CORS with python baseHTTPserver 501 (Unsupported method ('OPTIONS')) in chrome
Hi I need some help with base authentification while a ajax get/post request to a python baseHTTPserver.
I was able to change some lines of code in the python script for sending CORS headers. It works fine in modern browsers when I disable http base authentification.
If authentification is enabled i get a 501 (Unsupported method ('OPTIONS')) error (i chrome).
I spend hours with finding a solution an now i think iam on a good way. As i read in the topics below the HTTPRequestHandler might cause the problem but my pyton skills are not good enough to solve the problem.
If found some post about this topic here and here but iam not able to get it running with the script i have. Can someone help me to get it running?
Any help or ideas are would be highly appreciated.
# Copyright 2012-2013 Eric Ptak - trouch.com
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import os
import threading
import re
import codecs
import mimetypes as mime
import logging
from webiopi.utils import *
if PYTHON_MAJOR >= 3:
import http.server as BaseHTTPServer
else:
import BaseHTTPServer
try :
import _webiopi.GPIO as GPIO
except:
pass
WEBIOPI_DOCROOT = "/usr/share/webiopi/htdocs"
class HTTPServer(BaseHTTPServer.HTTPServer, threading.Thread):
def __init__(self, host, port, handler, context, docroot, index, auth=None):
BaseHTTPServer.HTTPServer.__init__(self, ("", port), HTTPHandler)
threading.Thread.__init__(self, name="HTTPThread")
self.host = host
self.port = port
if context:
self.context = context
if not self.context.startswith("/"):
self.context = "/" + self.context
if not self.context.endswith("/"):
self.context += "/"
else:
self.context = "/"
self.docroot = docroot
if index:
self.index = index
else:
self.index = "index.html"
self.handler = handler
self.auth = auth
self.running = True
self.start()
def get_request(self):
sock, addr = self.socket.accept()
sock.settimeout(10.0)
return (sock, addr)
def run(self):
info("HTTP Server binded on http://%s:%s%s" % (self.host, self.port, self.context))
try:
self.serve_forever()
except Exception as e:
if self.running == True:
exception(e)
info("HTTP Server stopped")
def stop(self):
self.running = False
self.server_close()
class HTTPHandler(BaseHTTPServer.BaseHTTPRequestHandler):
logger = logging.getLogger("HTTP")
def log_message(self, fmt, *args):
self.logger.debug(fmt % args)
def log_error(self, fmt, *args):
pass
def version_string(self):
return VERSION_STRING
def checkAuthentication(self):
if self.server.auth == None or len(self.server.auth) == 0:
return True
authHeader = self.headers.get('Authorization')
if authHeader == None:
return False
if not authHeader.startswith("Basic "):
return False
auth = authHeader.replace("Basic ", "")
if PYTHON_MAJOR >= 3:
auth_hash = encrypt(auth.encode())
else:
auth_hash = encrypt(auth)
if auth_hash == self.server.auth:
return True
return False
def requestAuthentication(self):
self.send_response(401)
self.send_header("WWW-Authenticate", 'Basic realm="webiopi"')
self.end_headers();
def sendResponse(self, code, body=None, type="text/plain"):
if code >= 400:
if body != None:
self.send_error(code, body)
else:
self.send_error(code)
else:
self.send_response(code)
self.send_header("Cache-Control", "no-cache")
self.send_header("Access-Control-Allow-Origin", "*")
self.send_header("Access-Control-Allow-Methods", "POST, GET")
self.send_header("Access-Control-Allow-Headers", " X-Custom-Header")
if body != None:
self.send_header("Content-Type", type);
self.end_headers();
self.wfile.write(body.encode())
def findFile(self, filepath):
if os.path.exists(filepath):
if os.path.isdir(filepath):
filepath += "/" + self.server.index
if os.path.exists(filepath):
return filepath
else:
return filepath
return None
def serveFile(self, relativePath):
if self.server.docroot != None:
path = self.findFile(self.server.docroot + "/" + relativePath)
if path == None:
path = self.findFile("./" + relativePath)
else:
path = self.findFile("./" + relativePath)
if path == None:
path = self.findFile(WEBIOPI_DOCROOT + "/" + relativePath)
if path == None and (relativePath.startswith("webiopi.") or relativePath.startswith("jquery")):
path = self.findFile(WEBIOPI_DOCROOT + "/" + relativePath)
if path == None:
return self.sendResponse(404, "Not Found")
realPath = os.path.realpath(path)
if realPath.endswith(".py"):
return self.sendResponse(403, "Not Authorized")
if not (realPath.startswith(os.getcwd())
or (self.server.docroot and realPath.startswith(self.server.docroot))
or realPath.startswith(WEBIOPI_DOCROOT)):
return self.sendResponse(403, "Not Authorized")
(type, encoding) = mime.guess_type(path)
f = codecs.open(path, encoding=encoding)
data = f.read()
f.close()
self.send_response(200)
self.send_header("Content-Type", type);
self.send_header("Content-Length", os.path.getsize(realPath))
self.end_headers()
self.wfile.write(data)
def processRequest(self):
self.request.settimeout(None)
if not self.checkAuthentication():
return self.requestAuthentication()
request = self.path.replace(self.server.context, "/").split('?')
relativePath = request[0]
if relativePath[0] == "/":
relativePath = relativePath[1:]
if relativePath == "webiopi" or relativePath == "webiopi/":
self.send_response(301)
self.send_header("Location", "/")
self.end_headers()
return
params = {}
if len(request) > 1:
for s in request[1].split('&'):
if s.find('=') > 0:
(name, value) = s.split('=')
params[name] = value
else:
params[s] = None
compact = False
if 'compact' in params:
compact = str2bool(params['compact'])
try:
result = (None, None, None)
if self.command == "GET":
result = self.server.handler.do_GET(relativePath, compact)
elif self.command == "POST":
length = 0
length_header = 'content-length'
if length_header in self.headers:
length = int(self.headers[length_header])
result = self.server.handler.do_POST(relativePath, self.rfile.read(length), compact)
else:
result = (405, None, None)
(code, body, type) = result
if code > 0:
self.sendResponse(code, body, type)
else:
if self.command == "GET":
self.serveFile(relativePath)
else:
self.sendResponse(404)
except (GPIO.InvalidDirectionException, GPIO.InvalidChannelException, GPIO.SetupException) as e:
self.sendResponse(403, "%s" % e)
except ValueError as e:
self.sendResponse(403, "%s" % e)
except Exception as e:
self.sendResponse(500)
raise e
def do_GET(self):
self.processRequest()
def do_POST(self):
self.processRequest()
Answer
The client should issue two requests, first one OPTIONS and then the GET request. The solution presented is not optimal, since we are answering the OPTIONS request with contents.
def do_OPTIONS(self):
self.sendResponse(200)
self.processRequest() # not good!
We should answer the OPTIONS request properly. If we do so, the client will issue the GET request after receiving a proper answer.
I was getting the 501 Unsupported method ('OPTIONS')) caused by CORS and by requesting the "Content-Type: application/json; charset=utf-8".
To solve the error, I enabled CORS in do_OPTIONS and enabled clients to request a specific content type.
My solution:
def do_OPTIONS(self):
self.send_response(200, "ok")
self.send_header('Access-Control-Allow-Origin', '*')
self.send_header('Access-Control-Allow-Methods', 'GET, OPTIONS')
self.send_header("Access-Control-Allow-Headers", "X-Requested-With")
self.send_header("Access-Control-Allow-Headers", "Content-Type")
self.end_headers()
def do_GET(self):
self.processRequest()