Final Step In Building TODO Backend- Creating Routes and Controllers

Finally, We reached at the End of this Tutorial Series.

In this Section, we will see how to configure the routes and controllers together and also one request to you is to keep a little more focus and have patience and faith in me : D, because from this point of time, you may get lost inside files and folder and nothing will make sense to you, and you wouldn't know what exactly is happening so have patience, in the end, everything will connect and make sense : )

So we will start with the routes, we have already defined our routes and their purpose.


Method	Path	Description
GET	/todos	Get all todos items
GET	/todos/:id	Get one todo item
POST	/todos	Create a new todo item
PUT	/todos/:id	Update a todo item
DELETE	/todos/:id	Delete a new todo item

As we can see in the table, we have 5 routes, so we will have 5 controllers. But there is one logical problem we have only 2 routes not 5, if you closely look at the Path column we only have /todos and /todos/:id and they are reused multiple times this is because we can future differentiate same route based on the HTTP methods ( GET, POST, PUT, DELETE, etc ). So you can see in the Method column, we have different HTTP methods for the same routes.

So let's start with the /todos route, this will return all tasks from database, now we will create a route and define the respective controller for it and then the process will repeat for other routes.

Create a todoRoutes.js file inside /routers folder we had created previously.

/todos/todoRouters.js

// import express
const express = require("express");

// controllers
const { getAllTodos } = require("../controllers/todoControllers");

// initialize route using express router
const todoRoute = express.Router();

// define the /todos + / => /todos/ route to get all todos
todoRoute
  .route("/")
  .get(getAllTodos);  // we will define and import this function soon

// export the route
module.exports = todoRoute;

Now, let's move onto the controller, create a todoControllers.js file inside /controllers and also now we will require our todo model we had created inside model/todos.js

/controllers/todoControllers.js

// import the todo model
const Todos = require("../models/todos");

const getAllTodos = (req, res) => {

 // mongoose find
  Todos.find({}) 

      .then((todos) => {

        res.status(200); // setting 200 ok  response status
        res.setHeader("Content-Type", "application/json");  // setting header as json
        res.json({ todos: todos });  // sending data to client in JSON 

      })
      .catch((err) => {

        res.status(500);   // setting 500 internal server error
        res.json({ error: err });   // sending error to client in JSON 

      });
};

// export the controllers
module.exports = {
  getAllTodos,
};

Now, lets link our router to our express app.

Open app.js file and import todoRouter from todoRouters.js :

//routes
const todoRouter = require("./routes/todoRoutes");

now, add the following line below your initialization of express app line 

.
.

const app = express();
.
.

app.use("/todos", todoRouter);

Updated app.js

// import express
const express = require("express");

//import mongoose
const mongoose = require("mongoose");

// import dotenv
const dotenv = require("dotenv");

// routers
const todoRouter = require("./routes/todoRoutes");

// load environment variable
dotenv.config({ path: ".env" });

// read env variable using process.env.<your_env_variable_name>
const PORT = process.env.PORT;
const dbURI = process.env.DATABASE_URL;

// making connection object
const connect = mongoose.connect(dbURI, {

  useNewUrlParser: true,
  useUnifiedTopology: true,

});

// connecting with database
connect.then(

  (db) => {
    console.log("Connected Successfully to Mongodb Server");
  },

  (err) => {
    console.log(err);
  }

);

// initialize express app
const app = express();

// sending a hello response on visiting http://localhost:3000/
app.get("/", (req, res) => {

  res
    .status(200)
    .json({ message: "Hi I am Server", data: "no data on this endpoint" });

});

app.use("/todos", todoRouter);

// listening for any HTTP requests on PORT 3000
app.listen(PORT, () => {

  console.log(`Server is running at http://localhost:${PORT}`);

});

Now if you visit http://localhost:3000/todos/ you should see the below response on your browser.

Output:

{"todos":[]}

Congratulations! You have created your very own REST API backend : )

Now, let's move on to completing our routes and controllers for all the remaining Endpoints.

Completing Routes And Controllers - CRUD Operations

We are almost done! Finally, let's implement the remaining routes and controllers, and after that, we will test our API Endpoints using Postman.

Now, the process remains the same for all other routes except the logic will change, like for delete route your controller will implement the logic to delete the todo using the provided todoID.

Lets, quickly define the route handlers for all the remaining routes

Final /todos/todoRouters.js

// import express
const express = require("express");

//controllers
const {
  getAllTodos,
  createTodo,
  getTodoById,
  updateTodo,
  deleteTodo,
  taskCompletionTime,
} = require("../controllers/todoControllers");

// initialize route using express router
const todoRoute = express.Router();

// define the /todos + / => /todos/ route to get all todos
todoRoute.route("/").get(getAllTodos).post(createTodo); // same route different method chained together
todoRoute.route("/:id").get(getTodoById).put(updateTodo).delete(deleteTodo);

// export the route
module.exports = todoRoute;

Kindly ignore the error and warning in the console they all will disappear soon : D

Remaining Controllers

Create Todo Controller

// import uniquid to generate unique ids
const uniquid = require("uniquid");

const createTodo = (req, res) => {
    const { description } = req.body;

    Todos.create({ taskID: uniquid(), description: description})
    .then((todo) => {
      res.status(200);
      res.setHeader("Content-Type", "application/json");
      res.json({ status: "Todo added successfully", data: todo });
    })
    .catch((err) => {
      res.status(404);
      res.json({ message: "Invalid Object Property", error: err });
    });
};

Get Single Todo Controller

const getTodoById = (req, res) => {
  Todos.findById(req.params.id)
    .then((todo) => {
        res.status(200);
        res.setHeader("Content-Type", "application/json");
        res.json(todo);
    })
    .catch((err) => {
      res.status(404);
      res.json({ message: "Id did not exists", error: err });
    });
};

Update Todo Controller

const updateTodo = (req, res, next) => {
     Todos.findByIdAndUpdate(
          { _id: req.params.id },
          {
            $set: req.body,
          },
          { new: true, useFindAndModify: false } //get updated result
        )
          .then((todo) => {
            res.status(200);
            res.setHeader("Content-Type", "application/json");
            res.json(todo);
          })
          .catch((err) => {
            res.status(404);
            res.json({ message: "unable to update", error: err });
     });
};

Delete Todo Controller

const deleteTodo = (req, res, next) => {
    Todos.findByIdAndRemove(req.params.id)
        .then((response) => {
            res.status(200);
            res.setHeader("Content-Type", "application/json");
            res.json({
              status: "Todo deleted successfully",
              response: response,
            });
          })
        .catch((err) => {
            res.status(404);
            res.json({ message: "unable to delete", error: err });
      });
};

Updated Controllers - Final

/controllers/todoControllers.js

// import uniquid to generate unique ids
const uniquid = require("uniquid");

// import the todo model
const Todos = require("../models/todos");

// get all todos
const getAllTodos = (req, res) => {
  // mongoose find
  Todos.find({})
    .then((todos) => {
      res.status(200); // setting 200 ok  response status
      res.setHeader("Content-Type", "application/json"); // setting header as json
      res.json({ todos: todos }); // sending data to client in JSON
    })
    .catch((err) => {
      res.status(500); // setting 500 internal server error
      res.json({ error: err }); // sending error to client in JSON
    });
};

// create task in todo
const createTodo = (req, res) => {
  const { description } = req.body;

  Todos.create({ taskID: uniquid(), description: description })
    .then((todo) => {
      res.status(200);
      res.setHeader("Content-Type", "application/json");
      res.json({ status: "Todo added successfully", data: todo });
    })
    .catch((err) => {
      res.status(404);
      res.json({ message: "Invalid Object Property", error: err });
    });
};

// get a single todo task
const getTodoById = (req, res) => {
  Todos.findById(req.params.id)
    .then((todo) => {
      res.status(200);
      res.setHeader("Content-Type", "application/json");
      res.json(todo);
    })
    .catch((err) => {
      res.status(404);
      res.json({ message: "Id did not exists", error: err });
    });
};

// update todo task
const updateTodo = (req, res, next) => {
  Todos.findByIdAndUpdate(
    { _id: req.params.id },
    {
      $set: req.body,
    },
    { new: true, useFindAndModify: false } //get updated result
  )
    .then((todo) => {
      res.status(200);
      res.setHeader("Content-Type", "application/json");
      res.json(todo);
    })
    .catch((err) => {
      res.status(404);
      res.json({ message: "unable to update", error: err });
    });
};

// delete single todo task
const deleteTodo = (req, res, next) => {
  Todos.findByIdAndRemove(req.params.id)
    .then((response) => {
      res.status(200);
      res.setHeader("Content-Type", "application/json");
      res.json({
        status: "Todo deleted successfully",
        response: response,
      });
    })
    .catch((err) => {
      res.status(404);
      res.json({ message: "unable to delete", error: err });
    });
};

// export the controllers
module.exports = {
  getAllTodos,
  createTodo,
  getTodoById,
  updateTodo,
  deleteTodo,
};

Browser can only perform GET request, so in order to perform POST, PUT, DELETE requests we will be using an industry-standard tool for testing APIs i.e Postman

Lastly, add following more lines into the app.js:

npm install cors

Cors module allows your frontend application to fetch data from this backend, which is running on different ORIGIN.Learn more about Browser's Same Origin Policy

// import cors on top
const cors = require("cors");

Now below this line add the following lines
const app = express();
.
.
app.use(cors());
app.use(express.json());
app.use(express.urlencoded({ extended: false }));

Updated app.js

// import express
const express = require("express");
//import mongoose
const mongoose = require("mongoose");
// import dotenv
const dotenv = require("dotenv");
const cors = require("cors");

// routers
const todoRouter = require("./routes/todoRoutes");

// load environment variable
dotenv.config({ path: ".env" });

// read env variable using process.env.<your_env_variable_name>
const PORT = process.env.PORT;
const dbURI = process.env.DATABASE_URL;

// making connection object
const connect = mongoose.connect(dbURI, {
  useNewUrlParser: true,
  useUnifiedTopology: true,
});

// connecting with database
connect.then(
  (db) => {
    console.log("Connected Successfully to Mongodb Server");
  },
  (err) => {
    console.log(err);
  }
);

// initialize express app
const app = express();

app.use(cors());
app.use(express.json());  // parse JSON data into JS object
app.use(express.urlencoded({ extended: false })); //allows you to accept form submitted data

// sending a hello response on visiting http://localhost:3000/
app.get("/", (req, res) => {
  res
    .status(200)
    .json({ message: "Hi I am Server", data: "no data on this endpoint" });
});

app.use("/todos", todoRouter);

// listening for any HTTP requests on PORT 3000
app.listen(PORT, () => {
  console.log(`Server is running at http://localhost:${PORT}`);
});

So Finally, Our Code is Completed, we had successfully created our REST API Backend using Nodejs, MongoDB, and Express. In the next section, we will test our backend using Postman

Get the Final Code on Github

Building Todo Backend Code

Workshop Video

Watch My Hands-On Workshop on Building A TODO REST API BAckend

https://youtu.be/hsGOl_28R10

Final Step In Building TODO Backend- Creating Routes and Controllers

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