chore: add authStrategy classes and tests (#843)

* chore: add authstrategy classes and tests

* chore: add inline documentation for authStrategies

Author: tiwarishubham635

Diff for: src/Twilio/AuthStrategy/AuthStrategy.php

@@ -0,0 +1,34 @@
+<?php
+namespace Twilio\AuthStrategy;
+
+/**
+ * Class AuthStrategy
+ * Abstract parent class for all authentication strategies - Basic, Bearer Token, NoAuth etc.
+ * @property string $authType The type of authentication strategy
+ */
+
+abstract class AuthStrategy {
+    private $authType;
+
+    public function __construct(string $authType) {
+        $this->authType = $authType;
+    }
+
+    public function getAuthType(): string {
+        return $this->authType;
+    }
+
+    /**
+     * Returns the value to be set in the authentication header
+     *
+     * @return string the authentication string
+     */
+    abstract public function getAuthString(): string;
+
+    /**
+     * Returns true if the authentication strategy requires authentication and false otherwise
+     *
+     * @return bool whether the authentication strategy requires authentication
+     */
+    abstract public function requiresAuthentication(): bool;
+}

Diff for: src/Twilio/AuthStrategy/BasicAuthStrategy.php

@@ -0,0 +1,38 @@
+<?php
+namespace Twilio\AuthStrategy;
+
+/**
+ * Class BasicAuthStrategy
+ * Implementation of the AuthStrategy for Basic authentication
+ * @property string $username
+ * @property string $password
+ */
+
+class BasicAuthStrategy extends AuthStrategy {
+    private $username;
+    private $password;
+
+    public function __construct(string $username, string $password) {
+        parent::__construct("basic");
+        $this->username = $username;
+        $this->password = $password;
+    }
+
+    /**
+     * Returns the base64 encoded string concatenating the username and password
+     *
+     * @return string the base64 encoded string
+     */
+    public function getAuthString(): string {
+        return base64_encode($this->username . ':' . $this->password);
+    }
+
+    /**
+     * Returns true since the basic authentication strategy requires authentication
+     *
+     * @return bool true
+     */
+    public function requiresAuthentication(): bool {
+       return true;
+    }
+}

Diff for: src/Twilio/AuthStrategy/NoAuthStrategy.php

@@ -0,0 +1,32 @@
+<?php
+namespace Twilio\AuthStrategy;
+
+/**
+ * Class NoAuthStrategy
+ * Implementation of the AuthStrategy for No Authentication
+ */
+
+class NoAuthStrategy extends AuthStrategy {
+
+    public function __construct() {
+        parent::__construct("noauth");
+    }
+
+    /**
+     * Returns an empty string since no authentication is required
+     *
+     * @return string an empty string
+     */
+    public function getAuthString(): string {
+        return "";
+    }
+
+    /**
+     * Returns false since the NoAuthStrategy does not require authentication
+     *
+     * @return bool false
+     */
+    public function requiresAuthentication(): bool {
+       return false;
+    }
+}

Diff for: src/Twilio/AuthStrategy/TokenAuthStrategy.php

@@ -0,0 +1,77 @@
+<?php
+namespace Twilio\AuthStrategy;
+
+use Twilio\Http\BearerToken\TokenManager;
+use Twilio\Jwt\JWT;
+
+/**
+ * Class TokenAuthStrategy
+ * Implementation of the AuthStrategy for Bearer Token Authentication
+ * @property string $token The bearer token
+ * @property TokenManager $tokenManager The manager for the bearer token
+ */
+
+class TokenAuthStrategy extends AuthStrategy {
+    private $token;
+    private $tokenManager;
+
+    public function __construct(TokenManager $tokenManager) {
+        parent::__construct("token");
+        $this->tokenManager = $tokenManager;
+    }
+
+    /**
+     * Checks if the token is expired or not
+     *
+     * @param string $token the token to be checked
+     *
+     * @return bool whether the token is expired or not
+     */
+    public function isTokenExpired(string $token): bool {
+        // Decode the JWT token
+        $decodedToken = JWT::decode($token);
+
+        // If the token doesn't have an expiration, consider it expired
+        if($decodedToken === null || $decodedToken->exp === null) {
+            return false;
+        }
+
+        // Calculate the expiration time with a buffer of 30 seconds
+        $expiresAt = $decodedToken->exp * 1000;
+        $bufferMilliseconds = 30 * 1000;
+        $bufferExpiresAt = $expiresAt - $bufferMilliseconds;
+
+        // Return true if the current time is after the expiration time with buffer
+        return time() > $bufferExpiresAt;
+    }
+
+    /**
+     * Fetches the bearer token
+     *
+     * @return string the bearer token
+     */
+    public function fetchToken(): string {
+        if(empty($this->token) || $this->isTokenExpired($this->token)) {
+            $this->token = $this->tokenManager->fetchToken();
+        }
+        return $this->token;
+    }
+
+    /**
+     * Returns the bearer token authentication string
+     *
+     * @return string the bearer token authentication string
+     */
+    public function getAuthString(): string {
+        return "Bearer " . $this->fetchToken();
+    }
+
+    /**
+     * Returns true since the bearer token authentication strategy requires authentication
+     *
+     * @return bool true
+     */
+    public function requiresAuthentication(): bool {
+        return true;
+    }
+}

Diff for: src/Twilio/Http/BearerToken/TokenManager.php

@@ -0,0 +1,18 @@
+<?php
+namespace Twilio\Http\BearerToken;
+
+/**
+ * Class TokenManager
+ * Abstract parent class for all token managers
+ * @property string $token The bearer token
+ * @property string $tokenManager The manager for the bearer token
+ */
+
+abstract class TokenManager {
+    /**
+     * Fetches the bearer token
+     *
+     * @return string the bearer token
+     */
+    abstract public function fetchToken(): string;
+}

Diff for: tests/Twilio/Unit/AuthStrategy/BasicAuthStrategyTest.php

@@ -0,0 +1,42 @@
+<?php
+
+
+namespace Twilio\Tests\Unit\AuthStrategy;
+
+use Twilio\Tests\Unit\UnitTest;
+use Twilio\AuthStrategy\BasicAuthStrategy;
+
+class BasicAuthStrategyTest extends UnitTest {
+    /**
+     * @var string
+     */
+    private $username;
+    /**
+     * @var string
+     */
+    private $password;
+    /**
+     * @var BasicAuthStrategy
+     */
+    private $basicAuthStrategy;
+
+    public function setUp(): void {
+        parent::setUp();
+        $this->username = "username";
+        $this->password = "password";
+        $this->basicAuthStrategy = new BasicAuthStrategy($this->username, $this->password);
+    }
+
+    public function testAuthType(): void {
+        $this->assertEquals('basic', $this->basicAuthStrategy->getAuthType());
+    }
+
+    public function testAuthString(): void {
+        $auth = base64_encode($this->username . ':' . $this->password);
+        $this->assertEquals($auth, $this->basicAuthStrategy->getAuthString());
+    }
+
+    public function testRequiresAuthentication(): void {
+        $this->assertTrue($this->basicAuthStrategy->requiresAuthentication());
+    }
+}

Diff for: tests/Twilio/Unit/AuthStrategy/NoAuthStrategyTest.php

@@ -0,0 +1,31 @@
+<?php
+
+
+namespace Twilio\Tests\Unit\AuthStrategy;
+
+use Twilio\Tests\Unit\UnitTest;
+use Twilio\AuthStrategy\NoAuthStrategy;
+
+class NoAuthStrategyTest extends UnitTest {
+    /**
+     * @var NoAuthStrategy
+     */
+    private $noAuthStrategy;
+
+    public function setUp(): void {
+        parent::setUp();
+        $this->noAuthStrategy = new NoAuthStrategy();
+    }
+
+    public function testAuthType(): void {
+        $this->assertEquals('noauth', $this->noAuthStrategy->getAuthType());
+    }
+
+    public function testEmptyAuthString(): void {
+        $this->assertEquals('', $this->noAuthStrategy->getAuthString());
+    }
+
+    public function testRequiresAuthentication(): void {
+        $this->assertFalse($this->noAuthStrategy->requiresAuthentication());
+    }
+}