Welcome everyone.
Here is a problem I have: I'm trying to send data with files to server using PHP and CURL. Server accepts data with 6 photos. And if there are less than 6 items in $_FILES array - it`s an error.
So if I send all 6 photos, everything goes perfectly. But if there are less photos, than value with empty photo goes to $_POST array.
I read Curl documentation but couldn`t find such possibility. How can it be done with CURL to send an empty value of File type?
I had the same problem and this works:
curl -F "[email protected]" -F "file_2=@/dev/null;filename=" -F "file_3=@/dev/null;filename="
/dev/null with NUL does the trick.I don't think this is possible: In a browser, an unused file input will simply not be attached to the request at all, so there is no "empty file field" value to parse.
$_FILES will be constructed by PHP when it receives the request carrying the uploaded files.
Not sure what you are trying to do here though - don't you already know the request will fail if you don't have six images to send in the first place?
s working. Yes, it fails if there are less than 6 images, and also fails if images are empty. I just could add an image 1*1px instead of empty images, but its not the solution that I need - because it shows all 6 photos and some of them just 1*1px. So I think you`re right - there is no such feature in Curl.I had the same problem. My PHP solution is to send data like browser does. Just try to use example 1:
Example 1
$postData = '------WebKitFormBoundarywPZdrW1CWvlHZ7xB
Content-Disposition: form-data; name="image[3]"; filename=""
Content-Type: application/octet-stream
------WebKitFormBoundarywPZdrW1CWvlHZ7xB--';
curl_setopt($ch, CURLOPT_POSTFIELDS, $post);
Works fine? Now we need some function to build this data automatically. Example 2 is simple illustration how to do it using CurlHelper::prepareMultiPartData() function. You need to create class CurlHelper before (code listed below).
Example 2
$data=array( //array can be multidimensional like this
'image' => array(
3 => curl_file_create('', '', ''),
),
);
$boundary = 'webkit';
$postData = CurlHelper::prepareMultiPartData($data, $boundary);
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, 'url');//TODO set your own url
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, $postData);
curl_setopt($ch, CURLOPT_HTTPHEADER, array("Content-Type: multipart/form-data; boundary=$boundary"));
$response = curl_exec($ch);
class CurlHelper
class CurlHelper {
/**
* @param array $data POST data. could be multidimensional array
* @param string $boundary if $boundary == '' it will be generated automatically
* @return string formatted POST data separeted with boundary like in browser.
*/
static function prepareMultiPartData($data, &$boundary){
$boundary = self::_createBoundary($boundary);
$boundaryMiddle = "--$boundary\r\n";
$boundaryLast = "--$boundary--\r\n";
$res = self::_prepareMultipartData($data, ["\r\n"]);
$res = join($boundaryMiddle, $res) . $boundaryLast;
return $res;
}
static private function _createBoundary($boundaryCustom = '') {
switch ($boundaryCustom) {
case '':
return uniqid('----').uniqid();
case 'chrome':
case 'webkit':
return uniqid('----WebKitFormBoundary').'FxB';
default:
return $boundaryCustom;
}
}
static private function _prepareMultipartData($data, $body, $keyTpl = ''){
$ph = '{key}';
if ( !$keyTpl ) {
$keyTpl = $ph;
}
foreach ($data as $k => $v) {
$paramName = str_replace($ph, $k, $keyTpl);
if ( (class_exists('CURLFile') && $v instanceof \CURLFile) || strpos($v, '@') === 0 ) {
if (is_string($v)) {
$buf = strstr($v,'filename=');
$buf = explode(';', $buf);
$filename = str_replace('filename=', '', $buf[0]);
$mimeType = (isset($buf[1])) ? str_replace('type=', '', $buf[1]) : 'application/octet-stream';
} else {
$filename = $v->name;
$mimeType = $v->mime;
}
$str = 'Content-Disposition: form-data; name="' . $paramName . '"; filename="' . $filename . "\"\r\n";
$str .= 'Content-Type: ' . $mimeType . "\r\n\r\n\r\n";
$body[] = $str;
} elseif ( is_array($v) ) {
$body = self::_prepareMultipartData($v, $body, $paramName.'['.$ph.']');
} else {
$body[] = 'Content-Disposition: form-data; name="' . $paramName . "\"\r\n\r\n" . $v . "\r\n";
}
}
return $body;
}
}
This is how you can always send a file input field even if it is empty:
<input type="text" name="team_logo" hidden>
<input type="file" name="team_logo">
I'm not familiar with curl, but this works in php laravel.
