app.py

import os
import functools
import urllib.parse

import flask

from markdown_svgbob.wrapper import text2svg
from markdown_svgbob.extension import svg2html


IS_DEBUG = os.getenv('ASCIIGRID_DEBUG', "0") == "1"


routes = flask.Blueprint('asciigrid', __name__)

text2svg_cached = functools.lru_cache(maxsize=1000)(text2svg)


@routes.route("/bob2svg", methods=['GET', 'POST', 'OPTIONS'])
def bob2svg():
    headers = {
        'Access-Control-Allow-Methods': "GET, POST, OPTIONS",
        'Access-Control-Max-Age': 86400,
    }

    req_origin = flask.request.headers.get('Origin', "")
    if req_origin.startswith("http://localhost"):
        origin = req_origin
    elif req_origin.startswith("http://127.0.0.1"):
        origin = req_origin
    elif req_origin.startswith("https://asciigrid.litprog.dev"):
        origin = req_origin
    elif req_origin.startswith("https://mbarkhau.github.io"):
        origin = req_origin
    else:
        origin = "https://mbarkhau.keybase.pub"

    headers['Access-Control-Allow-Origin'] = origin
    if flask.request.method == 'OPTIONS':
        return flask.Response("", headers=headers)

    if flask.request.method == 'POST':
        bob_data = flask.request.data
        if len(bob_data) > 1024 * 100:
            return flask.Response("Request too large", 400)
        bob_text = bob_data.decode('utf-8')
    else:
        bob_quoted = flask.request.args.get('d')
        if bob_quoted is None:
            return flask.Response("Missing parameter: ?d=<quoted_diagram_text>", 400)
        bob_text = urllib.parse.unquote(bob_quoted)

    svg_data = text2svg_cached(bob_text)

    if flask.request.args.get('fmt') == 'img_base64_svg':
        img_data = svg2html(svg_data, tag_type='img_base64_svg')
        headers['Content-Type'] = "image/svg+xml;base64"
        return flask.Response(img_data, headers=headers)

    headers['Content-Disposition'] = 'attachment; filename="diagram.svg"'
    headers['Content-Type'] = "image/svg+utf-8"
    return flask.Response(svg_data, headers=headers)


debug_routes = flask.Blueprint('asciigrid_debug', __name__)


@debug_routes.route('/headers.txt')
def debug_headers():
    header_str = str(flask.request.headers)
    return flask.Response(
        header_str,
        headers={'Content-Type': "text/plain"}
    )


@debug_routes.route("/")
def index():
    if 'backend' in flask.request.args:
        return flask.render_template("index.html")
    else:
        backend_url = flask.request.url.rstrip("/")
        return flask.redirect("?backend=" + backend_url, code=302)


app = flask.Flask(__name__, static_folder="", template_folder="")
app.register_blueprint(routes)


if IS_DEBUG:
    app.register_blueprint(debug_routes)