laravel header Allow Origin error while calling api

Probably because Ionic2 itself has not been allowed to make network requests to your endpoint.

You will need to update the Ionic2 app not the server-side (Laravel).

In your Ionic2 config.xml you most likely need to adjust the access attribute, see the documentation here:

https://cordova.apache.org/docs/en/latest/config_ref/#access

i create a api which return the list of users.i test it in postman app and working fine (return json) . but when i try to call it in ionic2 then it show me error in console.i try to insert header('Access-Control-Allow-Origin: *'); in public/index.php at the top . and also try to make a middleware and the handler() has following code

return $next($request)
        ->header('Access-Control-Allow-Origin', '*')
        ->header('Access-Control-Allow-Methods', 'GET, POST, PUT, DELETE, OPTIONS');

route/api.php

Route::group(['middleware' => ['Cors']] ,function(){

     Route::get('/nearby',['as' => 'people.nearby' , 'uses' => function(){
       return User::all();
     }]);
});

solved : i add

header('Access-Control-Allow-Origin: *');

api_routes.php:

<?php

$api = app('Dingo\Api\Routing\Router');

$api->version('v1', ['middleware' => 'cors'], function ($api) {

    $api->post('auth/login', 'App\Api\V1\Controllers\AuthController@login');
    $api->post('auth/signup', 'App\Api\V1\Controllers\AuthController@signup');
    $api->post('auth/recovery', 'App\Api\V1\Controllers\AuthController@recovery');
    $api->post('auth/reset', 'App\Api\V1\Controllers\AuthController@reset');

    // example of protected route
    $api->get('protected', ['middleware' => ['api.auth'], function () {     
        return \App\User::all();
    }]);

    // example of free route
    $api->get('free', function() {
        return \App\User::all();
    });

});

My config/cors.php:

return [
    'supportsCredentials' => false,
    'allowedOrigins' => ['*'],
    'allowedHeaders' => ['*'],
    'allowedMethods' => ['*'],
    'exposedHeaders' => [],
    'maxAge' => 0,
    'hosts' => [],
];

@victor-ponamariov My App working! Because PHP ini bug:

PHP Deprecated:  Automatically populating $HTTP_RAW_POST_DATA is deprecated and will be removed in a future version. To avoid this warning set 'always_populate_raw_post_data' to '-1' in php.ini and use the php://input stream instead. in Unknown on line 0

Update composer.json to:

"barryvdh/laravel-cors": "0.8.1",

I get the error message:

XMLHttpRequest cannot load http://mmorts.dev/api/v1/login. Response to preflight request doesn't pass access control check: The 'Access-Control-Allow-Origin' header contains multiple values '*, http://client.dev', but only one is allowed. Origin 'http://client.dev' is therefore not allowed access.