Add source selection with one criteria only

sib-replica/app/src/StrategyResult.tsx

@@ -12,7 +12,7 @@ export function StrategyResult(props: {strategy: Strategy}) {
 
     useEffect(() => {
         strategy.registerCallbackForStatusChange((status) => setStatus(status));
-        strategy.registerCallbackForMatchesChange((match) => setMatches(strategy.getResult().getMatches()));
+        strategy.registerCallbackForMatchesChange((match) => setMatches(strategy.getResult().getMatches().slice()));
     }, []);
 
     return (

sib-replica/app/src/lib/sourceProvider/SourceProviderBase.ts

@@ -13,6 +13,11 @@ export class SourceProviderBase implements SourceProvider {
         return this;
     }
 
+    public addSourceAll(sources: string[]): SourceProviderBase {
+        sources.forEach(source => this.sources.push(source));
+        return this;
+    }
+
     public getSources(): string[] {
         return this.sources;
     }

sib-replica/app/src/lib/strategy/StrategyComunicaSourceSelection.ts

@@ -0,0 +1,71 @@
+import { QueryEngine } from "@comunica/query-sparql";
+import { SourceProvider } from "../sourceProvider/SourceProvider";
+import User from "../user/User";
+import UserBase from "../user/UserBase";
+import { Targets } from "./Strategy";
+import { DynamicSparqlQuery } from "./StrategyBaseSparql";
+import StrategyComunica from "./StrategyComunica";
+import { SourceProviderBase } from "../sourceProvider/SourceProviderBase";
+
+/**
+ * A `StrategyBase` that uses Comunica to find results.
+ */
+export default class StrategyComunicaSourceSelection extends StrategyComunica {
+
+    private sparqlQueryFromSourceSelection: string | DynamicSparqlQuery;
+
+    /**
+     * @inheritdoc
+     */
+    constructor(name: string, description: string, sourceSelectionSparqlQuery: string | DynamicSparqlQuery, sparqlQueryFromSourceSelection: string | DynamicSparqlQuery, engine: any, sourceProvider: (targets: Targets) => SourceProvider) {
+        super(name, description, sourceSelectionSparqlQuery, engine, sourceProvider);
+        this.sparqlQueryFromSourceSelection = sparqlQueryFromSourceSelection;
+    }
+
+    public async execute(targets: Targets): Promise<void> {
+        this.setSources(targets);
+        this.setRunning();
+
+        const bindingsStream = await this.getEngine().queryBindings(this.getSparqlQuery(targets), {
+            lenient: true, // ignore HTTP fails
+            sources: this.getSources(),
+        });
+
+        const promises: Promise<void>[] = [];
+
+        bindingsStream.on('data', (binding: any) => {
+            //console.log(binding.toString());
+
+            const skillIndex: string = binding.has("instancesSkill")? binding.get('instancesSkill').value: "unknown";
+            const cityIndex: string = binding.has("instancesCity")? binding.get('instancesCity').value: "unknown";
+
+            const sources: string[] = [];
+
+            if (skillIndex !== "unknown") {
+                console.log("Source selection found source: ", skillIndex);
+                sources.push(skillIndex)
+            }
+
+            if (cityIndex !== "unknown") {
+                console.log("Source selection found source: ", cityIndex);
+                sources.push(cityIndex)
+            }
+
+            const strategy = new StrategyComunica("", "", this.sparqlQueryFromSourceSelection, new QueryEngine(), (t: Targets) => new SourceProviderBase().addSourceAll(sources));
+            strategy.registerCallbackForMatchesChange((matches) => matches.forEach(match => this.addMatchToResults(match.getUser())));
+            promises.push(strategy.execute(targets));
+          });
+
+        return new Promise<void>((resolve, reject) => {
+            bindingsStream.on('end', async () => {
+                await Promise.all(promises);
+                this.setTerminated();
+                resolve();
+            });
+            bindingsStream.on('error', (error: Error) => {
+                reject(error);
+            });
+        });
+    }
+
+}

sib-replica/app/src/queries.ts

@@ -110,4 +110,31 @@ export const skillCityTraversalMetaQuery = (t: Targets) => `SELECT DISTINCT ?use
 
   ${t.cities.map(c => `?indexCity${c} a <http://example.org#CityIndex>;
   <http://example.org#entry> ?user.`)}
+} LIMIT 100`;
+
+export const skillCityFromDistributedMetaIndexQuery = (t: Targets) => `SELECT DISTINCT ?indexes WHERE {
+  ${t.skills.map(s => `?${s} a <http://example.org#SourceSelectionIndexRegistration>;
+  <http://example.org#forProperty> <http://example.org#hasSkill>;
+  <http://example.org#forValue> "${s}";
+  <http://example.org#instancesIn> ?indexSkill${s};
+  <http://example.org#hasSource> ?source.`)}
+
+  ${t.cities.map(c => `?${c} a <http://example.org#SourceSelectionIndexRegistration>;
+  <http://example.org#forProperty> <http://example.org#hasLocation>;
+  <http://example.org#forValue> "${c}";
+  <http://example.org#instancesIn> ?indexCity${c};
+  <http://example.org#hasSource> ?source.`)}
+} LIMIT 100`;
+
+export const sourcesFromDistributedMetaIndexQuery = (t: Targets) => `SELECT DISTINCT ?instancesSkill ?instancesCity WHERE {
+  ${t.skills.reduce((ps, cs) => `${ps}\n?${cs} a <http://example.org#SourceSelectionIndexRegistration>;
+  <http://example.org#forProperty> <http://example.org#hasSkill>;
+  <http://example.org#forValue> "${cs}";
+  <http://example.org#instancesIn> ?instancesSkill;
+  <http://example.org#hasSource> ?source.\n`, "")}
+  ${t.cities.reduce((pc, cc) => `${pc}\n?${cc} a <http://example.org#SourceSelectionIndexRegistration>;
+  <http://example.org#forProperty> <http://example.org#hasLocation>;
+  <http://example.org#forValue> "${cc}";
+  <http://example.org#instancesIn> ?instancesCity;
+  <http://example.org#hasSource> ?source.`, "")}
 } LIMIT 100`;

sib-replica/app/src/strategies.ts

@@ -1,11 +1,12 @@
 import { Targets } from "./lib/strategy/Strategy";
 import { DistributedSourceProvider } from "./lib/sourceProvider/DistributedSourceProvider";
 import { FederatedSourceProvider } from "./lib/sourceProvider/FederatedSourceProvider";
-import { skillQuery, skillTraversalQuery, skillCityQuery, skillCityTraversalQuery, cityTraversalQuery, skillRootTraversalQuery, skillRootNamedGraphTraversalQuery, cityQuery, skillCityTraversalMetaQuery } from "./queries";
+import { skillQuery, skillTraversalQuery, skillCityQuery, skillCityTraversalQuery, cityTraversalQuery, skillRootTraversalQuery, skillRootNamedGraphTraversalQuery, cityQuery, skillCityTraversalMetaQuery, sourcesFromDistributedMetaIndexQuery } from "./queries";
 import StrategyComunica from "./lib/strategy/StrategyComunica";
 import StrategyFilter from "./lib/strategy/StrategyFilter";
 import { Match } from "./lib/match/Match";
 import { SourceProviderBase } from "./lib/sourceProvider/SourceProviderBase";
+import StrategyComunicaSourceSelection from "./lib/strategy/StrategyComunicaSourceSelection";
 
 const QueryEngine = require('@comunica/query-sparql').QueryEngine;
 const QueryEngineTraversal = require('@comunica/query-sparql-link-traversal').QueryEngine;
@@ -164,4 +165,12 @@ export const strategies = [
         new QueryEngineTraversal(),
         (t: Targets) => new DistributedSourceProvider(32).addMetaIndexes(),
     ),
+    new StrategyComunicaSourceSelection(
+        "Instances URL of selected skill(s) and city(ies) (distributed)",
+        "Gives the instances URL where we can find the selected skill(s) and city(ies) (distributed)",
+        sourcesFromDistributedMetaIndexQuery, 
+        skillCityQuery,
+        new QueryEngine(),
+        (t: Targets) => new DistributedSourceProvider(32).addMetaIndexes(),
+    ),
 ]