tryton/trytond/wsgi.py

# This file is part of Tryton.  The COPYRIGHT file at the top level of
# this repository contains the full copyright notices and license terms.
import base64
import http.client
import logging
import os
import sys
import traceback
import urllib.parse
try:
    from http import HTTPStatus
except ImportError:
    from http import client as HTTPStatus

from werkzeug.wrappers import Response
from werkzeug.routing import Map, Rule, BaseConverter
from werkzeug.exceptions import abort, HTTPException, InternalServerError
from werkzeug.contrib.fixers import ProxyFix
from werkzeug.wsgi import SharedDataMiddleware

import wrapt

from trytond.config import config
from trytond.protocols.wrappers import Request
from trytond.protocols.jsonrpc import JSONProtocol
from trytond.protocols.xmlrpc import XMLProtocol

__all__ = ['TrytondWSGI', 'app']

logger = logging.getLogger(__name__)


class Base64Converter(BaseConverter):

    def to_python(self, value):
        return base64.urlsafe_b64decode(value).decode('utf-8')

    def to_url(self, value):
        return base64.urlsafe_b64encode(value.encode('utf-8'))


class TrytondWSGI(object):

    def __init__(self):
        self.url_map = Map([], converters={
                'base64': Base64Converter,
                })
        self.protocols = [JSONProtocol, XMLProtocol]
        self.error_handlers = []

    def route(self, string, methods=None):
        def decorator(func):
            self.url_map.add(Rule(string, endpoint=func, methods=methods))
            return func
        return decorator

    @wrapt.decorator
    def auth_required(self, wrapped, instance, args, kwargs):
        request = args[0]
        if request.user_id:
            return wrapped(*args, **kwargs)
        else:
            response = Response(
                None, http.client.UNAUTHORIZED,
                {'WWW-Authenticate': 'Basic realm="Tryton"'})
            abort(http.client.UNAUTHORIZED, response=response)

    def check_request_size(self, request, size=None):
        if request.method not in {'POST', 'PUT', 'PATCH'}:
            return
        if size is None:
            if request.user_id:
                max_size = config.getint(
                    'request', 'max_size_authenticated')
            else:
                max_size = config.getint(
                    'request', 'max_size')
        else:
            max_size = size
        if max_size:
            content_length = request.content_length
            if content_length is None:
                abort(http.client.LENGTH_REQUIRED)
            elif content_length > max_size:
                abort(http.client.REQUEST_ENTITY_TOO_LARGE)

    def dispatch_request(self, request):
        adapter = self.url_map.bind_to_environ(request.environ)
        try:
            endpoint, request.view_args = adapter.match()
            max_request_size = getattr(endpoint, 'max_request_size', None)
            self.check_request_size(request, max_request_size)
            return endpoint(request, **request.view_args)
        except HTTPException as e:
            return e
        except Exception as e:
            tb_s = ''.join(traceback.format_exception(*sys.exc_info()))
            for path in sys.path:
                tb_s = tb_s.replace(path, '')
            e.__format_traceback__ = tb_s
            response = e
            for error_handler in self.error_handlers:
                rv = error_handler(e)
                if isinstance(rv, Response):
                    response = rv
            return response

    def wsgi_app(self, environ, start_response):
        for cls in self.protocols:
            if cls.content_type in environ.get('CONTENT_TYPE', ''):
                request = cls.request(environ)
                break
        else:
            request = Request(environ)

        origin = request.headers.get('Origin')
        origin_host = urllib.parse.urlparse(origin).netloc if origin else ''
        host = request.headers.get('Host')
        if origin and origin_host != host:
            cors = filter(
                None, config.get('web', 'cors', default='').splitlines())
            if origin not in cors:
                abort(HTTPStatus.FORBIDDEN)

        data = self.dispatch_request(request)
        if not isinstance(data, (Response, HTTPException)):
            for cls in self.protocols:
                for mimetype, _ in request.accept_mimetypes:
                    if cls.content_type in mimetype:
                        response = cls.response(data, request)
                        break
                else:
                    continue
                break
            else:
                for cls in self.protocols:
                    if cls.content_type in environ.get('CONTENT_TYPE', ''):
                        response = cls.response(data, request)
                        break
                else:
                    if isinstance(data, Exception):
                        response = InternalServerError(data)
                    else:
                        response = Response(data)
        else:
            response = data

        if origin and isinstance(response, Response):
            response.headers['Access-Control-Allow-Origin'] = origin
            response.headers['Vary'] = 'Origin'
            method = request.headers.get('Access-Control-Request-Method')
            if method:
                response.headers['Access-Control-Allow-Methods'] = method
            headers = request.headers.get('Access-Control-Request-Headers')
            if headers:
                response.headers['Access-Control-Allow-Headers'] = headers
            response.headers['Access-Control-Max-Age'] = config.getint(
                'web', 'cache_timeout')

        # TODO custom process response
        return response(environ, start_response)

    def __call__(self, environ, start_response):
        return self.wsgi_app(environ, start_response)


class SharedDataMiddlewareIndex(SharedDataMiddleware):
    def __call__(self, environ, start_response):
        if environ['REQUEST_METHOD'] not in {'GET', 'HEAD'}:
            return self.app(environ, start_response)
        return super(SharedDataMiddlewareIndex, self).__call__(
            environ, start_response)

    def get_directory_loader(self, directory):
        def loader(path):
            if path is not None:
                path = os.path.join(directory, path)
            else:
                path = directory
            if os.path.isdir(path):
                path = os.path.join(path, 'index.html')
            if os.path.isfile(path):
                return os.path.basename(path), self._opener(path)
            return None, None
        return loader


app = TrytondWSGI()
if config.get('web', 'root'):
    static_files = {
        '/': config.get('web', 'root'),
        }
    app.wsgi_app = SharedDataMiddlewareIndex(
        app.wsgi_app, static_files,
        cache_timeout=config.getint('web', 'cache_timeout'))
num_proxies = config.getint('web', 'num_proxies')
if num_proxies:
    app.wsgi_app = ProxyFix(app.wsgi_app, num_proxies=num_proxies)
import trytond.protocols.dispatcher
import trytond.bus