Adding custom code | Fern Documentation

This page covers how to add custom logic, methods, and dependencies to your PHP SDK.

Before getting started, read about how Fern SDKs use custom code and learn about the .fernignore file.

Adding custom logic

To get started adding custom code:

Create a new file and add your custom logic

src/Helper.php

1 <?php
2 
3 namespace YourNamespace;
4 
5 class Helper
6 {
7     public static function myHelper(): void
8     {
9         echo "Hello World!";
10     }
11 }

Add your file to `.fernignore`

.fernignore

1 # Specify files that shouldn't be modified by Fern
2 
3 src/Helper.php

Consume the helper

Now your users can consume the helper function by importing it from the SDK.

1 <?php
2 
3 use YourNamespace\Helper;
4 
5 Helper::myHelper();

Adding custom SDK methods

Fern also allows you to add custom methods to the SDK itself (e.g. client.my_method() ) by inheriting the Fern generated client and then extending it.

Update `generators.yml` configuration

Name your Fern-generated client something like BaseClient to reflect that this client will be extended.

generators.yml

1 - name: fernapi/fern-php-sdk
2   version: 1.25.1
3   config:
4     clientName: BaseClient

Import and extend the generated client

First, import the Fern generated base client and extend it. Then, add whatever methods you want.

src/MyClient.php

1 <?php
2 
3 namespace YourNamespace;
4 
5 class MyClient extends BaseClient
6 {
7     public function myHelper(): void
8     {
9         echo "Hello World!";
10     }
11 }

Update `.fernignore`

Add the MyClient.php to .fernignore.

.fernignore

1 + src/MyClient.php

Consume the method

Instead of constructing the generated client, your users will want to construct the extended client.

1 <?php
2 
3 use YourNamespace\MyClient;
4 
5 $client = new MyClient();