This issue of XML Daily Newslink is sponsored by:
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- Liberty Alliance Web Services Framework: A Technical Overview
- XML Base (Second Edition) Issued as a Proposed Edited Recommendation
- Addressing Doubts about REST
- Microsoft Working with Eclipse on Vista, ID Links
- OAI4J Open Source Client Library Supports OAI Metadata Specifications
- First Look: Safari 3.1 Adds Speed and HTML 5 Features
- Google Sees Surge in Web Use on Hot Mobile Phones
Liberty Alliance Web Services Framework: A Technical Overview
Conor Cahill, Carolina Canales (et al.), Liberty Technical Report
This overview document enumerates the major features of Liberty Web Services, a framework for identity-based services that provides added value for identity, security, and privacy above and beyond basic web services, and thereby makes identity data portable across domains. The term Liberty Web Services comprises the Identity Web Services Framework (ID-WSF) and the Identity Service Interface Specifications (ID-SIS) that take advantage of that framework. Together, these two pieces enable identity-based services—web services associated with the identity attributes of individual users. Why are identity-based services valuable? Fundamentally, because they enable a user's identity data to be portable across the many Web applications that, if able to access these attributes, can provide a more customized and meaningful experience to the user, whilst removing from that user the burden of manually repeatedly providing and managing their identity attributes at each. ID-WSF builds on many existing standards for networking and distributed computing, and adds specialized capabilities for handling identity-related information and tasks and for ensuring privacy and security. With ID-WSF providing the addressing, security and privacy plumbing—different ID-SIS specifications define the specific syntax and semantics for sharing different slices of your identity attributes. For instance, a Calendar SIS specifies how the travel service would query the user's Calendar Service for free blocks, or write an event. Other ID-SIS specifications either already exist or can be defined for other aspects of your identity, e.g., The user's personal profile, geolocation, presence, or wallet... An identity-based service is a web service associated with a particular user, i.e., a web service at which a user's calendar information can be accessed. Identity-based services require functionality beyond that necessary for basic web services not associated with a given user—particularly in the areas of identity, security, and privacy. Liberty ID-WSF specifications define the addressing, security and privacy plumbing—and different Liberty ID-SIS specifications define the specific syntax and semantics for sharing different slices of identity attributes. Together, ID-WSF and ID-SIS make identity data portable in a secure and privacy-respecting manner.
See also: Eve Maler's blog
XML Base (Second Edition) Issued as a Proposed Edited Recommendation
Jonathan Marsh and Richard Tobin (eds), W3C Technical Report
Members of the W3C XML Core Working Group have published a Proposed Edited Recommendation for "XML Base (Second Edition)." The document describes a facility, similar to that of HTML BASE, for defining base URIs for parts of XML documents. As a Proposed Edited Recommendation (PER), this second edition is not a new version of XML Base: its purpose is to clarify a number of issues that have become apparent since the first edition was published. Some of these were first published as separate errata, others were published in a public editor's draft in November 2006, and in December 2006. BASE allows authors to explicitly specify a document's base URI for the purpose of resolving relative URIs in links to external images, applets, form-processing programs, style sheets, and so on. The document describes a mechanism for providing base URI services to XLink, but as a modular specification so that other XML applications benefiting from additional control over relative URIs but not built upon XLink can also make use of it. The syntax consists of a single XML attribute named 'xml:base'. The specification does not give the 'xml:base' attribute any special status as far as XML validity is concerned. In a valid document the attribute must be declared in the DTD, and similar considerations apply to other schema languages. The deployment of XML Base is through normative reference by new specifications, for example XLink and the XML Infoset. Applications and specifications built upon these new technologies will natively support XML Base. The behavior of 'xml:base' attributes in applications based on specifications that do not have direct or indirect normative reference to XML Base is undefined. It is expected that a future RFC for XML Media Types will specify XML Base as the mechanism for establishing base URIs in the media types it defines. A companion document "Testing XML Base Conformance" from the W3C XML Core Working Group is also available. While "XML Base" does not specify an interface for determining the base URI of a node in an XML document, various other specifications directly or indirectly refer normatively to XML Base, and provide mechanisms by which the results of XML Base processing can be determined. Some of these specifications have test suites that include XML Base tests.
See also: the HTML version with diff markup
Addressing Doubts about REST
Stefan Tilkov, InfoQueue
Invariably, learning about REST means that you'll end up wondering just how applicable the concept really is for your specific scenario. And given that you're probably used to entirely different architectural approaches, it's only natural that you start doubting whether REST, or rather RESTful HTTP, really works in practice, or simply breaks down once you go beyond introductory, 'Hello, World'-level stuff. In this article, I will try to address ten of the most common doubts people have about REST when they start exploring it, especially if they have a strong background in the architectural approach behind SOAP/WSDL-based Web services. (1) REST may be usable for CRUD, but not for 'real' business logic. (2) There is no formal contract/no description language. (3) Who would actually want to expose so much of their application's implementation internals? (4) REST works with HTTP only, it's not transport protocol independent. (5) There is no practical, clear and consistent guidance on how to design RESTful applications. (6) REST does not support transactions. (7) REST is unreliable. (8) No pub/sub support: REST is fundamentally based on a client-server model, and HTTP always refers to a client and a server as the endpoints of communication. A client interacts with a server by sending requests and receiving responses. In a pub/sub model, an interested party subscribes to a particular category of information and gets notified each time something new appears. How could pub/sub be supported in a RESTful HTTP environment? We don't have to look far to see a perfect example of this: it's called syndication, and RSS and Atom Syndication are examples of it. A client queries for new information by issuing an HTTP against a resource that represents the collection of changes, e.g. for a particular category or time interval. This would be extremely inefficient, but isn't, because GET is the most optimized operation on the Web. In fact, you can easily imagine that a popular weblog server would have scale up much more if it had to actively notify each subscribed client individually about each change. Notification by polling scales extremely well... (9) No asynchronous interactions. (10) Lack of tools:—vendors are coming up with more and more (supposedly) easier and better support for RESTful HTTP development in their frameworks, e.g. Sun with JAX-RS (JSR 311) or Microsoft with the REST support in .NET 3.5 or the ADO.NET Data Services Framework... Is REST, and its most common implementation, HTTP, perfect? Of course not. Nothing is perfect, definitely not for every scenario, and most of the time not even for a single scenario. I've completely ignored a number of very reasonable problem areas that require more complicated answers, for example message-based security, partial updates and batch processing, and I solemnly promise to address these in a future installment.
See also: 'A Brief Introduction to REST'
Microsoft Working with Eclipse on Vista, ID Links
Paul Krill, InfoWorld
Microsoft's much-anticipated revelations about collaborations with the Eclipse Foundation Wednesday did not include joining the open-source tools foundation. But the two organizations are working together to enable use of Eclipse technology to build Java applications for Windows Vista. Also, Microsoft and Eclipse are collaborating on identity management via linking Eclipse's Higgins Project with Microsoft's CardSpace technology. Microsoft's efforts were detailed by Sam Ramji, Microsoft director of platform technology strategy, at the EclipseCon 2008 conference in Santa Clara, California. Ramji guided the audience through a list of efforts Microsoft has made in the open-source world, such as accommodations for PHP (Hypertext Preprocessor), JBoss, and Novell's Xen hypervisor. Ramji also said Microsoft itself has 200 projects hosted on its CodePlex open-source hosting site. Microsoft traditionally has been viewed as the anti-open-source company, but Ramji spared no detail looking to refute this notion, listing a myriad of projects undertaken over the years: "Today, we're architecting our participation in the open-source world." The Java enablement effort for Vista involves collaboration on an SWT (Standard Widget Toolkit) to work with Microsoft's WPF (Windows Presentation Foundation) technology for graphical presentation. This will enable Java to be used an authoring language to write WPF-enabled applications. Ramji wrote in his blog: "... the CardSpace team at Microsoft was already working actively with the Higgins Project to establish a secure, interoperable framework for user identity on the web—an architecture known as the Identity Metasystem. Since the inception of Higgins, the CardSpace team has worked very closely with the Higgins team, providing them the protocol documentation they needed to be able to build an identity selector that is interoperable with CardSpace, as well as placing those protocol specifications under the OSP so that they knew that it was safe to do so. We share a commitment to building a user-centric, privacy-preserving, secure, easy-to-use identity layer for the Internet..."
See also: Sam Ramji's blog 'Supernova'
OAI4J Open Source Client Library Supports OAI Metadata Specifications
Oskar Grenholm, Software Announcement
Software developers at the National Library of Sweden have announced the release of OAI4J, a client library for OAI-PMH and OAI-ORE written in Java, as Open Source. The project is hosted on SourceForge. OAI-PMH (The Open Archives Initiative Protocol for Metadata Harvesting) provides an application-independent interoperability framework based on metadata harvesting, where a "record" is returned in an XML-encoded byte stream in response to an OAI-PMH request for metadata from an item. Object Reuse and Exchange (OAI-ORE) specifications allow distributed repositories to exchange information about their constituent digital objects. These specifications include approaches for representing digital objects and repository services that facilitate access and ingest of these representations. OAI4J has been released as Open Source under the Apache License, version 2.0. Features for OAI-PMH: (1) convenient Java API that lets you perform queries and handle the harvested data in an object-oriented fashion; (2) it handles all the verbs and responses of OAI-PMH. The OAI-ORE support: (3) lets you create and build Resource Maps from scratch programmatically; (4) handles parsing of existing Resource Maps written as Atom feeds; (5) allows Resource Map objects to be serialized into Atom feeds; (6) can be extended to also handle RDF/XML parsing/serialization. The SourceForge download site provides links for a binary download, Java documentation for the API, and some examples to get you started.
See also: the Open Archives Initiative
First Look: Safari 3.1 Adds Speed and HTML 5 Features
Seth Weintraub, ComputerWorld
See also: the product description
Google Sees Surge in Web Use on Hot Mobile Phones
Staff, Reuters and CNET News.com
Google has seen an acceleration of Internet activity among mobile phone users in recent months since the company introduced faster Web services on selected phone models, fueling confidence the mobile Internet era is at hand, the company said on Tuesday. Early evidence showing sharp increases in Internet usage on phones, not just computers, has emerged from services Google has begun offering in recent months on Blackberry e-mail phones, Nokia devices for multimedia picture and video creators and business professionals and the Apple iPhone... The growing availability of flat-rate data plans from phone carriers instead of per-minute charges that previously discouraged Internet use, along with improved Web browsers on mobile phones as well as better-designed services from companies like Google are fueling the growth. Google made the pronouncement as it introduced a new software download for mobile phones running Microsoft's Windows Mobile software that conveniently positions a Google Web search window on the home screen of such phones. Similar versions of the search software which Google introduced for BlackBerry users in December and certain Nokia phones in February have sped up the time users take to perform Web searches by 40 percent and, in turn, driven usage. The software shortcuts the time it takes for people to perform Web searches on Google by eliminating initial search steps of finding a Web browser on the phone, opening the browser, waiting for network access, and getting to Google.com. By making a Google search box more convenient, mobile phone users have begun using the Internet more. Microsoft expects to have sold 20 million Windows Mobile devices by the end of its fiscal year in June, which together with Blackberry and Symbian-based phones represent upward of 85 percent of the Internet-ready smartphones sold in the world.
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