and you should be able to get your app started. (Essentially, grab the permanent token from Shopify and you will be able to make API calls and get all the data from the store you want).
Full answer by HussienK: https://stackoverflow.stackexchange.com/a/33790553 (CC BY-SA 4.0).
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