Added part 5 on manual pagination, sorting, and filtering

Author: Dan McGhan

javascript/rest-api/part-5-manual-pagination-sorting-and-filtering/hr_app/config/database.js

@@ -0,0 +1,10 @@
+module.exports = {
+  hrPool: {
+    user: process.env.HR_USER,
+    password: process.env.HR_PASSWORD,
+    connectString: process.env.HR_CONNECTIONSTRING,
+    poolMin: 10,
+    poolMax: 10,
+    poolIncrement: 0
+  }
+};

javascript/rest-api/part-5-manual-pagination-sorting-and-filtering/hr_app/config/web-server.js

@@ -0,0 +1,3 @@
+module.exports = {
+  port: process.env.HTTP_PORT || 3000
+};

javascript/rest-api/part-5-manual-pagination-sorting-and-filtering/hr_app/controllers/employees.js

@@ -0,0 +1,100 @@
+const employees = require('../db_apis/employees.js');
+
+async function get(req, res, next) {
+  try {
+    const context = {};
+
+    context.id = parseInt(req.params.id, 10);
+    context.skip = parseInt(req.query.skip, 10);
+    context.limit = parseInt(req.query.limit, 10);
+    context.sort = req.query.sort;
+    context.department_id = parseInt(req.query.department_id, 10);
+    context.manager_id = parseInt(req.query.manager_id, 10);
+
+    const rows = await employees.find(context);
+
+    if (req.params.id) {
+      if (rows.length === 1) {
+        res.status(200).json(rows[0]);
+      } else {
+        res.status(404).end();
+      }
+    } else {
+      res.status(200).json(rows);
+    }
+  } catch (err) {
+    next(err);
+  }
+}
+
+module.exports.get = get;
+
+function getEmployeeFromRec(req) {
+  const employee = {
+    first_name: req.body.first_name,
+    last_name: req.body.last_name,
+    email: req.body.email,
+    phone_number: req.body.phone_number,
+    hire_date: req.body.hire_date,
+    job_id: req.body.job_id,
+    salary: req.body.salary,
+    commission_pct: req.body.commission_pct,
+    manager_id: req.body.manager_id,
+    department_id: req.body.department_id
+  };
+
+  return employee;
+}
+
+async function post(req, res, next) {
+  try {
+    let employee = getEmployeeFromRec(req);
+
+    employee = await employees.create(employee);
+
+    res.status(201).json(employee);
+  } catch (err) {
+    next(err);
+  }
+}
+
+module.exports.post = post;
+
+async function put(req, res, next) {
+  try {
+    let employee = getEmployeeFromRec(req);
+
+    employee.employee_id = parseInt(req.params.id, 10);
+
+    employee = await employees.update(employee);
+
+    if (employee !== null) {
+      res.status(200).json(employee);
+    } else {
+      res.status(404).end();
+    }
+  } catch (err) {
+    next(err);
+  }
+}
+
+module.exports.put = put;
+
+async function del(req, res, next) {
+  try {
+    const id = parseInt(req.params.id, 10);
+
+    const success = await employees.delete(id);
+
+    if (success) {
+      res.status(204).end();
+    } else {
+      res.status(404).end();
+    }
+  } catch (err) {
+    next(err);
+  }
+}
+
+module.exports.delete = del;
+

javascript/rest-api/part-5-manual-pagination-sorting-and-filtering/hr_app/db_apis/employees.js

@@ -0,0 +1,178 @@
+const oracledb = require('oracledb');
+const database = require('../services/database.js');
+
+const baseQuery =
+ `select employee_id "id",
+    first_name "first_name",
+    last_name "last_name",
+    email "email",
+    phone_number "phone_number",
+    hire_date "hire_date",
+    job_id "job_id",
+    salary "salary",
+    commission_pct "commission_pct",
+    manager_id "manager_id",
+    department_id "department_id"
+  from employees
+  where 1 = 1`;
+
+const sortableColumns = ['id', 'last_name', 'email', 'hire_date', 'salary'];
+
+async function find(context) {
+  let query = baseQuery;
+  const binds = {};
+
+  if (context.id) {
+    binds.employee_id = context.id;
+ 
+    query += '\nand employee_id = :employee_id';
+  }
+ 
+  if (context.department_id) {
+    binds.department_id = context.department_id;
+ 
+    query += '\nand department_id = :department_id';
+  }
+ 
+  if (context.manager_id) {
+    binds.manager_id = context.manager_id;
+ 
+    query += '\nand manager_id = :manager_id';
+  }
+
+  if (context.sort === undefined) {
+    query += '\norder by last_name asc';
+  } else {
+    let [column, order] = context.sort.split(':');
+ 
+    if (!sortableColumns.includes(column)) {
+      throw new Error('Invalid "sort" column');
+    }
+ 
+    if (order === undefined) {
+      order = 'asc';
+    }
+ 
+    if (order !== 'asc' && order !== 'desc') {
+      throw new Error('Invalid "sort" order');
+    }
+ 
+    query += `\norder by "${column}" ${order}`;
+  }
+
+  if (context.skip) {
+    binds.row_offset = context.skip;
+
+    query += '\noffset :row_offset rows';
+  }
+
+  const limit = (context.limit > 0) ? context.limit : 30;
+
+  binds.row_limit = limit;
+
+  query += '\nfetch next :row_limit rows only';
+
+  const result = await database.simpleExecute(query, binds);
+
+  return result.rows;
+}
+
+module.exports.find = find;
+
+const createSql =
+ `insert into employees (
+    first_name,
+    last_name,
+    email,
+    phone_number,
+    hire_date,
+    job_id,
+    salary,
+    commission_pct,
+    manager_id,
+    department_id
+  ) values (
+    :first_name,
+    :last_name,
+    :email,
+    :phone_number,
+    :hire_date,
+    :job_id,
+    :salary,
+    :commission_pct,
+    :manager_id,
+    :department_id
+  ) returning employee_id
+  into :employee_id`;
+
+async function create(emp) {
+  const employee = Object.assign({}, emp);
+
+  employee.employee_id = {
+    dir: oracledb.BIND_OUT,
+    type: oracledb.NUMBER
+  }
+
+  const result = await database.simpleExecute(createSql, employee);
+
+  employee.employee_id = result.outBinds.employee_id[0];
+
+  return employee;
+}
+
+module.exports.create = create;
+
+const updateSql =
+ `update employees
+  set first_name = :first_name,
+    last_name = :last_name,
+    email = :email,
+    phone_number = :phone_number,
+    hire_date = :hire_date,
+    job_id = :job_id,
+    salary = :salary,
+    commission_pct = :commission_pct,
+    manager_id = :manager_id,
+    department_id = :department_id
+  where employee_id = :employee_id`;
+
+async function update(emp) {
+  const employee = Object.assign({}, emp);
+  const result = await database.simpleExecute(updateSql, employee);
+
+  if (result.rowsAffected && result.rowsAffected === 1) {
+    return employee;
+  } else {
+    return null;
+  }
+}
+
+module.exports.update = update;
+
+const deleteSql =
+ `begin
+
+    delete from job_history
+    where employee_id = :employee_id;
+
+    delete from employees
+    where employee_id = :employee_id;
+
+    :rowcount := sql%rowcount;
+
+  end;`
+
+async function del(id) {
+  const binds = {
+    employee_id: id,
+    rowcount: {
+      dir: oracledb.BIND_OUT,
+      type: oracledb.NUMBER
+    }
+  }
+  const result = await database.simpleExecute(deleteSql, binds);
+
+  return result.outBinds.rowcount === 1;
+}
+
+module.exports.delete = del;

javascript/rest-api/part-5-manual-pagination-sorting-and-filtering/hr_app/index.js

@@ -0,0 +1,86 @@
+const webServer = require('./services/web-server.js');
+const database = require('./services/database.js');
+const dbConfig = require('./config/database.js');
+const defaultThreadPoolSize = 4;
+
+// Increase thread pool size by poolMax
+process.env.UV_THREADPOOL_SIZE = dbConfig.hrPool.poolMax + defaultThreadPoolSize;
+
+async function startup() {
+  console.log('Starting application');
+
+  try {
+    console.log('Initializing database module');
+
+    await database.initialize();
+  } catch (err) {
+    console.error(err);
+
+    process.exit(1); // Non-zero failure code
+  }
+
+  try {
+    console.log('Initializing web server module');
+
+    await webServer.initialize();
+  } catch (err) {
+    console.error(err);
+
+    process.exit(1); // Non-zero failure code
+  }
+}
+
+startup();
+
+async function shutdown(e) {
+  let err = e;
+
+  console.log('Shutting down application');
+
+  try {
+    console.log('Closing web server module');
+
+    await webServer.close();
+  } catch (e) {
+    console.error(e);
+
+    err = err || e;
+  }
+
+  try {
+    console.log('Closing database module');
+
+    await database.close();
+  } catch (e) {
+    console.error(e);
+
+    err = err || e;
+  }
+
+  console.log('Exiting process');
+
+  if (err) {
+    process.exit(1); // Non-zero failure code
+  } else {
+    process.exit(0);
+  }
+}
+
+process.on('SIGTERM', () => {
+  console.log('Received SIGTERM');
+
+  shutdown();
+});
+
+process.on('SIGINT', () => {
+  console.log('Received SIGINT');
+
+  shutdown();
+});
+
+process.on('uncaughtException', err => {
+  console.log('Uncaught exception');
+  console.error(err);
+
+  shutdown(err);
+});