API V2 Upload Limit

Hi,

Thanks for your response. Below is my code what I am using.

$api_url = 'https://content.dropboxapi.com/2/files/upload_session/start'; 

To above my code is:

$headers = array('Authorization: Bearer ' . $token,
    'Content-Type: application/octet-stream',
    'Dropbox-API-Arg: '.
    json_encode(
        array(

            "close"=>false,
        )
    ),


    'Content-Type: application/octet-stream'
);


$ch = curl_init($api_url);

curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
curl_setopt($ch, CURLOPT_POST, true);

$path = $destPath . $to_zip_folder;
//echo $path;die;
$fp = fopen($path, 'rb');
$filesize = filesize($path);

curl_setopt($ch, CURLOPT_POSTFIELDS, '');
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_VERBOSE, 1); // debug

$response = curl_exec($ch);
$http_code = curl_getinfo($ch, CURLINFO_HTTP_CODE);

curl_close($ch);

response === {"session_id": "AAAAAAAAAFXd8SqjQyOldQ"}

http_code === 200

$api1_url = 'https://content.dropboxapi.com/2/files/upload_session/append_v2';

 To above API my code is:

$headers1 = array('Authorization: Bearer ' . $token,
        'Content-Type: application/octet-stream',
        'Dropbox-API-Arg: '.
        json_encode(
            array(

                    "cursor"=>$w,

                    "close" => false,
            )
        ),

        'Content-Type: application/octet-stream'
    );
   //print_r($headers1);die;



    $ch = curl_init($api1_url);

    curl_setopt($ch, CURLOPT_HTTPHEADER, $headers1);
    curl_setopt($ch, CURLOPT_POST, true);

    $path = $destPath . $to_zip_folder;
//echo $path;die;
    $fp = fopen($path, 'rb');
    $filesize = filesize($path);

    curl_setopt($ch, CURLOPT_POSTFIELDS, '');
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_VERBOSE, 1); // debug

    $response = curl_exec($ch);
    $http_code = curl_getinfo($ch, CURLINFO_HTTP_CODE);

    curl_close($ch);

response === null

http_code === 200

$api2_url = 'https://content.dropboxapi.com/2/files/upload_session/finish';

To above API my code is:

$headers2 = array('Authorization: Bearer ' . $token,
        'Content-Type: application/octet-stream',
        'Dropbox-API-Arg: ' .
        json_encode(
            array(

                "cursor"=>$w1,
                "commit"=>$q,

            )
        ),
        'Content-Type: application/octet-stream'
    );
   // print_r($headers2);die;
    $ch = curl_init($api2_url);

    curl_setopt($ch, CURLOPT_HTTPHEADER, $headers2);
    curl_setopt($ch, CURLOPT_POST, true);

    $path = $destPath . $to_zip_folder;
//echo $path;die;
    $fp = fopen($path, 'rb');
    $filesize = filesize($path);

    curl_setopt($ch, CURLOPT_POSTFIELDS, fread($fp,$filesize));
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_VERBOSE, 1); // debug

    $response = curl_exec($ch);
    $http_code = curl_getinfo($ch, CURLINFO_HTTP_CODE);

    curl_close($ch);

http_code === 413

if I use 

curl_setopt($ch, CURLOPT_POSTFIELDS, fread($fp,$filesize));

 then status_code = 413.

if I use 

curl_setopt($ch, CURLOPT_POSTFIELDS, '');

then it will save 0-byte file.

please suggest what curl should be for these three API?

Please help.