Basic Profile - Version 1.2 (BdAD)

This document defines the WS-I Basic Profile 1.2, consisting of a set of non-proprietary Web services specifications, along with clarifications, refinements, interpretations and amplifications of those specifications which promote interoperability

Status of this Document

This document is a Board Approval Draft; it has been approved for publication by the Working Group, and is submitted for consideration by the Board of Directors, and for public comment. It is a work in progress, and should not be considered as final; other documents may supersede this document.

Notice

The material contained herein is not a license, either expressly or impliedly, to any intellectual property owned or controlled by any of the authors or developers of this material or WS-I. The material contained herein is provided on an "AS IS" basis and to the maximum extent permitted by applicable law, this material is provided AS IS AND WITH ALL FAULTS, and the authors and developers of this material and WS-I hereby disclaim all other warranties and conditions, either express, implied or statutory, including, but not limited to, any (if any) implied warranties, duties or conditions of merchantability, of fitness for a particular purpose, of accuracy or completeness of responses, of results, of workmanlike effort, of lack of viruses, and of lack of negligence. ALSO, THERE IS NO WARRANTY OR CONDITION OF TITLE, QUIET ENJOYMENT, QUIET POSSESSION, CORRESPONDENCE TO DESCRIPTION OR NON-INFRINGEMENT WITH REGARD TO THIS MATERIAL.

IN NO EVENT WILL ANY AUTHOR OR DEVELOPER OF THIS MATERIAL OR WS-I BE LIABLE TO ANY OTHER PARTY FOR THE COST OF PROCURING SUBSTITUTE GOODS OR SERVICES, LOST PROFITS, LOSS OF USE, LOSS OF DATA, OR ANY INCIDENTAL, CONSEQUENTIAL, DIRECT, INDIRECT, OR SPECIAL DAMAGES WHETHER UNDER CONTRACT, TORT, WARRANTY, OR OTHERWISE, ARISING IN ANY WAY OUT OF THIS OR ANY OTHER AGREEMENT RELATING TO THIS MATERIAL, WHETHER OR NOT SUCH PARTY HAD ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES.

Feedback

The Web Services-Interoperability Organization (WS-I) would like to receive input, suggestions and other feedback ("Feedback") on this work from a wide variety of industry participants to improve its quality over time.

By sending email, or otherwise communicating with WS-I, you (on behalf of yourself if you are an individual, and your company if you are providing Feedback on behalf of the company) will be deemed to have granted to WS-I, the members of WS-I, and other parties that have access to your Feedback, a non-exclusive, non-transferable, worldwide, perpetual, irrevocable, royalty-free license to use, disclose, copy, license, modify, sublicense or otherwise distribute and exploit in any manner whatsoever the Feedback you provide regarding the work. You acknowledge that you have no expectation of confidentiality with respect to any Feedback you provide. You represent and warrant that you have rights to provide this Feedback, and if you are providing Feedback on behalf of a company, you represent and warrant that you have the rights to provide Feedback on behalf of your company. You also acknowledge that WS-I is not required to review, discuss, use, consider or in any way incorporate your Feedback into future versions of its work. If WS-I does incorporate some or all of your Feedback in a future version of the work, it may, but is not obligated to include your name (or, if you are identified as acting on behalf of your company, the name of your company) on a list of contributors to the work. If the foregoing is not acceptable to you and any company on whose behalf you are acting, please do not provide any Feedback.

1. Introduction

This document defines the WS-I Basic Profile 1.2 (hereafter, "Profile"), consisting of a set of non-proprietary Web services specifications, along with clarifications, refinements, interpretations and amplifications of those specifications which promote interoperability.

Section 1 introduces the Profile, and explains its relationships to other profiles.

Section 2, "Profile Conformance," explains what it means to be conformant to the Profile.

Each subsequent section addresses a component of the Profile, and consists of two parts; an overview detailing the component specifications and their extensibility points, followed by subsections that address individual parts of the component specifications. Note that there is no relationship between the section numbers in this document and those in the referenced specifications.

1.1 Relationships to Other Profiles

This Profile is derived from the Basic Profile 1.1 by incorporating any errata to date and including those requirements related to the serialization of envelopes and their representation in messages from the Simple SOAP Binding Profile 1.0.

This Profile is NOT intended to be composed with the Simple SOAP Binding Profile 1.0. The Attachments Profile 1.0 adds support for SOAP with Attachments, and is intended to be used in combination with this Profile.

1.2 Guiding Principles

The Profile was developed according to a set of principles that, together, form the philosophy of the Profile, as it relates to bringing about interoperability. This section documents these guidelines.

1.3 Compatibility with Basic Profile 1.1

There are a few requirements in the Basic Profile 1.2 that may present compatibility issues with clients, services and their artifacts that have been engineered for Basic Profile 1.1 conformance. However, in general, the Basic Profile WG members have tried to preserve as much forwards and backwards compatibility with the Basic Profile 1.1 as possible so as not to disenfranchise clients, services and their artifacts that have been deployed in conformance with the Basic Profile 1.1.

We use the term 'backward compatible' to mean that an artifact, client or service that is conformant to the Basic Profile 1.1 will behave consistently with an implementation that is conformant with the Basic Profile 1.2. We use the term 'forward compatible' to mean that an artifact, client or service that is conformant with the Basic Profile 1.2 specification will be consistent with that of an implementation that is conformant with the Basic Profile 1.1.

We have attempted to capture all known potential backwards and forwards compatibility issues below:

As noted above, some requirements may present issues of a forward or backward compatible nature with previously published versions of the profile. For convenience, such requirements and associated definitions are annotated in the following manner: Compat

1.4 Notational Conventions

The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC2119.

Normative statements of requirements in the Profile (i.e., those impacting conformance, as outlined in "Conformance Requirements") are presented in the following manner:

where "nnnn" is replaced by a number that is unique among the requirements in the Profile, thereby forming a unique requirement identifier.

Requirement identifiers can be considered to be namespace qualified, in such a way as to be compatible with QNames from Namespaces in XML. If there is no explicit namespace prefix on a requirement's identifier (e.g., "R9999" as opposed to "bp10:R9999"), it should be interpreted as being in the namespace identified by the conformance URI of the document section it occurs in. If it is qualified, the prefix should be interpreted according to the namespace mappings in effect, as documented below.

Some requirements clarify the referenced specification(s), but do not place additional constraints upon implementations. For convenience, clarifications are annotated in the following manner: C

Some requirements are derived from ongoing standardization work on the referenced specification(s). For convenience, such forward-derived statements are annotated in the following manner: xxxx, where "xxxx" is an identifier for the specification (e.g., "WSDL20" for WSDL Version 2.0). Note that because such work was not complete when this document was published, the specification that the requirement is derived from may change; this information is included only as a convenience to implementers.

As noted above, some requirements may present compatibility issues (whether forwards or backwards) with previously published versions of the profile. For convenience, such requirements are annotated in the following manner: Compat

Extensibility points in underlying specifications (see "Conformance Scope") are presented in a similar manner:

where "nnnn" is replaced by a number that is unique among the extensibility points in the Profile. As with requirement statements, extensibility statements can be considered namespace-qualified.

This specification uses a number of namespace prefixes throughout; their associated URIs are listed below. Note that the choice of any namespace prefix is arbitrary and not semantically significant.

1.5 Profile Identification and Versioning

This document is identified by a name (in this case, Basic Profile) and a version number (here, 1.2). Together, they identify a particular profile instance.

Version numbers are composed of a major and minor portion, in the form "major.minor". They can be used to determine the precedence of a profile instance; a higher version number (considering both the major and minor components) indicates that an instance is more recent, and therefore supersedes earlier instances.

Instances of profiles with the same name (e.g., "Example Profile 1.1" and "Example Profile 5.0") address interoperability problems in the same general scope (although some developments may require the exact scope of a profile to change between instances).

One can also use this information to determine whether two instances of a profile are backwards-compatible; that is, whether one can assume that conformance to an earlier profile instance implies conformance to a later one. Profile instances with the same name and major version number (e.g., "Example Profile 1.0" and "Example Profile 1.1") MAY be considered compatible. Note that this does not imply anything about compatibility in the other direction; that is, one cannot assume that conformance with a later profile instance implies conformance to an earlier one.

2 Profile Conformance

Conformance to the Profile is defined by adherence to the set of requirements defined for a specific target, within the scope of the Profile. This section explains these terms and describes how conformance is defined and used.

2.1 Conformance Requirements

Requirements state the criteria for conformance to the Profile. They typically refer to an existing specification and embody refinements, amplifications, interpretations and clarifications to it in order to improve interoperability. All requirements in the Profile are considered normative, and those in the specifications it references that are in-scope (see "Conformance Scope") should likewise be considered normative. When requirements in the Profile and its referenced specifications contradict each other, the Profile's requirements take precedence for purposes of Profile conformance.

Requirement levels, using RFC2119 language (e.g., MUST, MAY, SHOULD) indicate the nature of the requirement and its impact on conformance. Each requirement is individually identified (e.g., R9999) for convenience.

This requirement is identified by "R9999", applies to the target WIDGET (see below), and places a conditional requirement upon widgets; i.e., although this requirement must be met to maintain conformance in most cases, there are some situations where there may be valid reasons for it not being met (which are explained in the requirement itself, or in its accompanying text).

Each requirement statement contains exactly one requirement level keyword (e.g., "MUST") and one conformance target keyword (e.g., "MESSAGE"). The conformance target keyword appears in bold text (e.g. "MESSAGE"). Other conformance targets appearing in non-bold text are being used strictly for their definition and NOT as a conformance target. Additional text may be included to illuminate a requirement or group of requirements (e.g., rationale and examples); however, prose surrounding requirement statements must not be considered in determining conformance.

Definitions of terms in the Profile are considered authoritative for the purposes of determining conformance.

None of the requirements in the Profile, regardless of their conformance level, should be interpreted as limiting the ability of an otherwise conforming implementation to apply security countermeasures in response to a real or perceived threat (e.g., a denial of service attack).

2.2 Conformance Targets

Conformance targets identify what artifacts (e.g., SOAP message, WSDL description, UDDI registry data) or parties (e.g., SOAP processor, end user) requirements apply to.

This allows for the definition of conformance in different contexts, to assure unambiguous interpretation of the applicability of requirements, and to allow conformance testing of artifacts (e.g., SOAP messages and WSDL descriptions) and the behavior of various parties to a Web service (e.g., clients and service instances).

Requirements' conformance targets are physical artifacts wherever possible, to simplify testing and avoid ambiguity.

2.3 Conformance Scope

The scope of the Profile delineates the technologies that it addresses; in other words, the Profile only attempts to improve interoperability within its own scope. Generally, the Profile's scope is bounded by the specifications referenced by it.

The Profile's scope is further refined by extensibility points. Referenced specifications often provide extension mechanisms and unspecified or open-ended configuration parameters; when identified in the Profile as an extensibility point, such a mechanism or parameter is outside the scope of the Profile, and its use or non-use is not relevant to conformance.

Note that the Profile may still place requirements on the use of an extensibility point. Also, specific uses of extensibility points may be further restricted by other profiles, to improve interoperability when used in conjunction with the Profile.

Because the use of extensibility points may impair interoperability, their use should be negotiated or documented in some fashion by the parties to a Web service; for example, this could take the form of an out-of-band agreement.

The Profile's scope is defined by the referenced specifications in Appendix A, as refined by the extensibility points in Appendix B.

2.4 Claiming Conformance

Claims of conformance to the Profile can be made using the following mechanisms, as described in Conformance Claim Attachment Mechanisms, when the applicable Profile requirements associated with the listed targets have been met:

The conformance claim URI for this Profile is "http://ws-i.org/profiles/basic/1.2" .

3. Messaging

This section of the Profile incorporates the following specifications by reference, and defines extensibility points within them:

3.1 Message Serialization

The profile is intended to compose with mechanisms currently under development to describe whether messages are encoded as SIMPLE_SOAP_MESSAGEs or XOP_ENCODED_MESSAGEs. As such it does not mandate that both of those encodings be supported for any given operation. Indeed, neither of these encodings need be supported if an alternate encoding such as that described in the Attachments Profile 1.0 is used.

SOAP 1.1 defines an XML structure for transmitting messages, the envelope. The Profile places the following constraints on the use and serialization of the soap:Envelope element and its content:

This section of the Profile incorporates the following specifications by reference:

3.1.1 XML Envelope Serialization

R9701 An ENVELOPE MUST be serialized as XML 1.0.

3.1.2 Unicode BOMs

XML 1.0 allows UTF-8 encoding to include a BOM; therefore, receivers of envelopes must be prepared to accept them. The BOM is mandatory for XML encoded as UTF-16.

R4001 A RECEIVER MUST accept envelopes that include the Unicode Byte Order Mark (BOM).C

3.1.3 XML Declarations

Presence or absence of an XML declaration does not affect interoperability. Certain implementations might always precede their XML serialization with the XML declaration.

R1010 A RECEIVER MUST accept messages with envelopes that contain an XML Declaration. C

3.1.4 Character Encodings

The Profile requires XML processors to support the "UTF-8" and "UTF-16" character encodings, in order to aid interoperability.

As a consequence of this, in conjunction with SOAP 1.1's requirement to use the "text/xml" media type (which has a default character encoding of "us-ascii") on envelopes, the "charset" parameter must always be present on the envelope's content-type. A further consequence of this is that the encoding pseudo-attribute of XML declaration within the message is always ignored, in accordance with the requirements of both XML 1.0 and RFC3023, "XML Media Types".

The "charset" parameter of Content-Type HTTP header field must be used to determine the correct character encoding of the message, in absence of a "charset" parameter, the default value for charset (which is "us-ascii") must be used.

R1012 An ENVELOPE MUST be serialized using either UTF-8 or UTF-16 character encoding.

R1018 A SIMPLE_SOAP_MESSAGE MUST indicate the correct character encoding, using the "charset" parameter. C

R1019 A RECEIVER MUST ignore the encoding pseudo-attribute of the envelope's XML declaration.

3.2 SOAP Envelopes

This section of the Profile incorporates the following specifications by reference:

SOAP 1.1 defines a structure for composing messages, the envelope. The Profile mandates the use of that structure, and places the following constraints on its use:

3.2.1 SOAP Envelope Structure

R9980 An ENVELOPE MUST conform to the structure specified in SOAP 1.1 Section 4, "SOAP Envelope" (subject to amendment by the Profile).

R9981 An ENVELOPE MUST have exactly zero or one child elements of the soap:Body element.

While the combination of R2201 and R2210 (below) clearly imply that there may be at most one child element of the soap:Body, there is no explicit requirement in the Profile that articulates this constraint, leading to some confusion.

3.2.2 SOAP Envelope Namespace

SOAP 1.1 states that an envelope with a document element whose namespace name is other than "http://schemas.xmlsoap.org/soap/envelope/" should be discarded. The Profile requires that a fault be generated instead, to assure unambiguous operation.

R1015 A RECEIVER MUST generate a fault if they encounter an envelope whose document element is not soap:Envelope.

3.2.3 SOAP Body Namespace Qualification

The use of unqualified element names may cause naming conflicts, therefore qualified names must be used for the children of soap:Body.

R1014 The children of the soap:Body element in an ENVELOPE MUST be namespace qualified.

3.2.4 Disallowed Constructs

XML DTDs and PIs may introduce security vulnerabilities, processing overhead and semantic ambiguity when used in envelopes. As a result, certain XML constructs are disallowed by section 3 of SOAP 1.1.

Although published errata NE05 (see http://www.w3.org/XML/xml-names-19990114-errata) allows the namespace declaration xmlns:xml="http://www.w3.org/XML/1998/namespace" to appear, some older processors considered such a declaration to be an error. These requirements ensure that conformant artifacts have the broadest interoperability possible.

R1008 An ENVELOPE MUST NOT contain a Document Type Declaration. C

R1009 An ENVELOPE MUST NOT contain Processing Instructions. C

R1033 An ENVELOPE SHOULD NOT contain the namespace declaration xmlns:xml="http://www.w3.org/XML/1998/namespace". C

3.2.5 SOAP Trailers

The interpretation of sibling elements following the soap:Body element is unclear. Therefore, such elements are disallowed.

R1011 An ENVELOPE MUST NOT have any element children of soap:Envelope following the soap:Body element.

This requirement clarifies a mismatch between the SOAP 1.1 specification and the SOAP 1.1 XML Schema.

INCORRECT:

<soap:Envelope xmlns:soap='http://schemas.xmlsoap.org/soap/envelope/' >
  <soap:Body>
    <p:Process xmlns:p='http://example.org/Operations' />
  </soap:Body>
  <m:Data xmlns:m='http://example.org/information' >
  Here is some data with the message
  </m:Data>
</soap:Envelope>

CORRECT:

<soap:Envelope xmlns:soap='http://schemas.xmlsoap.org/soap/envelope/' >
  <soap:Body>
    <p:Process xmlns:p='http://example.org/Operations' >
	  <m:Data xmlns:m='http://example.org/information' >
  Here is some data with the message
      </m:Data>
    </p:Process>
  </soap:Body>
</soap:Envelope>

3.2.6 SOAP encodingStyle Attribute

The soap:encodingStyle attribute is used to indicate the use of a particular scheme in the encoding of data into XML. However, this introduces complexity, as this function can also be served by the use of XML Namespaces. As a result, the Profile prefers the use of literal, non-encoded XML.

R1005 An ENVELOPE MUST NOT contain soap:encodingStyle attributes on any of the elements whose namespace name is "http://schemas.xmlsoap.org/soap/envelope/".

R1006 An ENVELOPE MUST NOT contain soap:encodingStyle attributes on any element that is a child of soap:Body.

R1007 An ENVELOPE described in an rpc-literal binding MUST NOT contain soap:encodingStyle attribute on any element that is a grandchild of soap:Body.

3.2.7 SOAP mustUnderstand Attribute

The soap:mustUnderstand attribute has a restricted type of "xsd:boolean" that takes only "0" or "1". Therefore, only those two values are allowed.

R1013 An ENVELOPE containing a soap:mustUnderstand attribute MUST only use the lexical forms "0" and "1". C

3.2.8 xsi:type Attributes

In many cases, senders and receivers will share some form of type information related to the envelopes being exchanged.

R1017 A RECEIVER MUST NOT mandate the use of the xsi:type attribute in envelopes except as required in order to indicate a derived type (see XML Schema Part 1: Structures, Section 2.6.1).

3.2.9 SOAP1.1 attributes on SOAP1.1 elements

R1032 The soap:Envelope, soap:Header, and soap:Body elements in an ENVELOPE MUST NOT have attributes in the namespace "http://schemas.xmlsoap.org/soap/envelope/".

3.3 SOAP Processing Model

This section of the Profile incorporates the following specifications by reference:

SOAP 1.1 defines a model for the processing of envelopes. In particular, it defines rules for the processing of header blocks and the envelope body. It also defines rules related to generation of faults. The Profile places the following constraints on the processing model:

3.3.1 Mandatory Headers

SOAP 1.1's processing model is underspecified with respect to the processing of mandatory header blocks. Mandatory header blocks are those children of the soap:Header element bearing a soap:mustUnderstand attribute with a value of "1".

R1025 A RECEIVER MUST handle envelopes in such a way that it appears that all checking of mandatory header blocks is performed before any actual processing. SOAP12

This requirement guarantees that no undesirable side effects will occur as a result of noticing a mandatory header block after processing other parts of the message.

3.3.2 Generating mustUnderstand Faults

The Profile requires that receivers generate a fault when they encounter header blocks targeted at them, that they do not understand.

R1027 A RECEIVER MUST generate a "soap:MustUnderstand" fault when an envelope contains a mandatory header block (i.e., one that has a soap:mustUnderstand attribute with the value "1") targeted at the receiver (via soap:actor) that the receiver does not understand.SOAP12

3.3.3 SOAP Fault Processing

When a fault is generated, no further processing should be performed. In request-response exchanges, a fault message will be transmitted to the sender of the request, and some application level error will be flagged to the user.

Both SOAP and this Profile use the term 'generate' to denote the creation of a SOAP Fault. It is important to realize that generation of a Fault is distinct from its transmission, which in some cases is not required.

R1028 When a fault is generated by a RECEIVER, further processing SHOULD NOT be performed on the SOAP envelope aside from that which is necessary to rollback, or compensate for, any effects of processing the envelope prior to the generation of the fault. SOAP12

R1029 Where the normal outcome of processing a SOAP envelope would have resulted in the transmission of a SOAP response, but rather a fault is generated instead, a RECEIVER MUST transmit a fault in place of the response.

R1030 A RECEIVER that generates a fault SHOULD notify the end user that a fault has been generated when practical, by whatever means is deemed appropriate to the circumstance.

Note that there may be valid reasons (such as security considerations) why a fault may not be transmitted.

3.4 SOAP Faults

3.4.1 Identifying SOAP Faults

Some consumer implementations erroneously use only the HTTP status code to determine the presence of a Fault. Because there are situations where the Web infrastructure changes the HTTP status code, and for general reliability, the Profile requires that they examine the envelope. A Fault is an envelope that has a single child element of the soap:Body element, that element being a soap:Fault element.

R1107 A RECEIVER MUST interpret a SOAP message as a Fault when the soap:Body of the message has a single soap:Fault child.

3.4.2 SOAP Fault Structure

The Profile restricts the content of the soap:Fault element to those elements explicitly described in SOAP 1.1.

R1000 When an ENVELOPE is a Fault, the soap:Fault element MUST NOT have element children other than faultcode, faultstring, faultactor and detail.

INCORRECT:

<soap:Fault xmlns:soap='http://schemas.xmlsoap.org/soap/envelope/' >
  <faultcode>soap:Client</faultcode>
  <faultstring>Invalid message format</faultstring>
  <faultactor>http://example.org/someactor</faultactor>
  <detail>There were <b>lots</b> of elements in the message 
      that I did not understand
  </detail>
  <m:Exception xmlns:m='http://example.org/faults/exceptions' >
    <m:ExceptionType>Severe</m:ExceptionType>
  </m:Exception>
</soap:Fault>

CORRECT:

<soap:Fault xmlns:soap='http://schemas.xmlsoap.org/soap/envelope/' >
  <faultcode>soap:Client</faultcode>
  <faultstring>Invalid message format</faultstring>
  <faultactor>http://example.org/someactor</faultactor>
  <detail>
     <m:msg xmlns:m='http://example.org/faults/exceptions'>
         There were <b>lots</b> of elements in 
         the message that I did not understand
     </m:msg>
     <m:Exception xmlns:m='http://example.org/faults/exceptions'>
       <m:ExceptionType>Severe</m:ExceptionType>
     </m:Exception>
   </detail>
</soap:Fault>

3.4.3 SOAP Fault Namespace Qualification

The children of the soap:Fault element are local to that element, therefore namespace qualification is unnecessary.

R1001 When an ENVELOPE is a Fault, the element children of the soap:Fault element MUST be unqualified.

INCORRECT:

<soap:Fault xmlns:soap='http://schemas.xmlsoap.org/soap/envelope/' >
  <soap:faultcode>soap:Client</soap:faultcode>
  <soap:faultstring>Invalid message format</soap:faultstring>
  <soap:faultactor>http://example.org/someactor</soap:faultactor>
  <soap:detail>
      <m:msg xmlns:m='http://example.org/faults/exceptions'>
          There were <b>lots</b> of elements in the message that 
          I did not understand
      </m:msg>
  </soap:detail>
</soap:Fault>

CORRECT:

<soap:Fault xmlns:soap='http://schemas.xmlsoap.org/soap/envelope/' 
			xmlns='' >
  <faultcode>soap:Client</faultcode>
  <faultstring>Invalid message format</faultstring>
  <faultactor>http://example.org/someactor</faultactor>
  <detail>
      <m:msg xmlns:m='http://example.org/faults/exceptions'>
          There were <b>lots</b> of elements in the message that 
          I did not understand
      </m:msg>
  </detail>
</soap:Fault>

3.4.4 SOAP Fault Extensibility

For extensibility, additional attributes are allowed to appear on the detail element and additional elements are allowed to appear as children of the detail element.

R1002 A RECEIVER MUST accept faults that have any number of elements, including zero, appearing as children of the detail element. Such children can be qualified or unqualified.

R1003 A RECEIVER MUST accept faults that have any number of qualified or unqualified attributes, including zero, appearing on the detail element. The namespace of qualified attributes can be anything other than "http://schemas.xmlsoap.org/soap/envelope/".

3.4.5 SOAP Fault Language

Faultstrings are human-readable indications of the nature of a fault. As such, they may be in a particular language, and therefore the xml:lang attribute can be used to indicate the language of the faultstring.

Note that this requirement conflicts with the schema for SOAP appearing at its namespace URL. A schema without conflicts can be found at "http://ws-i.org/profiles/basic/1.1/soap-envelope-2004-01-21.xsd".

R1016 A RECEIVER MUST accept faults that carry an xml:lang attribute on the faultstring element.

3.4.6 SOAP Custom Fault Codes

SOAP 1.1 allows custom fault codes to appear inside the faultcode element, through the use of the "dot" notation.

Use of this mechanism to extend the meaning of the SOAP 1.1-defined fault codes can lead to namespace collision. Therefore, its use should be avoided, as doing so may cause interoperability issues when the same names are used in the right-hand side of the "." (dot) to convey different meaning.

Instead, the Profile encourages the use of the fault codes defined in SOAP 1.1, along with additional information in the detail element to convey the nature of the fault.

Alternatively, it is acceptable to define custom fault codes in a namespace controlled by the specifying authority.

A number of specifications have already defined custom fault codes using the "." (dot) notation. Despite this, their use in future specifications is discouraged.

R1004 When an ENVELOPE contains a faultcode element, the content of that element SHOULD be either one of the fault codes defined in SOAP 1.1 (supplying additional information if necessary in the detail element), or a Qname whose namespace is controlled by the fault's specifying authority (in that order of preference).

R1031 When an ENVELOPE contains a faultcode element the content of that element SHOULD NOT use of the SOAP 1.1 "dot" notation to refine the meaning of the fault.

It is recommended that applications that require custom fault codes either use the SOAP1.1 defined fault codes and supply additional information in the detail element, or that they define these codes in a namespace that is controlled by the specifying authority.

INCORRECT:

<soap:Fault xmlns:soap='http://schemas.xmlsoap.org/soap/envelope/'
            xmlns:c='http://example.org/faultcodes' >
  <faultcode>soap:Server.ProcessingError</faultcode>
  <faultstring>An error occurred while processing the message
  </faultstring>
</soap:Fault>

CORRECT:

<soap:Fault xmlns:soap='http://schemas.xmlsoap.org/soap/envelope/'
            xmlns:c='http://example.org/faultcodes' >
  <faultcode>c:ProcessingError</faultcode>
  <faultstring>An error occured while processing the message
  </faultstring>
</soap:Fault>

CORRECT:

<soap:Fault xmlns:soap='http://schemas.xmlsoap.org/soap/envelope/' >
  <faultcode>soap:Server</faultcode>
  <faultstring>An error occured while processing the message
  </faultstring>
</soap:Fault>

3.4.7 SOAP Defined Faults Action URI

WS-Addressing provides the URI http://www.w3.org/2005/08/addressing/soap/fault for "SOAP defined faults". However, it only recommends, rather than mandate its use for the SOAP1.1 defined MustUnderstand and VersionMismatch faults. This Profile mandates the use of the WS-Addressing defined wsa:Action value for SOAP1.1 defined MustUnderstand and VersionMismatch faults, for interoperability.

R1035 An ENVELOPE MUST use the http://www.w3.org/2005/08/addressing/soap/fault URI as the value for the wsa:Action element when present, for either of the SOAP1.1 defined VersionMismatch and MustUnderstand faults.

3.4.8 SOAP MustUnderstand or VersionMismatch fault Transmission

WS-Addressing does not violate the SOAP processing model, but in fact plays within the rules defined by the SOAP processing model. Thus, regardless of the value of the wsa:ReplyTo or wsa:FaultTo, should a message generate either a SOAP MustUnderstand or VersionMismatch fault, that fault SHOULD be transmitted to the sender of the message generating such fault on the HTTP response message.

Note that this is a SHOULD requirement, as there may be valid reasons why the fault is not transmitted at all.

R1036 A RECEIVER that receives a SOAP envelope that generates either a SOAP MustUnderstand or VersionMismatch fault SHOULD transmit such a fault on the HTTP response message, regardless of the value of the wsa:ReplyTo or wsa:FaultTo SOAP headers present in the message.

3.5 Use of WS-Addressing MAPs

This section of the Profile incorporates the following specifications by reference:

When using WS-Addressing, the Profile requires conformance to WS-Addressing 1.0 - Core, WS-Addressing - SOAP Binding and WS-Addressing WSDL Binding, Section 5.1 and places the following additional constraints.

3.5.1 Use of wsa:Action and WS-Addressing WSDL Binding

WS-Addressing 1.0 - WSDL Binding, Section 5.1 defines additional constraints on the cardinality of WS-Adressing Message Addressing Properties defined in WS-Addressing 1.0 - Core. These constraints are defined for every message involved in WSDL 1.1 transmission primitives. The Profile requires conformance to this section when WS-Addressing is used in conjunction with WSDL 1.1 description.

R1142 An ENVELOPE that includes a wsa:Action SOAP header block and which is described using WSDL 1.1 description MUST conform to WS-Addressing WSDL Binding, Section 5.1. C

3.5.2 Understanding WS-Addressing SOAP Header Blocks

WS-Addressing 1.0 -- SOAP Binding defines multiple SOAP header blocks (wsa:To, wsa:From, wsa:ReplyTo, wsa:FaultTo, wsa:Action, wsa:MessageID, and wsa:RelatesTo). These SOAP header blocks are part of the same module. A SOAP node that conforms to the Profile understands all of these SOAP header blocks (when it understands WS-Addressing) or none at all (when it does not understand WS-Addressing).

R1143 When a message contains multiple WS-Addressing SOAP header blocks with at least one of those header blocks containing a soap:mustUnderstand='1' attribute, then a RECEIVER MUST understand all the WS-Addressing SOAP header blocks or none of them. CCompat

3.5.3 Valid Range of Values for SOAPAction When WS-Addressing is Used

There may be some confusion as regards to the range of valid values for SOAPAction when WS-Addressing is used, given the SOAP 1.1 specification permits the use of relative URIs.

When composed with WS-Addressing, the valid range of values of SOAPAction should be limited to an absolute URI that matches the value specified for wsa:Action. The empty string ("") is also allowed for special cases such as security considerations. For example, when the wsa:Action header is encrypted, set SOAPAction to "" maybe a way to avoid leakage.

R1144 When wsa:Action MAP is present in an envelope, the containing MESSAGE MUST specify a SOAPAction HTTP header with either a value that is an absolute URI that has the same value as the value of the wsa:Action MAP, or a value of "" (empty string).

3.6 Use of SOAP in HTTP

This section of the Profile incorporates the following specifications by reference:

SOAP 1.1 defines a single protocol binding, for HTTP. The Profile mandates the use of that binding, and places the following constraints on its use:

3.6.1 HTTP Protocol Binding

Several versions of HTTP are defined. HTTP/1.1 has performance advantages, and is more clearly specified than HTTP/1.0.

R1141 A MESSAGE MUST be sent using either HTTP/1.1 or HTTP/1.0.

R1140 A MESSAGE SHOULD be sent using HTTP/1.1.

Note that support for HTTP/1.0 is implied in HTTP/1.1, and that intermediaries may change the version of a message; for more information about HTTP versioning, see RFC2145, "Use and Interpretation of HTTP Version Numbers."

3.6.2 HTTP Methods and Extensions

The SOAP1.1 specification defined its HTTP binding such that two possible methods could be used, the HTTP POST method and the HTTP Extension Framework's M-POST method. The Profile requires that only the HTTP POST method be used and precludes use of the HTTP Extension Framework.

R1132 A HTTP request MESSAGE MUST use the HTTP POST method.

R1108 A MESSAGE MUST NOT use the HTTP Extension Framework (RFC2774).

The HTTP Extension Framework is an experimental mechanism for extending HTTP in a modular fashion. Because it is not deployed widely and also because its benefits to the use of SOAP are questionable, the Profile does not allow its use.

3.6.3 SOAPAction HTTP Header

Testing has demonstrated that requiring the SOAPAction HTTP header field-value to be quoted increases interoperability of implementations. Even though HTTP allows unquoted header field-values, some SOAP implementations require that they be quoted.

SOAPAction is purely a hint to processors. All vital information regarding the intent of a message is carried in soap:Envelope.

R1109 The value of the SOAPAction HTTP header field in a HTTP request MESSAGE MUST be a quoted string. C

R1119 A RECEIVER MAY respond with a fault if the value of the SOAPAction HTTP header field in a message is not quoted. C

R1127 A RECEIVER MUST NOT rely on the value of the SOAPAction HTTP header to correctly process the message.SOAP12

CORRECT:

A WSDL Description that has:

<soapbind:operation soapAction="foo" />

results in a message with a SOAPAction HTTP header field of:

SOAPAction: "foo"

CORRECT:

A WSDL Description that has:

<soapbind:operation />

<soapbind:operation soapAction="" />

results in a message with a corresponding SOAPAction HTTP header field as follows:

SOAPAction: ""

3.6.4 HTTP Success Status Codes

HTTP uses the 2xx series of status codes to communicate success. In particular, 200 is the default for successful messages, but 202 can be used to indicate that a message has been submitted for processing. Additionally, other 2xx status codes may be appropriate, depending on the nature of the HTTP interaction.

R1124 An INSTANCE MUST use a 2xx HTTP status code on a response message that indicates the successful outcome of a HTTP request.

R1111 An INSTANCE SHOULD use a "200 OK" HTTP status code on a response message that contains an envelope that is not a fault.

R1112 An INSTANCE SHOULD use either a "200 OK" or "202 Accepted" HTTP status code for a response message that does not contain a SOAP envelope but indicates the successful outcome of a HTTP request.

Despite the fact that the HTTP 1.1 assigns different meanings to response status codes "200" and "202", in the context of the Profile they should be considered equivalent by the initiator of the request. The Profile accepts both status codes because some SOAP implementations have little control over the HTTP protocol implementation and cannot control which of these response status codes is sent.

3.6.5 HTTP Redirect Status Codes

There are interoperability problems with using many of the HTTP redirect status codes, generally surrounding whether to use the original method, or GET. The Profile mandates "307 Temporary Redirect", which has the semantic of redirection with the same HTTP method, as the correct status code for redirection. For more information, see the 3xx status code descriptions in RFC2616.

R1130 An INSTANCE MUST use the "307 Temporary Redirect" HTTP status code when redirecting a request to a different endpoint.

R1131 A CONSUMER MAY automatically redirect a request when it encounters a "307 Temporary Redirect" HTTP status code in a response.

RFC2616 notes that user-agents should not automatically redirect requests; however, this requirement was aimed at browsers, not automated processes (which many Web services will be). Therefore, the Profile allows, but does not require, consumers to automatically follow redirections.

3.6.6 HTTP Client Error Status Codes

HTTP uses the 4xx series of status codes to indicate failure due to a client error. Although there are a number of situations that may result in one of these codes, the Profile highlights those when the HTTP request does not have the proper media type, and when the anticipated method ("POST") is not used.

R1125 An INSTANCE MUST use a 4xx HTTP status code for a response that indicates a problem with the format of a request.

R1113 An INSTANCE SHOULD use a "400 Bad Request" HTTP status code, if a HTTP request message is malformed.

R1114 An INSTANCE SHOULD use a "405 Method not Allowed" HTTP status code if a HTTP request message's method is not "POST".

R1115 An INSTANCE SHOULD use a "415 Unsupported Media Type" HTTP status code if a HTTP request message's Content-Type header field-value is not permitted by its WSDL description.

Note that these requirements do not force an instance to respond to requests. In some cases, such as Denial of Service attacks, an instance may choose to ignore requests.

Also note that SOAP 1.1, Section 6.2 requires that SOAP Fault can only be returned with HTTP 500 "Internal Server Error" code. This profile doesn't change that requirement. When HTTP 4xx error status code is used, the response message should not contain a SOAP Fault.

Basic Profile Version 1.2

Board Approval Draft

2007-03-28

Abstract

Status of this Document

Notice

Feedback

Table of Contents

1. Introduction

1.1 Relationships to Other Profiles

1.2 Guiding Principles

1.3 Compatibility with Basic Profile 1.1

1.4 Notational Conventions

1.5 Profile Identification and Versioning

2 Profile Conformance

2.1 Conformance Requirements

2.2 Conformance Targets

2.3 Conformance Scope

2.4 Claiming Conformance

3. Messaging

3.1 Message Serialization

3.1.1 XML Envelope Serialization

3.1.2 Unicode BOMs

3.1.3 XML Declarations

3.1.4 Character Encodings

3.2 SOAP Envelopes

3.2.1 SOAP Envelope Structure

3.2.2 SOAP Envelope Namespace

3.2.3 SOAP Body Namespace Qualification

3.2.4 Disallowed Constructs

3.2.5 SOAP Trailers

3.2.6 SOAP encodingStyle Attribute

3.2.7 SOAP mustUnderstand Attribute

3.2.8 xsi:type Attributes

3.2.9 SOAP1.1 attributes on SOAP1.1 elements

3.3 SOAP Processing Model

3.3.1 Mandatory Headers

3.3.2 Generating mustUnderstand Faults

3.3.3 SOAP Fault Processing

3.4 SOAP Faults

3.4.1 Identifying SOAP Faults

3.4.2 SOAP Fault Structure

3.4.3 SOAP Fault Namespace Qualification

3.4.4 SOAP Fault Extensibility

3.4.5 SOAP Fault Language

3.4.6 SOAP Custom Fault Codes

3.4.7 SOAP Defined Faults Action URI

3.4.8 SOAP MustUnderstand or VersionMismatch fault Transmission

3.5 Use of WS-Addressing MAPs

3.5.1 Use of wsa:Action and WS-Addressing WSDL Binding

3.5.2 Understanding WS-Addressing SOAP Header Blocks

3.5.3 Valid Range of Values for SOAPAction When WS-Addressing is Used

3.6 Use of SOAP in HTTP

3.6.1 HTTP Protocol Binding

3.6.2 HTTP Methods and Extensions

3.6.3 SOAPAction HTTP Header

3.6.4 HTTP Success Status Codes

3.6.5 HTTP Redirect Status Codes

3.6.6 HTTP Client Error Status Codes