fix: Correct Parenting for Solid-PREP Notifications

Parent path is correctly determined only for non root resources. Parent notifications are only generated when resources have a parent.

Author: CxRes

lib/handlers/notify.js

@@ -11,6 +11,13 @@ const ALLOWED_RDF_MIME_TYPES = [
   'text/turtle'
 ]
 
+function getParent (path) {
+  if (path === '' || path === '/') return
+  const parent = libPath.dirname(path)
+  if (parent === '/') return
+  return `${parent}/`
+}
+
 function getActivity (method) {
   if (method === 'DELETE') {
     return 'Delete'
@@ -34,11 +41,7 @@ function handler (req, res, next) {
   const { method } = req
   const { statusCode } = res
   const eventID = res.getHeader('event-id')
-
-  const parent = `${libPath.dirname(req.path)}/`
-  const parentID = res.setEventID(parent)
   const fullUrl = new URL(req.path, `${req.protocol}://${req.hostname}/`)
-  const parentUrl = new URL(parent, fullUrl)
 
   // Date is a hack since node does not seem to provide access to send date.
   // Date needs to be shared with parent notification
@@ -48,53 +51,64 @@ function handler (req, res, next) {
   // If the resource itself newly created,
   // it could not have been subscribed for notifications already
   if (!((method === 'PUT' || method === 'PATCH') && statusCode === 201)) {
-    trigger({
-      generateNotification (
-        negotiatedFields
-      ) {
-        const mediaType = negotiatedFields['content-type']
+    try {
+      trigger({
+        generateNotification (
+          negotiatedFields
+        ) {
+          const mediaType = negotiatedFields['content-type']
 
-        if (ALLOWED_RDF_MIME_TYPES.includes(mediaType?.[0])) {
-          return `${headerTemplate(negotiatedFields)}\r\n${solidRDFTemplate({
-            activity: getActivity(method),
-            eventID,
-            object: String(fullUrl),
-            date: eventDate,
-            // We use eTag as a proxy for state for now
-            state: res.getHeader('ETag'),
-            mediaType
-          })}`
-        } else {
-          return defaultNotification({
-            ...(res.method === 'POST') && { location: res.getHeader('Content-Location') }
-          })
+          if (ALLOWED_RDF_MIME_TYPES.includes(mediaType?.[0])) {
+            return `${headerTemplate(negotiatedFields)}\r\n${solidRDFTemplate({
+              activity: getActivity(method),
+              eventID,
+              object: String(fullUrl),
+              date: eventDate,
+              // We use eTag as a proxy for state for now
+              state: res.getHeader('ETag'),
+              mediaType
+            })}`
+          } else {
+            return defaultNotification({
+              ...(res.method === 'POST') && { location: res.getHeader('Content-Location') }
+            })
+          }
         }
-      }
-    })
+      })
+    } catch (error) {
+      // Failed notification message
+    }
   }
 
   // Write a notification to parent container
   // POST in Solid creates a child resource
-  if (method !== 'POST') {
-    trigger({
-      path: parent,
-      generateNotification (
-        negotiatedFields
-      ) {
-        const mediaType = negotiatedFields['content-type']
-        if (ALLOWED_RDF_MIME_TYPES.includes(mediaType?.[0])) {
-          return `${headerTemplate(negotiatedFields)}\r\n${solidRDFTemplate({
-            activity: getParentActivity(method, statusCode),
-            eventID: parentID,
-            date: eventDate,
-            object: String(parentUrl),
-            target: statusCode === 201 ? String(fullUrl) : undefined,
-            eTag: undefined,
-            mediaType
-          })}`
+  const parent = getParent(req.path)
+  if (parent && method !== 'POST') {
+    try {
+      const parentID = res.setEventID(parent)
+      const parentUrl = new URL(parent, fullUrl)
+      trigger({
+        path: parent,
+        generateNotification (
+          negotiatedFields
+        ) {
+          const mediaType = negotiatedFields['content-type']
+          if (ALLOWED_RDF_MIME_TYPES.includes(mediaType?.[0])) {
+            return `${headerTemplate(negotiatedFields)}\r\n${solidRDFTemplate({
+              activity: getParentActivity(method, statusCode),
+              eventID: parentID,
+              date: eventDate,
+              object: String(parentUrl),
+              target: statusCode === 201 ? String(fullUrl) : undefined,
+              eTag: undefined,
+              mediaType
+            })}`
+          }
         }
-      }
-    })
+      })
+    } catch (error) {
+      // Failed notification message
+    }
   }
 
   next()