How To Build Shopify Apps With PHP (Tutorial Series)

In the previous article, through the Shopify developer, we set up the Shopify app that we’re going to use in this article. If you haven’t read the article yet or if you have no Shopify app ready yet, you may read the first part of this series to help you catch up.

Getting Started

To make your Shopify app work, your Shopify app must be authenticated by the store. That means that the shop owner must install your Shopify app and give you the permission you needed to work on their store. For example, displaying a list of available products. This process is mainly done by OAuth, which is a very highly secured method for communication between applications.

It is also important to know that every shop that installs your Shopify app, they have an access token that they need to use to keep their session running. That token can be saved to your database

Generating Shopify API Token

To build Shopify app using PHP, we’ll be using the client that I’m personally using which is the Shopify Generating API Token Guide by Alex. If you don’t have it yet, you may download it from GitHub and extract the files to your project.

Source Files

• inc – this folder contains a PHP file (functions.php) that contains a function that you can use to make Shopify actions like displaying the products from a collection.
• api_call_write_products.php – An example PHP file to make actions like modify a product. You can read the file and study it yourself. But in this tutorial, we’ll be making it from a scratch.
• generate_token.php – PHP file for generating token per store. This file we’ll be used after the store install the app.
• install.php – PHP file for Shopify app installment. self-explanatory.

install.php

<?php

// Set variables for our request
$shop = $_GET['shop'];

$api_key = "ASSIGN YOUR API KEY HERE";
$scopes = "read_orders,write_products";
$redirect_uri = "http://YOUR-DOMAIN-NAME.COM/generate_token.php";

// Build install/approval URL to redirect to
$install_url = "https://" . $shop . "/admin/oauth/authorize?client_id=" . $api_key . "&scope=" . $scopes . "&redirect_uri=" . urlencode($redirect_uri);

// Redirect
header("Location: " . $install_url);
die();
Code language: PHP (php)

Process Breakdown

First, assign the value of $_GET[‘shop’] to the variable $shop. If you don’t know where that value is coming from. It’s from the URL that the user will be visiting. For example:

https://example.com/install.php?shop=example.myshopify.com

$api_key variable is where you’ll be assigning your API key.
You can get your API key from your developer app page.

You may leave the $scope variable.

$redirect_uri should contain the URL of your generate_token.php file
$install_url is a variable that contains the complete URL where the user will be prompted to install the app.

After setting up the variables, redirection to the URL from $install_url variable will happen.

Important! You should only change the value of the $api_key and $redirect_uri variables.

generate_token.php

<?php
// Get our helper functions
require_once("inc/functions.php");

// Set variables for our request
$api_key = "ASSIGN YOUR API KEY HERE";
$shared_secret = "ASSIGN YOUR SECRET KEY HERE";

$params = $_GET; // Retrieve all request parameters
$hmac = $_GET['hmac']; // Retrieve HMAC request parameter

$params = array_diff_key($params, array('hmac' => '')); // Remove hmac from params
ksort($params); // Sort params lexographically
$computed_hmac = hash_hmac('sha256', http_build_query($params), $shared_secret);

// Use hmac data to check that the response is from Shopify or not
if (hash_equals($hmac, $computed_hmac)) {
	// Set variables for our request
	$query = array(
		"client_id" => $api_key, // Your API key
		"client_secret" => $shared_secret, // Your app credentials (secret key)
		"code" => $params['code'] // Grab the access key from the URL
	);
	// Generate access token URL
	$access_token_url = "https://" . $params['shop'] . "/admin/oauth/access_token";
	// Configure curl client and execute request
	$ch = curl_init();
	curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
	curl_setopt($ch, CURLOPT_URL, $access_token_url);
	curl_setopt($ch, CURLOPT_POST, count($query));
	curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query($query));
	$result = curl_exec($ch);
	curl_close($ch);
	// Store the access token
	$result = json_decode($result, true);
	$access_token = $result['access_token'];
	// Show the access token (don't do this in production!)
	echo $access_token;
} else {
	// Someone is trying to be shady!
	die('This request is NOT from Shopify!');
}
Code language: PHP (php)

Before we proceed, make sure you change the value of the variables $api_key and $shared_secret. Again, you can get this data from your developer app dashboard.

If you noticed, the code above is using cURL client to execute requests. These requests will give you a value which is a JSON data type and that needs to be decoded so that PHP can use this value.

After getting the access token, you may add a MySQL query to save the value of the $access_token variable for future use but if you want to learn how to easily store it in the database, then you might as well check this link below (trust me it’s very easy):

Installing the Shopify App

Once everything is set up, you may go to your project URL and run install.php. To do this, you must include the variable shop in the URL. For example:

https://example.com/example/install.php?shop=shop.myshopify.com

Make sure it’s the same URL from your app dashboard. Otherwise, you will encounter errors.

By going to your install.php, you will see this confirmation to install the app:

Conclusion

Congratulations! If you’ve seen the same page like mine, that means that your install.php and other files are working.

To display products using Shopify API and PHP. You may read the following article.