Multipart PUT upload using Curl and PHP to a REST endpoint - php

Question

I need to HTTP PUT a csv file and some POST fields using multipart POST with PHP and Curl to a REST API endpoint.
The contents of the file upload is stored in a variable $list. The other end point is $url.
$ch = curl_init($url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_PUT, true);
$post = array(
//Other Post fields array
);
curl_setopt($ch, CURLOPT_POSTFIELDS, $post);
$fh = fopen('php://memory', 'rw');
fwrite($fh, $list);
rewind($fh);
curl_setopt($ch, CURLOPT_INFILE, $fh);
curl_setopt($ch, CURLOPT_INFILESIZE, strlen($list));
$response = curl_exec($ch);
The above code seems to work the only problem is that the other end point requires a specific fieldname for the file upload. How do i set a filename ?
Am i doing something wrong ?
This is the PUT format they have mentioned on API
Content-Disposition: form-data; name="list[csv]"; filename="RackMultipart20110923-63966-hfpyg"
Content-Length: 33
Content-Type: text/csv
Content-Transfer-Encoding: binary
xxxx
yyyy
zzzz
-------------MultipartPost
Content-Disposition: form-data; name="list[list_type]"
Blacklist
-------------MultipartPost--

Answer 1

FYI that is multipart/form-data. You will need to build the body yourself I think, I don't think cURL could be made to build that sort of request with a PUT request. However, this is not a serious problem:
<?php
function recursive_array_mpfd ($array, $separator, &$output, $prefix = '') {
// Recurses through a multidimensional array and populates $output with a
// multipart/form-data string representing the data
foreach ($array as $key => $val) {
$name = ($prefix) ? $prefix."[".$key."]" : $key;
if (is_array($val)) {
recursive_array_mpfd($val, $separator, $output, $name);
} else {
$output .= "--$separator\r\n"
. "Content-Disposition: form-data; name=\"$name\"\r\n"
. "\r\n"
. "$val\r\n";
}
}
}
// This will hold the request body string
$requestBody = '';
// We'll need a separator
$separator = '-----'.md5(microtime()).'-----';
// First add the postfields
$post = array(
//Other Post fields array
);
recursive_array_mpfd($post, $separator, $requestBody);
// Now add the file
$list = "this,is,some,csv,data"; // The content of the file
$filename = "data.csv"; // The name of the file
$requestBody .= "--$separator\r\n"
. "Content-Disposition: form-data; name=\"list[list_type]\"; filename=\"$filename\"\r\n"
. "Content-Length: ".strlen($list)."\r\n"
. "Content-Type: text/csv\r\n"
. "Content-Transfer-Encoding: binary\r\n"
. "\r\n"
. "$list\r\n";
// Terminate the body
$requestBody .= "--$separator--";
// Let's go cURLing...
$ch = curl_init($url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_PUT, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, $requestBody);
curl_setopt($ch, CURLOPT_HTTPHEADER, array(
'Content-Type: multipart/form-data; boundary="'.$separator.'"'
));
$response = curl_exec($ch);
If you have any problems with this, try echo $requestBody; before the cURL request and make sure it looks like you expect it to.