OnDemandFormate

OnDemandFormate is a software pattern for generating data representations on demand at request time, rather than pre-rendering a fixed format. It enables dynamic selection of output formats through content negotiation or client parameters, allowing a single data source to serve multiple formats.

Core concepts include a formatter registry that maps formats to serializers (JSON, XML, CSV, etc.), a formatting pipeline that applies data transformation and localization, and streaming or lazy evaluation to handle large outputs.

Typical architecture includes a central engine, per-format formatters, and a request handler that negotiates the format and streams the result to the client. Implementations emphasize composability and security in output rendering.

Common formats include JSON, XML, CSV, YAML, HTML, and plain text. Formatting can integrate templates, localization, and data marshaling, with support for streaming large results.

Use cases include API endpoints serving multiple representations, data export services, reporting tools, and dashboards that adapt to client capabilities.

Benefits are flexibility and reduced need to store multiple formats; drawbacks include added request-time latency, complexity, and cache management challenges.

Status: OnDemandFormate is a descriptive term rather than a formal standard, appearing in pattern libraries and framework docs as a capability rather than a specification.

See also content negotiation, serializers, data formatting, streaming APIs, and template engines.