feat: add student history API endpoint (#77)

* feat: add student history API endpoint

* chore: update files

* refactor: move student history logic to separate module

* style: format student history module

* changing the file name and removing comments

* style: apply prettier formatting

* message

* improve user history API response time

* Change main entry point from index.js to server.js

* Add caching for student API endpoint

Implement caching for student data retrieval to improve performance.

---------

Co-authored-by: Jagdish Prajapati <jagadishdrp@gmail.com>

Author: Yashaswini-K-P

CODE_OF_CONDUCT.md

@@ -17,23 +17,23 @@ diverse, inclusive, and healthy community.
 Examples of behavior that contributes to a positive environment for our
 community include:
 
-* Demonstrating empathy and kindness toward other people
-* Being respectful of differing opinions, viewpoints, and experiences
-* Giving and gracefully accepting constructive feedback
-* Accepting responsibility and apologizing to those affected by our mistakes,
+- Demonstrating empathy and kindness toward other people
+- Being respectful of differing opinions, viewpoints, and experiences
+- Giving and gracefully accepting constructive feedback
+- Accepting responsibility and apologizing to those affected by our mistakes,
   and learning from the experience
-* Focusing on what is best not just for us as individuals, but for the
+- Focusing on what is best not just for us as individuals, but for the
   overall community
 
 Examples of unacceptable behavior include:
 
-* The use of sexualized language or imagery, and sexual attention or
+- The use of sexualized language or imagery, and sexual attention or
   advances of any kind
-* Trolling, insulting or derogatory comments, and personal or political attacks
-* Public or private harassment
-* Publishing others' private information, such as a physical or email
+- Trolling, insulting or derogatory comments, and personal or political attacks
+- Public or private harassment
+- Publishing others' private information, such as a physical or email
   address, without their explicit permission
-* Other conduct which could reasonably be considered inappropriate in a
+- Other conduct which could reasonably be considered inappropriate in a
   professional setting
 
 ## Enforcement Responsibilities
@@ -106,7 +106,7 @@ Violating these terms may lead to a permanent ban.
 ### 4. Permanent Ban
 
 **Community Impact**: Demonstrating a pattern of violation of community
-standards, including sustained inappropriate behavior,  harassment of an
+standards, including sustained inappropriate behavior, harassment of an
 individual, or aggression toward or disparagement of classes of individuals.
 
 **Consequence**: A permanent ban from any sort of public interaction within
@@ -126,4 +126,3 @@ enforcement ladder](https://github.com/mozilla/diversity).
 For answers to common questions about this code of conduct, see the FAQ at
 https://www.contributor-covenant.org/faq. Translations are available at
 https://www.contributor-covenant.org/translations.
-

README.md

@@ -10,16 +10,16 @@ It allows users to register with their LeetCode username and automatically fetch
 
 The goal of this project is to:
 
-- Encourage consistent problem-solving among students  
-- Create a competitive yet motivating environment  
-- Provide visibility into individual coding progress  
+- Encourage consistent problem-solving among students
+- Create a competitive yet motivating environment
+- Provide visibility into individual coding progress
 
 ---
 
-
-
 ## Screenshots
+
 A quick preview of the platform UI. The appearance may evolve as the project develops.
+
 ### Home Page
 
 ![Home Page](assets/home-page.png)
@@ -28,13 +28,10 @@ A quick preview of the platform UI. The appearance may evolve as the project dev
 
 ![Registration](assets/registration-page.png)
 
-
 ### Leaderboard
 
 ![Leaderboard](assets/leaderboard.png)
 
-
-
 ## Related Repositories
 
 - [leetcode-ranking-data](https://github.com/codepvg/leetcode-ranking-data) – The database repository where raw JSON data and historical stats are stored
@@ -65,6 +62,7 @@ leetcode-ranking/
 ### 1. Fork and clone the repository
 
 First, fork the repository to your GitHub account. Then clone it locally:
+
 ```bash
 git clone https://github.com/YOUR-USERNAME/leetcode-ranking.git
 cd leetcode-ranking
@@ -82,9 +80,9 @@ or
 
 ## Usage
 
-1. Open the registration page  
-2. Enter your name and LeetCode username  
-3. Submit the form  
+1. Open the registration page
+2. Enter your name and LeetCode username
+3. Submit the form
 4. View your ranking on the leaderboard after the next sync
 
 ---
@@ -93,7 +91,7 @@ or
 
 Contributions are welcome.
 
-- Fork the repository  
-- Create a new branch  
-- Make your changes  
-- Submit a Pull Request  
+- Fork the repository
+- Create a new branch
+- Make your changes
+- Submit a Pull Request

package.json

@@ -2,9 +2,10 @@
   "name": "leetcode-ranking",
   "version": "1.0.0",
   "description": "",
-  "main": "index.js",
+  "main": "server.js",
   "scripts": {
-    "dev": "node ./server.js"
+    "start": "node server.js",
+    "dev": "nodemon server.js"
   },
   "repository": {
     "type": "git",

scripts/fetch-student-info.js

@@ -0,0 +1,89 @@
+function getFileName(daysAgo) {
+  const now = new Date();
+  now.setDate(now.getDate() - daysAgo);
+
+  const year = now.getFullYear();
+  const month = String(now.getMonth() + 1).padStart(2, "0");
+  const date = String(now.getDate()).padStart(2, "0");
+  let day = now.getDay();
+  day = day === 0 ? 7 : day;
+
+  return `${year}-${month}-${date}-${day}.json`;
+}
+
+async function fetchStudentHistory(username) {
+  console.log("Fetching history for:", username);
+
+  let history = [];
+  let missingFilesCount = 0;
+  const maxDays = 365;
+  const chunkSize = 100;
+
+  let done = false;
+
+  for (let chunkStart = 0; chunkStart < maxDays; chunkStart += chunkSize) {
+    if (done) break;
+
+    const fetchPromises = [];
+    const chunkEnd = Math.min(chunkStart + chunkSize, maxDays);
+
+    for (let daysAgo = chunkStart; daysAgo < chunkEnd; daysAgo++) {
+      const fileName = getFileName(daysAgo);
+      const rawUrl = `https://raw.githubusercontent.com/codepvg/leetcode-ranking-data/main/daily/${fileName}`;
+
+      const p = fetch(rawUrl)
+        .then(async (res) => {
+          if (!res.ok) {
+            return { daysAgo, fileName, ok: false };
+          }
+          const data = await res.json();
+          return { daysAgo, fileName, ok: true, data };
+        })
+        .catch((err) => {
+          return { daysAgo, fileName, ok: false, error: err };
+        });
+
+      fetchPromises.push(p);
+    }
+
+    const results = await Promise.all(fetchPromises);
+
+    for (const result of results) {
+      if (!result.ok) {
+        missingFilesCount++;
+        if (missingFilesCount >= 7) {
+          done = true;
+          break;
+        }
+        continue;
+      }
+
+      missingFilesCount = 0;
+
+      const user = result.data.find((u) => u.id === username);
+
+      if (user) {
+        const dateStr = result.fileName.split("-").slice(0, 3).join("-");
+
+        history.push({
+          date: dateStr,
+          easy: user.data.easySolved,
+          medium: user.data.mediumSolved,
+          hard: user.data.hardSolved,
+        });
+      } else {
+        done = true;
+        break;
+      }
+    }
+  }
+
+  history.sort((a, b) => new Date(a.date) - new Date(b.date));
+
+  return {
+    username,
+    history,
+  };
+}
+
+module.exports = fetchStudentHistory;

server.js

@@ -1,13 +1,16 @@
 const express = require("express");
 const cors = require("cors");
 const path = require("path");
-const fs = require("fs");
+
 const app = express();
 const PORT = process.env.PORT || 3000;
 
+const fetchStudentHistory = require("./scripts/fetch-student-info");
+
 app.use(cors());
 app.use(express.static(path.join(__dirname, "frontend")));
 
+/* ---------------- HOME ROUTES ---------------- */
 app.get("/", (req, res) => {
   res.sendFile(path.join(__dirname, "frontend", "index.html"));
 });
@@ -28,6 +31,32 @@ app.get("/uptime", (req, res) => {
   res.json({ status: "Website is running ✅" });
 });
 
+const studentCache = new Map();
+
+app.get("/api/student/:username", async (req, res) => {
+  const username = req.params.username;
+
+  if (studentCache.has(username)) {
+    const cached = studentCache.get(username);
+    if (Date.now() - cached.timestamp < 5 * 60 * 1000) {
+      return res.json(cached.data);
+    }
+  }
+
+  try {
+    const data = await fetchStudentHistory(username);
+
+    studentCache.set(username, { timestamp: Date.now(), data });
+
+    res.json(data);
+  } catch (err) {
+    res.status(500).json({
+      error: "Failed to fetch student details",
+      details: err.message,
+    });
+  }
+});
+
 app.use((req, res) => {
   res.status(404).send("Page not found");
 });