Merge pull request #9010 from overleaf/jpa-ignore-404

[web] do not consider a 404 on the main pdf url as pdf caching failure

GitOrigin-RevId: 2d57ee92b79227baa58f2e71edbcf63a4848435d

services/web/frontend/js/features/pdf-preview/util/pdf-caching-transport.js

@@ -59,6 +59,15 @@ export function generatePdfCachingTransportFactory(PDFJS) {
         abortSignal,
       })
         .catch(err => {
+          if (
+            err.message === 'non successful response status: 404' &&
+            OError.getFullInfo(err).url === this.url
+          ) {
+            // Do not consider a 404 on the main pdf url as pdf caching failure.
+            // Still, bail out during the initial launch phase.
+            failedOnce = true
+            throw new PDFJS.MissingPDFException()
+          }
           metrics.failedCount++
           failedOnce = true
           if (!enablePdfCaching) {
@@ -75,7 +84,9 @@ export function generatePdfCachingTransportFactory(PDFJS) {
         .catch(err => {
           err = OError.tag(err, 'fatal pdf download error', errorInfo)
           console.error(err)
-          captureException(err, { tags: { fromPdfCaching: true } })
+          if (!(err instanceof PDFJS.MissingPDFException)) {
+            captureException(err, { tags: { fromPdfCaching: true } })
+          }
           this.reject(err)
         })
     }

services/web/frontend/js/features/pdf-preview/util/pdf-caching.js

@@ -274,12 +274,16 @@ function checkChunkResponse(response) {
  * @param {AbortSignal} abortSignal
  */
 export async function fallbackRequest({ url, start, end, abortSignal }) {
-  const response = await fetch(url, {
-    headers: { Range: `bytes=${start}-${end - 1}` },
-    signal: abortSignal,
-  })
-  checkChunkResponse(response)
-  return response.arrayBuffer()
+  try {
+    const response = await fetch(url, {
+      headers: { Range: `bytes=${start}-${end - 1}` },
+      signal: abortSignal,
+    })
+    checkChunkResponse(response)
+    return await response.arrayBuffer()
+  } catch (e) {
+    throw OError.tag(e, 'fallback request failed', { url, start, end })
+  }
 }
 
 /**