Final

README.md

@@ -1,32 +1,21 @@
 # COS498 HW3: PDF Document Management System
 
-This is Homework 3 for **COS498: Server Side Programming Languages** that demonstrates a PDF document management system with custom routing and validation modules.
+This is Homework 3 for **COS498: Server Side Programming Languages** that demonstrates a PDF document management system with custom routing.
 
 ## Project Overview
 
 This project implements a PDF document management system with the following features:
 - **Frontend**: Nginx serving static files and Handlebars templates
-- **Backend**: Node.js/Express server with custom routing and PDF management
+- **Backend**: Node.js/Express server with custom routing
-- **PDF Management**: PDF validation and secure serving system
+- **JSON Metadata**: Book and chapter metadata stored as JSON files
-- **Security**: Path validation and access control for PDF serving
-- **Database Integration**: SQLite database for book and chapter metadata
 - **Containerization**: Docker containers orchestrated with Docker Compose
 
 ## Features
 
 ### PDF Document Management
-- **PDF Validation Module**: Comprehensive validation before serving any PDF
 - **Custom Routing**: Dedicated routing module for book and chapter navigation  
-- **Security Controls**: Path validation and access restrictions
+- **JSON Metadata**: Book and chapter information stored in JSON format
-- **Database Integration**: SQLite database with books and chapters metadata
+- **File Serving**: Direct access to PDF files through designated routes
-
-### PDF Validation System
-- **File Existence Checks**: Validates PDF files exist before serving
-- **Path Security**: Prevents access outside designated directories
-- **Input Validation**: Sanitizes book names and filenames
-- **Extension Validation**: Only allows `.pdf` files
-- **File Size Limits**: Enforces maximum file size restrictions
-- **Error Responses**: Appropriate HTTP status codes (400, 403, 404, 413, 500)
 
 ### User Interface
 - **Book Browser**: Navigate through available books and chapters
@@ -52,14 +41,13 @@ COS498-HW3/
 │   ├── Dockerfile             # Backend container configuration
 │   ├── package.json           # Node.js dependencies and scripts
 │   ├── package-lock.json      # Locked dependency versions
-│   ├── server.js              # Node.js Express server with PDF management
+│   ├── server.js              # Node.js Express server
 │   ├── database/
-│   │   ├── backend.db         # SQLite database with book metadata
+│   │   └── backend.schema     # Database schema definition
-│   │   ├── backend.schema     # Database schema definition
-│   │   └── backend_initial.db # Initial database backup
 │   └── modules/
 │       ├── RoutingManager.js      # Custom routing module
-│       └── PDFValidationManager.js # PDF validation and security
+│       ├── PDFValidationManager.js # PDF validation module
+│       └── PDFDatabaseManager.js   # Database management module
 └── frontend/
     ├── Dockerfile             # Frontend container configuration
     ├── default.conf           # Nginx configuration
@@ -74,7 +62,9 @@ COS498-HW3/
         │   └── WaysOfTheWorld-Strayer/  # Sample textbook (git submodule)
         │       ├── README.md          # Book information
         │       ├── .git               # Submodule repository metadata
-        │       └── chapter1-23.pdf   # 23 chapter PDF files
+        │       ├── bookMetadata.json  # Book metadata
+        │       ├── chapter1-23.json   # Chapter metadata files
+        │       └── chapter1-23.pdf    # 23 chapter PDF files
         └── styles/
             └── main.css       # Application stylesheet
 ```

backend/database/backend.schema

@@ -13,30 +13,4 @@ CREATE TABLE IF NOT EXISTS "chapters" (
         "book_id"       INTEGER NOT NULL,
         PRIMARY KEY("id" AUTOINCREMENT),
         FOREIGN KEY("book_id") REFERENCES "books"("id")
-);
+);
-INSERT INTO chapters
-(chapter_number, display_name, filename, book_id)
-VALUES
-(1, "First Peoples; First Farmers", "chapter1.pdf", 1),
-(2, "First Civilizations", "chapter2.pdf", 1),
-(3, "State and Empire in Eurasia / North Africa", "chapter3.pdf", 1),
-(4, "Culture and Religion in Eurasia / North Africa", "chapter4.pdf", 1),
-(5, "Society and Inequality in Eurasia / North Africa", "chapter5.pdf", 1),
-(6, "Commonalities and Variations", "chapter6.pdf", 1),
-(7, "Commerce and Culture", "chapter7.pdf", 1),
-(8, "China and the World", "chapter8.pdf", 1),
-(9, "The Worlds Of Island", "chapter9.pdf", 1),
-(10, "The Worlds of Christendom", "chapter10.pdf", 1),
-(11, "Pastoral Peoples on the Global Stage", "chapter11.pdf", 1),
-(12, "The Worlds of the Fifteenth Century", "chapter12.pdf", 1),
-(13, "Political Transformations", "chapter13.pdf", 1),
-(14, "Economic Transformations", "chapter14.pdf", 1),
-(15, "Cultural Transformations", "chapter15.pdf", 1),
-(16, "Atlantic Revolutions, Global Echos", "chapter16.pdf", 1),
-(17, "Revolutions of Industrialization", "chapter17.pdf", 1),
-(18, "Colonial Encounters in Asia and Africa", "chapter18.pdf", 1),
-(19, "Empires in Collision", "chapter19.pdf", 1),
-(20, "Collapse at the Center", "chapter20.pdf", 1),
-(21, "Revolution, Socialism, and Global Conflict", "chapter21.pdf", 1),
-(22, "The End of Empire", "chapter22.pdf", 1),
-(23, "Capitalism and Culture", "chapter23.pdf", 1)

backend/modules/PDFDatabaseManager.js

@@ -0,0 +1,124 @@
+// Imports
+const sqlite3 = require('sqlite3').verbose();
+const fs = require('fs');
+const path = require('path');
+
+// Configuration Constants
+const DB_PATH = "database/backend.db";
+const SCHEMA_PATH = "database/backend.schema";
+const BOOK_PATH = "../frontend/public/books";
+
+// PDF Database Manager - Manages SQLite database for storing PDF metadata
+// Also handles scanning book directory and building DB
+class PDFDatabaseManager {
+    constructor() {
+        if (fs.existsSync(DB_PATH)) {
+            fs.unlinkSync(DB_PATH);
+        }
+        this.db = new sqlite3.Database(DB_PATH); 
+        this.createDatabase();
+        this.scanAndPopulateDatabase();
+    }
+
+    // Scans the books folder and adds all books / chapters to the database
+    async scanAndPopulateDatabase() {
+        const bookFolders = fs.readdirSync(BOOK_PATH);
+        bookFolders.forEach(folder => {
+            const bookDir = path.join(BOOK_PATH, folder);
+            const bookMetadataPath = path.join(bookDir, 'bookMetadata.json');
+            if (fs.existsSync(bookMetadataPath)) {
+                const bookMetadata = JSON.parse(fs.readFileSync(bookMetadataPath, 'utf-8'));
+                this.addBook(bookMetadata);
+
+                const chapterFiles = fs.readdirSync(bookDir).filter(file => file.endsWith('.json') && file !== 'bookMetadata.json');
+
+                chapterFiles.forEach(async chapterFile => {
+                    const chapterMetadataPath = path.join(bookDir, chapterFile);
+                    const chapterMetadata = JSON.parse(fs.readFileSync(chapterMetadataPath, 'utf-8'));
+                    chapterMetadata.book_id = await this.getBookIdByFolderName(folder);
+                    this.addChapter(chapterMetadata);
+                });
+            }
+        });
+    }
+
+    // Adds chapter metadata from FS to db
+    addChapter(chapterMetadata) {
+        let chapterQuery = `INSERT INTO chapters (chapter_number, display_name, filename, book_id) VALUES (?, ?, ?, ?)`;
+        this.db.run(chapterQuery, [chapterMetadata.chapter_number, chapterMetadata.display_name, chapterMetadata.filename, chapterMetadata.book_id]);
+    }
+
+    // Adds book metadata from FS to db
+    addBook(bookMetadata) {
+        let bookQuery = `INSERT INTO books (folder_name, display_name, author) VALUES (?, ?, ?)`;
+        this.db.run(bookQuery, [bookMetadata.folder_name, bookMetadata.display_name, bookMetadata.author]);
+    }
+
+    // Retrieves book ID by folder name
+    getBookIdByFolderName(folderName) {
+        return new Promise((resolve) => {
+            let query = `SELECT id FROM books WHERE folder_name = ?`;
+            this.db.get(query, [folderName], (err, row) => {
+                if (err) {
+                    resolve(null);
+                } else {
+                    resolve(row ? row.id : null);
+                }
+            });
+        });
+    }
+
+    // Creates the database if it doesn't exist
+    createDatabase() {
+        // Load DB schema from file and initialize database
+        const schema = fs.readFileSync(SCHEMA_PATH, 'utf-8');
+        this.db.exec(schema, (err) => {
+            if (err) {
+                console.error('Error creating database schema:', err.message);
+            } else {
+                console.log('Database schema created successfully.');
+            }
+        });
+    }
+
+    // List all books in the database
+    loadBooks() {
+        return new Promise((resolve, reject) => {
+            const query = 'SELECT id, folder_name, display_name, author FROM books ORDER BY display_name';
+            this.db.all(query, [], (err, rows) => {
+                const books = rows.map(row => ({
+                    id: row.id,
+                    name: row.folder_name,
+                    displayName: row.display_name,
+                    author: row.author
+                }));
+                resolve(books);
+            });
+        });
+    }
+
+    // List all chapters for a specific book
+    loadChapters(bookName) {
+        return new Promise((resolve, reject) => {
+            const query = `
+                SELECT c.id, c.chapter_number, c.display_name, c.filename, b.folder_name
+                FROM chapters c
+                JOIN books b ON c.book_id = b.id
+                WHERE b.folder_name = ?
+                ORDER BY c.chapter_number
+            `;
+            this.db.all(query, [bookName], (err, rows) => {
+                const chapters = rows.map(row => ({
+                    id: row.id,
+                    chapterNumber: row.chapter_number,
+                    filename: row.filename,
+                    displayName: row.display_name,
+                    url: `/pdf/${row.folder_name}/${row.filename}`
+                }));
+                resolve(chapters);
+            });
+        });
+    }
+}
+
+module.exports = PDFDatabaseManager;

backend/modules/PDFValidationManager.js

@@ -1,52 +1,25 @@
+// Imports
 const fs = require('fs').promises;
 const path = require('path');
 
-/**
+// Configuration Constants
- * PDF Validation Module - Validates PDF existence and access permissions
+const BOOK_PATH = "../frontend/public/books";
- * Ensures only authorized access to PDFs within designated folders
+
- */
+// PDF Validation Module - Validates PDF existence and access permissions
+// Ensures only authorized access to PDFs within designated folders
 class PDFValidationManager {
-    constructor(baseDir = '/app/frontend/public/books') {
+    // Validate if a requested PDF document exists and is accessible
-        this.baseDir = path.resolve(baseDir);
+    static async validatePDF(bookName, filename) {
-    }
-
-    /**
-     * Validate if a requested PDF document exists and is accessible
-     */
-    async validatePDF(bookName, filename) {
-        
         try {
-            // Construct file path
+            const filePath = path.resolve(BOOK_PATH, bookName, filename)
-            const filePath = path.resolve(this.baseDir, bookName, filename)
+            const file = await fs.stat(filePath);
-
+            if (file.isFile()) {
-            // Check if file exists and get file stats
+                return filePath;
-            const fileStats = await fs.stat(filePath);
+            } else {
-            if (!fileStats.isFile()) {
+                throw new Error('Invalid PDF request');
-                return {
+            } 
-                    valid: false,
+        } catch {
-                    error: 'File not found or is not a regular file',
+            throw new Error('Invalid PDF request');
-                    statusCode: 404
-                };
-            }
-
-            // All validations passed
-            return {
-                valid: true,
-                filePath: filePath,
-                fileStats: {
-                    size: fileStats.size,
-                    lastModified: fileStats.mtime,
-                    isFile: fileStats.isFile()
-                }
-            };
-            
-        } catch (error) {
-            console.error(`PDF validation error for ${bookName}/${filename}:`, error);
-            return {
-                valid: false,
-                error: 'Internal validation error',
-                statusCode: 500
-            };
         }
     }
 }

backend/modules/RoutingManager.js

@@ -1,154 +1,160 @@
-// Helper functions for server-side rendering
+// Imports
-function loadBooks(db) {
+const hbs = require('hbs');
-    return new Promise((resolve, reject) => {
+const express = require('express');
-        const query = 'SELECT id, folder_name, display_name, author FROM books ORDER BY display_name';
-        db.all(query, [], (err, rows) => {
-            if (err) {
-                console.error('Error loading books from database:', err.message);
-                resolve([]);
-            } else {
-                const books = rows.map(row => ({
-                    id: row.id,
-                    name: row.folder_name,
-                    displayName: row.display_name || row.folder_name.replace(/-/g, ' '),
-                    author: row.author
-                }));
-                resolve(books);
-            }
-        });
-    });
-}
 
-function loadChapters(db, bookName) {
+// Local Module Imports
-    return new Promise((resolve, reject) => {
+const PDFValidationManager = require('./PDFValidationManager');
-        const query = `
+const PDFDatabaseManager = require('./PDFDatabaseManager');
-            SELECT c.id, c.chapter_number, c.display_name, c.filename, b.folder_name
-            FROM chapters c
-            JOIN books b ON c.book_id = b.id
-            WHERE b.folder_name = ?
-            ORDER BY c.chapter_number
-        `;
-        db.all(query, [bookName], (err, rows) => {
-            if (err) {
-                console.error('Error loading chapters from database:', err.message);
-                resolve([]);
-            } else {
-                const chapters = rows.map(row => ({
-                    id: row.id,
-                    chapterNumber: row.chapter_number,
-                    filename: row.filename,
-                    displayName: row.display_name,
-                    url: `/pdf/${row.folder_name}/${encodeURIComponent(row.filename)}`
-                }));
-                resolve(chapters);
-            }
-        });
-    });
-}
 
-// Page Route handlers
+class RoutingManager {
-async function homePage(db, req, res) {
+    constructor(app) {
-    try {
+        this.databaseManager = new PDFDatabaseManager();
-        const books = await loadBooks(db);
+        this.db = this.databaseManager.db;
-        res.render('index', { 
+        this.app = app;
-            title: 'Book Viewer',
+    }
-            books: books,
+
-            selectedBook: null,
+    // Setup Routing Manager
-            selectedChapter: null,
+    setup() {
-            chapters: []
+        this.setupHandlebars();
-        });
+        this.middleware();
-    } catch (error) {
+        this.setupRoutes();
-        console.error('Error loading books for home page:', error);
+    }
-        res.render('index', {
+
-            title: 'Book Viewer',
+    // Setup Handlebars
-            books: [],
+    setupHandlebars() {
-            selectedBook: null,
+        // Handlebars - Views
-            selectedChapter: null,
+        this.app.set('view engine', 'hbs');
-            chapters: [],
+        this.app.set('views', '../frontend/views');
-            error: 'Failed to load books'
+        // Handlebars - Partials
+        hbs.registerPartials('../frontend/partials');
+        // Handlebars Helpers
+        hbs.registerHelper('eq', function(a, b) {
+            return a === b;
         });
     }
-}
 
-// Render page with specific book
+    // Middleware for Application
-async function bookPage(db, req, res) {
+    middleware() {
-    const bookName = req.params.bookName;
+        this.app.use(express.static('../frontend/public'));
-    
+        this.app.use(express.json());
-    try {
+        // this.app.use(cookieParser());
-        const [books, chapters] = await Promise.all([
+    }
-            loadBooks(db),
+
-            loadChapters(db, bookName)
+    // Setup Page Routes
-        ]);
+    setupRoutes() {
-        const selectedBook = books.find(book => book.name === bookName);
+        this.app.get('/', async (req, res) => {
-        
+            await this.homePage(req, res);
-        if (!selectedBook) {
+        });
-            return res.redirect('/');
+
+        this.app.get('/book/:bookName', async (req, res) => {
+            await this.bookPage(req, res);
+        });
+
+        this.app.get('/book/:bookName/chapter/:chapterFile', async (req, res) => {
+            await this.chapterPage(req, res);
+        });
+
+        this.app.get('/pdf/:bookName/:chapterFile', async (req, res) => {
+            await this.servePDF(req, res);
+        });
+    }
+
+    // Home Page Handler
+    async homePage(req, res) {
+        try {
+            const books = await this.databaseManager.loadBooks();
+            res.render('index', { 
+                title: 'Book Viewer',
+                books: books,
+                selectedBook: null,
+                selectedChapter: null,
+                chapters: []
+            });
+        } catch (error) {
+            res.render('index', {
+                title: 'Book Viewer',
+                books: [],
+                selectedBook: null,
+                selectedChapter: null,
+                chapters: [],
+                error: 'Failed to load books'
+            });
         }
-        
-        res.render('index', {
-            title: 'Book Viewer',
-            books: books,
-            selectedBook: selectedBook,
-            selectedChapter: null,
-            chapters: chapters
-        });
-    } catch (error) {
-        console.error('Error loading book page:', error);
-        res.redirect('/');
     }
-}
 
-// Render page with specific chapter
+    // Book Page Handler
-async function chapterPage(db, req, res) {
+    async bookPage(req, res) {
-    const bookName = req.params.bookName;
+        const bookName = req.params.bookName;
-    const chapterFile = decodeURIComponent(req.params.chapterFile);
+        try {
-    
+            const [books, chapters] = await Promise.all([
-    try {
+                this.databaseManager.loadBooks(),
-        const [books, chapters] = await Promise.all([
+                this.databaseManager.loadChapters(bookName)
-            loadBooks(db),
+            ]);
-            loadChapters(db, bookName)
+            const selectedBook = books.find(book => book.name === bookName);
-        ]);
+            
-        const selectedBook = books.find(book => book.name === bookName);
+            if (!selectedBook) {
-        const selectedChapter = chapters.find(chapter => chapter.filename === chapterFile);
+                return res.redirect('/');
-        
+            }
-        if (!selectedBook || !selectedChapter) {
+            
-            return res.redirect('/');
+            res.render('index', {
+                title: 'Book Viewer',
+                books: books,
+                selectedBook: selectedBook,
+                selectedChapter: null,
+                chapters: chapters
+            });
+        } catch (error) {
+            res.redirect('/');
         }
+    }
+    
+    // Chapter Page Handler
+    async chapterPage(req, res) {
+        const bookName = req.params.bookName;
+        const chapterFile = req.params.chapterFile;
         
-        res.render('index', {
+        try {
-            title: 'Book Viewer',
+            const [books, chapters] = await Promise.all([
-            books: books,
+                this.databaseManager.loadBooks(),
-            selectedBook: selectedBook,
+                this.databaseManager.loadChapters(bookName)
-            selectedChapter: selectedChapter,
+            ]);
-            chapters: chapters
+            const selectedBook = books.find(book => book.name === bookName);
-        });
+            const selectedChapter = chapters.find(chapter => chapter.filename === chapterFile);
-    } catch (error) {
+            
-        console.error('Error loading chapter page:', error);
+            if (!selectedBook || !selectedChapter) {
-        res.redirect('/');
+                return res.redirect('/');
+            }
+            
+            res.render('index', {
+                title: 'Book Viewer',
+                books: books,
+                selectedBook: selectedBook,
+                selectedChapter: selectedChapter,
+                chapters: chapters
+            });
+        } catch (error) {
+            res.redirect('/');
+        }
+    }
+
+    // PDF Serving Handler
+    async servePDF(req, res) {
+        const { bookName, chapterFile } = req.params;
+        try {
+            // Validate PDF using validation module
+            const filePath = await PDFValidationManager.validatePDF(bookName, chapterFile);
+            
+            // Serve the PDF file using sendFile
+            res.sendFile(filePath, (sendErr) => {
+                if (sendErr) {
+                    res.status(500).json({ error: 'Error serving PDF file' });
+                }
+            });
+            
+        } catch (error) {
+            res.status(500).json({ error: 'Invalid PDF request' });
+        }
     }
 }
 
-// Setup routes function
+module.exports = RoutingManager;
-function setupRoutes(app, db) {
-    // Page Routes
-    app.get('/', async (req, res) => {
-        await homePage(db, req, res);
-    });
-
-    app.get('/book/:bookName', async (req, res) => {
-        await bookPage(db, req, res);
-    });
-
-    app.get('/book/:bookName/chapter/:chapterFile', async (req, res) => {
-        await chapterPage(db, req, res);
-    });
-}
-
-module.exports = {
-    setupRoutes,
-    loadBooks,
-    loadChapters,
-    homePage,
-    bookPage,
-    chapterPage
-};

backend/server.js

@@ -1,85 +1,15 @@
+// Imports
 const express = require('express');
-const hbs = require('hbs');
+
-const cookieParser = require('cookie-parser');
-const path = require('path');
-const fs = require('fs');
-const sqlite3 = require('sqlite3').verbose();
 const app = express();
 const PORT = process.env.PORT || 3000;
 
-// Handlebars
+// Local Module Imports
-app.set('view engine', 'hbs');
-app.set('views', '../frontend/views');
-
-// Register partials directory
-hbs.registerPartials('../frontend/partials');
-
-// Register Handlebars helpers
-hbs.registerHelper('eq', function(a, b) {
-    return a === b;
-});
-
-hbs.registerHelper('encodeURIComponent', function(str) {
-    return encodeURIComponent(str);
-});
-
-// Database setup
-const dbPath = path.join(__dirname, 'database/backend.db');
-const db = new sqlite3.Database(dbPath, (err) => {
-    if (err) {
-        console.error('Error opening database:', err.message);
-    }
-});
-
-// Import routing module
 const RoutingManager = require('./modules/RoutingManager');
-const PDFValidationManager = require('./modules/PDFValidationManager');
-
-// Initialize PDF validation module
-const pdfValidator = new PDFValidationManager();
-
-// Middleware
-// Serve only specific static assets, not the entire public directory
-app.use(express.static('../frontend/public'));
-app.use(express.json());
-app.use(cookieParser());
 
 // Setup routes using RoutingManager
-RoutingManager.setupRoutes(app, db);
+const routingManager = new RoutingManager(app);
-
+routingManager.setup();
-// PDF serving route with validation
-app.get('/pdf/:bookName/:chapterFile', async (req, res) => {
-    const { bookName, chapterFile } = req.params;
-    
-    try {
-        // Validate PDF using validation module
-        const validation = await pdfValidator.validatePDF(bookName, chapterFile);
-        
-        if (!validation.valid) {
-            console.warn(`PDF validation failed: ${validation.error}`);
-            return res.status(validation.statusCode).json({ 
-                error: validation.error,
-                bookName,
-                chapterFile
-            });
-        }
-        
-        // Serve the PDF file using sendFile
-        res.sendFile(validation.filePath, (sendErr) => {
-            if (sendErr) {
-                console.error(`Error serving PDF file: ${sendErr.message}`);
-                if (!res.headersSent) {
-                    res.status(500).json({ error: 'Error serving PDF file' });
-                }
-            }
-        });
-        
-    } catch (error) {
-        console.error('Error in PDF serving route:', error);
-        res.status(500).json({ error: 'Internal server error' });
-    }
-});
-
 
 // Start server
 app.listen(PORT, '0.0.0.0', () => {

frontend/partials/chapters.hbs

@@ -1,7 +1,7 @@
 {{#if chapters}}
     {{#each chapters}}
     <div class="chapter-item {{#if (eq this.filename ../selectedChapter.filename)}}selected{{/if}}" data-chapter-url="{{this.url}}">
-        <a href="/book/{{../selectedBook.name}}/chapter/{{encodeURIComponent this.filename}}">{{this.displayName}}</a>
+        <a href="/book/{{../selectedBook.name}}/chapter/{{this.filename}}">{{this.displayName}}</a>
     </div>
     {{/each}}
 {{else}}

frontend/public/styles/main.css

@@ -162,6 +162,7 @@ body {
     border: 1px solid #e9ecef;
     transition: all 0.2s ease;
     font-size: 0.95rem;
+    width: 95%;
 }
 
 .chapter-item a {

frontend/views/index.hbs

@@ -1,2 +1 @@
-<!-- This content will be injected into the layout template -->
+<!-- Intentionally left empty to inject dynamic content via Handlebars in layout -->
-<!-- The main functionality is handled by the layout template and JavaScript -->