Attachments and SOAP Message Packaging
Attachments are generally used to carry binary data. InterSystems IRIS SOAP support provides three ways to package your SOAP messages. Before discussing detailed options, it is worthwhile to review these kinds of packaging.
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Package the message with all parts inline (without attachments). Use base-64 encoding for any binary data.
This is the default behavior of InterSystems IRIS web services and web clients, except when a web service receives an MTOM request (in which case, the service responds with an MTOM response).
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Package the message according to the MTOM (Message Transmission Optimization Mechanism) specification, which results in a slightly more compact message than an all-inline message. This is now the preferred approach for SOAP messages.
When you use this technique, the system automatically packages the SOAP messages appropriately. That is, the MIME parts are created as needed and are added to the message without your intervention.
Also by default, when InterSystems IRIS creates an MTOM package, it outputs binary streams using an attachment, and it outputs binary strings (%BinaryOpens in a new tab or %xsd.base64BinaryOpens in a new tab) inline; you can control this behavior.
For links to the specifications for MTOM, see SOAP Standards.
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Package the message according to the SOAP with Attachments specification, which results in a slightly more compact message than an all-inline message.
When you use this technique, you must manually create MIME parts, populate them with data, specify the MIME headers as appropriate, and attach the parts to the SOAP message. This usually requires more work than the MTOM technique. See Using SOAP with Attachments.
SOAP Messages with All-Inline Parts (Default)
The default way to package a SOAP message is to include all its elements as inline parts (that is, without attachments). Any binary data is included inline as base-64–encoded data. For example (with line breaks and spaces added for readability):
HTTP/1.1 200 OK
Date: Wed, 19 Nov 2008 21:57:50 GMT
Server: Apache
SET-COOKIE: CSPSESSIONID-SP-8080-UP-csp-gsoap-=003000010000248
guobl000000K7opwlDlY$XbvrGR1eYZsA--; path=/csp/mysamples/;
CACHE-CONTROL: no-cache
EXPIRES: Thu, 29 Oct 1998 17:04:19 GMT
PRAGMA: no-cache
TRANSFER-ENCODING: chunked
Connection: close
Content-Type: text/xml; charset=UTF-8
1d7b
<?xml version="1.0" encoding="UTF-8" ?>
<SOAP-ENV:Envelope xmlns:SOAP-ENV='https://schemas.xmlsoap.org/soap/envelope/'
xmlns:xsi='https://www.w3.org/2001/XMLSchema-instance'
xmlns:s='https://www.w3.org/2001/XMLSchema'>
<SOAP-ENV:Body>
<DownloadResponse xmlns="https://www.filetransfer.org">
<DownloadResult><Filename>sample.pdf</Filename>
<IsBinary>true</IsBinary>
<BinaryContents>
[very long binary content not shown here]
</BinaryContents></attachment></Upload>
</SOAP-ENV:Body>
</SOAP-ENV:Envelope>
Notice that this packaging does not use MIME, and there are no message boundaries.
SOAP Messages with MTOM Packaging
Another way to package a SOAP message is to use MIME parts as described in the MTOM (Message Transmission Optimization Mechanism) specification. Binary data can be placed into separate MIME parts without base-64 encoding. The SOAP message includes references to the separate parts as needed. For example (with line breaks and spaces added for readability):
HTTP/1.1 200 OK
Date: Wed, 19 Nov 2008 21:54:57 GMT
Server: Apache
SET-COOKIE: CSPSESSIONID-SP-8080-UP-csp-gsoap-=003000010
000247guhlx000000NW1KN5UtWg$CWY38$bbTOQ--; path=/csp/mysamples/;
CACHE-CONTROL: no-cache
EXPIRES: Thu, 29 Oct 1998 17:04:19 GMT
MIME-VERSION: 1.0
PRAGMA: no-cache
TRANSFER-ENCODING: chunked
Connection: close
Content-Type: multipart/related; type="application/xop+xml";
boundary=--boundary388.5294117647058824932.470588235294118--;
start="<0.B1150656.EC8A.4B5A.8835.A932E318190B>"; start-info="text/xml"
1ddb
----boundary388.5294117647058824932.470588235294118--
Content-Type: application/xop+xml; type="text/xml"; charset="UTF-8"
Content-Transfer-Encoding: 8bit
Content-Id: <0.B1150656.EC8A.4B5A.8835.A932E318190B>
<?xml version="1.0" encoding="UTF-8" ?>
<SOAP-ENV:Envelope xmlns:SOAP-ENV='https://schemas.xmlsoap.org/soap/envelope/'
xmlns:xsi='https://www.w3.org/2001/XMLSchema-instance'
xmlns:s='https://www.w3.org/2001/XMLSchema'>
<SOAP-ENV:Body>
<DownloadResponse xmlns="https://www.filetransfer.org">
<DownloadResult>
<Filename>sample.pdf</Filename>
<IsBinary>true</IsBinary>
<BinaryContents>
<xop:Include href="cid:1.B1150656.EC8A.4B5A.8835.A932E318190B"
xmlns:xop="https://www.w3.org/2004/08/xop/include"/>
</BinaryContents></DownloadResult></DownloadResponse>
</SOAP-ENV:Body>
</SOAP-ENV:Envelope>
----boundary388.5294117647058824932.470588235294118--
Content-Id: <1.B1150656.EC8A.4B5A.8835.A932E318190B>
Content-Transfer-Encoding: binary
CONTENT-TYPE: application/octet-stream
[very long binary content not shown here]
Notice the following differences compared to the default package:
-
The message has MIME parts and thus includes boundaries.
-
The MIME part has a Content-ID attribute.
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In the SOAP body, the element BinaryContents consists of a reference to that content ID.
SOAP with Attachments
A third way to package SOAP messages is to use the SOAP with Attachments specification, which also uses MIME parts, but packages the message somewhat differently from MTOM. An example follows (with line breaks and spaces added for readability):
HTTP/1.1 200 OK
Date: Mon, 09 Nov 2009 17:47:36 GMT
Server: Apache
SET-COOKIE: CSPSESSIONID-SP-8080-UP-csp-gsoap-=
000000010000213eMwn70000004swjTo4cGuInLMU1n7jaPg--; path=/csp/mysamples/;
CACHE-CONTROL: no-cache
EXPIRES: Thu, 29 Oct 1998 17:04:19 GMT
MIME-VERSION: 1.0
PRAGMA: no-cache
TRANSFER-ENCODING: chunked
Connection: close
Content-Type: multipart/related; type="text/xml";
boundary=--boundary2629.3529411764705883531.411764705882353--
1ca2
----boundary2629.3529411764705883531.411764705882353--
Content-Type: text/xml; charset="UTF-8"
Content-Transfer-Encoding: 8bit
<?xml version="1.0" encoding="UTF-8" ?>
<SOAP-ENV:Envelope xmlns:SOAP-ENV='https://schemas.xmlsoap.org/soap/envelope/'
xmlns:xsi='https://www.w3.org/2001/XMLSchema-instance'
xmlns:s='https://www.w3.org/2001/XMLSchema'>
<SOAP-ENV:Body><DownloadBinaryResponse xmlns="https://www.filetransfer.org">
<DownloadBinaryResult>MQ==</DownloadBinaryResult></DownloadBinaryResponse>
</SOAP-ENV:Body>
</SOAP-ENV:Envelope>
----boundary2629.3529411764705883531.411764705882353--
Content-Transfer-Encoding: binary
Content-Type: application/octet-stream
%PDF-1.4
%âãÏÓ
86 0 obj
<</Length 87 0 R
/Filter /FlateDecode
>>
stream
[stream not shown]
As with MTOM, there is a boundary string and the attachment is a MIME part. However, in contrast to MTOM, the MIME part does not have a content ID, and the SOAP body does not include any references to the MIME part.
