feat: add preview endpoint and UI for Ghost post content with media URL rewriting

apps/admin/src/components/EditorShell.tsx

@@ -17,6 +17,9 @@ export default function EditorShell({ onLogout, initialPostId, onBack }: { onLog
   const [toast, setToast] = useState<{ open: boolean; message: string; severity: 'success' | 'error' } | null>(null);
   const [promptText, setPromptText] = useState<string>('');
   const [activeStep, setActiveStep] = useState<number>(0);
+  const [previewHtml, setPreviewHtml] = useState<string>('');
+  const [previewLoading, setPreviewLoading] = useState<boolean>(false);
+  const [previewError, setPreviewError] = useState<string | null>(null);
 
   useEffect(() => {
     const savedId = initialPostId || localStorage.getItem('voxblog_draft_id');
@@ -104,6 +107,35 @@ export default function EditorShell({ onLogout, initialPostId, onBack }: { onLog
     }
   };
 
+  const refreshPreview = async () => {
+    try {
+      setPreviewLoading(true);
+      setPreviewError(null);
+      const res = await fetch('/api/ghost/preview', {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({
+          html: draft,
+          feature_image: meta.featureImage || undefined,
+        }),
+      });
+      if (!res.ok) throw new Error(await res.text());
+      const data = await res.json();
+      setPreviewHtml(data.html || '');
+    } catch (e: any) {
+      setPreviewError(e?.message || 'Failed to generate preview');
+    } finally {
+      setPreviewLoading(false);
+    }
+  };
+
+  useEffect(() => {
+    if (activeStep === 5) {
+      // Generate preview when entering Publish step
+      refreshPreview();
+    }
+  }, [activeStep]);
+
   // No inline post switching here; selection happens on Posts page
 
   return (
@@ -240,8 +272,24 @@ export default function EditorShell({ onLogout, initialPostId, onBack }: { onLog
           {activeStep === 5 && (
             <Box sx={{ display: 'grid', gap: 1 }}>
               <Typography variant="subtitle1">Publish</Typography>
-              <Typography variant="body2" sx={{ color: 'text.secondary' }}>Preview below is based on current editor HTML.</Typography>
-              <Box sx={{ p: 1.5, border: '1px solid #eee', borderRadius: 1, bgcolor: '#fff' }} dangerouslySetInnerHTML={{ __html: draft }} />
+              <Typography variant="body2" sx={{ color: 'text.secondary' }}>
+                Preview reflects Ghost media URL rewriting. Layout may differ from your Ghost theme.
+              </Typography>
+              <Stack direction="row" spacing={1}>
+                <Button size="small" variant="outlined" onClick={refreshPreview} disabled={previewLoading}>Refresh Preview</Button>
+                <Button size="small" variant="text" onClick={saveDraft}>Save Post</Button>
+              </Stack>
+              {previewLoading && (
+                <Box sx={{ p: 2, border: '1px dashed', borderColor: 'divider', borderRadius: 1 }}>Generating preview…</Box>
+              )}
+              {previewError && (
+                <Alert severity="error">{previewError}</Alert>
+              )}
+              {!previewLoading && !previewError && (
+                <Box sx={{ p: 1.5, border: '1px solid #eee', borderRadius: 1, bgcolor: '#fff' }}
+                  dangerouslySetInnerHTML={{ __html: previewHtml || draft }}
+                />
+              )}
               <Stack direction="row" spacing={1} sx={{ mt: 1 }}>
                 <Button variant="outlined" onClick={() => ghostPublish('draft')}>Save Draft to Ghost</Button>
                 <Button variant="contained" onClick={() => ghostPublish('published')}>Publish to Ghost</Button>

apps/api/src/ghost.ts

@@ -195,4 +195,69 @@ router.post('/post', async (req, res) => {
   }
 });
 
+// Preview endpoint: rewrite media URLs without copying, to render a faithful content preview
+router.post('/preview', async (req, res) => {
+  try {
+    const { html, feature_image } = req.body as { html: string; feature_image?: string };
+
+    const replacePairs: Array<{ from: string; to: string }> = [];
+    const origin = `${req.protocol}://${req.get('host')}`;
+
+    async function rewriteInternalMediaUrlPreview(src: string, _bucketFallback: string): Promise<string> {
+      try {
+        if (!src) return src;
+        // If this references our media proxy, ensure it points to the API origin
+        if (src.startsWith('/api/media/obj')) {
+          const out = `${origin}${src}`;
+          if (out !== src) replacePairs.push({ from: src, to: out });
+          return out;
+        }
+        if (/^https?:\/\//i.test(src)) {
+          try {
+            const uAbs = new URL(src);
+            if (uAbs.pathname === '/api/media/obj') {
+              const out = `${origin}${uAbs.pathname}${uAbs.search}`;
+              if (out !== src) replacePairs.push({ from: src, to: out });
+              return out;
+            }
+            return src;
+          } catch {
+            return src;
+          }
+        }
+        return src;
+      } catch {
+        return src;
+      }
+    }
+
+    async function rewriteHtmlImagesToPublicPreview(htmlIn: string, bucketFallback: string): Promise<string> {
+      if (!htmlIn) return htmlIn;
+      const re = /<img\b[^>]*src=["']([^"']+)["'][^>]*>/gi;
+      const matches = [...htmlIn.matchAll(re)];
+      if (matches.length === 0) return htmlIn;
+      let out = '';
+      let last = 0;
+      for (const m of matches) {
+        const idx = m.index || 0;
+        const full = m[0];
+        const srcAttr = m[1];
+        const newSrc = await rewriteInternalMediaUrlPreview(srcAttr, process.env.S3_BUCKET || '');
+        out += htmlIn.slice(last, idx) + full.replace(srcAttr, newSrc);
+        last = idx + full.length;
+      }
+      out += htmlIn.slice(last);
+      return out;
+    }
+
+    const rewrittenFeatureImage = await rewriteInternalMediaUrlPreview(feature_image || '', '');
+    const rewrittenHtml = await rewriteHtmlImagesToPublicPreview(html, '');
+
+    return res.json({ html: rewrittenHtml, feature_image: rewrittenFeatureImage, replacements: replacePairs });
+  } catch (err: any) {
+    console.error('Ghost preview failed:', err);
+    return res.status(500).json({ error: 'Ghost preview failed', detail: err?.message || String(err) });
+  }
+});
+
 export default router;