chrom中带有python-baseHTTPserver 501（不支持的方法（'OPTIONS'））的CORS

Question

嗨，当ajax向python-baseHTTPserver发出get/post请求时，我需要一些关于基本身份验证的帮助。

我可以在python脚本中更改一些代码行，以发送CORS头。当我禁用http基本身份验证时，它在现代浏览器中运行良好。

如果启用身份验证，则会出现501（不支持的方法（'OPTIONS'））错误（i chrome）。

我花了好几个小时寻找解决办法，现在我想我有个好办法。正如我在下面的主题中读到的，HTTPRequestHandler可能会导致这个问题，但是我的pyton技能还不足以解决这个问题。

如果找到关于这个主题here和here的文章，但我无法用我的脚本运行它。有人能帮我把它开动吗？

如有任何帮助或建议，将不胜感激。

    #   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 1

出现此错误是因为您的HTTPHandler上没有do_OPTIONS方法。它将处理OPTIONS请求。我怀疑你会有更多的问题，但这是一个好的开始；）

Answer 2

成功：

Ajax将向服务器发送一个OPTIONS请求，因此必须在没有身份验证的情况下向BaseHTTPRequestHandler添加一个do_options方法（发送响应代码200）。

之后，您可以像往常一样调用函数来处理请求。

这是我的解决方案（签入Safari 6.x、Firefox 20、OS x上的Chrome26）：

def do_OPTIONS(self):
    self.sendResponse(200)
    self.processRequest()

第二件事你必须改变的是你必须在processRequest函数中添加一个响应头。添加访问控制允许头：例如self.send_header("Access-Control-Allow-Headers", "Authorization")授权，允许ajax发送基本身份验证令牌。

工作脚本：

        #   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, OPTIONS")
                self.send_header("Access-Control-Allow-Headers", "Authorization")
                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_OPTIONS(self):
            self.sendResponse(200)
            self.processRequest()

        def do_GET(self):
            self.processRequest()

        def do_POST(self):
            self.processRequest()

Answer 3

客户端应该发出两个请求，首先是一个选项，然后是GET请求。提出的解决方案不是最优的，因为我们用内容来回答选项请求。

def do_OPTIONS(self):
            self.sendResponse(200)
            self.processRequest() # not good!

我们应该正确回答选项请求。如果我们这样做，客户机将在收到正确答案后发出GET请求。

我得到了由CORS和请求“Content Type:application/json；charset=utf-8”引起的501不支持的方法（“OPTIONS”）。

为了解决这个错误，我在do_选项中启用了CORS，并允许客户端请求特定的内容类型。

我的解决方案：

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()