Building an Image Generation Web Application with FastAPI

Welcome to the first lesson of our course on building an image generation web application with FastAPI! In this course, you'll learn how to create a user-friendly web interface for an AI-powered image generation service. By the end of this course, you'll have built a complete web application that allows users to generate images based on text prompts and view their generation history.

In this first lesson, we'll focus on creating the HTML structure for our application. This structure will serve as the foundation for our user interface, providing the elements that users will interact with to generate images and view their history.

Our application will have two main sections:

1. A "Generate Image" tab where users can enter prompts and customize their image generation.
2. A "View History" tab where users can see their previously generated images.

Before we dive into the code, let's understand how FastAPI handles HTML templates. In a FastAPI application, HTML files are typically stored in a folder called templates. FastAPI can use the Jinja2 templating engine, which allows us to include dynamic content in our HTML files. We'll see this in action when we link our CSS and JavaScript files.

Now, let's start building our HTML interface!

Before we start building the HTML for our image generation interface, let's take a moment to understand how our FastAPI application is organized. A clear file structure helps us stay organized as our project grows in complexity.

Here's the structure we'll be working with:

image-generator-app/
│
├── main.py                    # Entry point for running the FastAPI app
│
├── routers/                   # FastAPI route logic
│   └── image_generator_router.py
│
├── services/                  # Core logic for image generation
│   └── image_generator_service.py
│
├── models/                    # Manages data and helper logic
│   ├── image_manager.py
│   └── prompt_manager.py
│
├── data/                      # Data template for image prompt
│   └── image_prompt_template.txt
│
├── static/                    # Frontend static files (CSS, JS, etc.)
│   ├── style.css
│   └── script.js
│
└── templates/                 # HTML templates rendered by FastAPI
    └── image_generator.html

• routers/: Defines FastAPI routes and handles incoming requests.
• services/: Contains the logic for formatting prompts and generating images using AI.
• models/: Deals with image storage and loading of prompt templates.
• templates/ and static/: Support the front-end UI with HTML, CSS, and JavaScript.
• data/: Holds reusable text templates to guide consistent image generation prompts.

With this structure in mind, you'll find it easier to understand where each part of the code lives as we build out the HTML and connect it to our FastAPI backend that uses uvicorn as the web server.