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Building a Hex Color Identifier API with PHP, Laravel, and Docker

Hex Color identifier cover

Docker provides containers to run applications in isolation. Among other benefits of this architecture, one is allowing applications on the same server to run independently, reducing the likelihood of having a single point of failure in your project.

In this tutorial, we’ll build a hex color identifier API with PHP using the Laravel framework, containerize the application using Docker, then ship it to production on Code Capsules.

Here’s an example of a response we might get after querying the API.

Color API


You will need the following to complete the tutorial and host your application on Code Capsules:

  • A Code Capsules account.
  • Git set up and installed, and a registered GitHub account.
  • IDE or text editor of your choice.
  • PHP and composer installed.

Project Set Up

To begin, we need to create a project folder to house all our files.

In a terminal, navigate to the directory you'll be keeping the application files in. Run the commands below to create the project folder and navigate into it.

mkdir color-identifier
cd color-identifier

Create Laravel Project

From the project folder terminal, run the commands below to create a Laravel starter project called “ColorApi” and change directories into it.

composer create-project --prefer-dist laravel/laravel ColorApi
cd ColorApi

From now on the ColorApi folder will be referred to as the project root folder.

Initialize an Empty Git Repository

From the project’s root folder, enter the command git init to initialize a git repository. This will allow you to track changes to your app as you build it.

Linking to GitHub

Head over to GitHub and create a new repository. Then, in your project's root folder, run the command below from the terminal, replacing "username" and "repository_name" with your own values from GitHub.

git remote add origin

This will link your local repository to the one on GitHub.

Install Dependencies

Next, we'll install the dependencies we need to build our application. Open the composer.json file in the root folder and add the following entries to the "require" dictionary:

"require": {

    "ourcodeworld/name-that-color": "dev-master",
    "symfony/console": "6.0.*",
    "symfony/error-handler": "6.0.*",
    "symfony/finder": "6.0.*",
    "symfony/http-foundation": "6.0.*",
    "symfony/http-kernel": "6.0.*",
    "symfony/mailer": "6.0.*",
    "symfony/mime": "6.0.*",
    "symfony/process": "6.0.*",
    "symfony/routing": "6.0.*",
    "symfony/var-dumper": "6.0.*",
    "symfony/event-dispatcher": "6.0.*",
    "symfony/string": "6.0.*",
    "symfony/translation": "6.0.*",
    "symfony/translation-contracts": "3.0.*",
    "symfony/service-contracts": "3.0.*",
    "symfony/event-dispatcher-contracts": "3.0.*",
    "symfony/deprecation-contracts": "3.0.*"


Now run the command composer update from the terminal to install the packages.

Build Hex Color API

While in the ColorApi terminal, run the command below to create a controller for your API:

php artisan make:controller ColorController

This command will create a controller at app/Http/Controllers/ColorController.php. In big projects, controllers are meant to group similar request-handling logic in different methods, but the hex color API we’re building is relatively small and will only have one controller method.

Update the contents of ColorController.php so it looks like this:


namespace App\Http\Controllers;

require base_path('vendor/autoload.php');

use Illuminate\Http\Request;
use ourcodeworld\NameThatColor\ColorInterpreter;

class ColorController extends Controller
    public function convert($hexcode)
        $instance = new ColorInterpreter();

        $result = $instance->name($hexcode);

        // 1. Print the human name e.g "Deep Sea"
        echo $result["name"] . "\n";

        // 2. Print the hex code of the closest color with a name e.g "#01826B"
        echo $result["hex"] . "\n";

        return response()->json($result["name"]);

We require the autoload.php module on line 5 to automatically load the dependency we installed earlier and can now reference it on line 8.

The convert() method is responsible for converting a hex code to a human-readable name by leveraging the ColorInterpreter package we loaded on line 8. It takes in the hex code as an argument and returns the color name.

Create API Routes

With the controller in place, we’re left with linking it to a route that other applications or users can hit. Let’s create and link to this route by editing the routes/api.php file like this:


use Illuminate\Http\Request;
use Illuminate\Support\Facades\Route;
use App\Http\Controllers\ColorController;

Route::middleware('auth:sanctum')->get('/user', function (Request $request) {
    return $request->user();
Route::get('/color/{hexcode}',[ColorController::class, 'convert']);

On the last line, we add a route that accepts GET requests with a hexcode parameter on the api/color URL. We then link that route to the ColorController class convert() method. Your application should be able to accept requests on the api/color/{hexcode} route now.

Dockerize API

Our Laravel application can now run locally, but we need to install it in a Docker container for it to run on Code Capsules. To do this, add a Dockerfile to the /ColorApi folder. A Dockerfile is a set of instructions on how to build an image of your application and run it inside a docker container. Populate the Dockerfile with the code below:

FROM composer:2.0 as build
COPY . /app/
RUN composer install --prefer-dist --no-dev --optimize-autoloader --no-interaction --ignore-platform-reqs

FROM php:8.1-apache-buster as production
RUN echo "ServerName" >> /etc/apache2/apache2.conf

ENV APP_ENV=production

RUN docker-php-ext-configure opcache --enable-opcache && \
    docker-php-ext-install pdo pdo_mysql

COPY --from=build /app /var/www/html

RUN php artisan config:cache && \
    php artisan route:cache && \
    chmod 777 -R /var/www/html/storage/ && \
    chown -R www-data:www-data /var/www/

CMD ["php", "artisan", "serve", "--host="]

Naming the Dockerfile

The name Dockerfile should start with a capital letter ‘D’ and have no extension, otherwise it won’t work.

Understanding the Dockerfile

Let’s take a look at how the image is built and run in the Dockerfile.

In the first three lines, we require composer as the build stage and copy the project to the /app folder of the container. After copying all the src code for our app into the container, we run composer install with some optional parameters that create an efficient production build.

After installing the dependencies, we require PHP 8.1 as the production stage and set the "ServerName" variable to avoid getting a warning from the apache server. We then copy the app from the build stage into the production stage, specifically into the /var/www/html directory.

The last command tells Docker how to run your application after it has been built.

Add, Commit, and Push Git Changes

Our application is now ready for deployment. Let's add and commit all the files we created to our local repository and then push them to the remote one. Do this by running the commands listed below in a terminal while in the project’s root folder:

git add -A
git commit -m "Added hex color identifier app files"
git branch -M main
git push -u origin main

Your remote repository will now be up to date with your local one.

Deploy to Code Capsules

The final step is to deploy our app. Log into your Code Capsules account and link your remote GitHub repository to Code Capsules. Create a Docker Capsule and deploy the app there. You can reference this deployment guide to see how to do so in greater detail.

Once the build is complete, navigate to the "Configure" tab and scroll down to the "Network Port" section. Enter "8000" as the port number and click on "Update Capsule".

Network Port

That’s it! Your "Hex Color Identifier" app should be live and fully functional now. You should now be able to query the /api/color route.

Color API