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soap – Attachments with php's built-in SoapClient?

Posted by: admin July 12, 2020 Leave a comment


Is there a way I can add a soap attachment to a request using PHP’s built-in SoapClient classes? It doesn’t look like it’s supported, but maybe I can manually build the mime boundaries? I know the PEAR SOAP library supports them, but in order to use that I have to rewrite my entire library to use it.

How to&Answers:

Why don’t you just send files using Data URI scheme rather than implement SoapAttachment ? Here is an example :


$client = new SoapClient(null, array(
        'location' => "http://localhost/lab/stackoverflow/a.php?h=none",
        'uri' => "http://localhost/",
        'trace' => 1

// Method 1 Array
// File to upload
$file = "golf3.png";

// First Example
$data = array();
$data['name'] = $file;
$data['data'] = getDataURI($file, "image/png");
echo "Example 1: ";
echo ($return = $client->upload($data)) ? "File Uploaded : $return bytes" : "Error Uploading Files";

// Method 2 Objects
// File to upload
$file = "original.png";

// Second Example
$attachment = new ImageObj($file);
$param = new SoapVar($attachment, SOAP_ENC_OBJECT, "ImageObj");
$param = new SoapParam($param, "param");
echo "Example 2: ";
echo ($return = $client->uploadObj($attachment)) ? "File Uploaded : $return bytes" : "Error Uploading Files";


Example 1: File Uploaded : 976182 bytes
Example 2: File Uploaded : 233821 bytes


class UploadService {

    public function upload($args) {
        $file = __DIR__ . "/test/" . $args['name'];
        return file_put_contents($file, file_get_contents($args['data']));

    public function uploadObj($args) {
        $file = __DIR__ . "/test/" . $args->name;
        $data = sprintf("data://%s;%s,%s", $args->mime, $args->encoding, $args->data);
        return file_put_contents($file, file_get_contents($data));

try {
    $server = new SOAPServer(NULL, array(
            'uri' => 'http://localhost/'

} catch (SOAPFault $f) {
    print $f->faultstring;

Client Util

// Function Used
function getDataURI($image, $mime = '') {
    return 'data: ' . (function_exists('mime_content_type') ? 
            mime_content_type($image) : $mime) . ';base64,' . 

// Simple Image Object
class ImageObj{
    function __construct($file, $mime = "") {
        $this->file = $file;
        $this->name = basename($file);
        if (function_exists('mime_content_type')) {
            $this->mime = mime_content_type($file);
        } elseif (function_exists('finfo_open')) {
            $this->mime = finfo_file(finfo_open(FILEINFO_MIME_TYPE), $file);
        } else {
            $this->mime = $mime;

        $this->encoding = "base64";
        $this->data = base64_encode(file_get_contents($file));


Yes, you can build the MIME component of the message using something like imap_mail_compose.

You’ll need to construct a multipart message as they do in the first example, putting the XML from the $request parameter, from an overridden SoapClient::__doRequest method, into the first part of the MIME message.

Then you can do as others have shown in the first imap_mail_compose example to add one or more messages parts with attachments. These attachements can, but do not have to be base64 encoded, they can just as well be binary. The encoding for each part is specified by part-specific headers.

You’ll also need to cook up an appropriate set of HTTP headers, per the SwA Document @Baba linked to earlier.

Once it’s all said and done, you should have something looking like the examples from that document:

MIME-Version: 1.0
Content-Type: Multipart/Related; boundary=MIME_boundary; type=text/xml;
        start="<[email protected]>"
Content-Description: This is the optional message description.

Content-Type: text/xml; charset=UTF-8
Content-Transfer-Encoding: 8bit
Content-ID: <[email protected]>

<?xml version='1.0' ?>
<theSignedForm href="cid:[email protected]"/>

Content-Type: image/tiff
Content-Transfer-Encoding: binary
Content-ID: <[email protected]>

...binary TIFF image...

And you can send that across the wire with the aforementioned overridden SoapClient::__doRequest method. Things I have noticed in trying to implement it myself thus far:

  • You may need to create an href URI reference from each SOAP node to the corresponding attachment, something like href="cid:[email protected]" above
  • You will need to extract the boundary component from the MIME content returned by imap_mail_compose for use in an HTTP Content-Type header
  • Don’t forget the start component of the Content-Type header either, it should look something like this:
  • imap_mail_compose appears fairly minimal (but low hanging fruit), if it proves insufficient, consider Mail_Mime instead

Content-Type: Multipart/Related; boundary=MIME_boundary;
type=text/xml; start=””

Lastly, I’m not sure how evenly the various implementations of SwA are out there on the Internet… Suffice it to say, I’ve not been able to get an upload to a remote service with a crude implementation of what I’ve described above yet. It does seem like SwA is the typical SOAP attachment paradigm of choice though, from what I gather reading around on the net.