Adding custom code (PHP) | Fern Documentation

Enterprise feature

This feature is available only for the Enterprise plan. To get started, reach out to support@buildwithfern.com.

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

Adding custom logic

To get started adding custom code:

These steps cover adding a new custom file to the SDK. To preserve line-level edits to a generated file, use Replay instead.

Create a new file and add your custom logic

src/Helper.php

<?php
namespace YourNamespace;
class Helper
{
    public static function myHelper(): void
    {
        echo "Hello World!";
    }
}

Add your file to `.fernignore`

.fernignore

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

Consume the helper

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

<?php
use YourNamespace\Helper;
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 `sdk-config.yml` configuration

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

sdk-config.yml

targets:
  - language: php
    generation:
      naming:
        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

<?php
namespace YourNamespace;
class MyClient extends BaseClient
{
    public function myHelper(): void
    {
        echo "Hello World!";
    }
}

Update `.fernignore`

Add the MyClient.php to .fernignore.

.fernignore

+ src/MyClient.php

Consume the method

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

<?php
use YourNamespace\MyClient;
$client = new MyClient();

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

$client->myHelper();

Adding custom dependencies

To add packages that your custom code requires, list them in the target’s package.extraDependencies and package.extraDevDependencies in sdk-config.yml.