London 9 Shayan Mahnam Module-Databases

E-Commerce-API/.gitignore

@@ -0,0 +1,2 @@
+/node_modules
+.env

E-Commerce-API/app.js

@@ -1,8 +1,149 @@
+const { Pool } = require("pg");
+
 const express = require("express");
 const app = express();
+const cors = require("cors");
+const port = process.env.PORT || 5000;
+const bodyParser = require("body-parser");
+const dotenv = require("dotenv");
+
+dotenv.config();
+app.listen(port, () => console.log(`Listening on port ${port}`));
+app.use(cors());
+app.use(express.json());
+app.use(bodyParser.json());
+
+const db = new Pool({
+  user: process.env.DB_USERNAME,
+  host: process.env.DB_HOST,
+  database: process.env.DB_DATABASE,
+  password: process.env.DB_PASSWORD,
+  port: process.env.DB_PORT,
+});
+
+app.get("/products", (req, res) => {
+  if (req.query.name && req.query.name.length > 0) {
+    db.query(
+      `SELECT p.product_name as name, pa.unit_price as price, s.supplier_name  FROM products p INNER JOIN product_availability pa on (p.id = pa.prod_id) INNER JOIN suppliers s on (pa.supp_id = s.id) where p.product_name ilike $1`,
+      [`%${req.query.name}%`],
+      (error, result) => {
+        if (error) {
+          res.status(500).json({ error: "Internal Server Error" });
+        } else {
+          res.status(200).json(result.rows);
+        }
+      }
+    );
+  } else {
+    db.query(
+      "SELECT p.product_name as name, pa.unit_price as price, s.supplier_name  FROM products p INNER JOIN product_availability pa on (p.id = pa.prod_id) INNER JOIN suppliers s on (pa.supp_id = s.id)",
+      (error, result) => {
+        if (error) {
+          res.status(500).json({ error: "Internal Server Error" });
+        } else {
+          res.status(200).json(result.rows);
+        }
+      }
+    );
+  }
+});
+
+app.get("/customers/:id", (req, res) => {
+  db.query(
+    "SELECT * from customers where id=$1",
+    [`${req.params.id}`],
+    (error, result) => {
+      if (error) {
+        res.status(500).json({ error: "Internal Server Error" });
+      } else if (result.rows.length === 0) {
+        res.status(404).json({ error: "Customer does not exist" });
+      } else {
+        res.status(200).json(result.rows);
+      }
+    }
+  );
+});
+
+app.post("/customers", (req, res) => {
+  db.query(
+    "INSERT into customers (name, address, city, country) values ($1, $2, $3, $4) returning *",
+    [req.body.name, req.body.address, req.body.city, req.body.country],
+    (error, result) => {
+      if (error) {
+        res.status(500).json({ error: "Internal Server Error" });
+      } else {
+        res.status(201).json(result.rows[0]);
+      }
+    }
+  );
+});
+
+app.post("/products", (req, res) => {
+  db.query(
+    "INSERT into products (product_name) values ($1) returning *",
+    [req.body.product_name],
+    (error, result) => {
+      if (error) {
+        res.status(500).json({ error: "Internal Server Error" });
+      } else {
+        res.status(201).json(result.rows[0]);
+      }
+    }
+  );
+});
+
+app.post("/availability", (req, res) => {
+  if (
+    !Number.isInteger(req.body.unit_price) ||
+    Number(req.body.unit_price) <= 0
+  ) {
+    res.status(400).json({ error: "Price is not a positive integer" });
+    return;
+  }
+
+  db.query(
+    "SELECT * FROM products WHERE id = $1",
+    [req.body.prod_id],
+    (error, result) => {
+      if (error) {
+        console.error(error);
+        res.status(500).json({ error: "Internal Server Error" });
+      } else if (result.rows.length === 0) {
+        res.status(404).json({ error: "Product doesn't exist in db" });
+      } else {
+        db.query(
+          "SELECT * FROM suppliers WHERE id = $1",
+          [req.body.supp_id],
+          (error, result) => {
+            if (error) {
+              console.error(error);
+              res.status(500).json({ error: "Internal Server Error" });
+            } else if (result.rows.length === 0) {
+              res.status(404).json({ error: "Supplier doesn't exist in db" });
+            } else {
+              db.query(
+                "INSERT INTO product_availability (prod_id, supp_id, unit_price) VALUES ($1, $2, $3) RETURNING *",
+                [req.body.prod_id, req.body.supp_id, req.body.unit_price],
+                (error, result) => {
+                  if (error) {
+                    console.error(error);
+                    res.status(500).json({ error: "Internal Server Error" });
+                  } else {
+                    res.status(201).json(result.rows[0]);
+                  }
+                }
+              );
+            }
+          }
+        );
+      }
+    }
+  );
+});
+
+module.exports = app;
+
 // Your code to run the server should go here
 // Don't hardcode your DB password in the code or upload it to GitHub! Never ever do this ever.
 // Use environment variables instead:
 // https://www.codementor.io/@parthibakumarmurugesan/what-is-env-how-to-set-up-and-run-a-env-file-in-node-1pnyxw9yxj
-
-module.exports = app;