feat: add handling for empty result sets in backend

server/model/monitor.js

@@ -129,6 +129,7 @@ class Monitor extends BeanModel {
             mqttSuccessMessage: this.mqttSuccessMessage,
             mqttCheckType: this.mqttCheckType,
             databaseQuery: this.databaseQuery,
+            databaseQueryHandleEmptyAsFailure: this.isDatabaseQueryHandleEmptyAsFailure(),
             authMethod: this.authMethod,
             grpcUrl: this.grpcUrl,
             grpcProtobuf: this.grpcProtobuf,
@@ -271,6 +272,14 @@ class Monitor extends BeanModel {
         return Boolean(this.invertKeyword);
     }
 
+    /**
+     * Parse to boolean
+     * @returns {boolean} Is sql query empty result handled as failure?
+     */
+    isDatabaseQueryHandleEmptyAsFailure() {
+        return Boolean(this.databaseQueryHandleEmptyAsFailure);
+    }
+
     /**
      * Parse to boolean
      * @returns {boolean} Enable TLS for gRPC?
@@ -760,7 +769,7 @@ class Monitor extends BeanModel {
                 } else if (this.type === "sqlserver") {
                     let startTime = dayjs().valueOf();
 
-                    await mssqlQuery(this.databaseConnectionString, this.databaseQuery || "SELECT 1");
+                    await mssqlQuery(this.databaseConnectionString, this.databaseQueryHandleEmptyAsFailure, this.databaseQuery || "SELECT 1");
 
                     bean.msg = "";
                     bean.status = UP;
@@ -799,7 +808,7 @@ class Monitor extends BeanModel {
                 } else if (this.type === "postgres") {
                     let startTime = dayjs().valueOf();
 
-                    await postgresQuery(this.databaseConnectionString, this.databaseQuery || "SELECT 1");
+                    await postgresQuery(this.databaseConnectionString, this.databaseQueryHandleEmptyAsFailure, this.databaseQuery || "SELECT 1");
 
                     bean.msg = "";
                     bean.status = UP;
@@ -811,7 +820,7 @@ class Monitor extends BeanModel {
                     // TODO: rename `radius_password` to `password` later for general use
                     let mysqlPassword = this.radiusPassword;
 
-                    bean.msg = await mysqlQuery(this.databaseConnectionString, this.databaseQuery || "SELECT 1", mysqlPassword);
+                    bean.msg = await mysqlQuery(this.databaseConnectionString, this.databaseQueryHandleEmptyAsFailure, this.databaseQuery || "SELECT 1", mysqlPassword);
                     bean.status = UP;
                     bean.ping = dayjs().valueOf() - startTime;
                 } else if (this.type === "radius") {

server/server.js

@@ -837,6 +837,7 @@ let needSetup = false;
                 bean.mqttCheckType = monitor.mqttCheckType;
                 bean.databaseConnectionString = monitor.databaseConnectionString;
                 bean.databaseQuery = monitor.databaseQuery;
+                bean.databaseQueryHandleEmptyAsFailure = monitor.databaseQueryHandleEmptyAsFailure;
                 bean.authMethod = monitor.authMethod;
                 bean.authWorkstation = monitor.authWorkstation;
                 bean.authDomain = monitor.authDomain;

server/util-server.js

@@ -322,7 +322,7 @@ exports.dnsResolve = function (hostname, resolverServer, resolverPort, rrtype) {
  * @returns {Promise<(string[] | object[] | object)>} Response from
  * server
  */
-exports.mssqlQuery = async function (connectionString, query) {
+exports.mssqlQuery = async function (connectionString, handleEmptyResult, query) {
     let pool;
     try {
         pool = new mssql.ConnectionPool(connectionString);
@@ -330,7 +330,12 @@ exports.mssqlQuery = async function (connectionString, query) {
         if (!query) {
             query = "SELECT 1";
         }
-        await pool.request().query(query);
+        result = await pool.request().query(query);
+        if (Array.isArray(result.recordset)) {
+            if (handleEmptyResult && result.recordset.length === 0) {
+                throw new Error("No rows returned");
+            }
+        }
         pool.close();
     } catch (e) {
         if (pool) {
@@ -347,7 +352,7 @@ exports.mssqlQuery = async function (connectionString, query) {
  * @returns {Promise<(string[] | object[] | object)>} Response from
  * server
  */
-exports.postgresQuery = function (connectionString, query) {
+exports.postgresQuery = function (connectionString, handleEmptyResult, query) {
     return new Promise((resolve, reject) => {
         const config = postgresConParse(connectionString);
 
@@ -384,7 +389,13 @@ exports.postgresQuery = function (connectionString, query) {
                         if (err) {
                             reject(err);
                         } else {
-                            resolve(res);
+                            if (Array.isArray(res.rows)) {
+                                if (handleEmptyResult && res.rows.length === 0) {
+                                    reject(new Error("No rows returned"));
+                                } else {
+                                    resolve(res);
+                                }
+                            }
                         }
                         client.end();
                     });
@@ -405,7 +416,7 @@ exports.postgresQuery = function (connectionString, query) {
  * @param {?string} password The password to use
  * @returns {Promise<(string)>} Response from server
  */
-exports.mysqlQuery = function (connectionString, query, password = undefined) {
+exports.mysqlQuery = function (connectionString, handleEmptyResult, query, password = undefined) {
     return new Promise((resolve, reject) => {
         const connection = mysql.createConnection({
             uri: connectionString,
@@ -421,7 +432,7 @@ exports.mysqlQuery = function (connectionString, query, password = undefined) {
                 reject(err);
             } else {
                 if (Array.isArray(res)) {
-                    if (res.length === 0) {
+                    if (handleEmptyResult && res.length === 0) {
                         reject(new Error("No rows returned"));
                     } else {
                         resolve("Rows: " + res.length);