copyvios/app.py

#! /usr/bin/env python
import datetime
import functools
import hashlib
import json
import os
import time
import traceback
import urllib.parse
from typing import Any

from earwigbot.wiki.copyvios import globalize
from flask import make_response, redirect, render_template, request, session
from werkzeug import Response
from werkzeug.exceptions import HTTPException

from copyvios import app
from copyvios.api import format_api_error, handle_api_request
from copyvios.attribution import get_attribution_info
from copyvios.auth import clear_login_session, oauth_login_end, oauth_login_start
from copyvios.background import get_background
from copyvios.cache import cache
from copyvios.checker import (
    T_POSSIBLE,
    T_SUSPECT,
    CopyvioCheckError,
    ErrorCode,
    do_check,
)
from copyvios.cookies import get_cookies, get_new_cookies
from copyvios.highlighter import highlight_delta
from copyvios.misc import get_notice, get_permalink
from copyvios.query import CheckQuery
from copyvios.settings import process_settings
from copyvios.sites import update_sites

AnyResponse = Response | str | bytes

app.config.from_pyfile("config.py", True)
app.config["SESSION_COOKIE_SECURE"] = True
app.config["SESSION_COOKIE_SAMESITE"] = "Lax"
app.config["PERMANENT_SESSION_LIFETIME"] = datetime.timedelta(days=365)

app.logger.info(f"Flask server started {time.asctime()}")

globalize(num_workers=8)


@app.errorhandler(Exception)
def handle_errors(exc: Exception) -> AnyResponse | HTTPException:
    if isinstance(exc, HTTPException):
        return exc
    if app.debug:
        raise  # Use built-in debugger
    app.logger.exception("Caught exception:")
    error_page = render_template("error.html.jinja", traceback=traceback.format_exc())
    return make_response(error_page, 500)


@app.context_processor
def setup_context() -> dict[str, Any]:
    return {
        "T_POSSIBLE": T_POSSIBLE,
        "T_SUSPECT": T_SUSPECT,
        "ErrorCode": ErrorCode,
        "cache": cache,
        "dump_json": json.dumps,
        "get_attribution_info": get_attribution_info,
        "get_background": get_background,
        "get_cookies": get_cookies,
        "get_notice": get_notice,
        "get_permalink": get_permalink,
        "highlight_delta": highlight_delta,
    }


@app.after_request
def add_new_cookies(response: Response) -> Response:
    for cookie in get_new_cookies():
        response.headers.add("Set-Cookie", cookie)
    return response


@app.after_request
def write_access_log(response: Response) -> Response:
    app.logger.debug(
        f"{time.asctime()} {request.method} {request.path} "
        f"{request.values.to_dict()} -> {response.status_code}"
    )
    return response


@functools.lru_cache
def _get_hash(path: str, mtime: float) -> str:
    # mtime is used as part of the cache key
    with open(path, "rb") as fp:
        return hashlib.sha1(fp.read()).hexdigest()


def external_url_handler(
    error: Exception, endpoint: str, values: dict[str, Any]
) -> str:
    if endpoint == "static" and "file" in values:
        assert app.static_folder is not None
        path = os.path.join(app.static_folder, values["file"])
        mtime = os.path.getmtime(path)
        hashstr = _get_hash(path, mtime)
        return f"/static/{values['file']}?v={hashstr}"
    raise error


app.url_build_error_handlers.append(external_url_handler)


@app.route("/")
def index() -> AnyResponse:
    update_sites()
    query = CheckQuery.from_get_args()
    try:
        result = do_check(query)
        error = None
    except CopyvioCheckError as exc:
        if exc.code == ErrorCode.NOT_LOGGED_IN:
            target = "/login?next=" + urllib.parse.quote_plus(
                "/?" + request.query_string.decode(errors="ignore")
            )
            return redirect(target, 302)
        app.logger.exception(f"Copyvio check failed on {query}")
        result = None
        error = exc

    return render_template(
        "index.html.jinja",
        query=query,
        result=result,
        error=error,
        splash=not result,
    )


@app.route("/login", methods=["GET", "POST"])
def login() -> AnyResponse:
    try:
        redirect_url = oauth_login_start() if request.method == "POST" else None
        if redirect_url:
            return redirect(redirect_url, 302)
    except Exception as e:
        app.logger.exception("OAuth login start failed")
        error_str = str(e)
    else:
        if session.get("username") is not None:
            return redirect("/", 302)
        error_str = request.args.get("error")

    is_search = False
    if request.args.get("next", "").startswith("/?"):
        next_query = dict(urllib.parse.parse_qsl(request.args["next"]))
        if next_query.get("action") == "search":
            is_search = True

    return render_template("login.html.jinja", error=error_str, is_search=is_search)


@app.route("/logout", methods=["GET", "POST"])
def logout() -> AnyResponse:
    if request.method == "POST":
        clear_login_session()
        return redirect("/", 302)
    else:
        return render_template("logout.html.jinja")


@app.route("/oauth-callback")
def oauth_callback() -> AnyResponse:
    try:
        next_url = oauth_login_end()
    except Exception as e:
        app.logger.exception("OAuth login end failed")
        return redirect("/login?error=" + urllib.parse.quote_plus(str(e)), 302)
    else:
        return redirect(next_url, 302)


@app.route("/settings", methods=["GET", "POST"])
def settings() -> AnyResponse:
    status = process_settings() if request.method == "POST" else None
    update_sites()
    return render_template(
        "settings.html.jinja",
        status=status,
        default_site=cache.bot.wiki.get_site(),
        splash=True,
    )


@app.route("/api")
def api() -> AnyResponse:
    return render_template("api_help.html.jinja")


@app.route("/api.json")
def api_json() -> AnyResponse:
    if not request.args:
        return render_template("api_help.html.jinja")

    format = request.args.get("format", "json")
    if format in ["json", "jsonfm"]:
        update_sites()
        try:
            result = handle_api_request()
        except Exception as exc:
            app.logger.exception("API request failed")
            result = format_api_error("unhandled_exception", exc)
    else:
        errmsg = f"Unknown format: {format!r}"
        result = format_api_error("unknown_format", errmsg)

    if format == "jsonfm":
        return render_template("api_result.html.jinja", result=result)
    resp = make_response(json.dumps(result))
    resp.mimetype = "application/json"
    resp.headers["Access-Control-Allow-Origin"] = "*"
    return resp


if app.debug:
    # Silence browser 404s when testing
    @app.route("/favicon.ico")
    def favicon() -> AnyResponse:
        return app.send_static_file("favicon.ico")


if __name__ == "__main__":
    app.run()