Providing better error reporting is some cases,

netwerk-digitaal-erfgoed · Dec 6, 2023 · b08d2da · b08d2da
1 parent 7fd6af2
commit b08d2da
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Showing 2 changed files with 52 additions and 45 deletions.
diff --git a/src/lib/Generator.class.ts b/src/lib/Generator.class.ts
@@ -57,8 +57,8 @@ class Generator extends EventEmitter {
       stream.on('end', () => {
         this.emit('end', numberOfStatements)
       })
-    }).catch(e => {
-      throw e as Error
+    }).catch(_ => {
+      throw new Error(`The Generator did not run succesfully, it could not get the results from the endpoint ${this.source}`)
     })
   }
 }

diff --git a/src/lib/Iterator.class.ts b/src/lib/Iterator.class.ts
@@ -1,18 +1,17 @@
 /* eslint-disable @typescript-eslint/method-signature-style */
-import EventEmitter from 'node:events';
+import EventEmitter from "node:events";
 import type { SelectQuery } from "sparqljs";
 import type Stage from "./Stage.class.js";
 import type { NamedNode } from "@rdfjs/types";
 import getSPARQLQuery from "../utils/getSPARQLQuery.js";
 import { type Bindings } from "@comunica/types";
 import getSPARQLQueryString from "../utils/getSPARQLQueryString.js";
-import getEndpoint from '../utils/getEndpoint.js';
-import type { Endpoint, QueryEngine } from './types.js';
-import getEngine from '../utils/getEngine.js';
-import getEngineSource from '../utils/getEngineSource.js';
+import getEndpoint from "../utils/getEndpoint.js";
+import type { Endpoint, QueryEngine } from "./types.js";
+import getEngine from "../utils/getEngine.js";
+import getEngineSource from "../utils/getEngineSource.js";
 
 const DEFAULT_LIMIT = 10;
-
 declare interface Iterator {
   on(event: "data", listener: ($this: NamedNode) => void): this;
   on(event: "end", listener: (numResults: number) => void): this;
@@ -21,57 +20,65 @@ declare interface Iterator {
   emit(event: "end", numResults: number): boolean;
 }
 
-class Iterator
-  extends EventEmitter
-{
+class Iterator extends EventEmitter {
   private readonly query: SelectQuery;
   public readonly endpoint: Endpoint;
   private readonly engine: QueryEngine;
-  private source: string = ''
+  private source: string = "";
   private $offset = 0;
-  private totalResults = 0
+  private totalResults = 0;
 
   constructor(stage: Stage) {
-    super()
+    super();
     this.query = getSPARQLQuery(stage.configuration.iterator.query, "select");
-    this.query.limit = stage.configuration.iterator.batchSize ?? DEFAULT_LIMIT;
-    this.endpoint = getEndpoint(stage)
-    this.engine = getEngine(this.endpoint)
+    this.query.limit =
+      this.query.limit ??
+      stage.configuration.iterator.batchSize ??
+      DEFAULT_LIMIT;
+    this.endpoint = getEndpoint(stage);
+    this.engine = getEngine(this.endpoint);
   }
 
   public run(): void {
-    let resultsPerPage = 0
-    if (this.source === '') this.source = getEngineSource(this.endpoint)
+    let resultsPerPage = 0;
+    if (this.source === "") this.source = getEngineSource(this.endpoint);
     this.query.offset = this.$offset;
     const queryString = getSPARQLQueryString(this.query);
-    this.engine.queryBindings(queryString, {
-      sources: [this.source],
-    }).then(stream => {
-      stream.on('data', (binding: Bindings) => {
-        resultsPerPage++
-        if (!binding.has('this')) throw new Error('Missing binding $this in the Iterator result.')
-        const $this = binding.get('this')!
-        if ($this.termType !== 'NamedNode') {
-          throw new Error(`Binding $this in the Iterator result must be an Iri/NamedNode, but it is of type ${$this.termType}.`)
-        } else {
-          this.emit('data', $this)
-        }
-      });
+    this.engine
+      .queryBindings(queryString, {
+        sources: [this.source],
+      })
+      .then((stream) => {
+        stream.on("data", (binding: Bindings) => {
+          resultsPerPage++;
+          if (!binding.has("this"))
+            throw new Error("Missing binding $this in the Iterator result.");
+          const $this = binding.get("this")!;
+          if ($this.termType !== "NamedNode") {
+            throw new Error(
+              `Binding $this in the Iterator result must be an Iri/NamedNode, but it is of type ${$this.termType}.`
+            );
+          } else {
+            this.emit("data", $this);
+          }
+        });
 
-      stream.on('end', () => {
-        this.totalResults += resultsPerPage
-        this.$offset += this.query.limit!
-        if (resultsPerPage < this.query.limit!) {
-          this.emit('end', this.totalResults)
-        } else {
-          this.run()
-        }
+        stream.on("end", () => {
+          this.totalResults += resultsPerPage;
+          this.$offset += this.query.limit!;
+          if (resultsPerPage < this.query.limit!) {
+            this.emit("end", this.totalResults);
+          } else {
+            this.run();
+          }
+        });
+      })
+      .catch((_) => {
+        throw new Error(
+          `The Iterator did not run succesfully, it could not get the results from the endpoint ${this.source} (offset: ${this.$offset}, limit ${this.query.limit})`
+        );
       });
-    })
-    .catch(e => {
-      throw e
-    })
   }
 }
 
-export default Iterator
+export default Iterator;