app/errors.py

@@ -175,13 +175,21 @@ def handle_app_error(error: AppError) -> Response:
 
 def handle_rate_limit_exceeded(e: RateLimitExceeded) -> Response:
     g.s3_error_code = "SlowDown"
+    if request.path.startswith("/ui") or request.path.startswith("/buckets"):
+        wants_json = (
+            request.is_json or
+            request.headers.get("X-Requested-With") == "XMLHttpRequest" or
+            "application/json" in request.accept_mimetypes.values()
+        )
+        if wants_json:
+            return jsonify({"success": False, "error": {"code": "SlowDown", "message": "Please reduce your request rate."}}), 429
     error = Element("Error")
     SubElement(error, "Code").text = "SlowDown"
     SubElement(error, "Message").text = "Please reduce your request rate."
     SubElement(error, "Resource").text = request.path
     SubElement(error, "RequestId").text = getattr(g, "request_id", "")
     xml_bytes = tostring(error, encoding="utf-8")
-    return Response(xml_bytes, status=429, mimetype="application/xml")
+    return Response(xml_bytes, status="429 Too Many Requests", mimetype="application/xml")
 
 
 def register_error_handlers(app):

static/js/bucket-detail-main.js

@@ -99,6 +99,8 @@
   const previewMetadataList = document.getElementById('preview-metadata-list');
   const previewPlaceholder = document.getElementById('preview-placeholder');
   const previewPlaceholderDefault = previewPlaceholder ? previewPlaceholder.innerHTML : '';
+  const previewErrorAlert = document.getElementById('preview-error-alert');
+  const previewDetailsMeta = document.getElementById('preview-details-meta');
   const previewImage = document.getElementById('preview-image');
   const previewVideo = document.getElementById('preview-video');
   const previewAudio = document.getElementById('preview-audio');
@@ -1990,6 +1992,34 @@
     previewPlaceholder.classList.remove('d-none');
   };
 
+  let previewFailed = false;
+
+  const handlePreviewError = () => {
+    previewFailed = true;
+    if (downloadButton) {
+      downloadButton.classList.add('disabled');
+      downloadButton.removeAttribute('href');
+    }
+    if (presignButton) presignButton.disabled = true;
+    if (generatePresignButton) generatePresignButton.disabled = true;
+    if (previewDetailsMeta) previewDetailsMeta.classList.add('d-none');
+    if (previewMetadata) previewMetadata.classList.add('d-none');
+    const tagsPanel = document.getElementById('preview-tags');
+    if (tagsPanel) tagsPanel.classList.add('d-none');
+    const versionPanel = document.getElementById('version-panel');
+    if (versionPanel) versionPanel.classList.add('d-none');
+    if (previewErrorAlert) {
+      previewErrorAlert.textContent = 'Unable to load object \u2014 it may have been deleted, or the server returned an error.';
+      previewErrorAlert.classList.remove('d-none');
+    }
+  };
+
+  const clearPreviewError = () => {
+    previewFailed = false;
+    if (previewErrorAlert) previewErrorAlert.classList.add('d-none');
+    if (previewDetailsMeta) previewDetailsMeta.classList.remove('d-none');
+  };
+
   async function fetchMetadata(metadataUrl) {
     if (!metadataUrl) return null;
     try {
@@ -2011,6 +2041,7 @@
     previewPanel.classList.remove('d-none');
     activeRow = row;
     renderMetadata(null);
+    clearPreviewError();
 
     previewKey.textContent = row.dataset.key;
     previewSize.textContent = formatBytes(Number(row.dataset.size));
@@ -2036,25 +2067,69 @@
     if (previewUrl && lower.match(/\.(png|jpg|jpeg|gif|webp|svg|ico|bmp)$/)) {
       previewPlaceholder.innerHTML = '<div class="spinner-border spinner-border-sm text-secondary" role="status"></div><div class="small mt-2">Loading preview\u2026</div>';
       const currentRow = row;
-      previewImage.onload = () => {
+      fetch(previewUrl)
-        if (activeRow !== currentRow) return;
+        .then((r) => {
-        previewImage.classList.remove('d-none');
+          if (activeRow !== currentRow) return;
-        previewPlaceholder.classList.add('d-none');
+          if (!r.ok) {
-      };
+            previewPlaceholder.innerHTML = '<div class="small text-muted">Failed to load preview</div>';
-      previewImage.onerror = () => {
+            handlePreviewError();
-        if (activeRow !== currentRow) return;
+            return;
-        previewPlaceholder.innerHTML = '<div class="small text-muted">Failed to load preview</div>';
+          }
-      };
+          return r.blob();
-      previewImage.src = previewUrl;
+        })
+        .then((blob) => {
+          if (!blob || activeRow !== currentRow) return;
+          const url = URL.createObjectURL(blob);
+          previewImage.onload = () => {
+            if (activeRow !== currentRow) { URL.revokeObjectURL(url); return; }
+            previewImage.classList.remove('d-none');
+            previewPlaceholder.classList.add('d-none');
+          };
+          previewImage.onerror = () => {
+            if (activeRow !== currentRow) { URL.revokeObjectURL(url); return; }
+            URL.revokeObjectURL(url);
+            previewPlaceholder.innerHTML = '<div class="small text-muted">Failed to load preview</div>';
+          };
+          previewImage.src = url;
+        })
+        .catch(() => {
+          if (activeRow !== currentRow) return;
+          previewPlaceholder.innerHTML = '<div class="small text-muted">Failed to load preview</div>';
+          handlePreviewError();
+        });
     } else if (previewUrl && lower.match(/\.(mp4|webm|ogv|mov|avi|mkv)$/)) {
+      const currentRow = row;
+      previewVideo.onerror = () => {
+        if (activeRow !== currentRow) return;
+        previewVideo.classList.add('d-none');
+        previewPlaceholder.classList.remove('d-none');
+        previewPlaceholder.innerHTML = '<div class="small text-muted">Failed to load preview</div>';
+        handlePreviewError();
+      };
       previewVideo.src = previewUrl;
       previewVideo.classList.remove('d-none');
       previewPlaceholder.classList.add('d-none');
     } else if (previewUrl && lower.match(/\.(mp3|wav|flac|ogg|aac|m4a|wma)$/)) {
+      const currentRow = row;
+      previewAudio.onerror = () => {
+        if (activeRow !== currentRow) return;
+        previewAudio.classList.add('d-none');
+        previewPlaceholder.classList.remove('d-none');
+        previewPlaceholder.innerHTML = '<div class="small text-muted">Failed to load preview</div>';
+        handlePreviewError();
+      };
       previewAudio.src = previewUrl;
       previewAudio.classList.remove('d-none');
       previewPlaceholder.classList.add('d-none');
     } else if (previewUrl && lower.match(/\.(pdf)$/)) {
+      const currentRow = row;
+      previewIframe.onerror = () => {
+        if (activeRow !== currentRow) return;
+        previewIframe.classList.add('d-none');
+        previewPlaceholder.classList.remove('d-none');
+        previewPlaceholder.innerHTML = '<div class="small text-muted">Failed to load preview</div>';
+        handlePreviewError();
+      };
       previewIframe.src = previewUrl;
       previewIframe.style.minHeight = '500px';
       previewIframe.classList.remove('d-none');
@@ -2079,14 +2154,17 @@
         })
         .catch(() => {
           if (activeRow !== currentRow) return;
-          previewText.textContent = 'Failed to load preview';
+          previewText.classList.add('d-none');
+          previewPlaceholder.classList.remove('d-none');
+          previewPlaceholder.innerHTML = '<div class="small text-muted">Failed to load preview</div>';
+          handlePreviewError();
         });
     }
 
     const metadataUrl = row.dataset.metadataUrl;
     if (metadataUrl) {
       const metadata = await fetchMetadata(metadataUrl);
-      if (activeRow === row) {
+      if (activeRow === row && !previewFailed) {
         renderMetadata(metadata);
       }
     }
@@ -3993,6 +4071,10 @@
 
   const loadObjectTags = async (row) => {
     if (!row || !previewTagsPanel) return;
+    if (previewFailed) {
+      previewTagsPanel.classList.add('d-none');
+      return;
+    }
     const tagsUrl = row.dataset.tagsUrl;
     if (!tagsUrl) {
       previewTagsPanel.classList.add('d-none');

templates/bucket_detail.html

@@ -257,7 +257,8 @@
               Share Link
             </button>
           </div>
-          <div class="p-3 rounded mb-3" style="background: var(--myfsio-preview-bg);">
+          <div id="preview-error-alert" class="alert alert-warning d-none py-2 px-3 mb-3 small" role="alert"></div>
+          <div id="preview-details-meta" class="p-3 rounded mb-3" style="background: var(--myfsio-preview-bg);">
             <dl class="row small mb-0">
               <dt class="col-5 text-muted fw-normal">Last modified</dt>
               <dd class="col-7 mb-2 fw-medium" id="preview-modified"></dd>