mongo filtering via sql tree

plugins/dbgate-plugin-mongo/src/backend/driver.js

@@ -270,10 +270,11 @@ const driver = {
     return res.databases;
   },
   async readCollection(pool, options) {
-    const mongoCondition = convertToMongoCondition(options.condition);
-    console.log('******************* mongoCondition *****************')
-    console.log(JSON.stringify(mongoCondition, undefined, 2));
     try {
+      const mongoCondition = convertToMongoCondition(options.condition);
+      // console.log('******************* mongoCondition *****************');
+      // console.log(JSON.stringify(mongoCondition, undefined, 2));
+
       const collection = pool.__getDatabase().collection(options.pureName);
       if (options.countDocuments) {
         const count = await collection.countDocuments(convertObjectId(mongoCondition) || {});

plugins/dbgate-plugin-mongo/src/frontend/convertToMongoCondition.js

@@ -89,6 +89,38 @@ function convertToMongoCondition(filter) {
           $options: 'i',
         },
       };
+
+    case 'specificPredicate':
+      switch (filter.predicate) {
+        case 'exists':
+          return {
+            [convertLeftOperandToMongoColumn(filter.expr)]: {
+              $exists: true,
+            },
+          };
+        case 'notExists':
+          return {
+            [convertLeftOperandToMongoColumn(filter.expr)]: {
+              $exists: false,
+            },
+          };
+        case 'emptyArray':
+          return {
+            [convertLeftOperandToMongoColumn(filter.expr)]: {
+              $exists: true,
+              $eq: [],
+            },
+          };
+        case 'notEmptyArray':
+          return {
+            [convertLeftOperandToMongoColumn(filter.expr)]: {
+              $exists: true,
+              $type: 'array',
+              $ne: [],
+            },
+          };
+      }
+
     default:
       throw new Error(`Unknown condition type ${filter.conditionType}`);
   }