How to send “multipart/related” content type in PHP

Question

I need to send multipart/related content with PHP. The content will exist of 3 files (2x XML, 1xPDF) The XML-files need to be encoded as 7bit The PDF-file needs to be encoded as base64

I can build a file like this,but then i cant figure out how to send it with curl in PHP.

The content should be something like this (i stripped out most of the encoded pdf). This exapmle comes from another closed-source application:

MIME-Version: 1.0
Content-Type: multipart/related; 
    boundary="----=_Part_0_869724450.1481019442425"

------=_Part_0_869724450.1481019442425
Content-Type: application/vnd.cip4-jmf+xml; name=SubmitQueueEntry.jmf
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment; filename=SubmitQueueEntry.jmf
Content-ID: <5cba3621:158d3a34526:-7ffe@hp.com>
Content-Length: 465

<?xml version="1.0" encoding="UTF-8"?>
<JMF xmlns="http://www.CIP4.org/JDFSchema_1_1" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" SenderID="Alces 0.9.9.1" TimeStamp="2012-08-21T14:55:08-06:00" Version="1.3">
  <Command ID="ALCES_YECIYJ_4_20120821145508" Type="SubmitQueueEntry" xsi:type="CommandSubmitQueueEntry">
    <QueueSubmissionParams ReturnJMF="http://YOURHOSTNAME:9090/jmf" URL="cid:5cba3621:158d3a34526:-7fff@hp.com" />
  </Command>
</JMF>

------=_Part_0_869724450.1481019442425
Content-Type: application/vnd.cip4-jdf+xml; name=test.pdf.jdf
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment; filename=test.pdf.jdf
Content-ID: <5cba3621:158d3a34526:-7fff@hp.com>
Content-Length: 1536

<?xml version="1.0" encoding="UTF-8"?>
<JDF xmlns="http://www.CIP4.org/JDFSchema_1_1" Type="Combined" ID="rootNodeId" Status="Waiting" JobPartID="My Job Part ID" Version="1.3" Types="DigitalPrinting" DescriptiveName="My Job" JobID="My Job ID">
   <Comment Name="JobSpec">Photobook</Comment><ResourcePool>
      <Media Class="Consumable" ID="M001" Status="Available" />
      <DigitalPrintingParams Class="Parameter" ID="DPP001" Status="Available" />
      <RunList ID="RunList_1" Status="Available" Class="Parameter">
            <LayoutElement>
               <FileSpec MimeType="application/pdf" URL="cid:5cba3621:158d3a34526:-8000@hp.com" />
            </LayoutElement>
      </RunList>
      <Component ID="Component" ComponentType="FinalProduct" Status="Unavailable" Class="Quantity" />
   <NodeInfo ID="NI001" Class="Parameter" Status="Available" LastEnd="2015-01-21T13:14:40" JobPriority="50"><Comment Name="Instructions">Emboss with gold stitch</Comment><GeneralID IDUsage="EmbossText" IDValue="Sara and Michael's Wedding,EmbossFontSize 20pt" /></NodeInfo><CustomerInfo Class="Parameter" ID="CI001" Status="Available" /></ResourcePool>
   <ResourceLinkPool>
      <MediaLink rRef="M001" Usage="Input" />
      <DigitalPrintingParamsLink rRef="DPP001" Usage="Input" />
      <RunListLink rRef="RunList_1" Usage="Input" />
      <ComponentLink Usage="Output" rRef="Component" Amount="1" />
   <NodeInfoLink rRef="NI001" Usage="Input" /><CustomerInfoLink rRef="CI001" Usage="Input" /></ResourceLinkPool>
</JDF>

------=_Part_0_869724450.1481019442425
Content-Type: application/octet-stream; name=_113HN_test.pdf
Content-Transfer-Encoding: base64
Content-Disposition: attachment; filename=_113HN_test.pdf
Content-ID: <5cba3621:158d3a34526:-8000@hp.com>
Content-Length: 576230

JVBERi0xLjUNJeLjz9MNCjEgMCBvYmoNPDwvTWV0YWRhdGEgMiAwIFIvT0NQcm9wZXJ0aWVzPDwv
RDw8L09OWzUgMCBSXS9PcmRlciA2IDAgUi9SQkdyb3Vwc1tdPj4vT0NHc1s1IDAgUl0+Pi9QYWdl
cyAzIDAgUi9UeXBlL0NhdGFsb2c+Pg1lbmRvYmoNMiAwIG9iag08PC9MZW5ndGggMjcwNDIvU3Vi
dHlwZS9YTUwvVHlwZS9NZXRhZGF0YT4+c3RyZWFtDQo8P3hwYWNrZXQgYmVnaW49Iu+7vyIgaWQ9
...
bg0KMDAwMDM2NjI5NSAwMDAwMCBuDQowMDAwMzk1NDY2IDAwMDAwIG4NCjAwMDA0MTk5MjggMDAw
MDAgbg0KdHJhaWxlcg08PC9TaXplIDQxL1Jvb3QgMSAwIFIvSW5mbyA0MCAwIFIvSURbPEM3MjlE
QzVEMUYwODQzNDA4NEY0QTlBNEJBQTE4RjhCPjxDMjU2RDIxQjA5Q0Y0MjQ4QTA5REIzRDgxNjQw
NkMzMT5dPj4Nc3RhcnR4cmVmDTQyMDEyMQ0lJUVPRg0=
------=_Part_0_869724450.1481019442425--

I tried the following, but it gives a empty result:

  $url="1.2.3.4";
  $data = array('name' => basename($filePath), 'file' => '@' . realpath($filePath));
  $data = array('file' => '@' . realpath($filePath));

  curl_setopt($ch, CURLOPT_POST, 1);
  curl_setopt($ch, CURLOPT_POSTFIELDS, $data);
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
  curl_setopt($ch, CURLOPT_TIMEOUT, 300);
  curl_setopt($ch, CURLOPT_HTTPHEADER, array(
    'Content-type: multipart/related'
    )); 
  $result = curl_exec($ch);

  $info = curl_getinfo($ch);
//  curl_close($ch);

  if ($result === false || $info['http_code'] != 200) {
    $output = "No cURL data returned for $url [" . $info['http_code'] . "]";
    if (curl_error($ch))
      $output .= "\n" . curl_error($ch);
  }
  else {
    // 'OK' status; format $output data if necessary here:
    echo 'succes';
  }

Maybe it whould be a better approach to build the complete content with curl-options? Instead of building the content 'manualy' before...

Thanks in advance!

Answer 1

per https://stackoverflow.com/a/25998544/1067003 , libcurl has no built-in mechanism to encode requests as multipart/related (and this guy is the author and main developer of curl, so he'd know) meaning that you have to encode the body yourself.

i don't have access to a server to test on, but i think it would go something like this:

<?php
declare(strict_types = 1);
$files = array (
        new MultipartRelatedFile ( 'foo.php' ),
        new MultipartRelatedFile ( 'bar.php' ),
        new MultipartRelatedFile ( 'baz.php' ) 
);
$body = generateMultipartRelatedBody ( $files, $boundary );
$ch = curl_init ();
curl_setopt_array ( $ch, array (
        CURLOPT_HTTPHEADER => array (
                'Content-Type: multipart/related; boundary="' . $boundary.'"' 
        ),
        CURLOPT_POST => true,
        CURLOPT_POSTFIELDS => $body,
        CURLOPT_URL => 'http://127.0.0.1:9999' 
) );
curl_exec ( $ch );
class MultipartRelatedFile {
    public $path;
    public $postname;
    public $content_type;
    function __construct(string $path) {
        if (! is_readable ( $path )) {
            throw new \Exception ( 'file is not readable!' );
        }
        $this->path = $path;
        $this->content_type = mime_content_type ( $path );
        $this->postname = basename ( $path );
    }
}
/**
 * generate http body for a multipart/related POST request
 *
 * @param MultipartRelatedFile[] $files
 * @param string|null $boundary
 */
function generateMultipartRelatedBody(array $files, string &$boundary = NULL): string {
    if (null === $boundary) {
        $boundary = bin2hex ( random_bytes ( 10 ) );
    }
    $n = "\r\n";
    $body = '';
    foreach ( $files as $file ) {
        $body .= $boundary . $n;
        $body .= 'Content-Disposition: attachment; filename=' . $file->postname . $n;
        $body .= "Content-Type: " . $file->content_type . $n;
        $body .= $n . file_get_contents ( $file->path ) . $n;
    }
    $body .= $boundary . '--';
    return $body;
}

warning: short of making sure it looks correct-ish in a netcat server, this is untested code. i'd also like to point out that the specs doesn't mention any Content-Length header, and implies that Content-Id is optional if the filename is provided in some other way (like in Content-Disposition) AND the start header is not used. in any case, specs can be found here: https://www.rfc-editor.org/rfc/rfc2112

edit: forgot to add quotes (") around the boundary of the initial Content-Type header, fixed.