Cloudflare Worker: Achieving Purchasing Power Parity for your overseas products quickly

Due to different purchasing power in different countries and regions, overseas products need to set different prices for areas with different purchasing power.

To achieve purchasing power parity, two pieces of data are needed:

1. User location data
2. A list of purchasing power levels for different countries

The logic is simple: Location data -> Purchasing power level -> Match corresponding price information and apply

So how do we obtain these two pieces of data?

Location Data

Cloudflare Worker's request parameter contains very detailed location data, which allows us to easily obtain the location without using third-party services:

It includes latitude and longitude, region codes, etc. Our granularity is accurate to the country level, and we use the country code field here.

Purchasing Power Level Data

The purchasing power level can be downloaded from this gist: List of Purchasing Power Levels for Different Countries (opens new window)

Logic and Implementation Code

The general logic is as follows:

1. Retrieve the country code from the Worker's request parameter.
2. Use the country code to retrieve the purchasing power level from the list.
3. Match the corresponding discount information based on the level and apply it.

For simplicity, I directly apply different discounts for different countries in CleanClip (opens new window) (a clipboard tool on Mac). LemonSqueezy can apply discount codes like this: PRODUCT_URL + "?checkout%5Bdiscount_code%5D=" + discountCode

Some details:

• The discount information is stored in environment variables for easy modification.
• The Access-Control-Max-Age cache is set to 0 for easy modification and immediate effect. (Not setting it will cause the previous result to be retained for a long time, and it takes about 3-4 days for the changes to take effect. Setting it to 0 makes it take effect immediately.)
• This worker can be connected to other workers, and the price information can be maintained here for easy use in multiple pages and businesses.

import ppp from "./pppdata.js";

const flatppp = ppp.flatMap(category => category.countries.map( countryInfo => {
  return {
    range: category.range,
    countryCode: countryInfo.country,
    countryName: countryInfo.countryName
  }
}))

// Find the corresponding country in the purchasing power level list
function findCountry(countryCode) {
  return flatppp.find(deal => deal.countryCode == countryCode)
}

// Find the configured discount information in the environment variables based on the purchasing power level
function getDiscount(env, range) {
  switch(range) {
    case "0.0-0.1": return { code: env.level0_1 ?? "", discount: parseInt(env.level0_1_discount ?? "0") ?? 0 }
    case "0.1-0.2": return { code: env.level1_2 ?? "", discount: parseInt(env.level1_2_discount ?? "0") ?? 0 }
    case "0.2-0.3": return { code: env.level2_3 ?? "", discount: parseInt(env.level2_3_discount ?? "0") ?? 0 }
    case "0.3-0.4": return { code: env.level3_4 ?? "", discount: parseInt(env.level3_4_discount ?? "0") ?? 0 }
    case "0.4-0.5": return { code: env.level4_5 ?? "", discount: parseInt(env.level4_5_discount ?? "0") ?? 0 }
    case "0.5-0.6": return { code: env.level5_6 ?? "", discount: parseInt(env.level5_6_discount ?? "0") ?? 0 }
    case "0.6-0.7": return { code: env.level6_7 ?? "", discount: parseInt(env.level6_7_discount ?? "0") ?? 0 }
    case "0.7-0.8": return { code: env.level7_8 ?? "", discount: parseInt(env.level7_8_discount ?? "0") ?? 0 }
    case "0.8-0.9": return { code: env.level8_9 ?? "", discount: parseInt(env.level8_9_discount ?? "0") ?? 0 }
    case "0.9-1.0": return { code: env.level9_10 ?? "", discount: parseInt(env.level9_10_discount ?? "0") ?? 0 }
    case "1.0-1.1": return { code: env.level10_11 ?? "", discount: parseInt(env.level10_11_discount ?? "0") ?? 0 }
    case "1.1-1.2": return { code: env.level11_12 ?? "", discount: parseInt(env.level11_12_discount ?? "0") ?? 0 }
    case "1.2-1.3": return { code: env.level12_13 ?? "", discount: parseInt(env.level12_13_discount ?? "0") ?? 0 }
    case "1.3-1.4": return { code: env.level13_14 ?? "", discount: parseInt(env.level13_14_discount ?? "0") ?? 0 }
    default: return {code: "", discount: 0}
  }
}

export default {
  async fetch(request, env, ctx) {
    // Get the country code
    const countryCode = request.cf.country
    console.log(countryCode)

    // Find the country in the purchasing power list
    let countryPPP = findCountry(countryCode)
    console.log("find", countryPPP)

    // Get the corresponding discount information based on the country's purchasing power
    let discount = getDiscount(env, countryPPP.range)
    console.log(discount)

    // Return the result
    if (countryPPP && discount) {
      let result = JSON.stringify({
        range: countryPPP.range,
        countryCode: countryPPP.countryCode,
        countryName: countryPPP.countryName,
        discountCode: discount.code,
        discount: discount.discount
      });
      console.log("result", result);
      return new Response(result, {
        status: 200,
        headers: {
          "Content-Type": "application/json",
          "Access-Control-Allow-Origin": "*",
          "Access-Control-Allow-Headers": "*",
          "Access-Control-Allow-Methods": "GET, OPTIONS, POST, PUT, DELETE",
          "Access-Control-Max-Age": "0"
        }
      });
    } else {
      return new Response("Error", { status: 500, headers: {
        "Content-Type": "application/json",
        "Access-Control-Allow-Origin": "*",
        "Access-Control-Allow-Headers": "*",
        "Access-Control-Allow-Methods": "GET, OPTIONS, POST, PUT, DELETE",
        "Access-Control-Max-Age": "86400"
      }});
    }

    // Or directly 301 redirect to the specified discount link
    // let url = env.TARGET_DOMAIN
    // if (discountCode !== undefined && discountCode.length > 0) {
    //   url = env.TARGET_DOMAIN + "?checkout%5Bdiscount_code%5D=" + discountCode
    // }
    // var response = Response.redirect(url, 301);
  },
};

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Author: Sintone Li

Article address: https://cleanclip.cc/developer/cloudflare-worker-implements-purchasing-power-parity/