London | 26-SDC-Mar | Beko | Sprint 3 | Middleware exercises

custom-middlewares/.gitignore

@@ -0,0 +1 @@
+/node_modules

custom-middlewares/index.js

@@ -0,0 +1,75 @@
+const express = require('express');
+const app = express();
+
+const port = process.env.PORT || 3000;
+
+
+const usernameCustomMiddleware = (req, res, next) => {
+  const username = req.headers["username"];
+  req.name = username ? username : null;
+  next();
+}
+
+const jsonBodyMustBeAnArrayMiddleware = (req, res, next) => {
+  let raw = "";
+  let chunks = [];
+
+  req.on("data", (chunk) => {
+    chunks.push(chunk);
+  });
+
+  req.on("end", () => {
+    try {
+      raw = Buffer.concat(chunks).toString("utf8");
+      const parsed = JSON.parse(raw);
+
+      if (!Array.isArray(parsed)) {
+        return res.status(400).type("text").send("Bad Request: Expected a JSON array in the request body.");
+      }
+
+      const confirmString = parsed.every(item => typeof item === "string");
+
+      if (!confirmString) {
+        return res.status(400).type("text").send("Bad Request: Expected a JSON array of strings in the request body.");
+      }
+
+      req.body = parsed;
+      next();
+
+    } catch (error) {
+      return res.status(400).type("text").send("Bad Request: Invalid JSON in the request body.");
+    }
+
+  })
+
+  req.on("error", () => {
+    return res.status(400).type("text").send("Bad Request: Error reading the request body.");
+  })
+
+}
+
+
+app.post("/custom-middleware", usernameCustomMiddleware, jsonBodyMustBeAnArrayMiddleware, (req, res) => {
+  try {
+
+    const username = req.name;
+    const subject = req.body;
+    const count = subject.length;
+
+    const authentication = username
+      ? `You are authenticated as ${username}`
+      : "You are not authenticated";
+
+    let subjectResponse = `You have requested info about ${count} subject${count === 1 ? "" : "s"}`;
+    subjectResponse += count > 0 ? `: ${subject.join(", ")}.` : `.`;
+
+    res.status(200).type("text").send(`\n${authentication}\n${subjectResponse}`);
+
+  } catch (error) {
+    return res.status(500).type("text").send("Internal Server Error.");
+  }
+})
+
+app.listen(port, () => {
+  console.log(`Server is running on Port: ${port}`);
+})