Invoice Generator

A full-featured Spring Boot application for creating, managing, and distributing invoices. This project provides a web interface and a REST API to generate professional-looking PDF invoices and deliver them via email.

Features

• Web Interface: An intuitive web UI built with Thymeleaf and Bootstrap to create, view, and list invoices.
• REST API: A comprehensive REST API for programmatic invoice management.
• Dynamic PDF Generation: Generates clean, well-formatted PDF invoices using the OpenPDF library.
• Email Integration: Automatically sends generated PDF invoices as email attachments to customers using Spring Mail.
• Database Persistence: Saves all invoice data using Spring Data JPA, configured for an in-memory H2 database by default.
• PDF Caching: Implements a simple in-memory cache for recently generated PDFs to improve performance for repeated downloads.
• Docker Support: Includes a multi-stage dockerfile for easy containerization and deployment.

Technologies Used

• Backend: Java 21, Spring Boot 3
• Data: Spring Data JPA, H2 Database
• Web: Spring Web, Thymeleaf
• PDF: OpenPDF
• Email: Spring Boot Starter Mail
• Build: Maven
• Containerization: Docker

Getting Started

Prerequisites

• Java Development Kit (JDK) 21 or later
• Apache Maven
• An SMTP server (e.g., Gmail) for sending emails

Installation & Configuration

1. Clone the repository:

   git clone https://github.com/aravind556/invoicegenerator.git
   cd invoicegenerator

2. Configure Email Settings: The application uses environment variables to configure email credentials. Set the following variables in your environment or IDE's run configuration:

   • SPRING_MAIL_USERNAME: Your SMTP username (e.g., your.email@gmail.com).
   • SPRING_MAIL_PASSWORD: Your SMTP password or an app-specific password.

   These are referenced in src/main/resources/application.properties.

3. Build and Run the Application:

   ./mvnw spring-boot:run

   The application will start on http://localhost:8080.

Using Docker

You can also run the application using Docker.

1. Build the Docker image:

   docker build -t invoice-generator .

2. Run the Docker container: Pass your email credentials as environment variables to the container.

   docker run -p 8080:8080 \
     -e SPRING_MAIL_USERNAME="your-email@example.com" \
     -e SPRING_MAIL_PASSWORD="your-email-password" \
     invoice-generator

Usage

Web Interface

• Home Page (/): Navigate to http://localhost:8080 to see a list of all created invoices.
• Create Invoice (/invoices/create): Click the "Create New Invoice" button to access a form where you can enter customer details and add line items. Submitting the form creates the invoice, generates a PDF, and emails it to the customer.
• Invoice Detail (/invoices/{id}): View details of a specific invoice, including an embedded preview of the PDF.

API Endpoints

The API is available under the /Invoice path.

Method	Endpoint	Description
POST	/Invoice	Creates a new invoice from the JSON payload.
GET	/Invoice	Returns a list of all invoices.
GET	/Invoice/{id}/view	Returns the PDF file for inline viewing (in browser).
GET	/Invoice/{id}/pdf	Downloads the invoice as a PDF file.

Example POST /Invoice Body:

{
    "name": "Jane Doe",
    "email": "jane.doe@example.com",
    "items": [
        {
            "itemName": "Web Design Service",
            "quantity": 10,
            "unitPrice": 50.0,
            "discount": 5
        },
        {
            "itemName": "Logo Creation",
            "quantity": 1,
            "unitPrice": 300.0,
            "discount": 0
        }
    ]
}