Mercurial > code > home > repos > homeauto

comparison service/mqtt_to_rdf/src/graph_access.ts @ 1586:b459b5c3c33a

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
some rdf code. maybe copied from light9?
author drewp@bigasterisk.com
date Sun, 29 Aug 2021 13:45:31 -0700
parents
children
comparison
equal deleted inserted replaced
1585:c8092f6d70c0 1586:b459b5c3c33a
1 import { Literal, N3Store, Util, NamedNode, DataFactory } from "n3";
2 const { literal, namedNode } = DataFactory;
3
4 // workaround for uris that don't have good labels in the graph
5 export function labelFromUri(
6 uri: NamedNode,
7 prefix: string,
8 tailsToLabels: { [key: string]: string },
9 defaultLabel: string
10 ) {
11 let label = defaultLabel === undefined ? uri.value : defaultLabel;
12 Object.entries(tailsToLabels).forEach(([tail, useLabel]) => {
13 if (uri.equals(namedNode(prefix + tail))) {
14 label = useLabel as string;
15 }
16 });
17 return label;
18 }
19
20 export function graphLiteral(
21 store: N3Store,
22 subj: NamedNode,
23 pred: string,
24 notFoundResult?: string
25 ): Literal {
26 const keep: Array<Literal> = [];
27 store.forEach(
28 q => {
29 if (!Util.isLiteral(q.object)) {
30 throw new Error("non literal found");
31 }
32 let seen = false;
33 for (let other of keep) {
34 // why are we getting multiple matches for the same literal? seems like a bug
35 if (other.equals(q.object)) {
36 seen = true;
37 }
38 }
39 if (!seen) {
40 keep.push(q.object as Literal);
41 }
42 },
43 subj,
44 namedNode(pred),
45 null,
46 null
47 );
48 if (keep.length == 0) {
49 return literal(notFoundResult || "(missing)");
50 }
51 if (keep.length == 1) {
52 return keep[0];
53 }
54 console.log(`${subj.value} ${pred} had ${keep.length} objects:`, keep);
55 return keep[0];
56 }
57
58 export function graphUriValue(
59 store: N3Store,
60 subj: NamedNode,
61 pred: string
62 ): NamedNode | undefined {
63 const keep: Array<NamedNode> = [];
64 store.forEach(
65 q => {
66 if (!Util.isNamedNode(q.object)) {
67 throw new Error("non uri found");
68 }
69 keep.push(q.object as NamedNode);
70 },
71 subj,
72 namedNode(pred),
73 null,
74 null
75 );
76 if (keep.length == 0) {
77 return undefined;
78 }
79 if (keep.length == 1) {
80 return keep[0];
81 }
82 throw new Error("found multiple matches for pred");
83 }