refactor(mikrotikApplyService): enhance file retrieval logic with improved error handling and support for large files

backend/services/mikrotikApplyService.js

@@ -358,21 +358,74 @@ async function fetchExportViaFile(client) {
 
   await client.command('export', { compact: '', file: basename });
 
-  const printRes = await client.command('file/print', {
-    '.proplist': 'contents,.id',
-    '.query': [`name=${basename}`],
-  });
-  const data = printRes?.data;
-  const list = Array.isArray(data) ? data : (data ? [data] : []);
+  // REST API: file/print — пробуем GET с query в URL (некоторые версии ожидают это)
+  const qs = `?.proplist=.id,name,contents&name=${encodeURIComponent(basename)}`;
+  let printRes = await client.print(`file/print${qs}`);
+  let data = printRes?.data;
+  let list = Array.isArray(data) ? data : (data ? [data] : []);
+
+  // Если по name в URL не нашли — пробуем POST с .query в body
+  if (list.length === 0) {
+    printRes = await client.command('file/print', {
+      '.proplist': ['.id', 'name', 'contents'],
+      '.query': [`name=${basename}`],
+    });
+    data = printRes?.data;
+    list = Array.isArray(data) ? data : (data ? [data] : []);
+  }
+
+  // Если всё ещё пусто — печатаем все файлы и ищем по имени вручную
+  if (list.length === 0) {
+    printRes = await client.command('file/print', {
+      '.proplist': ['.id', 'name', 'contents'],
+    });
+    data = printRes?.data;
+    list = Array.isArray(data) ? data : (data ? [data] : []);
+    const found = list.find(
+      (f) =>
+        (f.name || '') === basename ||
+        (f.name || '').endsWith('/' + basename) ||
+        (f.name || '').endsWith(basename),
+    );
+    if (found) list = [found];
+  }
+
   const file = list[0];
-  if (!file || file.contents == null) {
+  if (!file) {
+    throw new Error('Failed to read export file from MikroTik (file not found after export)');
+  }
+
+  let config = String(file.contents || '');
+
+  // Для файлов >60KB API не возвращает contents в print — читаем через /file/read чанками
+  if (!config && file.name) {
+    const chunkSize = 32768;
+    let offset = 0;
+    const chunks = [];
+    for (;;) {
+      const readRes = await client.command('file/read', {
+        file: file.name,
+        offset: String(offset),
+        'chunk-size': String(chunkSize),
+      });
+      const rd = readRes?.data;
+      const chunk = Array.isArray(rd) ? (rd[0]?.data ?? rd[0]) : (rd?.data ?? rd);
+      const str = typeof chunk === 'string' ? chunk : (chunk ? String(chunk) : '');
+      if (!str) break;
+      chunks.push(str);
+      offset += str.length;
+      if (str.length < chunkSize) break;
+    }
+    config = chunks.join('');
+  }
+
+  if (!config) {
     try {
-      const id = file?.['.id'];
+      const id = file['.id'];
       if (id) await client.remove(`file/${id}`);
     } catch (_) {}
-    throw new Error('Failed to read export file from MikroTik');
+    throw new Error('Failed to read export file from MikroTik (file/print and file/read returned no contents)');
   }
-  const config = String(file.contents || '');
 
   try {
     const id = file['.id'];