114 行
3.2 KiB
Go
114 行
3.2 KiB
Go
package rdf
|
|
|
|
import (
|
|
"fmt"
|
|
)
|
|
|
|
const (
|
|
JSON_LD_CONTEXT = "@context"
|
|
)
|
|
|
|
// JSONLD is an alias for the generic map of keys to interfaces, presumably
|
|
// parsed from a JSON-encoded context definition file.
|
|
type JSONLD map[string]interface{}
|
|
|
|
// ParsingContext contains the results of the parsing as well as scratch space
|
|
// required for RDFNodes to be able to statefully apply changes.
|
|
type ParsingContext struct {
|
|
Result ParsedVocabulary
|
|
}
|
|
|
|
// RDFNode is able to operate on a specific key if it applies towards its
|
|
// ontology (determined at creation time). It applies the value in its own
|
|
// specific implementation on the context.
|
|
type RDFNode interface {
|
|
Apply(key string, value interface{}, ctx ParsedVocabulary) (bool, error)
|
|
}
|
|
|
|
// ParseVocabulary parses the specified input as an ActivityStreams context that
|
|
// specifies a Core, Extended, or Extension vocabulary.
|
|
func ParseVocabulary(registry *RDFRegistry, input JSONLD) (vocabulary *ParsedVocabulary, err error) {
|
|
_, err = parseJSONLDContext(registry, input)
|
|
return
|
|
}
|
|
|
|
// parseJSONLDContext implements a super basic JSON-LD @context parsing
|
|
// algorithm in order to build a set of nodes which will be able to parse the
|
|
// rest of the document.
|
|
func parseJSONLDContext(registry *RDFRegistry, input JSONLD) (nodes []RDFNode, err error) {
|
|
i, ok := input[JSON_LD_CONTEXT]
|
|
if !ok {
|
|
err = fmt.Errorf("no @context in input")
|
|
return
|
|
}
|
|
if inArray, ok := i.([]interface{}); ok {
|
|
// @context is an array
|
|
for _, iVal := range inArray {
|
|
if valMap, ok := iVal.(map[string]interface{}); ok {
|
|
// Element is a JSON Object (dictionary)
|
|
for alias, val := range valMap {
|
|
if s, ok := val.(string); ok {
|
|
var n []RDFNode
|
|
n, err = registry.getAliased(alias, s)
|
|
if err != nil {
|
|
return
|
|
}
|
|
nodes = append(nodes, n...)
|
|
} else if aliasedMap, ok := val.(map[string]interface{}); ok {
|
|
var n []RDFNode
|
|
n, err = registry.getAliasedObject(alias, aliasedMap)
|
|
if err != nil {
|
|
return
|
|
}
|
|
nodes = append(nodes, n...)
|
|
} else {
|
|
err = fmt.Errorf("@context value in dict in array is neither a dict nor a string")
|
|
return
|
|
}
|
|
}
|
|
} else if s, ok := iVal.(string); ok {
|
|
// Element is a single value
|
|
var n []RDFNode
|
|
n, err = registry.getFor(s)
|
|
if err != nil {
|
|
return
|
|
}
|
|
nodes = append(nodes, n...)
|
|
} else {
|
|
err = fmt.Errorf("@context value in array is neither a dict nor a string")
|
|
return
|
|
}
|
|
}
|
|
} else if inMap, ok := i.(map[string]interface{}); ok {
|
|
// @context is a JSON object (dictionary)
|
|
for alias, iVal := range inMap {
|
|
if s, ok := iVal.(string); ok {
|
|
var n []RDFNode
|
|
n, err = registry.getAliased(alias, s)
|
|
if err != nil {
|
|
return
|
|
}
|
|
nodes = append(nodes, n...)
|
|
} else if aliasedMap, ok := iVal.(map[string]interface{}); ok {
|
|
var n []RDFNode
|
|
n, err = registry.getAliasedObject(alias, aliasedMap)
|
|
if err != nil {
|
|
return
|
|
}
|
|
nodes = append(nodes, n...)
|
|
} else {
|
|
err = fmt.Errorf("@context value in dict is neither a dict nor a string")
|
|
return
|
|
}
|
|
}
|
|
} else {
|
|
// @context is a single value
|
|
s, ok := i.(string)
|
|
if !ok {
|
|
err = fmt.Errorf("single @context value is not a string")
|
|
}
|
|
return registry.getFor(s)
|
|
}
|
|
return
|
|
}
|