Server/Backend deploy config

{ // vercel.json
  "builds": [{ "src": "index.js", "use": "@vercel/node" }],
  "routes": [{ "src": "/(.*)", "dest": "/index.js" }]
}

Query vs Params

Best practice for RESTful API design is that path params are used to identify a specific resource or resources, while query parameters are used to sort/filter those resources.

http://localhost:5000/orders/?email=mr.es20x@gmail.com
// are same
http://localhost:5000/orders?email=mr.es20x@gmail.com

Posted data is undefined?

• add

app.use(express.json());

• this will convert the json into a js object

Posting sample

const postStudent = (name) => {
  fetch("https://backend-integration-test.vercel.app/register", {
    method: "POST",
    headers: {
      "Content-Type": "application/json",
    },
    body: JSON.stringify({ name: name }),
  })
    .then((res) => res.json())
    .then((data) => setStudents(data));
};

MongoDB

• get the mongoDB_URI. It may looks like mongodb+srv://sohanemon:<password>@<clusterName>.2gtvyou.mongodb.net/?retryWrites=true&w=majority or mongodb://localhost:8000/"
• then set as a client

const { MongoClient } = require("mongodb");
// step: 1
const client = new MongoClient(process.env.MONGODB_URI);

• retrieve the collection from database

try {
  // step: 2
  const collection = client.db("<myDbName").collection("<myCollectionName>");
  // myCollectionName collection is inside the myDbName database
} finally {
}

• operate different operations on collection variable now

Insert/Create/Post

const runMongo = async () => {
  try {
    const collection = client.db("users").collection("students");
    const doc = {
      name: "rafi",
    };
    // step: 3
    collection.insertOne(doc);
  } finally {
  }
};

make sure to run runMongo()

as it is async then we can use runMongo().catch(console.log)

• now send the fetched data from frontend to the server as

try {
    const collection = client.db("users").collection("students");
    app.post("/register", async (req, res) => {
      const doc = req.body;
      // step: 3
      const result = await collection.insertOne(doc);
      res.send(result);
    });

Get/Read

• find() / findOne takes query and options as parameter

try {
    const collection = client.db("users").collection("students");

    app.get("/students", async (req, res) => {
      // step: 3
      const cursor = collection.find({});
      // await is not required here bcoz find returns a cursor not a promise
      // step: 4
      const result = await cursor.toArray();
      // .toArray() returns a promise to await is required
      res.json(result);
    });

  }...

• findOne doesn't return any cursor. So, await should be used with findOne function as it returns a promise
• by hovering on any function, vs code shows what actually a function return like this. Anything after : or => determines what actually returning there.

app.get("/student/:_id", async (req, res) => {
  const _id = req.params._id;
  const result = await collection.findOne({ _id: ObjectId(_id) });
  res.json(result);
});

Update/Put/Patch

• Similar to other it also have updateOne and updateMany function

app.put("/update/:_id", async (req, res) => {
  const _id = req.params._id;
  const doc = req.body;
  const result = await collection.updateOne(
    { _id: ObjectId(_id) },
    {
      $set: doc,
    }
  );
  res.send(result);
});

Delete

• deleteOne function takes a query argument. Which describes about the items.
• for deleting an item using _id one should pass using ObjectId function.

app.delete("/delete/:_id", async (req, res) => {
  const _id = req.params._id;
  // step: 4
  const result = await collection.deleteOne({ _id: ObjectId(_id) });
  res.send(result);
});