How to send custom HTTP header in response?

Question

I want to send json data in my HTTP Header.

I am using Codeigniter PHP, so I did this in my controller:

header('Content-Type: application/json');'

This is my code:

$request = array(

    'request' => $_GET['request'],
    'device_id' => $_GET['device_id'],
    'launch_date'=> $_GET['launch_date'],
    'allowed_hours'=>$_GET['allowed_hours'],
    'site_id'=>$_GET['site_id'],
    'product'=>$_GET['product'],
    'software_version'=>$_GET['software_version'],
    'platform_os'=>$_GET['platform_os'],
    'platform'=>$_GET['platform'],
    'platform_model'=>$_GET['platform_model']

     );
$response = array(
    'response_code' =>200 ,
    'device_id'=>$_GET['device_id'],
    'allowed_hours'=>$_GET['allowed_hours'],
    'product'=>'mlc',
    'prov_ur'=>NULL 
);

header('Content-Type: application/json');
echo json_encode( $response );

But when I print my header I get

A PHP Error was encountered

Severity: Notice

Message: Undefined index: request

Filename: admin/license.php

Line Number: 22

A PHP Error was encountered

Severity: Notice

Message: Undefined index: allowed_hours

Filename: admin/license.php

Line Number: 25

A PHP Error was encountered

Severity: Notice

Message: Undefined index: allowed_hours

Filename: admin/license.php

Line Number: 40

{"response_code":200,"device_id":"70D0D01FBAD2","allowed_hours":null,"product":"mlc","prov_ur":null}array(10) { ["Host"]=> string(14) "192.168.50.123" ["Connection"]=>
string(10) "keep-alive" ["Cache-Control"]=> string(9) "max-age=0" ["Accept"]=> string(74) "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,/;q=0.8" ["Upgrade-Insecure-Requests"]=> string(1) "1" ["User-Agent"]=>
string(110) "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/47.0.2526.111 Safari/537.36"
["Accept-Encoding"]=> string(19) "gzip, deflate, sdch"
["Accept-Language"]=> string(14) "en-US,en;q=0.8" ["Cookie"]=>
string(518) "cisession=OhhBBhVodwwf7Tb55AVsU32ClMS5cgmxBl15WHA%2BrGnvo1kiK%2B67BWeAuJVSV2MY25zZd0riHC9cyx9fiigiBuqkPMT%2FKE9d6et%2FXaE3F7I59P9%2FEzy5byQ5nEkJq5xwXoH1I7%2B7v62cQL21%2Bjfnk3AwIy4luM7N51IUuTqg7TxunoZFD1gJO84r8degY1imNpmDk2W%2FjsQPn9bQpkWJ9KVMxxViFDaELEU0rIfYmif%2BdvXjK9W%2Fj7iWQxZYE9ZGazgBTKlLO%2BJZHNdPrdmGPFTzTUROZdffpF%2Bb25bRMPEJsZ9CE2mdVuSn%2FEu678utd0lcd9bh%2BDbTDikrHP4jBFOLbZfWKT%2F9r5GkMBrLBl%2BlvPx9RbAq%2FIsjeA1V7c6JYf41TO1bG2XKT14QFHm8m0qY8HCal%2B%2BR8tZe9i3zy24%3Dcfc459942e4ef82a5554257216a19d621f446a25" ["If-Modified-Since"]=> string(29) "Thu, 01 Jan 1970 00:00:00 GMT" }

{"response_code":200,"device_id":"70D0D01FBAD2","allowed_hours":null,"product":"mlc","prov_ur":null}

in my response. I don't want to send other data in my HTTP header response.

Upadted Code as per CI

public function index()
{
    $request = array(
        'request' => $this->get('request'),
        'device_id' => $this->get('device_id'),
        'launch_date'=> $this->get('launch_date'),
        'allowed_hours'=>$this->get('allowed_hours'),
        'site_id'=> $this->get('site_id'),
        'product'=>$this->get('product'),
        'software_version'=> $this->get('software_version'),
        'platform_os'=> $this->get('platform_os'),
        'platform'=> $this->get('platform'),
        'platform_model'=> $this->get('platform_model')
    );

    $response = array(
        'response_code' =>200 ,
        'device_id'=> $this->get('device_id'),
        'allowed_hours'=> $this->get('allowed_hours'),
        'product'=>'mlc',
        'prov_ur'=>NULL 
    );

    $this->output->set_content_type('Content-Type: application/json');

    return $this->output
    ->set_content_type('Content-Type: application/json')
    ->set_output(json_encode($response));

    echo $response;

}

Answer 1

The problem is that some of your $_GET variables aren't set, this will throw an error (the extra output text you have) and can be prevent by checking if they are empty first before using them.

$request = array(
    'request' => !empty($_GET['request']) ? $_GET['request'] : '',
    'device_id' => !empty($_GET['device_id']) ? $_GET['device_id'] : '',
    'launch_date'=> !empty($_GET['launch_date']) ? $_GET['launch_date'] : '',
    'allowed_hours'=> !empty($_GET['allowed_hours']) ? $_GET['allowed_hours'] : '',
    'site_id'=> !empty($_GET['site_id']) ? $_GET['site_id'] : '',
    'product'=> !empty($_GET['product']) ? $_GET['product'] : '',
    'software_version'=> !empty($_GET['software_version']) ? $_GET['software_version'] : '',
    'platform_os'=> !empty($_GET['platform_os']) ? $_GET['platform_os'] : '',
    'platform'=> !empty($_GET['platform']) ? $_GET['platform'] : '',
    'platform_model'=> !empty($_GET['platform_model']) ? $_GET['platform_model'] : ''
);

$response = array(
    'response_code' =>200 ,
    'device_id'=> !empty($_GET['device_id']) ? $_GET['device_id'] : '',
    'allowed_hours'=> !empty($_GET['allowed_hours']) ? $_GET['allowed_hours'] : '',
    'product'=>'mlc',
    'prov_ur'=>NULL 
);

header('Content-Type: application/json');
echo json_encode( $response );