Enhance socket management and error handling in template events

- Increased the maximum HTTP buffer size for the Socket.IO server to improve data handling capabilities.
- Added error handling in `handlePreviewTemplateEvent` and `handleRenderTemplatePDFEvent` methods to log errors and return error messages through callbacks.
- Implemented a check for unknown object types in the `TemplateManager` to prevent processing errors and return appropriate error messages.

src/socket/socketmanager.js

@@ -23,6 +23,7 @@ export class SocketManager {
     // Create Socket.IO server - CORS applies to HTTP long-polling transport
     const allowedOrigins = config.server.corsOrigins || ['*'];
     const io = new Server(server, {
+      maxHttpBufferSize: 1e8,
       cors: {
         origin: (origin, callback) => {
           // Allow requests with no origin (e.g. same-origin, Postman, native apps)

src/socket/socketuser.js

@@ -306,24 +306,42 @@ export class SocketUser {
   }
 
   async handlePreviewTemplateEvent(data, callback) {
+    try {
       const result = await this.templateManager.renderTemplate(
         data._id,
         data.content,
         data.testObject,
         data.scale
       );
+      if (typeof callback === 'function') {
         callback(result);
       }
+    } catch (err) {
+      logger.error('Preview template event error:', err);
+      if (typeof callback === 'function') {
+        callback({ error: err.message });
+      }
+    }
+  }
 
   async handleRenderTemplatePDFEvent(data, callback) {
+    try {
       const result = await this.templateManager.renderPDF(
         data._id,
         data.content,
         data.object,
         1
       );
+      if (typeof callback === 'function') {
         callback(result);
       }
+    } catch (err) {
+      logger.error('Render template PDF event error:', err);
+      if (typeof callback === 'function') {
+        callback({ error: err.message });
+      }
+    }
+  }
   async handleGenerateHostOtpEvent(data, callback) {
     const result = await generateHostOTP(data._id);
     callback(result);

src/templates/templatemanager.js

@@ -407,6 +407,9 @@ export class TemplateManager {
       } else {
         const objectType = documentTemplate?.objectType;
         const model = getModelByName(objectType);
+        if (model == null) {
+          return { error: `Unknown object type: ${objectType}` };
+        }
         const defaultKeys = Object.keys(model.schema.obj);
         const defaultValues = {};
         for (const key of defaultKeys) {