Check a domain for green hosting

Overview

CO2.js comes with a handy function which lets you check if one domain or an array of domains is served from a green web host. Under the hood, this function uses the Greencheck API to return results.

In this tutorial, you will install CO2.js in a Node environment. Then, you will check the green hosting status of one or more domains.

Before starting

You can follow along with this tutorial in your local development environment, or by using the button below to launch the project in Gitpod.

Local development

If you are following along this tutorial locally, you will need to have the following setup on your machine:

• Node version 14 or later
• NPM version 6 or later

Learning goals

• How to install CO2.js using NPM
• How to check green hosting for one domain
• How to check green hosting for multiple domains

Setting up

If you are following along using the Gitpod starter template, you can skip this section.

Otherwise, create a new folder locally called co2js-node and navigate into that folder. Then, initialise NPM.

mkdir co2js-node
cd co2js-node
npm init -y

Next, create an hosting.js file, and open it in your code editor of choice. We will write the code for this tutorial inside the hosting.js file.

Installing CO2.js

Inside your project folder, run the following command to install CO2.js as a dependency.

npm install @tgwf/co2

Initialise CO2.js

In your project’s hosting.js file, add the following code to include the CO2.js hosting module in your code.

const { hosting } = require("@tgwf/co2");

The hosting module includes a check() function. We will be using this to perform our green hosting checks.

Check one domain for green hosting

To check if a single domain is green hosted, you can pass the following parameters into the check function:

• domain: string the website domain you want to check for green hosting.
• userAgentIdentifier: string Optional since v0.14.2 the name of the project, product, or app which is performing the check.

When checking a single domain, this function returns a boolean response (true for green hosted, false for not).

Adding the code below to the hosting.js file allows us to check if the domain google.com is served from a green web host.

hosting.check("google.com", "myGreenWebApp").then((result) => {
  console.log(result);
});

Running the code above returns the following result:

node hosting.js

# Output:
# true

Check multiple domains for green hosting

To check if more than one domain is green hosted, you can pass the following parameters into the check function:

• domains: array an array of strings representing website domain you want to check for green hosting.
• userAgentIdentifier: string Optional since v0.14.2 the name of the project, product, or app which is performing the check.

When checking multiple domains, this function returns an array of any green domains that are found.

Adding the code below to the hosting.js file allows us to check if the domains google.com, facebook.com, and twitter.com are served from a green web hosts.

const domains = ["google.com", "facebook.com", "twitter.com"];

hosting.check(domains, "myGreenWebApp").then((result) => {
  console.log(result);
});

Running the code above returns the following result:

node hosting.js

# Output:
# ['google.com', 'facbook.com']

Wrapping up

You now know how to use CO2.js to check one or more domains for green hosting.

Troubleshooting

Use a valid domain

The domain/s passed to the check() function must not include any protocol, port, or path information.

• climateaction.tech Accepted
• https://climateaction.tech Incorrect
• climateaction.tech/events Incorrect

Why is a domain being returned as not green?

When a green hosting check is performed for a domain, we will return either green: true (it's a green host) or green: false (not a green host).

If you're expecting a green result, but not getting it, there are a few reasons why this might be happening. We've covered these in our FAQ - Why does my website show up as grey in the Green Web Checker?.