request.files is empty from php curl request - php

Question

I am trying to convert this curl request to php.
curl -X POST -F "file=#test_img.jpg" "http://127.0.0.1:5000/FileUploading/UploadImage/"test_img.jpg"
This request is working correctly with the following flask-RESTful code
class UploadImage(Resource):
def post(self, fname):
file = request.files['file']
if file:
# From flask uploading tutorial
filename = secure_filename(file.filename)
file.save(os.path.join("Images/", filename))
return jsonify({"Path": "Images/" + filename})
else:
# return error
return {'False'}
However, the following php curl request returns error 400 as it seems the request.files parameter is empty.
$file_name = "test_img.jpg";
$post_data = array(
"file" => "#" . $file_name,
"type" => 'image/jpg'
);
$ch = curl_init();
debug_to_console(http_build_query($post_data));
$host = "http://127.0.0.1:5000";
$url = $host . "/FileUploading/UploadImage/" . $file_name;
debug_to_console($url);
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_POST, 1);
$file_param = 'file=' . $file_name;
curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query($post_data));
$headers = array();
$headers[] = "Content-Type: multipart/form-data";
debug_to_console($headers);
curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
$result = curl_exec($ch);
if (curl_errno($ch)) {
debug_to_console('Error:' . curl_error($ch));
}
curl_close($ch);
I don't know what i am doing wrong in this php request

Answer 1

first off, don't try to upload files using the # method, it was deprecated in PHP 5.5, disabled-by-default in PHP 5.6, and completely removed in PHP 7.0.0, in modern PHP, use CURLFile to upload files. also in line 10 you don't urlencode $file_name, that's a bug. and in line 17 you're trying to encode it to application/x-www-form-urlencoded-format (via http_build_query), but the command you're trying to convert is using multipart/form-data-format, when you give CURLOPT_POSTFIELDS a string (as returned by http_build_query), curl will send it as application/x-www-form-urlencoded by default but to make curl send it in multipart/form-data-format (as you want), set CURLOPT_POSTFIELDS to an array, not a string, and curl will send it in multipart/form-data.