fix: too many connect error (#71)

* add fetch all struct

* add other database implement

* rename method name

* adjust the order of functions

* eslint

* eslint

* eslint

* eslint

* eslint

* fix error end when fetch schema batch

src/lib/connectors/index.ts

@@ -16,6 +16,11 @@ export interface Connector {
     tableName: string,
     structureFetched: (tableName: string, structure: string) => void
   ) => Promise<void>;
+  getTableStructureBatch: (
+    databaseName: string,
+    tableNameList: string[],
+    structureFetched: (tableName: string, structure: string) => void
+  ) => Promise<void>;
 }
 
 export const newConnector = (connection: Connection): Connector => {

src/lib/connectors/mssql/index.ts

@@ -117,6 +117,39 @@ const getTableStructure = async (
   );
 };
 
+const getTableStructureBatch = async (
+  connection: Connection,
+  databaseName: string,
+  tableNameList: string[],
+  structureFetched: (tableName: string, structure: string) => void
+): Promise<void> => {
+  const pool = await getMSSQLConnection(connection);
+  const request = pool.request();
+
+  await Promise.all(
+    tableNameList.map(async (tableName) => {
+      const { recordset } = await request.query(
+        `SELECT COLUMN_NAME, DATA_TYPE, IS_NULLABLE FROM ${databaseName}.INFORMATION_SCHEMA.COLUMNS WHERE TABLE_SCHEMA='dbo' AND TABLE_NAME='${tableName}';`
+      );
+      const columnList = [];
+      // Transform to standard schema string.
+      for (const row of recordset) {
+        columnList.push(
+          `${row["COLUMN_NAME"]} ${row["DATA_TYPE"].toUpperCase()} ${
+            String(row["IS_NULLABLE"]).toUpperCase() === "NO" ? "NOT NULL" : ""
+          }`
+        );
+      }
+      structureFetched(
+        tableName,
+        `CREATE TABLE [${tableName}] (
+        ${columnList.join(",\n")}
+      );`
+      );
+    })
+  );
+};
+
 const newConnector = (connection: Connection): Connector => {
   return {
     testConnection: () => testConnection(connection),
@@ -130,6 +163,17 @@ const newConnector = (connection: Connection): Connector => {
       structureFetched: (tableName: string, structure: string) => void
     ) =>
       getTableStructure(connection, databaseName, tableName, structureFetched),
+    getTableStructureBatch: (
+      databaseName: string,
+      tableNameList: string[],
+      structureFetched: (tableName: string, structure: string) => void
+    ) =>
+      getTableStructureBatch(
+        connection,
+        databaseName,
+        tableNameList,
+        structureFetched
+      ),
   };
 };
 

src/lib/connectors/mysql/index.ts

@@ -111,6 +111,29 @@ const getTableStructure = async (
   structureFetched(tableName, rows[0]["Create Table"] || "");
 };
 
+const getTableStructureBatch = async (
+  connection: Connection,
+  databaseName: string,
+  tableNameList: string[],
+  structureFetched: (tableName: string, structure: string) => void
+): Promise<void> => {
+  const conn = await getMySQLConnection(connection);
+
+  await Promise.all(
+    tableNameList.map(async (tableName) => {
+      const [rows] = await conn.query<RowDataPacket[]>(
+        `SHOW CREATE TABLE \`${databaseName}\`.\`${tableName}\`;`
+      );
+      if (rows.length !== 1) {
+        throw new Error("Unexpected number of rows.");
+      }
+      structureFetched(tableName, rows[0]["Create Table"] || "");
+    })
+  ).finally(() => {
+    conn.destroy();
+  });
+};
+
 const newConnector = (connection: Connection): Connector => {
   return {
     testConnection: () => testConnection(connection),
@@ -124,6 +147,17 @@ const newConnector = (connection: Connection): Connector => {
       structureFetched: (tableName: string, structure: string) => void
     ) =>
       getTableStructure(connection, databaseName, tableName, structureFetched),
+    getTableStructureBatch: (
+      databaseName: string,
+      tableNameList: string[],
+      structureFetched: (tableName: string, structure: string) => void
+    ) =>
+      getTableStructureBatch(
+        connection,
+        databaseName,
+        tableNameList,
+        structureFetched
+      ),
   };
 };
 

src/lib/connectors/postgres/index.ts

@@ -121,6 +121,42 @@ const getTableStructure = async (
   );
 };
 
+const getTableStructureBatch = async (
+  connection: Connection,
+  databaseName: string,
+  tableNameList: string[],
+  structureFetched: (tableName: string, structure: string) => void
+): Promise<void> => {
+  connection.database = databaseName;
+  const client = newPostgresClient(connection);
+  await client.connect();
+  await Promise.all(
+    tableNameList.map(async (tableName) => {
+      const { rows } = await client.query(
+        `SELECT column_name, data_type, is_nullable FROM information_schema.columns WHERE table_schema='public' AND table_name=$1;`,
+        [tableName]
+      );
+      const columnList = [];
+      // TODO(steven): transform it to standard schema string.
+      for (const row of rows) {
+        columnList.push(
+          `${row["column_name"]} ${row["data_type"].toUpperCase()} ${
+            String(row["is_nullable"]).toUpperCase() === "NO" ? "NOT NULL" : ""
+          }`
+        );
+      }
+      structureFetched(
+        tableName,
+        `CREATE TABLE \`${tableName}\` (
+        ${columnList.join(",\n")}
+      );`
+      );
+    })
+  ).finally(async () => {
+    await client.end();
+  });
+};
+
 const newConnector = (connection: Connection): Connector => {
   return {
     testConnection: () => testConnection(connection),
@@ -134,6 +170,17 @@ const newConnector = (connection: Connection): Connector => {
       structureFetched: (tableName: string, structure: string) => void
     ) =>
       getTableStructure(connection, databaseName, tableName, structureFetched),
+    getTableStructureBatch: (
+      databaseName: string,
+      tableNameList: string[],
+      structureFetched: (tableName: string, structure: string) => void
+    ) =>
+      getTableStructureBatch(
+        connection,
+        databaseName,
+        tableNameList,
+        structureFetched
+      ),
   };
 };
 

src/pages/api/connection/db_schema.ts

@@ -22,14 +22,14 @@ const handler = async (req: NextApiRequest, res: NextApiResponse) => {
         structure,
       });
     };
-    Promise.all(
-      rawTableNameList.map(async (tableName) =>
-        connector.getTableStructure(db, tableName, structureFetched)
-      )
-    ).then(() => {
-      res.status(200).json({
-        data: tableStructures,
-      });
+    await connector.getTableStructureBatch(
+      db,
+      rawTableNameList,
+      structureFetched
+    );
+
+    res.status(200).json({
+      data: tableStructures,
     });
   } catch (error: any) {
     res.status(400).json({