From 2134ed8c1d7f7a27b4449e4a2248a0ab3635b67b Mon Sep 17 00:00:00 2001
From: David de Boer <david@ddeboer.nl>
Date: Fri, 1 Dec 2023 15:40:50 +0100
Subject: [PATCH] feat: Handle distribution timeouts

---
 jest.config.js               |  8 ++++----
 src/analyzer/distribution.ts | 34 ++++++++++++++++++++++++++++------
 2 files changed, 32 insertions(+), 10 deletions(-)

diff --git a/jest.config.js b/jest.config.js
index 1fce51f..9fd82fe 100644
--- a/jest.config.js
+++ b/jest.config.js
@@ -10,10 +10,10 @@ export default {
   coverageReporters: ['json-summary', 'text'],
   coverageThreshold: {
     global: {
-      lines: 24.48,
-      statements: 24.48,
-      branches: 13.88,
-      functions: 23.52,
+      lines: 23.52,
+      statements: 23.52,
+      branches: 13.51,
+      functions: 22.85,
     },
   },
   transform: {
diff --git a/src/analyzer/distribution.ts b/src/analyzer/distribution.ts
index e3c9e03..587ae9f 100644
--- a/src/analyzer/distribution.ts
+++ b/src/analyzer/distribution.ts
@@ -7,7 +7,16 @@ import namedNode = DataFactory.namedNode;
 import blankNode = DataFactory.blankNode;
 import literal = DataFactory.literal;
 
-async function probe(distribution: Distribution) {
+class NetworkError {
+  constructor(
+    public readonly url: string,
+    public readonly message: string
+  ) {}
+}
+
+async function probe(
+  distribution: Distribution
+): Promise<Response | NetworkError> {
   if (distribution.isSparql()) {
     return fetch(distribution.accessUrl!, {
       method: 'POST',
@@ -19,10 +28,15 @@ async function probe(distribution: Distribution) {
     });
   }
 
-  return fetch(distribution.accessUrl!, {
-    method: 'HEAD',
-    headers: {Accept: distribution.mimeType!},
-  });
+  try {
+    return await fetch(distribution.accessUrl!, {
+      signal: AbortSignal.timeout(5000),
+      method: 'HEAD',
+      headers: {Accept: distribution.mimeType!},
+    });
+  } catch (e) {
+    return new NetworkError(distribution.accessUrl!, (e as Error).name);
+  }
 }
 
 export class DistributionAnalyzer implements Analyzer {
@@ -49,7 +63,15 @@ export class DistributionAnalyzer implements Analyzer {
         ),
       ]);
 
-      if (result.status >= 200 && result.status < 400) {
+      if (result instanceof NetworkError) {
+        store.addQuad(
+          quad(
+            action,
+            namedNode('https://schema.org/error'),
+            literal(result.message) // TODO: find a URI for this, for example TimeoutError.
+          )
+        );
+      } else if (result.status >= 200 && result.status < 400) {
         const dataDownload = namedNode(result.url);
         store.addQuad(
           quad(action, namedNode('https://schema.org/result'), dataDownload)