Update readme, add user info

Author: hailwood

README.md

@@ -3,6 +3,118 @@
 [![Latest Version on Packagist](https://img.shields.io/packagist/v/webfox/laravel-xero-oauth2.svg?style=flat-square)](https://packagist.org/packages/webfox/laravel-xero-oauth2)
 [![Total Downloads](https://img.shields.io/packagist/dt/webfox/laravel-xero-oauth2.svg?style=flat-square)](https://packagist.org/packages/webfox/laravel-xero-oauth2)
 
+This package integrates the new reccomended package of [xeroapi/xero-php-oauth2](https://github.com/XeroAPI/xero-php-oauth2) using the Oauth 2.0 spec with
+Laravel.
+
+## Installation
+
+You can install this package via composer using the following command:
+```
+composer require webfox/laravel-xero-oauth2
+```
+
+The package will automatically register itself.
+
+You can publish the configuration file with:
+```
+php artisan vendor:publish --provider="Webfox\Xero\XeroServiceProvider" --tag="config"
+```
+
+You'll want to set the scopes required for your application in the config file.
+
+You should add your Xero keys to your .env file using the following keys:
+```
+XERO_CLIENT_ID=
+XERO_CLIENT_SECRET=
+```
+
+## Using the Package
+
+This package registers two bindings into the service container you'll be interested in:
+* `\XeroAPI\XeroPHP\Api\AccountingApi::class` this is the main api for Xero - see the [xeroapi/xero-php-oauth2 docs](https://github.com/XeroAPI/xero-php-oauth2/tree/master/docs) for usage.
+  When you first resolve this dependency if the stored credentials are expired it will automatically refresh the token.
+* `Webfox\Xero\OauthCredentialManager` this is the credential manager - The Accounting API requires we pass through a tenant ID on each request, this class is how you'd access that. 
+  This is also where we can get information about the authenticating user. See below for an example.
+
+*app\Http\Controllers\XeroController.php*
+```php
+<?php
+
+namespace App\Http\Controllers;
+
+use Illuminate\Http\Request;
+use App\Http\Controllers\Controller;
+use Webfox\Xero\OauthCredentialManager;
+
+class XeroController extends Controller
+{
+
+    public function index(Request $request, OauthCredentialManager $xeroCredentials)
+    {
+        try {
+            // Check if we've got any stored credentials
+            if ($xeroCredentials->exists()) {
+                /* 
+                 * We have stored credentials so we can resolve the AccountingApi, 
+                 * If we were sure we already had some stored credentials then we could just resolve this through the controller
+                 * But since we use this route for the initial authentication we cannot be sure!
+                 */
+                $xero             = resolve(\XeroAPI\XeroPHP\Api\AccountingApi::class);
+                $organisationName = $xero->getOrganisations($xeroCredentials->getTenantId())->getOrganisations()[0]->getName();
+                $user             = $xeroCredentials->getUser();
+                $username         = "{$user['given_name']} {$user['family_name']} ({$user['username']})";
+            }
+        } catch (\throwable $e) {
+            // This can happen if the credentials have been revoked or there is an error with the organisation (e.g. it's expired)
+            $error = $e->getMessage();
+        }
+
+        return view('xero', [
+            'connected'        => $xeroCredentials->exists(),
+            'error'            => $error ?? null,
+            'organisationName' => $organisationName ?? null,
+            'username'         => $username ?? null
+        ]);
+    }
+
+}
+```
+
+*resources\views\xero.blade.php*
+```
+@extends('_layouts.main')
+
+@section('content')        
+@if($error)
+    <h1>Your connection to Xero failed</h1>
+    <p>{{ $error }}</p>
+    <a href="{{ route('xero.auth.authorize') }}" class="btn btn-primary btn-large mt-4">
+        Reconnect to Xero
+    </a>
+@elseif($connected)
+    <h1>You are connected to Xero</h1>
+    <p>{{ $organisationName }} via {{ $username }}</p>
+    <a href="{{ route('xero.auth.authorize') }}" class="btn btn-primary btn-large mt-4">
+        Reconnect to Xero
+    </a>
+@else
+    <h1>You are not connected to Xero</h1>
+    <a href="{{ route('xero.auth.authorize') }}" class="btn btn-primary btn-large mt-4">
+        Connect to Xero
+    </a>
+@endif
+@endsection
+```
+
+*routes/web.php*
+```php
+/* 
+ * We name this route xero.auth.success as by default the config looks for a route with this name to redirect back to
+ * after authentication has succeeded. The name of this route can be changed in the config file.
+ */
+Route::get('/manage/xero', [\App\Http\Controllers\XeroController::class, 'index'])->name('xero.auth.success');
+```
+
 ## License
 
 The MIT License (MIT). Please see [License File](LICENSE.md) for more information.

src/OauthCredentialManager.php

@@ -102,6 +102,22 @@ public function store(AccessTokenInterface $token, $tenantId = null)
         ]);
     }
 
+    public function getUser()
+    {
+        $jwt = new \XeroAPI\XeroPHP\JWTClaims();
+        $jwt->setTokenId($this->data('id_token'));
+        $decodedToken = $jwt->decode();
+
+        return [
+            'given_name'  => $decodedToken->getGivenName(),
+            'family_name' => $decodedToken->getFamilyName(),
+            'email'       => $decodedToken->getEmail(),
+            'user_id'     => $decodedToken->getXeroUserId(),
+            'username'    => $decodedToken->getPreferredUsername(),
+            'session_id'  => $decodedToken->getGlobalSessionId()
+        ];
+    }
+
     protected function data($key = null)
     {
         if (!$this->exists()) {