If you want a successful Shopify application (and by successful I mean store owners use it!), then it needs to be the workaround for an obstacle. If you're lucky, many store owners will want this same workaround.

So where do you start? The Shopify forum.

The developers forum has a plethora of ideas (and wants) from Shopify store owners.

Next, you need to choose a programming language. There are currently two official Shopify APIs. You don't have to use one of these APIs. You can develop your own (in any language you should choose).

The two APIs are the shopify_php_api (PHP) and the shopify_api (Ruby).

PHP is a language I have been using for over ten years.  No matter how much better anyone ever says a language is over PHP, it will always hold top spot in my list of languages that I could use to develop a web application.

That being said, while working with Shopify these past few months, I have been learning Ruby. If Ruby is a beautiful painting then Ruby on Rails is an original Picasso.

Resources

What resources will your application be using? You'll find all the information you need in the API Documentation.

Is it going to read from these resources, or will it need to write from them as well?

Once you've gotten this straightened out, you'll need an API Key and Secret. This is done in the Shopify Partners account. This is also where you will choose whether your application has read access or read and write access. You cannot change this at a later time! If you end up wanting to change the access your application has, you will then have to create a whole new application.

Your application is created, now start developing!

Authentication

There are a few steps to authenticate your application against a shop. First, if you don't have the shop you must prompt the merchant for their store.

Once you have the store you can redirect the user to the installation URL for your application.

http://somestore.myshopify.com/admin/api/auth?api_key=YOUR_API_KEY

The Return URL

Once a store owner installs your application, and every time they wish to login, they will be redirected to your application's return URL.

Appended to this URL will be four parameters.

• shop
  example: somestore.myshopify.com
• timestamp
  example: 123456789
• signature
  32 character hash
• t   (token)
  32 character hash

Currently for authenticating, you will only need the shop and the token. The current APIs create a password by generating the md5 hash of the application's API Key and the authorization token.

All requests are then formatted with HTTP basic authentication. For instance:

http://YOUR_API_KEY:COMPUTED_PASSWORD@somestore.myshopify.com/admin/products.xml

The Preferences URL

The preferences URL is optional.

The Support URL

The support URL is optional.

Both of these URLs have the shop appended to them when clicked.

Application Links

Application links allow you to place a link to your application in the admin areas of the store merchants.

You can specify where your link should show up, an icon, and where the link should be directed to. If your link is in a top level area, say the Products Overview, only the shop URL will be appended to the URL. If you are in a specific area, like the page for a specific product, both the shop URL and the ID of the product will be appended.

This concludes the article on the anatomy of a Shopify Application! I hope you enjoyed it.