shopify-graphql-example.go

// This is a simple example how you can get data from the GraphQL endpoint of
// your Shopify store.
// For the explanatory article please visit:

package main

import (
	"bytes"
	"io/ioutil"
	"fmt"
	"log"
	"net/http"
	"strconv"
	"time"
	"os"

	"github.com/valyala/fastjson"
)

// Please make sure that the following environment variables 
// SHOPIFY_TOKEN & SHOPIFY_GRAPHQL_ENDPOINT are set
//
// to do this in bash:
// export SHOPIFY_TOKEN=YourSuperSecretToken
// export SHOPIFY_GRAPHQL_ENDPOINT=https://YOUR-STOTE.myshopify.com/admin/api/graphql.json
//
// to do this in fish:
// set -x SHOPIFY_TOKEN YourSuperSecretToken
// set -x SHOPIFY_GRAPHQL_ENDPOINT https://YOUR-STOTE.myshopify.com/admin/api/graphql.json
var token = os.Getenv("SHOPIFY_TOKEN")
var endpoint = os.Getenv("SHOPIFY_GRAPHQL_ENDPOINT")

func startRequest(body []byte) (*http.Response, error) {
	client := http.Client{
		Timeout: time.Second * 120,
	}
	req, err := http.NewRequest("POST", endpoint, bytes.NewBuffer(body))
	if err != nil {
		return nil, fmt.Errorf( "error building request: %s", err)
	}
	req.Header.Add("X-Shopify-Access-Token",token)
	req.Header.Add("Content-Type", "application/graphql")

	resp, err := client.Do(req)
	if err != nil {
		return nil, fmt.Errorf( "error executing request: %s", err)
	}
	return resp, nil
}

func getItemPrice(sku string) (float32, error) {
	query := `{
  inventoryItems(first:1, query:"sku:` + sku + `") {
    edges{
      node{
        sku
        variant {
          price
        }
      }
    }
  }
}`
	resp, err := startRequest([]byte(query))
	defer resp.Body.Close()
	body, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		return 0, fmt.Errorf( "error reading response body: %s", err)
	}
	p := fastjson.GetString(body, "data", "inventoryItems", "edges", "0", "node", "variant", "price")
	if fastjson.Exists(body, "error") {
		return 0, fmt.Errorf("shopify responded with an error: %s", fastjson.GetString(body, "error"))
	}
	if fastjson.Exists(body, "data", "inventoryItems", "edges", "0", "node", "variant", "price") == false {
		return 0, fmt.Errorf("item could not be found in shopify: %s", sku)
	}
	price, err:= strconv.ParseFloat(p, 32)
	if err != nil {
		return 0, fmt.Errorf( "error reading response body: %s", err)
	}
	return float32(price), nil
}

func main() {
	price, err := getItemPrice("your_SKU") // The SKU you are looking for
	if err != nil {
		log.Fatalf("could not get price from shopify: %s", err)
	}
	fmt.Println("Price:", price)
}