refactor: improved structure of connection core

src/main/libs/clients/MySQLClient.js

@@ -0,0 +1,129 @@
+'use strict';
+import mysql from 'mysql';
+import { AntaresCore } from '../AntaresCore';
+
+export class MySQLClient extends AntaresCore {
+   /**
+    * @memberof MySQLClient
+    */
+   async connect () {
+      if (!this._poolSize)
+         this._connection = mysql.createConnection(this._params);
+      else
+         this._connection = mysql.createPool({ ...this._params, connectionLimit: this._poolSize });
+   }
+
+   /**
+    * @memberof MySQLClient
+    */
+   destroy () {
+      this._connection.end();
+   }
+
+   /**
+    * Executes an USE query
+    *
+    * @param {*} schema
+    * @memberof MySQLClient
+    */
+   use (schema) {
+      const sql = `USE \`${schema}\``;
+      return this.raw(sql);
+   }
+
+   /**
+    * @returns {string} SQL string
+    * @memberof MySQLClient
+    */
+   getSQL () {
+      // SELECT
+      const selectArray = this._query.select.reduce(this._reducer, []);
+      let selectRaw = '';
+
+      if (selectArray.length)
+         selectRaw = selectArray.length ? `SELECT ${selectArray.join(', ')} ` : 'SELECT * ';
+
+      // FROM
+      let fromRaw = '';
+
+      if (!this._query.update.length && !Object.keys(this._query.insert).length && !!this._query.from)
+         fromRaw = 'FROM';
+      else if (Object.keys(this._query.insert).length)
+         fromRaw = 'INTO';
+
+      fromRaw += this._query.from ? ` ${this._query.schema ? `\`${this._query.schema}\`.` : ''}\`${this._query.from}\` ` : '';
+
+      // WHERE
+      const whereArray = this._query.where.reduce(this._reducer, []);
+      const whereRaw = whereArray.length ? `WHERE ${whereArray.join(' AND ')} ` : '';
+
+      // UPDATE
+      const updateArray = this._query.update.reduce(this._reducer, []);
+      const updateRaw = updateArray.length ? `SET ${updateArray.join(', ')} ` : '';
+
+      // INSERT
+      let insertRaw = '';
+
+      if (Object.keys(this._query.insert).length) {
+         const fieldsList = [];
+         const valueList = [];
+         const fields = this._query.insert;
+
+         for (const key in fields) {
+            if (fields[key] === null) continue;
+            fieldsList.push(key);
+            valueList.push(fields[key]);
+         }
+
+         insertRaw = `(${fieldsList.join(', ')}) VALUES (${valueList.join(', ')}) `;
+      }
+
+      // GROUP BY
+      const groupByArray = this._query.groupBy.reduce(this._reducer, []);
+      const groupByRaw = groupByArray.length ? `GROUP BY ${groupByArray.join(', ')} ` : '';
+
+      // ORDER BY
+      const orderByArray = this._query.orderBy.reduce(this._reducer, []);
+      const orderByRaw = orderByArray.length ? `ORDER BY ${orderByArray.join(', ')} ` : '';
+
+      // LIMIT
+      const limitRaw = this._query.limit.length ? `LIMIT ${this._query.limit.join(', ')} ` : '';
+
+      return `${selectRaw}${updateRaw ? 'UPDATE' : ''}${insertRaw ? 'INSERT ' : ''}${this._query.delete ? 'DELETE ' : ''}${fromRaw}${updateRaw}${whereRaw}${groupByRaw}${orderByRaw}${limitRaw}${insertRaw}`;
+   }
+
+   /**
+    * @param {string} sql raw SQL query
+    * @param {boolean} [nest]
+    * @returns {Promise}
+    * @memberof MySQLClient
+    */
+   async raw (sql, nest) {
+      const nestTables = nest ? '.' : false;
+      const resultsArr = [];
+      const queries = sql.split(';');
+
+      if (process.env.NODE_ENV === 'development') this._logger(sql);// TODO: replace BLOB content with a placeholder
+
+      for (const query of queries) {
+         if (!query) continue;
+
+         const { rows, report, fields } = await new Promise((resolve, reject) => {
+            this._connection.query({ sql: query, nestTables }, (err, response, fields) => {
+               if (err)
+                  reject(err);
+               else {
+                  resolve({
+                     rows: Array.isArray(response) ? response : false,
+                     report: !Array.isArray(response) ? response : false,
+                     fields
+                  });
+               }
+            });
+         });
+         resultsArr.push({ rows, report, fields });
+      }
+
+      return resultsArr.length === 1 ? resultsArr[0] : resultsArr;
+   }
+}