# Extract MTOM Attachment

## Contents
Overview Configuration

## Overview
Message Transmission Optimization Mechanism (MTOM) provides a way to send binary data to Web Services within standard SOAP messages. MTOM leverages the include mechanism defined by XML Optimized Packaging (XOP) whereby binary data can be sent as a MIME attachment (similar to SOAP with Attachments) to a SOAP message. The binary data can then be referenced in the SOAP message using the `<xop:Include>` element. The following MTOM message contains a binary image that has been Base64-encoded so that it can be inserted as the contents of the `<image>` element:
    <?xml version="1.0" encoding="UTF-8"?>
    <soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
     <soap:Body>
      <uploadGraphic xmlns="www.example.org">
       <image>/aWKKapGGyQ=</image>
      </uploadGraphic>
     </soap:Body>
    </soap:Envelope>
When the Enterprise Gateway receives this request, the Extract MTOM Content filter can be used to extract the Base64-encoded content from the `<image>` element, replace it with an `<xop:Include>` element, which contains a reference to a newly created MIME part that contains the binary content. The following request shows the resulting MTOM message:
    POST /services/uploadImages HTTP/1.1
    Host: SOAPbox
    Content-Type: Multipart/Related;boundary=MIME_boundary;
        type="application/xop+xml";
        start="<mymessage.xml@example.org>";
        start-info="text/xml"

    --MIME_boundary
    Content-Type: application/xop+xml;
        charset=UTF-8;
        type="text/xml"
    Content-Transfer-Encoding: 8bit
    Content-ID: <mymessage.xml@example.org>

    <?xml version="1.0" encoding="UTF-8"?>
    <soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
     <soap:Body>
      <uploadGraphic xmlns="www.example.org">
       <image>
         <xop:Include xmlns:xop='http://www.w3.org/2004/08/xop/include'
              href='cid:http://example.org/myimage.gif'/>
       </image>
      </uploadGraphic>
     </soap:Body>
    </soap:Envelope>

    --MIME_boundary
    Content-Type: image/gif
    Content-Transfer-Encoding: binary
    Content-ID: <http://example.org/myimage.gif>

    // binary octets for image

    --MIME_boundary
It is important to note the following points: The Base64-encoded contents of the `<image>` element have been replaced by the `<xop:Include>` element. The `<xop:Include>` element points to a MIME part using the `href` attribute. The value of the `href` attribute corresponds to the value of the `Content-ID` HTTP header of the MIME part that contains the binary octets of the actual image file.
## Configuration
Complete the following fields to configure this filter: Name: Enter an appropriate name for the filter. XPath Location: Use an XPath expression to locate the encoded data elements. For example, in the sample SOAP request message above, you would configure an XPath expression to point to the `<image>` element. For more information, see the Configuring XPath Expressions topic.