The XML Expert's Path to Web Applications

Web applications offer a golden opportunity for domain experts who work with XML documents to leverage their domain expertise, their knowledge of document engineering principles, and their skills in XML technology. Current XML technologies provide a full stack of modeling languages, implementation languages, and tools for Web applications that is stable, platform independent, and based on open standards. Combining principles and proven practices from document and software engineering, we identify architectures, modeling techniques, and implementation strategies that let end-user developers who are conversant with XML technologies create their own Web applications.

Meta(data)morphosis

This article offers a case study in the creation and metamorphosis of a corpus of transcriptions intended for web publication. It discusses a process for encoding, proofing, and publishing a collection of brief periodical documents (largely reviews) on the subject of authors published in the Women Writers Project’s established Women Writers Online corpus, as part of an initiative investigating the transatlantic reception of early women’s texts. Both encoding and publication in the initiative, Cultures of Reception, were driven by the particular characteristics of this collection and the importance of establishing links to the existing materials in Women Writers Online. This article discusses steps that the Cultures of Reception team took to prepare the encoded texts for publication—including development of a web-based tool systematizing human intervention—and then explains the goals and design of Women Writers in Review, the interface that is used to publish these texts.

XQuery is not (just) a query language: Web application development with XQuery

XQuery is widely known as a query language for XML, but it’s also a full-fledged, functional programming language which, with a limited number of implementation-provided extensions, can serve in a web development context as both the query language and the programming language. When you have data in XML form that needs to be delivered in some way on the web, using XQuery as the server-side programming language has significant practical advantages. After briefly describing those advantages, this paper will lay out techniques for developing web applications in XQuery—techniques that will reduce complexity and help developers produce well-organized, testable, portable code that will be comparatively easy to build upon and maintain over time. Topics include using MVC, keeping functions testable, and facilitating code portability by using available standardizations like RESTXQ and by isolating implementation-specific functions into separate modules.

Message Format Persistence in Large Enterprise Systems

It is more efficient to store messages as-is or with minimal modification than it is to develop a new (typically relational) schema to re-map and store the data in the messages. Yet, persistent models and message models have different needs, so naïve message persistence may not be ideal. We review the approach used in two enterprise integration efforts where XML message formats are directly or nearly-directly used to persist data and enable functions in the enterprise, avoiding costly and fragile mapping layers and the associated impedance mismatch. We also make the general case that the message model is more critical to enterprise architecture (as distinct from system architecture) and should therefore be preeminent during enterprise design. Actual integration efforts on the HealthCare.gov Data Services Hub and a large insurance provider are discussed, and simplified, non-proprietary example documents are used to illustrate the concepts concretely. We also review and define the Data Hub pattern for integrating data in the service of real-time, transactional loads that support service oriented communication across systems via messages. The architectural implications of sharing message and persistent document structures, rather than using a separate persistence model, is far-reaching and affects multiple layers or “tiers” in the overall architecture. The extent of this change illustrates that NoSQL technology, which can store message-like persistent forms, drives a fundamentally different architectural approach rather than merely being another persistence option.

The Kiln XML Publishing Framework

Kiln, previously known as xMod, is an open source multi-platform framework for building and deploying complex websites whose source content is primarily in TEI/XML. It brings together various independent software components into an integrated whole that provides the infrastructure and base functionality for such sites. Separation of roles is central to Kiln's design, allowing people with different backgrounds, knowledge and skills to work simultaneously on the same project without interfering with one another’s work. Developed and maintained at King’s College London it has been used to generate more than 50 websites for digital humanities research projects which have very different source materials and customised functionality.

XSLT as a Modern, Powerful Static Website Generator

In scientific, technical, and medical (STM) publishing, XML is a common data format for typeset products. Electronic renditions are regularly created from these XML sources, too. However, these HTML renderings are mainly considered as an alternative rendering with no added value, and most users of STM literature still consume the content in PDF format or on paper. Hogrefe Publishing decided to market its flagship reference product, the Clinical Handbook of Psychotropic Drugs, as a standalone electronic version. The electronic version should offer quicker lookups by several criteria, such as substance name, trade name, indication, and interaction. In addition, it should be mobile-friendly so that healthcare professionals can use their mobile phones to access the content, including large tables. Although single-source publishing in STM is not considered a “sub rosa” application of XML at all, there are remarkably few known examples of standalone, enriched Web applications that are derived from a printed reference work and published in parallel. This paper argues that this kind of application can be created from XML with relatively moderate effort using modern XSLT versions and that this approach is superior to what has recently become popular for content-driven Web sites – Markdown content and static site generators written in procedural languages.