FastAPI API Integration for Image Generation Service

Introduction to FastAPI API Integration

Welcome to the fifth lesson of our course on building an image generation service with FastAPI! In our previous lessons, we've built several key components of our application: the PromptManager for formatting user inputs, the ImageManager for storing and processing images, the ImageGeneratorService for connecting to Google's Gemini API, and most recently, the ImageGeneratorRouter, which handles input validation and response formatting. Now it's time to bring everything together by creating the FastAPI application that will expose our functionality through HTTP endpoints. This is the final piece of our backend architecture that will allow users to interact with our image generation service through a web interface. Our FastAPI API will have three main routes: A route to serve the main HTML page A route to handle image generation requests A route to retrieve all previously generated images By the end of this lesson, you'll have a complete FastAPI API that integrates with the router we built previously, providing a clean interface for clients to generate and retrieve images.

Setting Up the FastAPI Application

Let's start by creating our FastAPI application. We'll set up the basic structure in our app/main.py file: Python import os from fastapi import FastAPI, Request, HTTPException from fastapi.templating import Jinja2Templates from fastapi.staticfiles import StaticFiles from routers.image_generator_router import ImageGeneratorRouter import uvicorn app = FastAPI(title="Image Generator API") # Get the directory of the current script BASE_DIR = os.path.dirname(os.path.abspath(__file__)) # Set up templates templates = Jinja2Templates(directory=os.path.join(BASE_DIR, "templates")) # Set up static files app.mount("/static", StaticFiles(directory=os.path.join(BASE_DIR, "static")), name="static") # Create router instance image_generator_router = ImageGeneratorRouter() We create a FastAPI application instance by calling FastAPI() with a title for our API. We determine the base directory of the current script and set up Jinja2Templates to handle our HTML templates, passing the directory where our templates are located. We also mount a static files directory to serve static assets like CSS, JavaScript, and images. Finally, we create an instance of our ImageGeneratorRouter . This router handles the business logic for our API endpoints.

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Python

@app.get("/")
async def index(request: Request):
    return templates.TemplateResponse("image_generator.html", {"request": request})

@app.get("/")
async def index(request: Request):
    return templates.TemplateResponse("image_generator.html", {"request": request})

Python

from fastapi import Body
from typing import Dict

@app.post("/api/generate_image")
async def generate_image(user_input: str = Body(..., embed=True)):
    response = image_generator_router.generate_image(user_input)
    
    # Check if the response is a tuple (indicating an error)
    if isinstance(response, tuple):
        body, status_code = response
        if "error" in body:
            raise HTTPException(status_code=status_code, detail=body["error"])
    
    return response

from fastapi import Body
from typing import Dict

@app.post("/api/generate_image")
async def generate_image(user_input: str = Body(..., embed=True)):
    response = image_generator_router.generate_image(user_input)
    
    # Check if the response is a tuple (indicating an error)
    if isinstance(response, tuple):
        body, status_code = response
        if "error" in body:
            raise HTTPException(status_code=status_code, detail=body["error"])
    
    return response

HTML

<img src="data:image/png;base64,...">

<img src="data:image/png;base64,...">

Python

@app.get("/api/get_images")
async def get_images():
    return image_generator_router.get_images()

@app.get("/api/get_images")
async def get_images():
    return image_generator_router.get_images()

Python

import uvicorn

if __name__ == "__main__":
    uvicorn.run("main:app", host="0.0.0.0", port=8000, reload=True)

import uvicorn

if __name__ == "__main__":
    uvicorn.run("main:app", host="0.0.0.0", port=8000, reload=True)

Python

@app.get("/")
async def index(request: Request):
    return templates.TemplateResponse("image_generator.html", {"request": request})

Python

from fastapi import Body
from typing import Dict

@app.post("/api/generate_image")
async def generate_image(user_input: str = Body(..., embed=True)):
    response = image_generator_router.generate_image(user_input)
    
    # Check if the response is a tuple (indicating an error)
    if isinstance(response, tuple):
        body, status_code = response
        if "error" in body:
            raise HTTPException(status_code=status_code, detail=body["error"])
    
    return response

HTML

<img src="data:image/png;base64,...">

Python

@app.get("/api/get_images")
async def get_images():
    return image_generator_router.get_images()

Python

import uvicorn

if __name__ == "__main__":
    uvicorn.run("main:app", host="0.0.0.0", port=8000, reload=True)

Introduction to FastAPI API Integration

Setting Up the FastAPI Application

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Defining API Routes

Index Route

Generate Image Route

Get Images Route

Configuring the FastAPI Server

Summary and Practice Preview