XMLMODS

XMLMODS is a framework for describing, validating, and applying modifications to XML documents. It defines an XML-based patch language and a companion schema that encodes a sequence of changes in a portable, machine-readable form. The goal is to enable granular updates to XML data without the need to replace entire documents, support auditability, and facilitate reversible edits in environments where XML is the primary data representation.

Core concepts include patch documents, change sets, and operation semantics. A patch document lists one or more operations such as add, delete, replace, move, or copy. Each operation specifies a target location within the source document using path expressions, and an optional new content or value. Patches may include preconditions, metadata (author, timestamp, rationale), and integrity checksums to ensure compatibility and traceability.

Process: a patch set is created against a baseline XML document, validated against the XMLMODS schema, and then applied by a patch processor to produce a new document. The framework supports conflict detection, versioning, and optional rollback to the original state if preconditions fail.

Implementation and usage: XMLMODS has been implemented in several open-source libraries across languages and can be integrated with existing XML tooling—parsers, validators, and transformation engines. It is used in content management, configuration management, and data synchronization workflows where trackable, incremental updates are desirable.

Relation to other standards: XMLMODS complements transformation languages like XSLT and standard XML diff/patch approaches, offering a domain-specific patch semantics while remaining independent from full document reserialization. It is distinct from the XQuery Update Facility in its focus on patch description and provenance rather than in-place query-based modification.

See also: XML, XSLT, XML Diff, XML Path Language, Patch (computing).