Support query instead of table

Author: AgustinSRG

README.md

@@ -52,6 +52,7 @@ In order to configure the source, set the following variables:
 | MYSQL_PASSWORD | MySQL password. |
 | MYSQL_DB_NAME | MySQL database name. |
 | MYSQL_TABLE | MySQL table name. |
+| MYSQL_QUERY | MySQL query to use instead of the table. Example: `SELECT * FROM iris WHERE species = 'setosa'` |
 | MYSQL_MAX_CONNECTIONS | Max connections in the MySQL connection pool. |
 | SOURCE_FIELDS | List of fields, split by commas. Example: `sepallength,sepalwidth,petallength,petalwidth,species` |
-| SOURCE_FIELDS_TYPES | For each field, its type. Types are: `nominal`, `numeric`, `logic`, `date` and `text`. |
+| SOURCE_FIELDS_TYPES | For each field, its type. Types are: `nominal`, `numeric`, `logic`, `date` and `text`. Example: `numeric,numeric,numeric,numeric,nominal` |

src/config.ts

@@ -41,7 +41,7 @@ export class Config {
     public mysqlUser: string;
     public mysqlPassword: string;
     public mysqlDatabase: string;
-    public mysqlTable: string;
+    public mysqlTableLike: string;
     public mysqlConnections: number;
 
     public deepintURL: string;
@@ -73,7 +73,11 @@ export class Config {
         this.mysqlUser = process.env.MYSQL_USER || "root";
         this.mysqlPassword = process.env.MYSQL_PASSWORD || "";
         this.mysqlDatabase = process.env.MYSQL_DB_NAME || "test";
-        this.mysqlTable = process.env.MYSQL_TABLE || "iris";
+        const mysqlTable = process.env.MYSQL_TABLE || "iris";
+        const mysqlQuery = process.env.MYSQL_QUERY || "";
+
+        this.mysqlTableLike = mysqlQuery ? ("( " +  mysqlQuery + " ) as query_tmp_table") : ("`" + mysqlTable + "`");
+
         this.mysqlConnections = parseInt(process.env.MYSQL_MAX_CONNECTIONS, 10) || 4;
 
         this.deepintURL = process.env.DEEPINT_API_URL || "https://app.deepint.net/api/v1/";

src/source.ts

@@ -171,7 +171,7 @@ export class DataSource {
      * @param instances Instances
      */
     public async pushInstances(instances: InstanceType[][]): Promise<void> {
-        let sentence = "INSERT INTO `" + Config.getInstance().mysqlTable + "`(";
+        let sentence = "INSERT INTO " + Config.getInstance().mysqlTableLike + "(";
 
         sentence += this.fields.map(f => "`" + f.name + "`").join(",");
 
@@ -206,7 +206,7 @@ export class DataSource {
      * @returns Instances count
      */
     public async countInstances(filter: QueryTree): Promise<number> {
-        let sentence = "SELECT COUNT(*) AS `count` FROM `" + Config.getInstance().mysqlTable + "`";
+        let sentence = "SELECT COUNT(*) AS `count` FROM " + Config.getInstance().mysqlTableLike + "";
         const values = [];
 
 
@@ -266,7 +266,7 @@ export class DataSource {
             sentence += "*";
         }
 
-        sentence += " FROM `" + Config.getInstance().mysqlTable + "`";
+        sentence += " FROM " + Config.getInstance().mysqlTableLike + "";
 
         const cond1 = toSQLCondition(this.fields, filter);
 
@@ -336,7 +336,7 @@ export class DataSource {
         const fieldName = this.fields[feature].name;
         query = (query || "").toLowerCase();
 
-        sentence += '`' + fieldName + '` FROM `' + Config.getInstance().mysqlTable + '`';
+        sentence += '`' + fieldName + '` FROM ' + Config.getInstance().mysqlTableLike + '';
 
         if (cond1.sql) {
             if (query) {