ZA | 25-SDC-July | Luke Manyamazi | Sprint 3 | Middleware Exercises

.gitignore

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+node_modules/

Implement-Laptop-Allocation/implementLaptop.py

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+from dataclasses import dataclass
+from enum import Enum
+from typing import List, Dict
+
+
+# Define possible operating systems
+class OperatingSystem(Enum):
+    MACOS = "macOS"
+    ARCH = "Arch Linux"
+    UBUNTU = "Ubuntu"
+
+
+# Define Person and Laptop
+@dataclass
+class Person:
+    name: str
+    age: int
+    preferred_operating_system: List[OperatingSystem]
+
+
+@dataclass
+class Laptop:
+    id: int
+    manufacturer: str
+    model: str
+    operating_system: OperatingSystem
+
+
+# Function to calculate sadness
+def sadness_for_person(person: Person, laptop: Laptop) -> int:
+    """How sad a person is with this laptop."""
+    if laptop.operating_system in person.preferred_operating_system:
+        return person.preferred_operating_system.index(laptop.operating_system)
+    else:
+        return 100  # Very sad if OS not in their list
+
+
+# Simple laptop allocation
+def allocate_laptops(people: List[Person], laptops: List[Laptop]) -> Dict[str, Laptop]:
+    """
+    Give each person one laptop.
+    Try to reduce sadness.
+    """
+    allocated = {}
+    available_laptops = laptops.copy()
+
+    for person in people:
+        best_laptop = None
+        best_sadness = 999
+
+        # Try to find the best laptop for this person
+        for laptop in available_laptops:
+            s = sadness_for_person(person, laptop)
+            if s < best_sadness:
+                best_sadness = s
+                best_laptop = laptop
+
+        # Give them the best one we found
+        allocated[person.name] = best_laptop
+        available_laptops.remove(best_laptop)
+
+    return allocated
+
+
+# Testing data
+def main():
+    laptops = [
+        Laptop(1, "Dell", "XPS 13", OperatingSystem.ARCH),
+        Laptop(2, "Dell", "XPS 15", OperatingSystem.UBUNTU),
+        Laptop(3, "Apple", "MacBook Air", OperatingSystem.MACOS),
+        Laptop(4, "Dell", "Inspiron", OperatingSystem.UBUNTU),
+    ]
+
+    people = [
+        Person("Imran", 22, [OperatingSystem.UBUNTU, OperatingSystem.ARCH, OperatingSystem.MACOS]),
+        Person("Eliza", 34, [OperatingSystem.ARCH, OperatingSystem.UBUNTU, OperatingSystem.MACOS]),
+        Person("Sam", 29, [OperatingSystem.MACOS, OperatingSystem.UBUNTU]),
+        Person("Tariq", 25, [OperatingSystem.ARCH]),
+    ]
+
+    allocations = allocate_laptops(people, laptops)
+
+    print("=== Laptop Allocations ===")
+    total_sadness = 0
+    for name, laptop in allocations.items():
+        person = next(p for p in people if p.name == name)
+        sad = sadness_for_person(person, laptop)
+        total_sadness += sad
+        print(f"{name} gets {laptop.model} ({laptop.operating_system.value}) - sadness {sad}")
+
+    print(f"\nTotal sadness: {total_sadness}")
+
+
+if __name__ == "__main__":
+    main()

Middleware-custom/app.js

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+const express = require('express');
+const app = express();
+const PORT = 3000;
+
+// Middleware 1: Check username header
+app.use((req, res, next) => {
+  req.username = req.headers['x-username'] || null;
+  next();
+});
+
+// Middleware 2: Parse JSON and check if body is string array
+app.use((req, res, next) => {
+  if (req.method !== 'POST') return next();
+
+  let body = '';
+  req.on('data', chunk => {
+    body += chunk.toString();
+  });
+
+  req.on('end', () => {
+    try {
+      req.body = JSON.parse(body);
+    } catch (error) {
+      return res.status(400).send('Error: Invalid JSON');
+    }
+
+    // Simple array check
+    if (!Array.isArray(req.body)) {
+      return res.status(400).send('Error: Send a JSON array');
+    }
+
+    // Simple string check
+    for (let item of req.body) {
+      if (typeof item !== 'string') {
+        return res.status(400).send('Error: All items must be strings');
+      }
+    }
+
+    req.subjects = req.body;
+    next();
+  });
+});
+
+// POST endpoint
+app.post('/', (req, res) => {
+  const name = req.username ? `authenticated as ${req.username}` : 'not authenticated';
+  const count = req.subjects.length;
+  const word = count === 1 ? 'subject' : 'subjects';
+  const list = req.subjects.join(', ');
+
+  res.send(`You are ${name}.\n\nYou asked about ${count} ${word}: ${list}.`);
+});
+
+app.listen(PORT, () => {
+  console.log('Custom server started on port 3000');
+});