Initial set up

Author: WyriHaximus

composer.json

@@ -0,0 +1,24 @@
+{
+    "name": "api-clients/contracts",
+    "description": "PHP API Clients wide contracts",
+    "license": "MIT",
+    "authors": [
+        {
+            "name": "Cees-Jan Kiewiet",
+            "email": "ceesjank@gmail.com"
+        }
+    ],
+    "require": {
+        "php": "^8.2"
+    },
+    "autoload": {
+        "psr-4": {
+            "ApiClients\\Contracts\\": "src/"
+        }
+    },
+    "config": {
+        "platform": {
+            "php": "8.2.13"
+        }
+    }
+}

src/HTTP/Headers/AuthenticationInterface.php

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+<?php
+
+namespace ApiClients\Contracts\HTTP\Headers;
+
+interface AuthenticationInterface
+{
+    public function authHeader() : string;
+}