I followed the exact steps mentioned in theLaracast : What's New in Laravel 5.3: Laravel Passportto implementapi authenticationusingoauth2.

Myweb.phpfile in the client/consumer project looks like:

use Illuminate\Http\Request;


Route::get('/', function () {
$query = http_build_query([
     'client_id' => 2,
     'redirect_uri' => 'http://offline.xyz.com/callback',
     'response_type' => 'code',
     'scope' => '',
    ]);

return redirect ('http://api.xyz.com/oauth/authorize?'.$query);
});

Route::get('/callback', function (Request $request){
$http= new GuzzleHttp\Client;

$response = $http->post('http://api.xyz.com/oauth/token',[
    'form_params' => [
            'grant_type' => 'authorization_code',
            'client_id' => 2 , 
            'client_secret' => 'tUGYrNeWCGAQt220n88CGoXVu7TRDyZ20fxAlFcL' ,
            'redirect_uri' => 'http://offline.xyz.com/callback',
            'code' => $request->code,
        ],
    ]);

return json_decode((string) $response->getBody(), true);
});

I am getting the permission request page where I need toauthorizeto allow my client to access the api. But, once I click authorize, I am being redirected to the page where it shows the following message:

{"error":"invalid_client","message":"Client authentication failed"}

How to resolve this?

I did not installlaravel/passportin the offline project.Am I missing out something? I have followed and implemented what exactly was mentioned in the video tutorial. Do I have to include something else that I'm not aware of? (I have a very basic knowledge on oauth2).

If it helps, I am trying to implement an offline system which will periodically send data to an online system when there is an internet connection. So I thought I can build anapiand sendpostrequest with information to be stored.

use Illuminate\Http\Request;


Route::get('/', function () {
$query = http_build_query([
     'client_id' => 2,
     'redirect_uri' => 'http://offline.xyz.com/callback',
     'response_type' => 'code',
     'scope' => '',
    ]);

return redirect ('http://api.xyz.com/oauth/authorize?'.$query);
});

Route::get('/callback', function (Request $request){
$http= new GuzzleHttp\Client;

$response = $http->post('http://api.xyz.com/oauth/token',[
    'form_params' => [
            'grant_type' => 'authorization_code',
            'client_id' => 2 , 
            'client_secret' => 'tUGYrNeWCGAQt220n88CGoXVu7TRDyZ20fxAlFcL' ,
            'redirect_uri' => 'http://offline.xyz.com/callback',
            'code' => $request->code,
        ],
    ]);

return json_decode((string) $response->getBody(), true);
});

我拿到了许可请求页面，我需要authorize让我的客户访问API。但是，一旦我点击授权，我被重定向到网页上显示以下消息：

{"error":"invalid_client","message":"Client authentication failed"}

如何解决这个问题？

我没有装laravel/passport在脱机项目。我错过了什么吗？我必须遵循和贯彻的究竟是在视频教程中提到的。我有什么我不知道？（我有一个很基本的知识oauth2）。

如果可以，我想实现一个离线系统将定期发送数据到在线系统的时候有一个互联网连接。所以我想我可以建立一个api和发送帖子请求与信息存储