LODE 2.0

Semantic artefact URL*

URL File

Resource URI (optional)

Select a format*

Language code (optional)

Show warnings

Live OWL Documentation Environment (LODE) is a service that automatically extracts classes, object properties, data properties, named individuals, annotation properties, general axioms and namespace declarations from an OWL and OWL2 ontology, and renders them as ordered lists, together with their textual definitions, in a human-readable HTML page designed for browsing and navigation by means of embedded links.

This LODE service is an open source development, and can be freely used, as described in this document. It may be used in conjunction with content negotiation to display this human-readable version of an OWL ontology when the user accesses the ontology using a web browser, or alternatively to deliver the OWL ontology itself when the user accesses the ontology using an ontology editing tool such as Protégé and NeOn Toolkit. An exemplar implementation of such content negotiation is given in the Best Practice Recipes for Publishing RDF Vocabularies by using the .htaccess file:

AddType application/rdf+xml .rdf

# Rewrite engine setup
RewriteEngine On
            
# Rewrite rule to serve HTML content
RewriteCond %{HTTP_ACCEPT} !application/rdf\+xml.*(text/html|application/xhtml\+xml)
RewriteCond %{HTTP_ACCEPT} text/html [OR]
RewriteCond %{HTTP_ACCEPT} application/xhtml\+xml [OR]
RewriteCond %{HTTP_USER_AGENT} ^Mozilla/.*
RewriteRule ^ontology\$ https://w3id.org/lode/http://www.mydomain.com/ontology [R=303,L]

# Rewrite rule to serve RDF/XML content if requested
RewriteCond %{HTTP_ACCEPT} application/rdf\+xml
RewriteRule ^ontology\$ ontology.owl [R=303]

# Choose the default response
RewriteRule ^ontology\$ ontology.owl [R=303]

Depending on the parameters specified, the HTML page created by LODE takes into account both ontological axioms and annotations. The CSSs used for the resulting HTML page are based on the W3C CSSs for Recommendation documents.

API Documentation

The LODE 2.0 API exposes a single endpoint — /extract — available via both GET (URL-based) and POST (file upload). It processes a semantic artefact and returns a human-readable HTML documentation page.

Parameters

Parameter	Method	Type	Required	Description	Example
`url`	GET	string	Yes	Full URL of the semantic artefact to process. Both semantic artefacts URIs and direct links to RDF files (e.g. `.ttl`, `.rdf`, `.owl`) are accepted.	`url=http://purl.org/spar/fabio.ttl` [or] `url=http://purl.org/spar/fabio/`
`file`	POST	file	Yes	The semantic artefact file to upload and process. Accepted formats: `.rdf`, `.owl`, `.ttl`, `.n3`, `.nt`, `.xml`.	`file={LOCAL_PATH}`
`read_as`	GET POST	enum	No	How to interpret the RDF graph. One of `owl`, `rdf`, `skos`. Defaults to `owl`.	`read_as=owl`
`resource`	GET POST	string (URI)	No	URI of a specific resource to render. If omitted, the full artefact is documented.	`resource=http://purl.org/spar/fabio/ArchivalDocument`
`lang`	GET POST	string	No	Preferred language code for annotations (e.g. `en`, `it`, `fr`). Defaults to `en`.	`lang=en`
`warnings`	GET POST	boolean	No	When set to `true`, the documentation page also lists structural warnings raised during parsing (e.g. malformed restrictions, OWL 2 DL violations). Defaults to `false`.	`warnings=true`
`imported`	GET POST	boolean	No	OWL only. When set to `true`, the axioms contained in the ontologies directly imported by the target artefact are included in the documentation. If both `imported` and `closure` are specified, only `imported` is used.	`imports=True`
`closure`	GET POST	boolean	No	OWL only. When set to `true`, the transitive closure of all imported ontologies is included in the documentation. If both `imported` and `closure` are specified, only `imported` is used.	`closure=True`
`cache`	GET	boolean	No	URL only. When `true` (default), the processed URL is served from a 4-hour server-side cache when available. Set to `false` to discard the cached copy and re-fetch the URL, so updates to the ontology are picked up immediately; the fresh result then replaces the cache.	`cache=false`

Examples

/extract?url=http://purl.org/spar/fabio.ttl&read_as=owl
/extract?url=http://purl.org/spar/fabio&read_as=owl
/extract?url=http://www.w3.org/2004/09/fresnel&read_as=owl&warnings=true
/extract?url=http://purl.org/spar/fabio&read_as=owl&imported=true&lang=en
/extract?url=http://purl.org/spar/fabio&read_as=owl&closure=true
/extract?url=http://purl.org/spar/fabio&read_as=owl&resource=http://purl.org/spar/fabio/Abstract&lang=it
/extract?url=http://purl.org/spar/fabio&read_as=owl&cache=false