README
¶
RDF Export
Serializes []message.Triple to standard RDF formats using the vocabulary registry for IRI resolution.
Supported Formats
| Format | Extension | Description |
|---|---|---|
Turtle |
.ttl |
Compact, human-readable with prefix declarations and subject grouping |
NTriples |
.nt |
Line-based, one triple per line, fully expanded IRIs |
JSONLD |
.jsonld |
JSON with @context and @graph for web APIs |
Usage
import "github.com/c360studio/semstreams/vocabulary/export"
triples := []message.Triple{
{Subject: "acme.ops.robotics.gcs.drone.001", Predicate: "robotics.battery.level", Object: 85.5},
{Subject: "acme.ops.robotics.gcs.drone.001", Predicate: "robotics.flight.armed", Object: true},
}
// Write Turtle to a writer
err := export.Serialize(os.Stdout, triples, export.Turtle)
// Get N-Triples as a string
s, err := export.SerializeToString(triples, export.NTriples)
IRI Resolution
The package resolves dotted-notation identifiers to IRIs automatically:
Subjects are converted based on entity ID structure:
- Valid 6-part entity IDs:
acme.ops.robotics.gcs.drone.001becomes{base}/entities/acme/ops/robotics/gcs/drone/001 - Other subjects: dots are converted to slashes under
{base}/subjects/
Predicates resolve through the vocabulary registry:
- Registered predicates use their
StandardIRI(e.g.,robotics.battery.levelwith a registered IRI maps to that IRI) - Unregistered predicates generate
{base}/predicates/domain/category/property
Objects are typed by Go type inference:
| Go Type | RDF Datatype | Output |
|---|---|---|
string (entity ID) |
Resource | <iri> |
string (other) |
xsd:string |
"text" |
int, int64, etc. |
xsd:integer |
42 |
float64 |
xsd:double |
"85.5"^^xsd:double |
bool |
xsd:boolean |
true |
time.Time |
xsd:dateTime |
"2024-01-15T10:30:00Z"^^xsd:dateTime |
Options
WithBaseIRI
Override the default base IRI used for generated subject and predicate URIs:
err := export.Serialize(w, triples, export.Turtle,
export.WithBaseIRI("https://example.org"))
WithSubjectIRIFunc
Provide a custom function to map entity ID strings to IRIs. When set, this replaces the default subject IRI generation entirely (WithBaseIRI has no effect on subjects):
err := export.Serialize(w, triples, export.JSONLD,
export.WithSubjectIRIFunc(func(subject string) string {
return "https://example.org/entities/" + subject
}))
Prefix Management
Turtle and JSON-LD output automatically compact IRIs using well-known prefixes (OWL, SKOS, Dublin Core, PROV-O, Schema.org, FOAF, SSN/SOSA, XSD). Only prefixes that appear in the output are declared.
API
| Function | Description |
|---|---|
Serialize(w, triples, format, ...opts) |
Write triples to an io.Writer |
SerializeToString(triples, format, ...opts) |
Return serialized output as a string |
Related Documentation
- Vocabulary Package - Registry API, predicate registration, IRI mappings
- Vocabulary Guide - Predicate design and naming conventions
Documentation
¶
Overview ¶
Package export serializes []message.Triple to standard RDF formats.
Supported formats:
- Turtle (.ttl) — compact, human-readable with prefix declarations and subject grouping
- N-Triples (.nt) — line-based, one triple per line, no abbreviations
- JSON-LD (.jsonld) — JSON with @context and @graph for web APIs
The package uses the existing vocabulary infrastructure for IRI resolution:
- Registered predicates map to their StandardIRI via vocabulary.GetPredicateMetadata
- Entity ID subjects are parsed via message.ParseEntityID and converted to hierarchical IRIs
- Object values are typed using XSD datatypes based on Go type inference
Basic usage:
triples := []message.Triple{
{Subject: "acme.ops.robotics.gcs.drone.001", Predicate: "robotics.battery.level", Object: 85.5},
{Subject: "acme.ops.robotics.gcs.drone.001", Predicate: "robotics.flight.armed", Object: true},
}
// Write Turtle to stdout
err := export.Serialize(os.Stdout, triples, export.Turtle)
// Get N-Triples as a string
s, err := export.SerializeToString(triples, export.NTriples)
// Custom base IRI
err = export.Serialize(w, triples, export.JSONLD, export.WithBaseIRI("https://example.org"))
Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
Types ¶
type Format ¶
type Format int
Format identifies an RDF serialization format.
const ( // Turtle is the Terse RDF Triple Language format (.ttl). // Compact and human-readable with prefix declarations and subject grouping. Turtle Format = iota // NTriples is the N-Triples format (.nt). // Line-based, one triple per line, fully expanded IRIs. NTriples // JSONLD is the JSON-LD format (.jsonld). // JSON with @context and @graph for web API consumption. JSONLD )
type Option ¶
type Option func(*options)
Option configures serialization behavior.
func WithBaseIRI ¶
WithBaseIRI overrides the default SemStreamsBase IRI used for generated URIs.
func WithSubjectIRIFunc ¶
WithSubjectIRIFunc provides a custom function to map entity ID strings to IRIs. When set, this replaces the default subject IRI generation logic entirely; WithBaseIRI has no effect on subjects when a custom function is provided.
Source Files