initial commit

server/models/db.js

@@ -0,0 +1,141 @@
+import dotenv from 'dotenv';
+import {Pool} from 'pg';
+dotenv.config();
+
+const pool = new Pool(process.env.DATABASE_URL ? {connectionString: process.env.DATABASE_URL} : {
+    user: process.env.DB_USER,
+    host: process.env.DB_HOST,
+    database: process.env.DB_NAME,
+    password: process.env.DB_PASSWORD,
+    port: parseInt(process.env.DB_PORT || '5432', 10),
+});
+
+
+/**
+ * Generic query function for PostgreSQL database.
+ * @template T
+ * @param {string} text
+ * @param {any[]} [params]
+ * @return {Promise<T[]>}
+ */
+async function query(text, params= []) {
+    const start = Date.now();
+    const res = await pool.query(text, params).then(qr => qr);
+    const duration = Date.now() - start;
+    if (params) for (let i = 0; i < params.length; i++) text = text.replace("$".concat(String(i + 1)), params[i]);
+    console.log('executed query', {text, duration, rows: res.rowCount});
+    /**@type T[]*/
+    return res.rows;
+}
+
+/**
+ * function to insert data into a table.
+ * @template T
+ * @param {string} table The name of the table to insert data into.
+ * @param {Object.<string, any>} map The {keys: values} to insert data into.
+ * @returns {Promise<T[] | Error>} Returns inserted value if the insertion was successful, error otherwise.
+ * */
+async function insert(table, map) {
+    const valuePlaceholders = Object.keys(map).map((_, index) => `$${index + 1}`).join(", ");
+    const queryText = `INSERT INTO ${table} (${Object.keys(map).join(", ")}) VALUES (${valuePlaceholders}) RETURNING *`;
+    return await query(queryText, Object.values(map))
+        .then(resRows => {
+            if (resRows.length === 0) {
+                console.error('Insert failed: No rows affected');
+                return new Error('Insert failed: No rows affected');
+            }
+            console.log('Insert successful:', resRows);
+            return resRows;
+        })
+        .catch(err => {
+            console.error('Insert error:', err);
+            return err;
+        });
+}
+
+/**
+ * Function to update data in a table.
+ * @template T
+ * @param {string} table
+ * @param {Object.<string, any>} updateMap The {keys: values} to update.
+ * @param {Object.<string, any>} conditions The conditions to match to update.
+ * @returns {Promise<T[] | Error>} Returns updated rows if the insertion was successful, error otherwise.
+ */
+async function update(table, updateMap, conditions) {
+    if (Object.keys(updateMap).length === 0) {
+        console.error('Update failed: No fields to update');
+        return new Error('Update failed: No fields to update');
+    }
+    if (Object.keys(conditions).length === 0) {
+        console.error('Update failed: No conditions specified');
+        return new Error('Update failed: No conditions specified');
+    }
+    const setClause = Object.keys(updateMap).map((key, index) => `${key} = ${index + 1}`).join(', ');
+    const whereClause = Object.entries(conditions).map(([key, value]) => `${key} = ${value}`).join(' AND ');
+    return await query(`UPDATE ${table} SET ${setClause} WHERE ${whereClause} RETURNING *`, Object.values(updateMap))
+        .then(resRows => {
+            if (resRows.length === 0) {
+                console.error('Update failed: No rows affected');
+                return new Error('Update failed: No rows affected');
+            }
+            console.log('Update successful:', resRows);
+            return resRows;
+        })
+        .catch(err => {
+            console.error('Update error:', err);
+            return err;
+        });
+}
+
+/**
+ * Function to delete a row from a table by ID.
+ * @template T
+ * @param {string} table The name of the table to delete from.
+ * @param {Object.<string, any>} conditions The conditions to match to delete row/rows.
+ * @return {Promise<T[] | Error>} Returns true if the deletion was successful, false otherwise.
+ */
+async function remove(table, conditions = {}) {
+    if (!conditions || Object.keys(conditions).length === 0) {
+        console.error('Delete failed: No identifier specified');
+        return new Error('Delete failed: No identifier specified');
+    }
+    const whereClause = Object.entries(conditions).map(([key, _], index) => `${key} = ${index + 1}`).join(' AND ');
+    const queryText = `DELETE FROM ${table} WHERE ${whereClause} RETURNING *`;
+    return await query(queryText, Object.values(conditions))
+        .then(resRows => {
+            if (resRows.length === 0) {
+                console.error('Delete failed: No rows affected');
+                return new Error('Delete failed: No rows affected');
+            }
+            console.log('Delete successful:', resRows);
+            return resRows;
+        })
+        .catch(err => {
+            console.error('Delete error:', err);
+            return err;
+        });
+}
+
+/**
+ * Function to get rows from a table based on conditions.
+ * @template T
+ * @param {string} table The name of the table to query.
+ * @param {{}} conditions The conditions to match rows.
+ * @return {Promise<T[]>} Returns an array of rows that match the conditions.
+ */
+async function get(table, conditions = {}) {
+    if (Object.keys(conditions).length === 0) {
+        return await query(`SELECT * FROM "${table}"`);
+    }
+    const whereClause = Object.entries(conditions).map(([key, _], index) => `${key} = $${index + 1}`).join(' AND ');
+    return await query(`SELECT * FROM ${table} WHERE ${whereClause}`, Object.values(conditions));
+}
+
+export default {
+    pool,
+    query,
+    insert,
+    update,
+    remove,
+    get,
+};