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The following settings are available on the Advanced tab:
Allow RPC Schema Validation:
When the Allow RPC Schema Validation checkbox is selected,
the filter makes a best attempt to validate an RPC-encoded
SOAP message. An RPC-encoded message is defined in the WSDL as having an operation
with the following characteristics:
-
The
style attribute of the <soap:operation>
element is set to document.
-
The
use attribute of the <soap:body>
element is set to rpc.
For details on the possible values for these attributes, see
Section 3.5
of the WSDL specification.
The problem with RPC-encoded SOAP messages in terms of schema validation
is that the schema contained in the WSDL file does not necessarily fully
define the format of the SOAP message, unlike with
document-literal style messages. With an RPC-encoded
operation, the format of the message can be defined by a combination of
the SOAP operation name, WSDL message parts, and schema-defined types.
As a result, the schema extracted from a WSDL file may not be able to
validate a message.
Another problem with RPC-encoded messages is that type information is
included in each element that appears in the SOAP message. For such element
definitions to be validated by a schema, the type declarations must be removed,
which is precisely what the Schema Validation filter does if
the checkbox is selected on this tab. It removes the type declarations and then
makes a best attempt to validate the message.
However, as explained earlier, if some of the elements in the SOAP message are
taken from the WSDL file instead of the schema (for example, when the SOAP operation
name in the WSDL file is used as the wrapper element beneath the SOAP Body instead of
a schema-defined type), the schema is not able to validate the message.
Inline MTOM Attachments into Message:
Message Transmission Optimization Mechanism (MTOM) provides a way to send binary data
to Web Services in 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 from within the SOAP message using the <xop:Include> element.
The following SOAP request contains a binary image that has been Base64-encoded so that
it can be inserted as the contents of the <image> element:
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<?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>
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When this message is converted to an MTOM message by the Enterprise Gateway
(for example, using the Extract
MTOM Content filter)
the Base64-encoded content from the <image> element is replaced
with an <xop:Include> element. This contains a reference to a
newly created MIME part that contains the binary content. The following request
shows the resulting MTOM message:
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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
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When attempting to validate the MTOM message with an XML Schema, it is
crucial that you are aware of the format of the <image>
element. Will it contain the Base64-encoded binary data, or will it contain
the <xop:include> element with a reference to a MIME part?
For example, the XML Schema definition for <image> element
might look as follows:
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<xsd:element name="image" maxOccurs="1" minOccurs="1"
type="xsd:base64Binary"
xmime:expectedContentTypes="*/*"
xsi:schemaLocation="http://www.w3.org/2005/05/xmlmime"
xmlns:xmime="http://www.w3.org/2005/05/xmlmime"/>
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In this case, the XML Schema validator expects the contents of the
<image> element to be base64Binary.
However,if the message has been formatted as an MTOM message, the
<image> element contains a child element,
<xop:Include> that the schema knows nothing about.
This causes the schema validator to report an error and the schema
validation fails.
To resolve this issue, select the
Inline MTOM Attachments into Message checkbox on the
Advanced tab. At runtime, the schema validator replaces
the value of the <xop:Include> element with the
Base64-encoded contents of the MIME part to which it refers. This means
that the message now adheres to the definition of the <image>
element in the XML Schema (the element contains data of type
base64Binary).
This standard procedure of interpreting XOP messages is described in
Section 3.2 Interpreting XOP Packages of the XML-binary Optimized
Packaging (XOP) specification.
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