feat: Add S3 metadata handling and soft-lock mechanism in backend, enhance ASNs, Domains, and IPRanges managers with ETag support and change preview functionality for improved data integrity and user experience

backend/server.js

@@ -55,6 +55,36 @@ function buildNestedGatewayBlocks(gatewayGroups, baseIndentSpaces = 4) {
     return buildAt(0, baseIndentSpaces);
 }
 
+// Helper: read text file from S3 and return { body, etag, lastModified, contentLength }
+async function readS3TextObject(key) {
+    const params = { Bucket: BUCKET_NAME, Key: key };
+    const data = await s3.getObject(params).promise();
+    return {
+        body: data.Body.toString('utf-8'),
+        etag: data.ETag ? String(data.ETag).replace(/\"/g, '"') : undefined,
+        lastModified: data.LastModified ? data.LastModified.toISOString() : undefined,
+        contentLength: typeof data.ContentLength === 'number' ? data.ContentLength : undefined
+    };
+}
+
+// Helper: head object and return current ETag
+async function headS3ObjectEtag(key) {
+    const head = await s3.headObject({ Bucket: BUCKET_NAME, Key: key }).promise();
+    return head.ETag ? String(head.ETag).replace(/\"/g, '"') : undefined;
+}
+
+// Simple in-memory soft locks with TTL
+const locks = new Map(); // key -> { owner, expiresAt }
+function cleanupExpiredLocks() {
+    const now = Date.now();
+    for (const [k, v] of locks.entries()) {
+        if (!v || typeof v.expiresAt !== 'number' || v.expiresAt <= now) {
+            locks.delete(k);
+        }
+    }
+}
+setInterval(cleanupExpiredLocks, 30_000);
+
 // Get domains from S3
 app.get('/api/domains', async (req, res) => {
     const params = {
@@ -73,6 +103,15 @@ app.get('/api/domains', async (req, res) => {
             const type = parts[1] || '';
             return { domain, type };
         });
+        if (data.ETag) {
+            res.set('ETag', String(data.ETag));
+        }
+        if (data.LastModified) {
+            res.set('Last-Modified', new Date(data.LastModified).toUTCString());
+        }
+        if (typeof data.ContentLength === 'number') {
+            res.set('Content-Length-Source', String(data.ContentLength));
+        }
         res.json(domains);
     } catch (error) {
         if (error.code === 'NoSuchKey') {
@@ -84,10 +123,22 @@ app.get('/api/domains', async (req, res) => {
     }
 });
 
-// Update domains in S3
+// Update domains in S3 with optimistic concurrency via ETag check
 app.post('/api/domains', async (req, res) => {
-    const { domains } = req.body;
-    const fileContent = domains.map(d => `${d.domain} ${d.type}`).join('\n');
+    const { domains, etag } = req.body;
+    const fileContent = (domains || []).map(d => `${String(d.domain || '').trim()} ${String(d.type || '').trim()}`.trim()).filter(Boolean).join('\n');
+
+    // Concurrency guard: if client sent etag, ensure current ETag matches
+    try {
+        if (etag) {
+            const current = await headS3ObjectEtag(FILE_KEY).catch(() => undefined);
+            if (current && current.replace(/\"/g, '"') !== String(etag)) {
+                return res.status(412).json({ message: 'Precondition Failed: ETag mismatch' });
+            }
+        }
+    } catch (e) {
+        // ignore if head fails due to NoSuchKey; proceed to create
+    }
 
     const params = {
         Bucket: BUCKET_NAME,
@@ -97,7 +148,8 @@ app.post('/api/domains', async (req, res) => {
     };
 
     try {
-        await s3.putObject(params).promise();
+        const put = await s3.putObject(params).promise();
+        res.set('ETag', put.ETag || '');
         res.send('File updated successfully');
     } catch (error) {
         console.error(error);
@@ -123,6 +175,9 @@ app.get('/api/asns', async (req, res) => {
             const type = parts[1] || '';
             return { domain, type };
         });
+        if (data.ETag) res.set('ETag', String(data.ETag));
+        if (data.LastModified) res.set('Last-Modified', new Date(data.LastModified).toUTCString());
+        if (typeof data.ContentLength === 'number') res.set('Content-Length-Source', String(data.ContentLength));
         res.json(asns);
     } catch (error) {
         if (error.code === 'NoSuchKey') {
@@ -136,8 +191,17 @@ app.get('/api/asns', async (req, res) => {
 
 // Update ASNs in S3
 app.post('/api/asns', async (req, res) => {
-    const { domains: asns } = req.body; // Keep name 'domains' for consistency
-    const fileContent = asns.map(a => `${a.domain} ${a.type}`).join('\n');
+    const { domains: asns, etag } = req.body; // Keep name 'domains' for consistency
+    const fileContent = (asns || []).map(a => `${String(a.domain || '').trim()} ${String(a.type || '').trim()}`.trim()).filter(Boolean).join('\n');
+
+    try {
+        if (etag) {
+            const current = await headS3ObjectEtag('bgp_data/asns.txt').catch(() => undefined);
+            if (current && current.replace(/\"/g, '"') !== String(etag)) {
+                return res.status(412).json({ message: 'Precondition Failed: ETag mismatch' });
+            }
+        }
+    } catch {}
 
     const params = {
         Bucket: BUCKET_NAME,
@@ -147,7 +211,8 @@ app.post('/api/asns', async (req, res) => {
     };
 
     try {
-        await s3.putObject(params).promise();
+        const put = await s3.putObject(params).promise();
+        if (put.ETag) res.set('ETag', String(put.ETag));
         res.send('File updated successfully');
     } catch (error) {
         console.error(error);
@@ -173,6 +238,9 @@ app.get('/api/domains-new', async (req, res) => {
             const community = parts[1] || '';
             return { domain, community };
         });
+        if (data.ETag) res.set('ETag', String(data.ETag));
+        if (data.LastModified) res.set('Last-Modified', new Date(data.LastModified).toUTCString());
+        if (typeof data.ContentLength === 'number') res.set('Content-Length-Source', String(data.ContentLength));
         res.json(domains);
     } catch (error) {
         if (error.code === 'NoSuchKey') {
@@ -186,8 +254,17 @@ app.get('/api/domains-new', async (req, res) => {
 
 // Update domains-new in S3
 app.post('/api/domains-new', async (req, res) => {
-    const { domains } = req.body;
-    const fileContent = domains.map(d => `${d.domain} ${d.community}`).join('\n');
+    const { domains, etag } = req.body;
+    const fileContent = (domains || []).map(d => `${String(d.domain || '').trim()} ${String(d.community || '').trim()}`.trim()).filter(Boolean).join('\n');
+
+    try {
+        if (etag) {
+            const current = await headS3ObjectEtag('bgp_data/domains_community.txt').catch(() => undefined);
+            if (current && current.replace(/\"/g, '"') !== String(etag)) {
+                return res.status(412).json({ message: 'Precondition Failed: ETag mismatch' });
+            }
+        }
+    } catch {}
 
     const params = {
         Bucket: BUCKET_NAME,
@@ -197,7 +274,8 @@ app.post('/api/domains-new', async (req, res) => {
     };
 
     try {
-        await s3.putObject(params).promise();
+        const put = await s3.putObject(params).promise();
+        if (put.ETag) res.set('ETag', String(put.ETag));
         res.send('File updated successfully');
     } catch (error) {
         console.error(error);
@@ -223,6 +301,9 @@ app.get('/api/ip-ranges', async (req, res) => {
             const community = parts[1] || '';
             return { ipRange, community };
         });
+        if (data.ETag) res.set('ETag', String(data.ETag));
+        if (data.LastModified) res.set('Last-Modified', new Date(data.LastModified).toUTCString());
+        if (typeof data.ContentLength === 'number') res.set('Content-Length-Source', String(data.ContentLength));
         res.json(ipRanges);
     } catch (error) {
         if (error.code === 'NoSuchKey') {
@@ -236,8 +317,17 @@ app.get('/api/ip-ranges', async (req, res) => {
 
 // Update IP ranges in S3
 app.post('/api/ip-ranges', async (req, res) => {
-    const { ipRanges } = req.body;
-    const fileContent = ipRanges.map(ip => `${ip.ipRange} ${ip.community}`).join('\n');
+    const { ipRanges, etag } = req.body;
+    const fileContent = (ipRanges || []).map(ip => `${String(ip.ipRange || '').trim()} ${String(ip.community || '').trim()}`.trim()).filter(Boolean).join('\n');
+
+    try {
+        if (etag) {
+            const current = await headS3ObjectEtag('bgp_data/ips.txt').catch(() => undefined);
+            if (current && current.replace(/\"/g, '"') !== String(etag)) {
+                return res.status(412).json({ message: 'Precondition Failed: ETag mismatch' });
+            }
+        }
+    } catch {}
 
     const params = {
         Bucket: BUCKET_NAME,
@@ -247,7 +337,8 @@ app.post('/api/ip-ranges', async (req, res) => {
     };
 
     try {
-        await s3.putObject(params).promise();
+        const put = await s3.putObject(params).promise();
+        if (put.ETag) res.set('ETag', String(put.ETag));
         res.send('File updated successfully');
     } catch (error) {
         console.error(error);
@@ -554,49 +645,71 @@ app.post('/api/filters', async (req, res) => {
     }
 });
 
-// Новый эндпоинт для получения дат последнего изменения файлов S3
+// Эндпоинт метаданных S3 по ключевым файлам (Last-Modified, ETag, Content-Length)
 app.get('/api/s3/last-modified', async (req, res) => {
     try {
-        const results = await Promise.allSettled([
-            s3.headObject({ Bucket: BUCKET_NAME, Key: 'bgp_data/domains_community.txt' }).promise(),
-            s3.headObject({ Bucket: BUCKET_NAME, Key: 'bgp_data/domains_community.txt' }).promise(),
-            s3.headObject({ Bucket: BUCKET_NAME, Key: 'bgp_data/asns.txt' }).promise(),
-            s3.headObject({ Bucket: BUCKET_NAME, Key: 'servers.json' }).promise(),
-            s3.headObject({ Bucket: BUCKET_NAME, Key: 'filters.json' }).promise()
-        ]);
-
-        const response = {
-            domainsLastModified: null,
-            domainsNewLastModified: null,
-            asnsLastModified: null,
-            serversLastModified: null,
-            filtersLastModified: null
-        };
-
-        // Обрабатываем результаты
-        if (results[0].status === 'fulfilled') {
-            response.domainsLastModified = results[0].value.LastModified ? results[0].value.LastModified.toISOString() : null;
-        }
-        if (results[1].status === 'fulfilled') {
-            response.domainsNewLastModified = results[1].value.LastModified ? results[1].value.LastModified.toISOString() : null;
-        }
-        if (results[2].status === 'fulfilled') {
-            response.asnsLastModified = results[2].value.LastModified ? results[2].value.LastModified.toISOString() : null;
-        }
-        if (results[3].status === 'fulfilled') {
-            response.serversLastModified = results[3].value.LastModified ? results[3].value.LastModified.toISOString() : null;
-        }
-        if (results[4].status === 'fulfilled') {
-            response.filtersLastModified = results[4].value.LastModified ? results[4].value.LastModified.toISOString() : null;
-        }
-
-        res.json(response);
+        const keys = [
+            { name: 'domainsNew', key: 'bgp_data/domains_community.txt' },
+            { name: 'asns', key: 'bgp_data/asns.txt' },
+            { name: 'servers', key: 'servers.json' },
+            { name: 'filters', key: 'filters.json' },
+            { name: 'ipRanges', key: 'bgp_data/ips.txt' }
+        ];
+        const results = await Promise.allSettled(
+            keys.map(k => s3.headObject({ Bucket: BUCKET_NAME, Key: k.key }).promise())
+        );
+        const out = {};
+        results.forEach((r, idx) => {
+            const name = keys[idx].name;
+            if (r.status === 'fulfilled') {
+                out[name] = {
+                    lastModified: r.value.LastModified ? r.value.LastModified.toISOString() : null,
+                    etag: r.value.ETag || null,
+                    contentLength: typeof r.value.ContentLength === 'number' ? r.value.ContentLength : null
+                };
+            } else {
+                out[name] = null;
+            }
+        });
+        res.json(out);
     } catch (error) {
         console.error('Error fetching last modified dates from S3:', error);
         res.status(500).send('Error fetching last modified dates from S3');
     }
 });
 
+// Soft-lock endpoints
+// GET lock status
+app.get('/api/locks/:resource', (req, res) => {
+    cleanupExpiredLocks();
+    const { resource } = req.params;
+    const info = locks.get(resource);
+    if (!info) return res.json({ locked: false });
+    res.json({ locked: true, owner: info.owner, expiresAt: info.expiresAt });
+});
+
+// POST acquire/refresh lock
+app.post('/api/locks/:resource', (req, res) => {
+    cleanupExpiredLocks();
+    const { resource } = req.params;
+    const { owner = 'anonymous', ttlSeconds = 120 } = req.body || {};
+    const now = Date.now();
+    const existing = locks.get(resource);
+    if (existing && existing.expiresAt > now && existing.owner !== owner) {
+        return res.status(423).json({ message: 'Resource is locked by another user', owner: existing.owner, expiresAt: existing.expiresAt });
+    }
+    const expiresAt = now + Math.max(30, Math.min(600, Number(ttlSeconds) || 120)) * 1000;
+    locks.set(resource, { owner, expiresAt });
+    res.json({ locked: true, owner, expiresAt });
+});
+
+// DELETE release lock
+app.delete('/api/locks/:resource', (req, res) => {
+    const { resource } = req.params;
+    locks.delete(resource);
+    res.json({ released: true });
+});
+
 // Generate MikroTik configuration from filters
 app.get('/api/filters/generate-config', async (req, res) => {
     const params = {

frontend/src/ASNsNewManager.jsx

@@ -19,6 +19,10 @@ const API_URL = '/api';
 
 function ASNsNewManager() {
   const [items, setItems] = useState([]);
+  const [originalItems, setOriginalItems] = useState([]);
+  const [etag, setEtag] = useState('');
+  const [lastModified, setLastModified] = useState('');
+  const [contentLength, setContentLength] = useState(null);
   const [newItem, setNewItem] = useState({ asn: '', community: '' });
   const [newInvalid, setNewInvalid] = useState({ asn: false, community: false });
   const [error, setError] = useState('');
@@ -66,14 +70,33 @@ function ASNsNewManager() {
   const isValidCommunity = (value) => /^(\d+|\d+:\d+)$/.test(String(value).trim());
 
   useEffect(() => {
+    // Acquire soft lock
+    const owner = localStorage.getItem('uiOwner') || `ui-${Math.random().toString(36).slice(2,8)}`;
+    localStorage.setItem('uiOwner', owner);
+    const resource = 'asns';
+    const acquire = async () => {
+      try { await axios.post(`${API_URL}/locks/${resource}`, { owner, ttlSeconds: 180 }); } catch {}
+    };
+    acquire();
+    const interval = setInterval(acquire, 60_000);
     fetchItems();
+    return () => {
+      clearInterval(interval);
+      axios.delete(`${API_URL}/locks/${resource}`).catch(() => {});
+    };
   }, []);
 
   const fetchItems = async () => {
     setLoading(true);
     try {
       const response = await axios.get(`${API_URL}/asns`);
-      setItems(response.data.map(item => ({ asn: item.domain, community: item.type })));
+      const mapped = response.data.map(item => ({ asn: item.domain, community: item.type }));
+      setItems(mapped);
+      setOriginalItems(mapped);
+      setEtag(response.headers?.etag || '');
+      setLastModified(response.headers?.['last-modified'] || '');
+      const lengthHeader = response.headers?.['content-length-source'];
+      setContentLength(typeof lengthHeader !== 'undefined' ? Number(lengthHeader) : null);
       setError('');
     } catch (error) {
       console.error('Error fetching ASNs:', error);
@@ -135,12 +158,64 @@ function ASNsNewManager() {
     }
   };
 
+  const deduplicate = (arr) => {
+    const seen = new Set();
+    const out = [];
+    for (const i of arr) {
+      const key = String(i.asn).trim();
+      if (!key) continue;
+      if (seen.has(key)) continue;
+      seen.add(key);
+      out.push({ asn: key, community: String(i.community || '').trim() });
+    }
+    return out;
+  };
+
+  const computeDiff = (before, after) => {
+    const mapBefore = new Map(before.map(i => [i.asn, i]));
+    const mapAfter = new Map(after.map(i => [i.asn, i]));
+    const added = [];
+    const removed = [];
+    const changed = [];
+    for (const [k, v] of mapAfter) {
+      if (!mapBefore.has(k)) { added.push(v); continue; }
+      const prev = mapBefore.get(k);
+      if (String(prev.community) !== String(v.community)) changed.push({ from: prev, to: v });
+    }
+    for (const [k, v] of mapBefore) {
+      if (!mapAfter.has(k)) removed.push(v);
+    }
+    return { added, removed, changed };
+  };
+
+  const [showDiff, setShowDiff] = useState(false);
+  const [diff, setDiff] = useState({ added: [], removed: [], changed: [] });
+
+  const handlePreviewDiff = () => {
+    const valid = items.filter(i => isValidAsn(i.asn) && isValidCommunity(i.community))
+      .map(i => ({ asn: String(i.asn).trim(), community: String(i.community).trim() }));
+    const unique = deduplicate(valid);
+    setDiff(computeDiff(originalItems, unique));
+    setShowDiff(true);
+  };
+
   const handleSaveChanges = async () => {
     setLoading(true);
     try {
       // API ожидает domains: [{domain, type}]
-      const valid = items.filter(i => isValidAsn(i.asn) && isValidCommunity(i.community));
-      await axios.post(`${API_URL}/asns`, { domains: valid.map(i => ({ domain: i.asn, type: i.community })) });
+      const valid = items.filter(i => isValidAsn(i.asn) && isValidCommunity(i.community))
+        .map(i => ({ asn: String(i.asn).trim(), community: String(i.community).trim() }));
+      const unique = deduplicate(valid);
+      const payload = { domains: unique.map(i => ({ domain: i.asn, type: i.community })), etag };
+      const response = await axios.post(`${API_URL}/asns`, payload, { validateStatus: () => true });
+      if (response.status === 412) {
+        setError('Данные изменились в S3 (ETag mismatch). Обновите список и попробуйте снова.');
+        return;
+      }
+      if (response.status >= 400) throw new Error(`Save failed with status ${response.status}`);
+      setEtag(response.headers?.etag || etag);
+      setOriginalItems(unique);
+      setItems(unique);
       setSuccess('Изменения успешно сохранены!');
       setTimeout(() => setSuccess(''), 3000);
     } catch (error) {
@@ -157,9 +232,17 @@ function ASNsNewManager() {
     const lines = text.split(/\r?\n/).map(l => l.trim()).filter(Boolean);
     const parsed = lines.map(l => {
       const [a, c] = l.split(/\s+/);
-      return { asn: a || '', community: c || '' };
+      return { asn: (a || '').trim(), community: (c || '').trim() };
+    }).filter(i => isValidAsn(i.asn) && isValidCommunity(i.community));
+    setItems(prev => {
+      const merged = [...prev, ...parsed];
+      const map = new Map();
+      for (const it of merged) {
+        const key = String(it.asn).trim();
+        if (!map.has(key)) map.set(key, { asn: key, community: String(it.community).trim() });
+      }
+      return Array.from(map.values());
     });
-    setItems(prev => [...prev, ...parsed]);
   };
 
   const handleExport = () => {
@@ -369,6 +452,13 @@ function ASNsNewManager() {
                   <IconDownload className="icon me-2" />
                   Экспорт CSV
                 </button>
+                <button 
+                  className="btn btn-outline-secondary"
+                  onClick={handlePreviewDiff}
+                  disabled={loading}
+                >
+                  Предпросмотр изменений
+                </button>
                 <button 
                   className="btn btn-outline-secondary"
                   onClick={clearInvalid}
@@ -408,6 +498,13 @@ function ASNsNewManager() {
                 </div>
               </div>
             </div>
+            {(etag || lastModified) && (
+              <div className="card-status-bottom bg-transparent px-3 py-2 text-muted small">
+                <span className="me-3">ETag: <code>{etag || '—'}</code></span>
+                <span className="me-3">Last-Modified: {lastModified || '—'}</span>
+                <span>Размер (байт): {contentLength ?? '—'}</span>
+              </div>
+            )}
             <div className="table-responsive">
               <table className="table card-table table-vcenter table-nowrap mb-0">
                 <thead>

frontend/src/Dashboard.jsx

@@ -98,9 +98,9 @@ function Dashboard() {
         const onlineServers = servers.filter(server => server.status === 'Онлайн').length;
 
         // Получаем дату последнего обновления
-        const lastModified = s3Res.status === 'fulfilled' && s3Res.value.data?.domainsLastModified 
-          ? new Date(s3Res.value.data.domainsLastModified).toLocaleString()
-          : new Date().toLocaleString();
+          // Новый формат: объект с ключами { domainsNew, asns, servers, filters, ipRanges }
+          const lmRaw = s3Res.status === 'fulfilled' ? s3Res.value.data?.domainsNew?.lastModified : null;
+          const lastModified = lmRaw ? new Date(lmRaw).toLocaleString() : new Date().toLocaleString();
 
         setStats({
           domainsCount: domainsRes.status === 'fulfilled' ? domainsRes.value.data.length : 0,

frontend/src/DomainsNewManager.jsx

@@ -19,6 +19,10 @@ const API_URL = '/api';
 
 function DomainsNewManager() {
   const [items, setItems] = useState([]);
+  const [originalItems, setOriginalItems] = useState([]);
+  const [etag, setEtag] = useState('');
+  const [lastModified, setLastModified] = useState('');
+  const [contentLength, setContentLength] = useState(null);
   const [newItem, setNewItem] = useState({ domain: '', community: '' });
   const [newInvalid, setNewInvalid] = useState({ domain: false, community: false });
   const [error, setError] = useState('');
@@ -71,7 +75,20 @@ function DomainsNewManager() {
   const isValidCommunity = (value) => /^(\d+|\d+:\d+)$/.test(String(value).trim());
 
   useEffect(() => {
+    // Acquire soft lock
+    const owner = localStorage.getItem('uiOwner') || `ui-${Math.random().toString(36).slice(2,8)}`;
+    localStorage.setItem('uiOwner', owner);
+    const resource = 'domains-new';
+    const acquire = async () => {
+      try { await axios.post(`${API_URL}/locks/${resource}`, { owner, ttlSeconds: 180 }); } catch {}
+    };
+    acquire();
+    const interval = setInterval(acquire, 60_000);
     fetchItems();
+    return () => {
+      clearInterval(interval);
+      axios.delete(`${API_URL}/locks/${resource}`).catch(() => {});
+    };
   }, []);
 
   const fetchItems = async () => {
@@ -79,6 +96,11 @@ function DomainsNewManager() {
     try {
       const response = await axios.get(`${API_URL}/domains-new`);
       setItems(response.data);
+      setOriginalItems(response.data);
+      setEtag(response.headers?.etag || '');
+      setLastModified(response.headers?.['last-modified'] || '');
+      const lengthHeader = response.headers?.['content-length-source'];
+      setContentLength(typeof lengthHeader !== 'undefined' ? Number(lengthHeader) : null);
       setError('');
     } catch (error) {
       console.error('Error fetching domains-new:', error);
@@ -140,12 +162,65 @@ function DomainsNewManager() {
     }
   };
 
+  const deduplicate = (arr) => {
+    const seen = new Set();
+    const out = [];
+    for (const i of arr) {
+      const key = String(i.domain).trim().toLowerCase();
+      if (!key) continue;
+      if (seen.has(key)) continue;
+      seen.add(key);
+      out.push({ domain: key, community: String(i.community || '').trim() });
+    }
+    return out;
+  };
+
+  const computeDiff = (before, after) => {
+    const mapBefore = new Map(before.map(i => [i.domain, i]));
+    const mapAfter = new Map(after.map(i => [i.domain, i]));
+    const added = [];
+    const removed = [];
+    const changed = [];
+    for (const [k, v] of mapAfter) {
+      if (!mapBefore.has(k)) { added.push(v); continue; }
+      const prev = mapBefore.get(k);
+      if (String(prev.community) !== String(v.community)) changed.push({ from: prev, to: v });
+    }
+    for (const [k, v] of mapBefore) {
+      if (!mapAfter.has(k)) removed.push(v);
+    }
+    return { added, removed, changed };
+  };
+
+  const [showDiff, setShowDiff] = useState(false);
+  const [diff, setDiff] = useState({ added: [], removed: [], changed: [] });
+
+  const handlePreviewDiff = () => {
+    const valid = items.filter(i => isValidDomain(i.domain) && isValidCommunity(i.community))
+      .map(i => ({ domain: i.domain.trim().toLowerCase(), community: String(i.community).trim() }));
+    const unique = deduplicate(valid);
+    setDiff(computeDiff(originalItems, unique));
+    setShowDiff(true);
+  };
+
   const handleSaveChanges = async () => {
     setLoading(true);
     try {
-      // сохраняем только валидные строки
-      const valid = items.filter(i => isValidDomain(i.domain) && isValidCommunity(i.community));
-      await axios.post(`${API_URL}/domains-new`, { domains: valid });
+      // сохраняем только валидные строки + дедупликация
+      const valid = items.filter(i => isValidDomain(i.domain) && isValidCommunity(i.community))
+        .map(i => ({ domain: i.domain.trim().toLowerCase(), community: String(i.community).trim() }));
+      const unique = deduplicate(valid);
+      const response = await axios.post(`${API_URL}/domains-new`, { domains: unique, etag }, { validateStatus: () => true });
+      if (response.status === 412) {
+        setError('Данные изменились в S3 (ETag mismatch). Обновите список и попробуйте снова.');
+        return;
+      }
+      if (response.status >= 400) {
+        throw new Error(`Save failed with status ${response.status}`);
+      }
+      setEtag(response.headers?.etag || etag);
+      setOriginalItems(unique);
+      setItems(unique);
       setSuccess('Изменения успешно сохранены!');
       setTimeout(() => setSuccess(''), 3000);
     } catch (error) {
@@ -162,9 +237,18 @@ function DomainsNewManager() {
     const lines = text.split(/\r?\n/).map(l => l.trim()).filter(Boolean);
     const parsed = lines.map(l => {
       const [d, c] = l.split(/\s+/);
-      return { domain: (d || '').toLowerCase(), community: c || '' };
+      return { domain: (d || '').toLowerCase(), community: (c || '').trim() };
+    }).filter(i => isValidDomain(i.domain) && isValidCommunity(i.community));
+    // merge and dedup
+    setItems(prev => {
+      const merged = [...prev, ...parsed];
+      const map = new Map();
+      for (const it of merged) {
+        const key = String(it.domain).trim().toLowerCase();
+        if (!map.has(key)) map.set(key, { domain: key, community: String(it.community).trim() });
+      }
+      return Array.from(map.values());
     });
-    setItems(prev => [...prev, ...parsed]);
   };
 
   const handleExport = () => {
@@ -333,7 +417,7 @@ function DomainsNewManager() {
                 Действия
               </h3>
             </div>
-            <div className="card-body">
+          <div className="card-body">
               <div className="d-grid gap-2">
                 <button 
                   className="btn btn-primary"
@@ -352,6 +436,13 @@ function DomainsNewManager() {
                     </>
                   )}
                 </button>
+                <button 
+                  className="btn btn-outline-secondary"
+                  onClick={handlePreviewDiff}
+                  disabled={loading}
+                >
+                  Предпросмотр изменений
+                </button>
                 <button 
                   className="btn btn-outline-secondary"
                   onClick={fetchItems}
@@ -414,6 +505,13 @@ function DomainsNewManager() {
                 </div>
               </div>
             </div>
+            { (etag || lastModified) && (
+              <div className="card-status-bottom bg-transparent px-3 py-2 text-muted small">
+                <span className="me-3">ETag: <code>{etag || '—'}</code></span>
+                <span className="me-3">Last-Modified: {lastModified || '—'}</span>
+                <span>Размер (байт): {contentLength ?? '—'}</span>
+              </div>
+            )}
             <div className="table-responsive">
               <table className="table card-table table-vcenter table-nowrap mb-0">
                 <thead>
@@ -555,6 +653,27 @@ function DomainsNewManager() {
           </div>
         </div>
       )}
+      {/* Diff Modal */}
+      {showDiff && (
+        <div className="modal modal-blur fade show" style={{display: 'block'}} tabIndex="-1">
+          <div className="modal-dialog modal-lg modal-dialog-centered" role="document">
+            <div className="modal-content">
+              <button type="button" className="btn-close" onClick={() => setShowDiff(false)}></button>
+              <div className="modal-header"><h3 className="modal-title">Изменения</h3></div>
+              <div className="modal-body">
+                <div className="row g-3">
+                  <div className="col-md-4"><div className="card"><div className="card-body"><strong>Добавлено</strong><div className="text-muted">{diff.added.length}</div></div></div></div>
+                  <div className="col-md-4"><div className="card"><div className="card-body"><strong>Удалено</strong><div className="text-muted">{diff.removed.length}</div></div></div></div>
+                  <div className="col-md-4"><div className="card"><div className="card-body"><strong>Изменено</strong><div className="text-muted">{diff.changed.length}</div></div></div></div>
+                </div>
+              </div>
+              <div className="modal-footer">
+                <button className="btn" onClick={() => setShowDiff(false)}>Закрыть</button>
+              </div>
+            </div>
+          </div>
+        </div>
+      )}
       {/* datalist больше не нужен, т.к. используем кастомный автокомплит */}
     </>
   );

frontend/src/IPRangesManager.jsx

@@ -19,6 +19,10 @@ const API_URL = '/api';
 
 function IPRangesManager() {
   const [items, setItems] = useState([]);
+  const [originalItems, setOriginalItems] = useState([]);
+  const [etag, setEtag] = useState('');
+  const [lastModified, setLastModified] = useState('');
+  const [contentLength, setContentLength] = useState(null);
   const [newItem, setNewItem] = useState({ ipRange: '', community: '' });
   const [newInvalid, setNewInvalid] = useState({ ipRange: false, community: false });
   const [error, setError] = useState('');
@@ -82,7 +86,20 @@ function IPRangesManager() {
   const isValidCommunity = (value) => /^(\d+|\d+:\d+)$/.test(String(value).trim());
 
   useEffect(() => {
+    // Acquire soft lock
+    const owner = localStorage.getItem('uiOwner') || `ui-${Math.random().toString(36).slice(2,8)}`;
+    localStorage.setItem('uiOwner', owner);
+    const resource = 'ip-ranges';
+    const acquire = async () => {
+      try { await axios.post(`${API_URL}/locks/${resource}`, { owner, ttlSeconds: 180 }); } catch {}
+    };
+    acquire();
+    const interval = setInterval(acquire, 60_000);
     fetchItems();
+    return () => {
+      clearInterval(interval);
+      axios.delete(`${API_URL}/locks/${resource}`).catch(() => {});
+    };
   }, []);
 
   const fetchItems = async () => {
@@ -90,6 +107,11 @@ function IPRangesManager() {
     try {
       const response = await axios.get(`${API_URL}/ip-ranges`);
       setItems(response.data);
+      setOriginalItems(response.data);
+      setEtag(response.headers?.etag || '');
+      setLastModified(response.headers?.['last-modified'] || '');
+      const lengthHeader = response.headers?.['content-length-source'];
+      setContentLength(typeof lengthHeader !== 'undefined' ? Number(lengthHeader) : null);
       setError('');
     } catch (error) {
       console.error('Error fetching ip-ranges:', error);
@@ -151,11 +173,64 @@ function IPRangesManager() {
     }
   };
 
+  const deduplicate = (arr) => {
+    const seen = new Set();
+    const out = [];
+    for (const i of arr) {
+      const key = String(i.ipRange).trim();
+      if (!key) continue;
+      if (seen.has(key)) continue;
+      seen.add(key);
+      out.push({ ipRange: key, community: String(i.community || '').trim() });
+    }
+    return out;
+  };
+
+  const computeDiff = (before, after) => {
+    const mapBefore = new Map(before.map(i => [i.ipRange, i]));
+    const mapAfter = new Map(after.map(i => [i.ipRange, i]));
+    const added = [];
+    const removed = [];
+    const changed = [];
+    for (const [k, v] of mapAfter) {
+      if (!mapBefore.has(k)) { added.push(v); continue; }
+      const prev = mapBefore.get(k);
+      if (String(prev.community) !== String(v.community)) changed.push({ from: prev, to: v });
+    }
+    for (const [k, v] of mapBefore) {
+      if (!mapAfter.has(k)) removed.push(v);
+    }
+    return { added, removed, changed };
+  };
+
+  const [showDiff, setShowDiff] = useState(false);
+  const [diff, setDiff] = useState({ added: [], removed: [], changed: [] });
+
+  const handlePreviewDiff = () => {
+    const valid = items.filter(i => isValidCidr(i.ipRange) && isValidCommunity(i.community))
+      .map(i => ({ ipRange: i.ipRange.trim(), community: String(i.community).trim() }));
+    const unique = deduplicate(valid);
+    setDiff(computeDiff(originalItems, unique));
+    setShowDiff(true);
+  };
+
   const handleSaveChanges = async () => {
     setLoading(true);
     try {
-      const valid = items.filter(i => isValidCidr(i.ipRange) && isValidCommunity(i.community));
-      await axios.post(`${API_URL}/ip-ranges`, { ipRanges: valid });
+      const valid = items.filter(i => isValidCidr(i.ipRange) && isValidCommunity(i.community))
+        .map(i => ({ ipRange: i.ipRange.trim(), community: String(i.community).trim() }));
+      const unique = deduplicate(valid);
+      const response = await axios.post(`${API_URL}/ip-ranges`, { ipRanges: unique, etag }, { validateStatus: () => true });
+      if (response.status === 412) {
+        setError('Данные изменились в S3 (ETag mismatch). Обновите список и попробуйте снова.');
+        return;
+      }
+      if (response.status >= 400) {
+        throw new Error(`Save failed with status ${response.status}`);
+      }
+      setEtag(response.headers?.etag || etag);
+      setOriginalItems(unique);
+      setItems(unique);
       setSuccess('Изменения успешно сохранены!');
       setTimeout(() => setSuccess(''), 3000);
     } catch (error) {
@@ -172,9 +247,17 @@ function IPRangesManager() {
     const lines = text.split(/\r?\n/).map(l => l.trim()).filter(Boolean);
     const parsed = lines.map(l => {
       const [cidr, c] = l.split(/\s+/);
-      return { ipRange: cidr || '', community: c || '' };
+      return { ipRange: (cidr || '').trim(), community: (c || '').trim() };
+    }).filter(i => isValidCidr(i.ipRange) && isValidCommunity(i.community));
+    setItems(prev => {
+      const merged = [...prev, ...parsed];
+      const map = new Map();
+      for (const it of merged) {
+        const key = String(it.ipRange).trim();
+        if (!map.has(key)) map.set(key, { ipRange: key, community: String(it.community).trim() });
+      }
+      return Array.from(map.values());
     });
-    setItems(prev => [...prev, ...parsed]);
   };
 
   const handleExport = () => {
@@ -384,6 +467,13 @@ function IPRangesManager() {
                   <IconDownload className="icon me-2" />
                   Экспорт CSV
                 </button>
+                <button 
+                  className="btn btn-outline-secondary"
+                  onClick={handlePreviewDiff}
+                  disabled={loading}
+                >
+                  Предпросмотр изменений
+                </button>
                 <button 
                   className="btn btn-outline-secondary"
                   onClick={clearInvalid}
@@ -423,6 +513,13 @@ function IPRangesManager() {
                 </div>
               </div>
             </div>
+            {(etag || lastModified) && (
+              <div className="card-status-bottom bg-transparent px-3 py-2 text-muted small">
+                <span className="me-3">ETag: <code>{etag || '—'}</code></span>
+                <span className="me-3">Last-Modified: {lastModified || '—'}</span>
+                <span>Размер (байт): {contentLength ?? '—'}</span>
+              </div>
+            )}
             <div className="table-responsive">
               <table className="table card-table table-vcenter table-nowrap mb-0">
                 <thead>
@@ -569,6 +666,27 @@ function IPRangesManager() {
           </div>
         </div>
       )}
+      {/* Diff Modal */}
+      {showDiff && (
+        <div className="modal modal-blur fade show" style={{display: 'block'}} tabIndex="-1">
+          <div className="modal-dialog modal-lg modal-dialog-centered" role="document">
+            <div className="modal-content">
+              <button type="button" className="btn-close" onClick={() => setShowDiff(false)}></button>
+              <div className="modal-header"><h3 className="modal-title">Изменения</h3></div>
+              <div className="modal-body">
+                <div className="row g-3">
+                  <div className="col-md-4"><div className="card"><div className="card-body"><strong>Добавлено</strong><div className="text-muted">{diff.added.length}</div></div></div></div>
+                  <div className="col-md-4"><div className="card"><div className="card-body"><strong>Удалено</strong><div className="text-muted">{diff.removed.length}</div></div></div></div>
+                  <div className="col-md-4"><div className="card"><div className="card-body"><strong>Изменено</strong><div className="text-muted">{diff.changed.length}</div></div></div></div>
+                </div>
+              </div>
+              <div className="modal-footer">
+                <button className="btn" onClick={() => setShowDiff(false)}>Закрыть</button>
+              </div>
+            </div>
+          </div>
+        </div>
+      )}
       {/* datalist больше не нужен, т.к. используем кастомный автокомплит */}
     </>
   );