app.py

from fastapi import FastAPI, Request, Form
from fastapi.responses import HTMLResponse, RedirectResponse
import sqlite3

app = FastAPI()

conn = sqlite3.connect("chat.db", check_same_thread=False)
c = conn.cursor()

c.execute("""
CREATE TABLE IF NOT EXISTS users(
username TEXT,
password TEXT
)
""")

c.execute("""
CREATE TABLE IF NOT EXISTS messages(
username TEXT,
message TEXT
)
""")

conn.commit()


@app.get("/", response_class=HTMLResponse)
def home():
    return """
    <h1>Emalawi19 Chat</h1>
    <a href='/login'>Login</a><br>
    <a href='/register'>Register</a>
    """


@app.get("/register", response_class=HTMLResponse)
def register_page():
    return """
    <h2>Register</h2>
    <form method="post">
    <input name="username" placeholder="username"><br>
    <input name="password" type="password" placeholder="password"><br>
    <button type="submit">Register</button>
    </form>
    """


@app.post("/register")
def register(username: str = Form(...), password: str = Form(...)):
    c.execute("INSERT INTO users VALUES(?,?)",(username,password))
    conn.commit()
    return RedirectResponse("/login", status_code=302)


@app.get("/login", response_class=HTMLResponse)
def login_page():
    return """
    <h2>Login</h2>
    <form method="post">
    <input name="username"><br>
    <input name="password" type="password"><br>
    <button type="submit">Login</button>
    </form>
    """


@app.post("/login")
def login(username: str = Form(...), password: str = Form(...)):
    user = c.execute(
        "SELECT * FROM users WHERE username=? AND password=?",
        (username,password)
    ).fetchone()

    if user:
        return RedirectResponse(f"/chat/{username}", status_code=302)

    return "Login failed"


@app.get("/chat/{username}", response_class=HTMLResponse)
def chat(username: str):

    msgs = c.execute("SELECT username,message FROM messages").fetchall()

    chat_html = ""

    for u,m in msgs:
        chat_html += f"<p><b>{u}</b>: {m}</p>"

    return f"""
    <h2>Emalawi19 Chat - {username}</h2>

    <div>{chat_html}</div>

    <form action="/send/{username}" method="post">
    <input name="message">
    <button>Send</button>
    </form>
    """


@app.post("/send/{username}")
def send(username: str, message: str = Form(...)):
    c.execute("INSERT INTO messages VALUES(?,?)",(username,message))
    conn.commit()
    return RedirectResponse(f"/chat/{username}", status_code=302)


# IMPORTANT: start server
if __name__ == "__main__":
    import uvicorn
    uvicorn.run(app, host="0.0.0.0", port=7860)