| RFC 3288 |
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This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited.
Copyright (C) The Internet Society (2002). All Rights Reserved.
This memo specifies a Simple Object Access Protocol (SOAP) binding to the Blocks Extensible Exchange Protocol core (BEEP). A SOAP binding describes how SOAP messages are transmitted in the network.
The SOAP is an XML-based (extensible markup language) messaging protocol used to implement a wide variety of distributed messaging models. It defines a message format and describes a variety of message patterns, including, but not limited to, RPC, asynchronous event notification, unacknowledged messages, and forwarding via SOAP intermediaries.
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This memo specifies how SOAP 1.1 envelopes[1] are transmitted using a BEEP profile[2]. In the W3C, the XMLP effort is evolving SOAP. Accordingly, this memo provides a mechanism for negotiating the use of new features.
Throughout this memo, the term "envelope" refers to the "SOAP-Env:Envelope" element defined in Section 4 of [1]. Further, the terms "peer", "client", "server", "one-to-one", and "one-to-many" are used in the context of BEEP. In particular, Sections 2.1 and 2.1.1 of [2] discuss BEEP roles and exchange styles.
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The BEEP profile for SOAP is identified as
http://iana.org/beep/soap
in the BEEP "profile" element during channel creation.
In BEEP, when the first channel is successfully created, the "serverName" attribute in the "start" element identifies the "virtual host" associated with the peer acting in the server role, e.g.,
<start number='1' serverName='stockquoteserver.example.com'>
<profile uri='http://iana.org/beep/soap' />
</start>
The "serverName" attribute is analagous to HTTP's "Host" request-header field (c.f., Section 14.23 of [3]).
There are two states in the BEEP profile for SOAP, "boot" and "ready":
Regardless, no state change occurs.
The boot message is used for two purposes:
- resource identification:
- each channel bound to the BEEP profile for SOAP provides access to a single resource (a network data object or service).
- feature negotiation:
- if new features of SOAP (such as compression) emerge, their use can be negotiated.
The DTD syntax for the boot message and its response are:
<!ELEMENT bootmsg EMPTY>
<!ATTLIST bootmsg
resource CDATA #REQUIRED
features NMTOKENS "">
<!ELEMENT bootrpy EMPTY>
<!ATTLIST bootrpy
features NMTOKENS "">
The boot message contains a mandatory and an optional attribute:
SOAP Profile Feature Registration Template defines a registration template for optional features.
If the peer acting in the server role recognizes the requested resource, it replies with the boot response that contains one optional attribute:
Otherwise, if the boot message is improperly formed, or if the requested resource isn't recognized, the peer acting in the server role replies with an error message (c.f., Section 7.1 of [2]).
Typically, the boot message and its response are exchanged during channel initialization (c.f., Section 2.3.1.2 of [2]).
For example, here the boot message and its response are exchanged during channel initialization:
C: <start number='1' serverName='stockquoteserver.example.com'>
C: <profile uri='http://iana.org/beep/soap'>
C: <![CDATA[<bootmsg resource='/StockQuote' />]]>
C: </profile>
C: </start>
S: <profile uri='http://iana.org/beep/soap'>
S: <![CDATA[<bootrpy />]]>
S: </profile>
The channel bound to the BEEP profile for SOAP is now in the "ready" state.
Alternatively, here is an example in which the boot exchange is unsuccessful:
C: <start number='1' serverName='stockquoteserver.example.com'>
C: <profile uri='http://iana.org/beep/soap'>
C: <![CDATA[<bootmsg resource='/StockPick' />]]>
C: </profile>
C: </start>
S: <profile uri='http://iana.org/beep/soap'>
S: <![CDATA[<error code='550'>resource not
S: supported</error>]]>
S: </profile>
Although the channel was created successfully, it remains in the "boot" state.
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The BEEP profile for SOAP transmits envelopes encoded as UTF-8 using the media type "application/xml"[4], e.g.,
MSG 1 1 . 0 364
Content-Type: application/xml
<SOAP-ENV:Envelope
xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"
SOAP-ENV:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">
<SOAP-ENV:Body>
<m:GetLastTradePrice xmlns:m="Some-URI">
<symbol>DIS</symbol>
</m:GetLastTradePrice>
</SOAP-ENV:Body>
</SOAP-ENV:Envelope>
END
In addition, the BEEP profile for SOAP also allows envelopes to be transmitted as the root part of a "multipart/related"[5] content, and with subordinate parts referenced using the rules of Section 3 of [6] (i.e., using either the "Content-ID:"[7] or "Content-Location:"[8] headers), e.g.,
MSG 1 2 . 364 668
Content-Type: multipart/related; boundary="MIME_boundary";
type=application/xml;
start="<claim061400a.xml@claiming-it.com>"
--MIME_boundary
Content-Type: application/xml
Content-ID: <claim061400a.xml@claiming-it.com>
<?xml version='1.0' ?>
<SOAP-ENV:Envelope
xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/">
<SOAP-ENV:Body>
..
<theSignedForm href="cid:claim061400a.tiff@claiming-it.com" />
..
</SOAP-ENV:Body>
</SOAP-ENV:Envelope>
--MIME_boundary
Content-Type: image/tiff
Content-Transfer-Encoding: binary
Content-ID: <claim061400a.tiff@claiming-it.com>
...binary TIFF image...
--MIME_boundary--
END
Consistent with Section 2 of [6], it is strongly recommended that the multipart contain a "start" parameter, and that the root part contain a "Content-ID:" header. However, because BEEP provides an 8bit-wide path, a "transformative" Content-Transfer-Encoding (e.g., "base64" or "quoted-printable") should not be used. Further note that MIME[9] requires that the value of the "Content-ID" header be globally unique.
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A one-way message involves sending a message without any response being returned.
The BEEP profile for SOAP achieves this using a one-to-many exchange, in which the client sends a "MSG" message containing an envelope, and the server immediately sends back a "NUL" message, before processing the contents of the envelope.
A request/response exchange involves sending a request, which results in a response being returned.
The BEEP profile for SOAP achieves this using a one-to-one exchange, in which the client sends a "MSG" message containing an envelope, and the server sends back a "RPY" message containing an envelope.
Finally, the BEEP profile for SOAP does not use the "ERR" message for SOAP faults when performing one-to-one exchanges — whatever response is generated by the server is always returned in the "RPY" message.
A request/N-responses exchange involves sending a request, which results in zero or more responses being returned.
The BEEP profile for SOAP achieves this using a one-to-many exchange, in which the client sends a "MSG" message containing an envelope, and the server sends back zero or more "ANS" messages, each containing an envelope, followed by a "NUL" message.
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This memo defines two URL schemes, "soap.beep" and "soap.beeps", which identify the use of SOAP over BEEP over TCP. Note that, at present, a "generic" URL scheme for SOAP is not defined.
The "soap.beep" URL scheme uses the "generic URI" syntax defined in Section 3 of [10], specifically:
The values of both the scheme and authority components are case-insensitive.
For example, the URL
soap.beep://stockquoteserver.example.com/StockQuote
might result in the example shown in Profile Initialization.
The "soap.beep" URL scheme indicates the use of the BEEP profile for SOAP running over TCP/IP.
If the authority component contains a domain name and a port number, e.g.,
soap.beep://stockquoteserver.example.com:1026
then the DNS is queried for the A RRs corresponding to the domain name, and the port number is used directly.
If the authority component contains a domain name and no port number, e.g.,
soap.beep://stockquoteserver.example.com
the SRV algorithm[11] is used with a service parameter of "soap-beep" and a protocol parameter of "tcp" to determine the IP/TCP addressing information. If no appropriate SRV RRs are found (e.g., for "_soap-beep._tcp.stockquoteserver.example.com"), then the DNS is queried for the A RRs corresponding to the domain name and the port number used is assigned by the IANA for the registration in Registration: The System (Well-Known) TCP port number for SOAP over BEEP.
If the authority component contains an IP address, e.g.,
soap.beep://10.0.0.2:1026
then the DNS is not queried, and the IP address is used directly. If a port number is present, it is used directly; otherwise, the port number used is assigned by the IANA for the registration in Registration: The System (Well-Known) TCP port number for SOAP over BEEP.
While the use of literal IPv6 addresses in URLs is discouraged, if a literal IPv6 address is used in a "soap.beep" URL, it must conform to the syntax specified in [12].
The "soap.beeps" URL scheme is identical, in all ways, to the "soap.beep" URL scheme specified in The soap.beep URL Scheme, with the exception that prior to starting the BEEP profile for SOAP, the BEEP session must be tuned for privacy. In particular, note that both URL schemes use the identical algorithms and parameters for address resolution as specified in Resolving IP/TCP Address Information (e.g., the same service name for SRV lookups, the same port number for TCP, and so on).
There are two ways to perform privacy tuning on a BEEP session, either:
Regardless, upon completion of the negotiation process, a tuning reset occurs in which both BEEP peers issue a new greeting. Consult Section 3 of [2] for an example of how a BEEP peer may choose to issue different greetings based on whether privacy is in use.
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When a feature for the BEEP profile for SOAP is registered, the following information is supplied:
- Feature Identification:
- specify a string that identifies this feature. Unless the feature is registered with the IANA, the feature's identification must start with "x-".
- Feature Semantics:
- specify the semantics of the feature.
- Contact Information:
- specify the electronic contact information for the author of the feature.
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- Profile Identification:
- http://iana.org/beep/soap
- Messages exchanged during Channel Creation:
- bootmsg, bootrpy
- Messages starting one-to-one exchanges:
- bootmsg, SOAP-Env:Envelope
- Messages in positive replies:
- bootrpy, SOAP-Env:Envelope
- Messages in negative replies:
- error
- Messages in one-to-many exchanges:
- SOAP-Env:Envelope
- Message Syntax:
- SOAP-Env:Envelope as defined in Section 4 of [1] and [6]
- Message Semantics:
- c.f., [1]
- Contact Information:
- Eamon O'Tuathail <eamon.otuathail@clipcode.com>, Marshall Rose <mrose@dbc.mtview.ca.us>
- URL scheme name:
- soap.beep
- URL scheme syntax:
- c.f., The soap.beep URL Scheme
- Character encoding considerations:
- c.f., the "generic URI" syntax defined in Section 3 of [10]
- Intended usage:
- identifies a SOAP resource made available using the BEEP profile for SOAP
- Applications using this scheme:
- c.f., "Intended usage", above
- Interoperability considerations:
- n/a
- Security Considerations:
- c.f., Security Considerations
- Relevant Publications:
- c.f., [1], [6], and [2]
- Contact Information:
- Eamon O'Tuathail <eamon.otuathail@clipcode.com>, Marshall Rose <mrose@dbc.mtview.ca.us>
- Author/Change controller:
- the IESG
- URL scheme name:
- soap.beeps
- URL scheme syntax:
- c.f., The soap.beeps URL Scheme
- Character encoding considerations:
- c.f., the "generic URI" syntax defined in Section 3 of [10]
- Intended usage:
- identifies a SOAP resource made available using the BEEP profile for SOAP after the BEEP session has been tuned for privacy
- Applications using this scheme:
- c.f., "Intended usage", above
- Interoperability considerations:
- n/a
- Security Considerations:
- c.f., Security Considerations
- Relevant Publications:
- c.f., [1], [6], and [2]
- Contact Information:
- Eamon O'Tuathail <eamon.otuathail@clipcode.com>, Marshall Rose <mrose@dbc.mtview.ca.us>
- Author/Change controller:
- the IESG
- Protocol Number:
- TCP
- Message Formats, Types, Opcodes, and Sequences:
- c.f., Profile Initialization
- Functions:
- c.f., [1]
- Use of Broadcast/Multicast:
- none
- Proposed Name:
- SOAP over BEEP
- Short name:
- soap-beep
- Contact Information:
- Eamon O'Tuathail <eamon.otuathail@clipcode.com>, Marshall Rose <mrose@dbc.mtview.ca.us>
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Although service provisioning is a policy matter, at a minimum, all implementations must provide the following tuning profiles:
- for authentication:
- http://iana.org/beep/SASL/DIGEST-MD5
- for confidentiality:
- http://iana.org/beep/TLS (using the TLS_RSA_WITH_3DES_EDE_CBC_SHA cipher)
- for both:
- http://iana.org/beep/TLS (using the TLS_RSA_WITH_3DES_EDE_CBC_SHA cipher supporting client-side certificates)
Further, implementations may choose to offer MIME-based security services providing message integrity and confidentiality, such as OpenPGP[13] or S/MIME[14].
Regardless, consult [2]'s Section 9 for a discussion of BEEP-specific security issues.
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| Eamon O'Tuathail | |
| Clipcode.com | |
| 24 Thomastown Road | |
| Dun Laoghaire | |
| Dublin | |
| IE | |
| Phone: | +353 1 2350 424 |
| EMail: | eamon.otuathail@clipcode.com |
| URI: | http://www.clipcode.com/ |
| Marshall T. Rose | |
| Dover Beach Consulting, Inc. | |
| POB 255268 | |
| Sacramento, CA 95865-5268 | |
| US | |
| Phone: | +1 916 483 8878 |
| EMail: | mrose@dbc.mtview.ca.us |
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The authors gratefully acknowledge the contributions of: Christopher Ferris, Huston Franklin, Alexey Melnikov, Bill Mills, and Roy T. Fielding.
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The IANA has registered the profile specified in Registration: The SOAP Profile, and selected an IANA-specific URI, e.g.,
http://iana.org/beep/soap
The IANA has registered "soap.beep" and "soap.beeps" as URL schemes, as specified in Registration: The soap.beep URL Scheme and Registration: The soap.beeps URL Scheme, respectively.
The IANA has also registered "SOAP over BEEP" as a TCP port number, as specified in Registration: The System (Well-Known) TCP port number for SOAP over BEEP.
Finally, the IANA maintains a list of SOAP profile features, c.f., SOAP Profile Feature Registration Template. The IESG is responsible for assigning a designated expert to review the specification prior to the IANA making the assignment. Prior to contacting the IESG, developers of SOAP profile features must use the mailing list beepwg@lists.beepcore.org to solicit commentary.
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Copyright (C) The Internet Society (2002). All Rights Reserved.
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