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Last modified: September 13, 2010
XML Daily Newslink. Monday, 13 September 2010

A Cover Pages Publication
Provided by OASIS and Sponsor Members
Edited by Robin Cover

This issue of XML Daily Newslink is sponsored by:
Microsoft Corporation

CalWSRest: Restful Web Service Protocol for Calendaring Version 1.0
Michael A. Douglass (ed), CalConnect TC-XML Proposal

Members of the Calendaring and Scheduling Consortium (CalConnect) have published CalWSRest: Restful Web Service Protocol for Calendaring Version 1.0 as a XML Technical Committee (TC-XML) Proposal and have contributed the specification to OASIS via the OASIS Web Services Calendar (WS-Calendar) Technical Committee. The contribution communicated through Dave Thewlis may be incorporated into the OASIS WS-Calendar specification.

The CalConnect document CD1011 describes a RESTful web service for calendar access and update. From the 'Introduction': 'The CalWS protocol is built upon and makes the same assumptions about structure as the CalDAV protocol defined in RFC 4791 and related specifications. It does not require nor assume the WebDAV nor CalDAV protocol but does make use of some of the same elements and structures in the CalDAV XML namespace. Calendar resources, for example events and tasks are stored as named resources (files) inside special collections (folders) known as 'Calendar Collections'. This specification can be looked upon as a layer built on top of CalDAV and defines the basic operations which allow creation, retrieval, update and deletion. In addition, query and freebusy operations are defined to allow efficient, partial retrieval of calendar data. This does not mean that a CalWS service must be built on CalDAV, merely that a degree of conformity is established such that services built in that manner do not have a significant mismatch. It is assumed that some CalWS services will be built without any CalDAV support.

The CalWS protocol is an HTTP based RESTful protocol using a limited set of methods. Each request may be followed by a response containing status information. The following methods are specified in the protocol description: PUT, POST, GET, DELETE. To avoid various issues with certain methods being blocked clients may use the X-HTTP-Method-Override: header to specify the intended operation. A service or resource will have a number of properties which describe the current state of that service or resource. These properties are accessed through a GET on the target resource or service with an HTTP ACCEPT header specifying 'application/xrd+xml'. The following operations are defined by the CalWSRest specification: (1) Retrieval and update of service and resource properties; (2) Creation of a calendar object; (3) Retrieval of a calendar object; (4) Update of a calendar object; (5) Deletion of a calendar object; (6) Query; (7) Free-busy query. Out of scope: Access Control, Provisioning, Copy/Move, Creating Collections, Retrieving collections, or Setting service and resource properties

Properties and link relations: properties and related services and entities are defined by absolute URIs which correspond to the extended relation type defined in 'Web-Linking'; certain of these property URIs correspond to CalDAV preconditions, where each URL is prefixed by the designated relations and properties namespace... Other properties: 'supported-features property' defines the features supported by the target; 'max-attendees-per-instance' defines the maximum number of attendees allowed per event or task; 'max-date-time' defines the maximum date/time allowed on an event or task' 'max-instances' defines the maximum number of instances allowed per event or task; 'created link property' is a date-time value which appears within a link relation describing collections or entities (etc)..."

See also: OASIS WS-Calendar Version 1.0 Working Draft 11

Updated IETF Standards Track Spec for xCal: The XML format for iCalendar
Cyrus Daboo, Mike Douglass, and Steven Lees (eds), IETF Internet Draft

IETF has published a revised version of the specification xCal: The XML format for iCalendar which defines xCal as an XML format for iCalendar data. The purpose of this specification is to define xCal "such that iCalendar data to be converted to XML, and then back to iCalendar, without losing any semantic meaning in the data. Anyone creating XML calendar data according to this specification will know that their data can be converted to a valid iCalendar representation as well." Recent changes in the specification include removal of the 'ordwk' and 'weekday' markup elements from the 'byday' element in a recurrence rule so that the 'byday' element now takes a text value which is the same as the value used in RFC 5545; addition of examples of an iCalendar object converted to xCal; fixing MIME type registration 'xml+calendar corrected'; adding description to XML extension discussing how to handle binary data in XML.

Background: "The iCalendar data format defined in IETF RFC 5545 ('Internet Calendaring and Scheduling Core Object Specification -- iCalendar) is a widely deployed interchange format for calendaring and scheduling data. While many applications and services consume and generate calendar data, iCalendar is a specialized format that requires its own parser/generator. In contrast, XML-based formats are widely used for interoperability between applications, and the many tools that generate, parse, and manipulate XML make it easier to work with than iCalendar.

Two key design considerations in the xCal specification are: (1) Round-tripping (converting an iCalendar instance to XML and back) that will give the same result as the starting point; (2) Preservation of the semantics of the iCalendar data; while a simple consumer can easily browse the calendar data in XML, a full understanding of iCalendar is still required in order to modify and/or fully comprehend the calendar data...

When converting component, property and parameter values from XML into iCalendar, the names should be converted to uppercase. Although iCalendar names are case insensitive, common practice is to keep them all uppercase following the actual definitions in RFC 5545. XML extensions are converted back to iCalendar in one of two ways, depending on whether the extensions are in the iCalendar XML namespace, or in an external namespace. Extensions that are part of the iCalendar XML namespace must have element names that being with 'x-', and will be converted back to the equivalent extension property in iCalendar. For example, the 'x-foo' element will convert to the 'X-FOO' iCalendar property. Extensions that are in a namespace other than the iCalendar XML namespace should be preserved in the iCalendar representation using the designated XML iCalendar property..."

See also: the related OASIS WS-Calendar spec development activity

Trusted Computing Group WG to Create Cloud Computing Security Framework
Ellen Messmer, Network World

The Trusted Computing Group (TCG) has announced the formation of a new working group aimed at publishing an open standards framework for cloud computing security that could serve as a blueprint for service providers, their customers and vendors building security products. Known as the Trusted Multi-Tenant Infrastructure Work Group, there are about 50 TCG members participating, including HP, IBM, AMD, and Microsoft. The group also will receive input from U.S. Defense Department representatives and the U.K. government; TCG has in all about 110 members that have worked over the years on standards-based initiatives in the area of trusted computing, including 'Trusted Network Connect' and the 'Trusted Platform Module'...

The latest plan is intended to put forward a security framework for cloud computing, including private, public and hybrid cloud environments as well as virtualized and non-virtualized ones. The Trusted Multi-Tenant Infrastructure Work Group will make use of existing open standards to define end-to-end security, both virtual and physical, in a cloud-computing environment, including capabilities such as encryption and integrity monitoring... The goal is to create a framework document for cloud-computing security that will not only serve as a baseline for security compliance and auditing, but also might also encourage the introduction of new products..."

From the text of the TCG announcement and FAQ: "The framework will: (1) Help assess the trustworthiness of provider systems; (2) Enable real-time assessment of compliance as part of the provisioning process; (3) Provide implementation guidance; (4) Identify and address gaps in standards to enable trust. The actual framework will consist of policies, best practices, standards and conformance criteria that will be used by product vendors and by integrators and IT users to create and evaluate multi-tenant infrastructure. Multi-tenant infrastructure refers to unrelated users of shared computing infrastructure and is a fundamental characteristic of cloud computing...

TCG has updated its IF-MAP (Metadata Access Protocol) used to enable standardized data sharing among a wide variety of devices and applications, including cloud security. The IF-MAP Metadata Access Protocol is based on a powerful publish/subscribe model. IF-MAP is being used today to support network security applications using equipment from different vendors, and is expected to be used in cloud computing to enable real-time communication among devices including network infrastructure devices and servers. It also has been used to integrate physical security devices, supervisory control and data acquisition (SCADA) networks and unified communications platforms. The updated IF-MAP specification, version 2.0, adds new capabilities to the powerful publish/subscribe client/server protocol, designed to make IF-MAP more directly compatible with existing, vendor-specific approaches. The new specification also makes it easier and faster for different industry groups to use the IF-MAP protocol by separating the base protocol from the metadata definitions that standardize how different types of information are represented..."

See also: the Trusted Computing Group announcement

METS Profile: Checklist and Case for Documenting PREMIS-METS Decisions
Sally Vermaaten, D-Lib Magazine

"Shared metadata practices foster preservation and interoperability in several ways. They facilitate inter-repository exchange, the development of reusable metadata tools, and repository self-assessments and audits. Despite the benefits of shared practices, there has been little convergence on best practices for a widely used metadata strategy, PREMIS in METS. Converging on shared PREMIS-METS strategies would support key interoperability and preservation functions, including inter-repository exchange, tool development, self-assessment of metadata strategies, and identification of trusted digital repositories...

As to PREMIS: 'The Preservation Metadata: Implementation Strategies Working Group', convened by OCLC and RLG, initially developed the PREMIS data dictionary as a specification with the goal of creating an implementable set of "core" preservation metadata elements, with broad applicability within the digital preservation community. Supporting XML schemas allow for implementation of the core metadata element set and are maintained in the Network Development and MARC Standards Office of the Library of Congress. The METS XML schema is a standard for encoding descriptive, administrative, and structural metadata regarding objects within a digital library, expressed using the W3C XML schema language; the METS standard is maintained in the Network Development and MARC Standards Office of the Library of Congress, and is being developed as an initiative of the Digital Library Federation...

This paper proposes documenting PREMIS-METS metadata decisions in METS profiles as a beneficial internal practice and a powerful and efficient way of sharing and comparing metadata strategies and thereby facilitating best practices. The paper then presents a tool to help implementers document PREMIS-METS decisions in a METS profile. This tool is a checklist of 13 key PREMIS-METS issues that a repository should consider documenting in their METS profiles. Each of the 13 issues is illustrated with examples from METS profiles currently registered with the Library of Congress.

Consistently documenting and sharing PREMIS-METS decisions in a central pool of METS profiles is one way that a shared view of PREMIS-METS best practices for particular content types or functions could be reached. The checklist presented in this paper helps implementers document PREMIS-METS decisions in a METS profile; it incorporates information from an analysis of METS profiles registered with the Library of Congress as well as an array of PREMIS-METS resources. By supporting documentation of PREMIS-METS issues in METS registered profiles, this checklist could also support comparisons of metadata strategies and convergence on PREMIS-METS best practices..."

See also: the U.S. Library of Congress standards

W3C XML Security Working Group Publishes Five XML Security Drafts
Staff, W3C Announcement

Members of the W3C XML Security Working Group have published five working drafts. This Working Group was chartered to evaluate and act on recommendations in a Workshop report for developing the XML Security specifications on the basis of lessons learned from implementation and deployment experience to date.

Three of the revised specifications relate to an ongoing effort to rework XML Signature and Canonical XML in order to address issues around performance, streaming, robustness, and attack surface. The specification XML Signature Syntax and Processing Version 2.0 defines XML digital signature processing rules and syntax. XML Signatures provide integrity, message authentication, and/or signer authentication services for data of any type, whether located within the XML that includes the signature or elsewhere. Canonical XML Version 2.0 describes a method for generating a physical representation, the canonical form, of an XML document that accounts for the permissible changes. Except for limitations regarding a few unusual cases, if two documents have the same canonical form, then the two documents are logically equivalent within the given application context. Note that two documents may have differing canonical forms yet still be equivalent in a given context based on application-specific equivalence rules for which no generalized XML specification could account.

The specification XML Signature Streaming Profile of XPath 1.0 defines a streamable profile of XPath 1.0 suitable for use with XML Signature 2.0. In the context of XML Signature, "streaming is absolutely essential for network appliances which need to perform XML Signature and Encryption operations for messages on the wire. It is also important for performance sensitive application as streaming, by conserving memory, greatly reduces memory allocation, deallocation and garbage collection calls, thereby improving performance."

The updated XML Signature Best Practices Working Draft collects best practices for implementers and users of the XML Signature specification. Most of these best practices are related to improving security and mitigating attacks, yet others are for best practices in the practical use of XML Signature, such as signing XML that doesn't use namespaces, for example. The updated XML Security RELAX NG Schemas draft serves to publish RELAX NG schemas for XML Security specifications, including XML Signature 1.1, and XML Signature Properties. These RELAX NG schemas are highly modularized. This modularization has two significant advantages. First, it is easy to create schemas dedicated to enveloped or enveloping signatures. Second, it is easy to create schemas for imposing tight constraints where 'xsd:any' in the original XSD schemas does not impose such tight constraints..."

See also: the W3C XML Security Working Group

Novell Cloud Manager Tackles Private Cloud Vendor Lock-In
Nancy Gohring, InfoWorld

"With the Cloud Manager software announcement, Novell hopes to address the vendor lock-in problem facing enterprises building private clouds. The Cloud Manager offering allows IT staff to manage virtualized resources that may be based on different hypervisors, including VMware, Microsoft's Hyper-V, and Xen virtual servers, all from a single management tool...

When workers or business units want access to new services they typically have to call the IT department and work through a provisioning process that could take months. They may also have to pay for new hardware and software. Allowing them to self-provision resources from a private cloud cuts the time it takes to set up new services and allows them to pay only for the resources they use... Cloud Manager also includes tools that allow end users to provision their own computing resources, even those that may be hosted across data centers on multiple hypervisors. The provisioning console can display a catalog of services, as well as service tiers with different prices, that the end user can choose from..."

From the text of the announcement: "Novell Cloud Manager is designed for the heterogeneous reality of most IT environments, giving users the freedom and flexibility to create and manage private clouds which support all leading hypervisors, operating systems and hardware platforms. Cloud Manager enforces an organization's internal approval process, as well as best practices like ITIL. Security profiles can be configured at the user, group, workload and business service levels, ensuring consistent application of security policies and rights management.

Novell Cloud Manager fully automates the process of provisioning new workloads. Beyond simply managing the request and approval workflow, Novell Cloud Manager automatically creates and deploys workloads into the virtual environment based on a service catalog of predefined workload templates. Template-based provisioning standardizes workloads with the corporate service catalog and ensures adherence to corporate policy. If necessary, customized configuration changes, such as increased memory or disk space, can be made at the time of the request. Novell Cloud Manager even determines the optimal location to deploy the new workload. Workload provisioning times are dramatically shortened..."

See also: the Novell announcement

New W3C Resources for HTML and CSS Authors on Character Encodings
Staff, W3C Announcement

"The W3C Internationalization Core Working Group has just published six (6) new articles and updated a further five articles and a tutorial to help HTML and CSS authors understand how to work with character encodings on the Web.

For instance, there are articles that explore how to choose an encoding, how to declare it in various flavours of HTML and XHTML, what you need to know about the byte-order mark and normalization, and when to use (or not use) character escapes...

Article titles: 'Character encodings for beginners'; 'Handling character encodings in HTML and CSS'; Character encodings: Essential concepts'; Choosing & applying a character encoding'; Declaring character encodings in HTML'; Declaring character encodings in CSS'; The byte-order mark (BOM) in HTML'; Normalization in HTML and CSS'; Characters or markup?'; Using character escapes in markup and CSS.'

"The mission of the W3C Internationalization Activity is to ensure that W3C's formats and protocols are usable worldwide in all languages and in all writing systems. The Internationalization Core Working Group reviews specifications produced by other W3C Working Groups, looking for any issues that would cause barriers to deployment and use due to language, script, region or culture. The Internationalization Interest Group is a public group supporting the activity of the Internationalization Working Group; anyone can participate in the Interest Group by simply joining one of the mailing lists. The ITS (Internationalization Tag Set) Interest Group aims to foster a community of users of the Internationalization Tag Set (ITS) by promoting its adoption and gathering information for its further development. ITS provides a set of concepts that can be mapped to markup and that make it easier to internationalize and localize documents. The Japanese Layout Task Force is creating a document about requirements for general Japanese layout realized with technologies like CSS, SVG and XSL-FO—and much of the discussion if in Japanese."

See also: the W3C Internationalization (I18N) Activity


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