Dropbox PHP v2上传问题

Question

I did a php cURL code, the result is success but the problem it return the size 0, can anyone help me out, I do use the code on this page Dropbox v2 API - large file uploads I'm not sure why the file size is zero. can anyone help me out?

Also this is the return from the request cURL

{"name": "2.jpg", "path_lower": "/images/2.jpg", "id": "id:92FZUH08Y6AAAAAVVAAAEA", "client_modified": "2015-12-10T11:02:38Z", "server_modified": "2015-12-10T11:02:38Z", "rev": "1c40f677f1", "size": 0}

Thanks,

UPDATE (CODE):

$filename='2.jpg';
$cheaders = array('Authorization: Bearer =TOKEN=','Content-Type: application/octet-stream','Dropbox-API-Arg: {"path":"/images/'.$filename.'", "mode":"add"}');
$ch = curl_init('https://content.dropboxapi.com/2/files/upload');
curl_setopt($ch, CURLOPT_HTTPHEADER, $cheaders );
curl_setopt($ch, CURLOPT_POST, true);
$fpath = '/home2/public_html/uploads/'.$filename;
$fp = fopen($fpath, 'rb');
curl_setopt($ch, CURLOPT_INFILE, $fp);
curl_setopt($ch, CURLOPT_INFILESIZE, filesize($fpath));
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$response = curl_exec($ch);
curl_close($ch);
fclose($fp);

Answer 1

This version of the code seems to trick curl into acting like it's a PUT request, but has it send "POST" as necessary.

<?php

$path = 'test_php_upload.txt';
$fp = fopen($path, 'rb');
$size = filesize($path);

$cheaders = array('Authorization: Bearer =TOKEN=',
                  'Content-Type: application/octet-stream',
                  'Dropbox-API-Arg: {"path":"/test/'.$path.'", "mode":"add"}');

$ch = curl_init('https://content.dropboxapi.com/2/files/upload');
curl_setopt($ch, CURLOPT_HTTPHEADER, $cheaders);
curl_setopt($ch, CURLOPT_PUT, true);
curl_setopt($ch, CURLOPT_CUSTOMREQUEST, 'POST');
curl_setopt($ch, CURLOPT_INFILE, $fp);
curl_setopt($ch, CURLOPT_INFILESIZE, $size);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$response = curl_exec($ch);

echo $response;
curl_close($ch);
fclose($fp);

?>

That yields:

{"name": "test_php_upload.txt", "path_lower": "/test/test_php_upload.txt", "id": "id:25N5ksooX-sAAAAAAAHcWg", "client_modified": "2015-12-10T22:35:07Z", "server_modified": "2015-12-10T22:35:07Z", "rev": "56384021eccc7", "size": 15}