shorty/main.py at master · dragdev-studios/shorty · GitHub

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from random import choice
from string import ascii_letters, digits
from urllib.parse import quote_plus
from fnmatch import fnmatch

import aiohttp
import aiosqlite
from fastapi import FastAPI, HTTPException, Header, Request
from fastapi.responses import HTMLResponse, RedirectResponse, JSONResponse
from fastapi.staticfiles import StaticFiles

# Starlette is automatically installed with fastapi, but requirements plugin doesn't realise that.
# noinspection PyPackageRequirements
from starlette.background import BackgroundTask

import models
from ratelimit import buckets, Ratelimit

allowed_statuses = list(range(100, 400))

usable = quote_plus(ascii_letters + digits)

sessions = {}

EMBED_DATA = """
<!DOCTYPE HTML>
<html>
<head>
<title>Shorty</title>
<meta name="description" value="A self-hosted link shortener and vanity provider."/>
<meta name="theme-color" value="#ffd866"/>
</head>
<body>
<h1>Uh?</h1>
<p>Our systems detected that you're a bot, and uh, we don't allow bots. If you're not a bot, then that sucks.</p>
<p>If you are a bot, go away.</p>
<p>With love, dragdev studios</p>
</body>
</html>
"""
EMBED_RESPONSE = HTMLResponse(EMBED_DATA, 200)

app = FastAPI(title="Shorty", description="Self-hosted link shortener that also serves as a vanity link provider.")
app.db = None
limits = buckets
ratelimits = {
    "/s": [10, 300],
}


@app.middleware("http")
async def handle_ratelimit(request: Request, call_next):
    ip = request.client.host
    route = request.url.path
    for p in ratelimits.keys():
        if fnmatch(route, p):
            if ip not in buckets.keys():
                buckets[ip] = {}
            if p not in buckets[ip].keys():
                buckets[ip][p] = Ratelimit(route=p, hits=ratelimits[p][0], cooldown=ratelimits[p][1])
            rl = buckets[ip][p]
            if rl.ratelimited:
                return JSONResponse(
                    {"retry_after": rl.retry_after * 1000, "retry_after_precision": "milliseconds"}, 429
                )
            response = await call_next(request)
            buckets[ip][p].add_hit()
            break
    else:
        response = await call_next(request)
    return response


async def update_usage(serve, ua, src: str = "short"):
    if "Mozilla" not in ua:
        return  # safe bet that it was a bot crawling.
    await app.db.execute(
        """
        UPDATE '?'
        SET uses=uses+1
        WHERE serve='?';""",
        (src, serve),
    )
    await app.db.commit()


@app.on_event("startup")
async def startup():
    app.db = await aiosqlite.connect("./main.db")
    await app.db.execute(
        """
        CREATE TABLE IF NOT EXISTS short (
            source TEXT NOT NULL,
            serve TEXT PRIMARY KEY,
            uses INT DEFAULT 0,
            expire TEXT DEFAULT '9999-12-31 23:59:59.999999',
            token TEXT NOT NULL
        );
        """
    )
    await app.db.execute(
        """
        CREATE TABLE IF NOT EXISTS vanity (
            source TEXT NOT NULL,
            serve TEXT PRIMARY KEY,
            uses INT DEFAULT 0,
            token TEXT NOT NULL
        );
        """
    )
    await app.db.commit()


@app.on_event("shutdown")
async def shutdown():
    await app.db.close()


@app.get("/{path}")
async def get_vanity_or_shortened(path: str, user_agent: str = Header("No User Agent")):
    if "Mozilla" not in user_agent:
        return EMBED_RESPONSE
    async with app.db.execute(
        """
            SELECT source FROM short WHERE serve=?
            """,
        (path,),
    ) as cursor:
        source = await cursor.fetchone()
        if not source:
            raise HTTPException(404, "Invalid code.")
        source = source[0]

    return RedirectResponse(source, 308, background=BackgroundTask(update_usage, source, user_agent, "short"))


@app.post("/s")
async def create_shortened_url(body: models.ShortenBody, host: str = Header(...)):
    """
    Creates a shortened URL.
    If you specify length. the output path will be that many characters long. By default it's 8."""
    try:
        async with aiohttp.ClientSession() as session:
            async with session.get(body.source) as response:
                if response.status not in allowed_statuses:
                    raise HTTPException(400, f"Invalid URL (got status {response.status})")
    except aiohttp.ClientError as e:
        raise HTTPException(400, f"Invalid URL (failed to connect, {e})")
    code = "".join([choice(usable) for _ in range(body.length)])
    if not code or body.length < 3:
        raise HTTPException(400, "path length was too short.")
    shortened = models.Shortened(
        body.source,
        "None",
        models.Shortened.calculate_offset(body.expire or 999_999_999_999_999_999_999_999),
        0,
        "None",
        connection=app.db,
    )
    try:
        await shortened.create(code)
    except aiosqlite.IntegrityError:
        raise HTTPException(400, "Too many links are using this length - Please increase.")
    return {"url": f"https://{host}/{code}", "code": code}


@app.delete("/s/{code}")
async def delete_shortened_code(code: str, token: str):
    """Deletes a shortened URL."""
    async with app.db.execute(
        """
            SELECT source, token FROM short WHERE serve=?
            """,
        (code,),
    ) as cursor:
        source = await cursor.fetchone()
        if not source:
            raise HTTPException(404, "Invalid code.")
        _, key = source
        if key != token:
            raise HTTPException(401, "Unauthorized")
    await app.db.execute("DELETE FROM short WHERE serve=?", (code,))
    await app.db.commit()
    return JSONResponse({}, 204)


@app.post("/v")
async def create_vanity_url(body: models.ShortenBody, host: str = Header(...)):
    """
    Creates a shortened URL.
    If you specify length. the output path will be that many characters long. By default it's 8."""
    try:
        async with aiohttp.ClientSession() as session:
            async with session.get(body.source) as response:
                if response.status not in allowed_statuses:
                    raise HTTPException(400, f"Invalid URL (got status {response.status})")
    except aiohttp.ClientError as e:
        raise HTTPException(400, f"Invalid URL (failed to connect, {e})")
    code = "".join([choice(usable) for _ in range(body.length)])
    if not code or body.length < 4:
        raise HTTPException(400, "path length was too short.")
    shortened = models.Shortened(
        body.source,
        "None",
        models.Shortened.calculate_offset(body.expire or 999_999_999_999_999_999_999_999),
        0,
        "None",
        connection=app.db,
    )
    try:
        await shortened.create(code)
    except aiosqlite.IntegrityError:
        raise HTTPException(400, "Too many links are using this length - Please increase.")
    return {"url": f"https://{host}/{code}", "code": code}


@app.delete("/v/{code}")
async def delete_vanity_code(code: str, token: str):
    """Deletes a shortened URL."""
    async with app.db.execute(
        """
            SELECT source, token FROM short WHERE serve=?
            """,
        (code,),
    ) as cursor:
        source = await cursor.fetchone()
        if not source:
            raise HTTPException(404, "Invalid code.")
        _, key = source
        if key != token:
            raise HTTPException(401, "Unauthorized")
    await app.db.execute("DELETE FROM short WHERE serve=?", (code,))
    await app.db.commit()
    return JSONResponse({}, 204)


app.mount("/", StaticFiles(directory="./static", html=True))