http.py

'''
Created on 2015/11/10

:author: hubo
'''

from vlcp.protocol.http import HttpProtocolException, HttpRequestEvent, escape, escape_b, _createstatus
import traceback
from vlcp.event.stream import Stream, MemoryStream
from vlcp.event import EventHandler
from vlcp.event.runnable import RoutineContainer
import base64
import uuid
import json
from vlcp.event.core import QuitException
from contextlib import closing
try:
    from Cookie import SimpleCookie, Morsel
    from urlparse import parse_qs, urlunsplit, urljoin, urlsplit
    from urllib import unquote, quote, unquote_plus
    unquote_to_bytes = unquote
    quote_from_bytes = quote
    unquote_plus_to_bytes = unquote_plus
except Exception:
    from http.cookies import SimpleCookie, Morsel
    from urllib.parse import parse_qs, urlunsplit, urljoin, urlsplit, unquote_to_bytes, quote_from_bytes
    # There is not an unquote_plus_to_bytes in urllib.parse, but it is simple
    def unquote_plus_to_bytes(s):
        if isinstance(s, str):
            return unquote_to_bytes(s.replace('+', ' '))
        else:
            return unquote_to_bytes(s.replace(b'+', b' '))
import re
from email.message import Message
from vlcp.server.module import call_api
import functools
import logging
import os.path
import sys
if sys.version_info[0] >= 3:
    from email.parser import BytesFeedParser
else:
    from email.parser import FeedParser
    BytesFeedParser = FeedParser

class HttpInputException(Exception):
    pass

class HttpExitException(Exception):
    pass

class HttpRewriteLoopException(Exception):
    pass

pathrep = re.compile(r'[\/]+')

_replace_characters = ['>', '<', '|', '?', '*', ':', '"', '\'', '!', '$', '{', '}']
def _safename(name):
    name = os.path.normpath(os.path.basename(name))
    if '\x00' in name or '/' in name or '\\' in name:
        raise HttpInputException('Bad file name')
    for c in _replace_characters:
        name.replace(c, '_')
    return name

class Environment(object):
    """
    Environment object used in HTTP handlers
    """
    def __init__(self, event, container = None, defaultencoding = 'utf-8'):
        try:
            self.event = event
            self.host = event.host
            self.fullpath = event.path
            self.path_match = getattr(event, 'path_match', None)
            self.path = getattr(event, 'realpath', self.fullpath)
            self.originalpath = getattr(event, 'originalpath', self.fullpath)
            self.rewritefrom = getattr(event, 'rewritefrom', None)
            self.querystring = getattr(event, 'querystring', None)
            self.method = event.method
            self.connection = event.connection
            self.container = container
            if self.container is None:
                self.container = self.connection
            if hasattr(self.connection.socket, 'ssl_version'):
                self.https = True
            else:
                self.https = False
            self.connmark = event.connmark
            self.xid = event.xid
            self.protocol = event.createby
            if not self.host:
                self.host = getattr(self.protocol, 'defaulthost', None)
                if not self.host:
                    self.host = str(self.connection.localaddr[0]) + ':' + str(self.connection.localaddr[1])
                    self.host = self.host.encode('ascii')
            self.headers = event.headers
            self.headerdict = event.headerdict
            self.setcookies = event.setcookies
            self.inputstream = event.stream
            self.encoding = defaultencoding
            self._sendHeaders = False
            self.outputstream = None
            self.showerrorinfo = self.protocol.showerrorinfo
            # Parse cookies
            self.rawcookie = self.headerdict.get(b'cookie')
            if self.rawcookie is not None and not isinstance(self.rawcookie, str):
                self.rawcookie = self.rawcookie.decode(defaultencoding)
            if hasattr(event, 'status'):
                self.status = event.status
            self.sent_headers = getattr(event, 'sent_headers', [])
            self.sent_cookies = getattr(event, 'sent_cookies', [])
            if self.rawcookie:
                self.cookies = dict((k, v.value.encode(defaultencoding)) for k,v in SimpleCookie(self.rawcookie).items())
            else:
                self.cookies = {}
            # Parse query string
            if self.querystring:
                result = parse_qs(self.querystring, True)
                def convert(k,v):
                    try:
                        k = str(k.decode('ascii'))
                    except Exception:
                        raise HttpInputException('Form-data key must be ASCII')
                    if not k.endswith('[]'):
                        v = v[-1]
                    else:
                        k = k[:-2]
                    return (k,v)
                self.args = dict(convert(k,v) for k,v in result.items())
            else:
                self.args = {}
            self.exception = None
        except Exception as exc:
            # Delay the exception
            self.exception = exc
    def __repr__(self, *args, **kwargs):
        r = self.method.upper() + b' ' + self.path + (b', ' + self.connection.remoteaddr[0].encode(self.encoding)
                                                      if self.connection.remoteaddr
                                                      else b'')
        if not isinstance(r, str):
            return r.decode(self.encoding)
        else:
            return r
    def start_response(self, status = 200, headers = [], clearheaders = True, disabletransferencoding = False):
        "Start to send response"
        if self._sendHeaders:
            raise HttpProtocolException('Cannot modify response, headers already sent')
        self.status = status
        self.disabledeflate = disabletransferencoding
        if clearheaders:
            self.sent_headers = headers[:]
        else:
            self.sent_headers.extend(headers)
        
    startResponse = start_response
    
    def header(self, key, value, replace = True):
        "Send a new header"
        if hasattr(key, 'encode'):
            key = key.encode('ascii')
        if hasattr(value, 'encode'):
            value = value.encode(self.encoding)
        if replace:
            self.sent_headers = [(k,v) for k,v in self.sent_headers if k.lower() != key.lower()]
        self.sent_headers.append((key, value))
    def rawheader(self, kv, replace = True):
        """
        Add a header with "<Header>: Value" string
        """
        if hasattr(kv, 'encode'):
            kv = kv.encode(self.encoding)
        k,v = kv.split(b':', 1)
        self.header(k, v.strip(), replace)
    def setcookie(self, key, value, max_age=None, expires=None, path='/', domain=None, secure=None, httponly=False):
        """
        Add a new cookie
        """
        newcookie = Morsel()
        newcookie.key = key
        newcookie.value = value
        newcookie.coded_value = value
        if max_age is not None:
            newcookie['max-age'] = max_age
        if expires is not None:
            newcookie['expires'] = expires
        if path is not None:
            newcookie['path'] = path
        if domain is not None:
            newcookie['domain'] = domain
        if secure:
            newcookie['secure'] = secure
        if httponly:
            newcookie['httponly'] = httponly
        self.sent_cookies = [c for c in self.sent_cookies if c.key != key]
        self.sent_cookies.append(newcookie)
    def bufferoutput(self):
        """
        Buffer the whole output until write EOF or flushed.
        """
        new_stream = Stream(writebufferlimit=None)
        if self._sendHeaders:
            # An extra copy
            self.container.subroutine(new_stream.copy_to(self.outputstream, self.container, buffering=False))
        self.outputstream = Stream(writebufferlimit=None)
    def _startResponse(self):
        if not hasattr(self, 'status'):
            self.start_response(200, clearheaders=False)
        if all(k.lower() != b'content-type' for k,_ in self.sent_headers):
            self.header('Content-Type', 'text/html; charset=' + self.encoding, False)
        # Process cookies
        for c in self.sent_cookies:
            self.rawheader(c.output(), False)
        self.protocol.start_response(self.connection, self.xid, self.status, self.sent_headers, self.outputstream, self.disabledeflate)
        self._sendHeaders = True
    async def rewrite(self, path, method = None, keepresponse = True):
        "Rewrite this request to another processor. Must be called before header sent"
        if self._sendHeaders:
            raise HttpProtocolException('Cannot modify response, headers already sent')
        if getattr(self.event, 'rewritedepth', 0) >= getattr(self.protocol, 'rewritedepthlimit', 32):
            raise HttpRewriteLoopException
        newpath = urljoin(quote_from_bytes(self.path).encode('ascii'), path)
        if newpath == self.fullpath or newpath == self.originalpath:
            raise HttpRewriteLoopException
        extraparams = {}
        if keepresponse:
            if hasattr(self, 'status'):
                extraparams['status'] = self.status
            extraparams['sent_headers'] = self.sent_headers
            extraparams['sent_cookies'] = self.sent_cookies
        r = HttpRequestEvent(self.host,
                               newpath,
                               self.method if method is None else method,
                               self.connection,
                               self.connmark,
                               self.xid,
                               self.protocol,
                               headers = self.headers,
                               headerdict = self.headerdict,
                               setcookies = self.setcookies,
                               stream = self.inputstream,
                               rewritefrom = self.fullpath,
                               originalpath = self.originalpath,
                               rewritedepth = getattr(self.event, 'rewritedepth', 0) + 1,
                               **extraparams
                               )
        await self.connection.wait_for_send(r)
        self._sendHeaders = True
        self.outputstream = None
    async def redirect(self, path, status = 302):
        """
        Redirect this request with 3xx status
        """
        location = urljoin(urlunsplit((b'https' if self.https else b'http',
                                                                     self.host,
                                                                     quote_from_bytes(self.path).encode('ascii'),
                                                                     '',
                                                                     ''
                                                                     )), path)
        self.start_response(status, [(b'Location', location)])
        await self.write(b'<a href="' + self.escape(location, True) + b'">' + self.escape(location) + b'</a>')
        await self.flush(True)
    def nl2br(self, text):
        """
        Replace \'\n\' with \'<br/>\\n\'
        """
        if isinstance(text, bytes):
            return text.replace(b'\n', b'<br/>\n')
        else:
            return text.replace('\n', '<br/>\n')
    def escape(self, text, quote = True):
        """
        Escape special characters in HTML
        """
        if isinstance(text, bytes):
            return escape_b(text, quote)
        else:
            return escape(text, quote)
    async def error(self, status=500, allowredirect = True, close = True, showerror = None, headers = []):
        """
        Show default error response
        """
        if showerror is None:
            showerror = self.showerrorinfo
        if self._sendHeaders:
            if showerror:
                typ, exc, tb = sys.exc_info()
                if exc:
                    await self.write('<span style="white-space:pre-wrap">\n', buffering = False)
                    await self.writelines((self.nl2br(self.escape(v)) for v in traceback.format_exception(typ, exc, tb)), buffering = False)
                    await self.write('</span>\n', close, False)
        elif allowredirect and status in self.protocol.errorrewrite:
            await self.rewrite(self.protocol.errorrewrite[status], b'GET')
        elif allowredirect and status in self.protocol.errorredirect:
            await self.redirect(self.protocol.errorredirect[status])
        else:
            self.start_response(status, headers)
            typ, exc, tb = sys.exc_info()
            if showerror and exc:
                await self.write('<span style="white-space:pre-wrap">\n', buffering = False)
                await self.writelines((self.nl2br(self.escape(v)) for v in traceback.format_exception(typ, exc, tb)), buffering = False)
                await self.write('</span>\n', close, False)
            else:
                await self.write(b'<h1>' + _createstatus(status) + b'</h1>', close, False)
    async def write(self, data, eof = False, buffering = True):
        """
        Write output to current output stream
        """
        if not self.outputstream:
            self.outputstream = Stream()
            self._startResponse()
        elif (not buffering or eof) and not self._sendHeaders:
            self._startResponse()
        if not isinstance(data, bytes):
            data = data.encode(self.encoding)
        await self.outputstream.write(data, self.connection, eof, False, buffering)
    async def writelines(self, lines, eof = False, buffering = True):
        """
        Write lines to current output stream
        """
        for l in lines:
            await self.write(l, False, buffering)
        if eof:
            await self.write(b'', eof, buffering)
    async def flush(self, eof = False):
        """
        Flush the current output stream buffer
        """
        await self.write(b'', eof, False)
    def output(self, stream, disabletransferencoding = None):
        """
        Set output stream and send response immediately
        """
        if self._sendHeaders:
            raise HttpProtocolException('Cannot modify response, headers already sent')
        self.outputstream = stream
        try:
            content_length = len(stream)
        except Exception:
            pass
        else:
            self.header(b'Content-Length', str(content_length).encode('ascii'))
        if disabletransferencoding is not None:
            self.disabledeflate = disabletransferencoding
        self._startResponse()
    def outputdata(self, data):
        """
        Send output with fixed length data
        """
        if not isinstance(data, bytes):
            data = str(data).encode(self.encoding)
        self.output(MemoryStream(data))
    async def close(self):
        """
        Close this request, send all data. You can still run other operations in the handler.
        """
        if not self._sendHeaders:
            self._startResponse()
        if self.inputstream is not None:
            self.inputstream.close(self.connection.scheduler)
        if self.outputstream is not None:
            await self.flush(True)
        if hasattr(self, 'session') and self.session:
            self.session.unlock()
    def exit(self, output=b''):
        "Exit current HTTP processing"
        raise HttpExitException(output)
    async def parseform(self, limit = 67108864, tostr = True, safename = True):
        '''
        Parse form-data with multipart/form-data or application/x-www-form-urlencoded
        In Python3, the keys of form and files are unicode, but values are bytes
        If the key ends with '[]', it is considered to be a list:
        a=1&b=2&b=3          =>    {'a':1,'b':3}
        a[]=1&b[]=2&b[]=3    =>    {'a':[1],'b':[2,3]}
        :param limit: limit total input size, default to 64MB. None = no limit. Note that all the form
        data is stored in memory (including upload files), so it is dangerous to accept a very large input.
        :param tostr: convert values to str in Python3. Only apply to form, files data are always bytes
        :param safename: if True, extra security checks are performed on filenames to reduce known security risks.
        '''
        if tostr:
            def _str(s):
                try:
                    if not isinstance(s, str):
                        return s.decode(self.encoding)
                    else:
                        return s
                except Exception:
                    raise HttpInputException('Invalid encoding in post data: ' + repr(s))
        else:
            def _str(s):
                return s
        try:
            form = {}
            files = {}
            # If there is not a content-type header, maybe there is not a content.
            if b'content-type' in self.headerdict and self.inputstream is not None:
                contenttype = self.headerdict[b'content-type']
                m = Message()
                # Email library expects string, which is unicode in Python 3
                try:
                    m.add_header('Content-Type', str(contenttype.decode('ascii')))
                except UnicodeDecodeError:
                    raise HttpInputException('Content-Type has non-ascii characters')
                if m.get_content_type() == 'multipart/form-data':
                    fp = BytesFeedParser()
                    fp.feed(b'Content-Type: ' + contenttype + b'\r\n\r\n')
                    total_length = 0
                    while True:
                        try:
                            await self.inputstream.prepareRead(self.container)
                            data = self.inputstream.readonce()
                            total_length += len(data)
                            if limit is not None and total_length > limit:
                                raise HttpInputException('Data is too large')
                            fp.feed(data)
                        except EOFError:
                            break
                    msg = fp.close()
                    if not msg.is_multipart() or msg.defects:
                        # Reject the data
                        raise HttpInputException('Not valid multipart/form-data format')
                    for part in msg.get_payload():
                        if part.is_multipart() or part.defects:
                            raise HttpInputException('Not valid multipart/form-data format')
                        disposition = part.get_params(header='content-disposition')
                        if not disposition:
                            raise HttpInputException('Not valid multipart/form-data format')
                        disposition = dict(disposition)
                        if 'form-data' not in disposition or 'name' not in disposition:
                            raise HttpInputException('Not valid multipart/form-data format')
                        if 'filename' in disposition:
                            name = disposition['name']
                            filename = disposition['filename']
                            if safename:
                                filename = _safename(filename)
                            if name.endswith('[]'):
                                files.setdefault(name[:-2], []).append({'filename': filename, 'content': part.get_payload(decode=True)})
                            else:
                                files[name] = {'filename': filename, 'content': part.get_payload(decode=True)}
                        else:
                            name = disposition['name']
                            if name.endswith('[]'):
                                form.setdefault(name[:-2], []).append(_str(part.get_payload(decode=True)))
                            else:
                                form[name] = _str(part.get_payload(decode=True))
                elif m.get_content_type() == 'application/x-www-form-urlencoded' or \
                        m.get_content_type() == 'application/x-url-encoded':
                    if limit is not None:
                        data = await self.inputstream.read(self.container, limit + 1)
                        if len(data) > limit:
                            raise HttpInputException('Data is too large')
                    else:
                        data = await self.inputstream.read(self.container)
                    result = parse_qs(data, True)
                    def convert(k,v):
                        try:
                            k = str(k.decode('ascii'))
                        except Exception:
                            raise HttpInputException('Form-data key must be ASCII')
                        if not k.endswith('[]'):
                            v = _str(v[-1])
                        else:
                            k = k[:-2]
                            v = [_str(i) for i in v]
                        return (k,v)
                    form = dict(convert(k,v) for k,v in result.items())
                else:
                    # Other formats, treat like no data
                    pass
            self.form = form
            self.files = files                
        except Exception as exc:
            raise HttpInputException('Failed to parse form-data: ' + str(exc))
    async def sessionstart(self):
        "Start session. Must start service.utils.session.Session to use this method"
        if not hasattr(self, 'session') or not self.session:
            self.session, setcookies = await call_api(self.container, 'session', 'start', {'cookies':self.rawcookie})
            for nc in setcookies:
                self.sent_cookies = [c for c in self.sent_cookies if c.key != nc.key]
                self.sent_cookies.append(nc)
    async def sessiondestroy(self):
        """
        Destroy current session. The session object is discarded and can no longer be used in other requests.
        """
        if hasattr(self, 'session') and self.session:
            setcookies = await call_api(self.container, 'session', 'destroy', {'sessionid':self.session.id})
            self.session.unlock()
            del self.session
            for nc in setcookies:
                self.sent_cookies = [c for c in self.sent_cookies if c.key != nc.key]
                self.sent_cookies.append(nc)
    def basicauth(self, realm = b'all', nofail = False):
        "Try to get the basic authorize info, return (username, password) if succeeded, return 401 otherwise"
        if b'authorization' in self.headerdict:
            auth = self.headerdict[b'authorization']
            auth_pair = auth.split(b' ', 1)
            if len(auth_pair) < 2:
                raise HttpInputException('Authorization header is malformed')
            if auth_pair[0].lower() == b'basic':
                try:
                    userpass = base64.b64decode(auth_pair[1])
                except Exception:
                    raise HttpInputException('Invalid base-64 string')
                userpass_pair = userpass.split(b':', 1)
                if len(userpass_pair) != 2:
                    raise HttpInputException('Authorization header is malformed')
                return userpass_pair
        if nofail:
            return (None, None)
        else:
            self.basicauthfail(realm)
    def basicauthfail(self, realm = b'all'):
        """
        Return 401 for authentication failure. This will end the handler.
        """
        if not isinstance(realm, bytes):
            realm = realm.encode('ascii')
        self.start_response(401, [(b'WWW-Authenticate', b'Basic realm="' + realm + b'"')])
        self.exit(b'<h1>' + _createstatus(401) + b'</h1>')
    def getrealpath(self, root, path):
        '''
        Return the real path on disk from the query path, from a root path.
        The input path from URL might be absolute '/abc', or point to parent '../test',
        or even with UNC or drive '\\test\abc', 'c:\test.abc',
        which creates security issues when accessing file contents with the path.
        With getrealpath, these paths cannot point to files beyond the root path.
        
        :param root: root path of disk files, any query is limited in root directory.
        
        :param path: query path from URL.
        '''
        if not isinstance(path, str):
            path = path.decode(self.encoding)
        # In windows, if the path starts with multiple / or \, the os.path library may consider it an UNC path
        # remove them; also replace \ to /
        path = pathrep.subn('/', path)[0]
        # The relative root is considered ROOT, eliminate any relative path like ../abc, which create security issues
        # We can use os.path.relpath(..., '/') but python2.6 os.path.relpath is buggy 
        path = os.path.normpath(os.path.join('/', path))
        # The normalized path can be an UNC path, or event a path with drive letter
        # Send bad request for these types
        if os.path.splitdrive(path)[0]:
            raise HttpInputException('Bad path')
        return os.path.join(root, path[1:])
    def _tostr(self, arg):
        if isinstance(arg, list):
            return [self._tostr(v) for v in arg]
        elif not isinstance(arg, str):
            return arg.decode(self.encoding)
        else:
            return arg
    def argstostr(self):
        "Query string arguments are bytes in Python3. This function Convert bytes to string with env.encoding(default to utf-8)."
        self.args = dict((k, self._tostr(v)) for k,v in self.args.items())
        return self.args
    def cookietostr(self):
        "Cookie values are bytes in Python3. This function Convert bytes to string with env.encoding(default to utf-8)."
        self.cookies = dict((k, (v.decode(self.encoding) if not isinstance(v, str) else v)) for k,v in self.cookies.items())
        return self.cookies
    async def createcsrf(self, csrfarg = '_csrf'):
        """
        Create a anti-CSRF token in the session
        """
        await self.sessionstart()
        if not csrfarg in self.session.vars:
            self.session.vars[csrfarg] = uuid.uuid4().hex
    def outputjson(self, obj):
        """
        Serialize `obj` with JSON and output to the client
        """
        self.header('Content-Type', 'application/json')
        self.outputdata(json.dumps(obj).encode('ascii'))
    

async def _handler(container, event, func):
    try:
        env = Environment(event, container)
        try:
            if env.exception:
                raise HttpInputException('Bad request')
            r = func(env)
            if r:
                timeout, _ = await env.container.execute_with_timeout(getattr(env.protocol, 'processtimeout', None), r)
                if timeout:
                    if container and hasattr(container, 'logger'):
                        container.logger.warning('Timeout in HTTP processing, env=%r:', env)
                    await env.error(500, showerror=False)
        except HttpExitException as exc:
            if exc.args[0]:
                await env.write(exc.args[0])
        except HttpInputException:
            # HTTP 400 Bad Request
            await env.error(400)
        except QuitException:
            raise
        except Exception:
            if container and hasattr(container, 'logger'):
                container.logger.exception('Unhandled exception in HTTP processing, env=%r:', env)
            await env.error(500)
        await env.close()
    except QuitException:
        raise
    except Exception:
        # Must ignore all exceptions, or the whole handler is unregistered
        pass

def http(container = None):
    "wrap a WSGI-style class method to a HTTPRequest event handler"
    def decorator(func):
        @functools.wraps(func)
        def handler(self, event):
            return _handler(self if container is None else container, event, lambda env: func(self, env))
        return handler
    return decorator

def statichttp(container = None):
    "wrap a WSGI-style function to a HTTPRequest event handler"
    def decorator(func):
        @functools.wraps(func)
        def handler(event):
            return _handler(container, event, func)
        if hasattr(func, '__self__'):
            handler.__self__ = func.__self__
        return handler
    return decorator


class Dispatcher(EventHandler):
    def __init__(self, scheduler=None, daemon=False, vhost = ''):
        EventHandler.__init__(self, scheduler=scheduler, daemon=daemon)
        self.vhost = vhost
    def routeevent(self, path, routinemethod, container = None, host = None, vhost = None, method = [b'GET', b'HEAD']):
        '''
        Route specified path to a routine factory
        
        :param path: path to match, can be a regular expression
         
        :param routinemethod: factory function routinemethod(event), event is the HttpRequestEvent
        
        :param container: routine container. If None, default to self for bound method, or event.connection if not
         
        :param host: if specified, only response to request to specified host
        
        :param vhost: if specified, only response to request to specified vhost.
                      If not specified, response to dispatcher default vhost.
        
        :param method: if specified, response to specified methods
        '''
        regm = re.compile(path + b'$')
        if vhost is None:
            vhost = self.vhost
        if container is None:
            container = getattr(routinemethod, '__self__', None)
        def ismatch(event):
            # Check vhost
            if vhost is not None and getattr(event.createby, 'vhost', '') != vhost:
                return False
            # First parse the path
            # RFC said we should accept absolute path
            psplit = urlsplit(event.path)
            if psplit.path[:1] != b'/':
                # For security reason, ignore unrecognized path
                return False
            if psplit.netloc and host is not None and host != psplit.netloc:
                # Maybe a proxy request, ignore it
                return False
            if getattr(event.createby, 'unquoteplus', True):
                realpath = unquote_plus_to_bytes(psplit.path)
            else:
                realpath = unquote_to_bytes(psplit.path)
            m = regm.match(realpath)
            if m is None:
                return False
            event.realpath = realpath
            event.querystring = psplit.query
            event.path_match = m
            return True
        def func(event, scheduler):
            try:
                if event.canignore:
                    # Already processed
                    return
                event.canignore = True
                c = event.connection if container is None else container
                c.subroutine(routinemethod(event), False)
            except Exception:
                pass
        for m in method:
            self.registerHandler(HttpRequestEvent.createMatcher(host, None, m, _ismatch = ismatch), func)
    def route(self, path, routinemethod, container = None, host = None, vhost = None, method = [b'GET', b'HEAD']):
        '''
        Route specified path to a WSGI-styled routine factory
        
        :param path: path to match, can be a regular expression
         
        :param routinemethod: factory function routinemethod(env), env is an Environment object
                see also utils.http.Environment
        
        :param container: routine container
        
        :param host: if specified, only response to request to specified host
        
        :param vhost: if specified, only response to request to specified vhost.
                      If not specified, response to dispatcher default vhost.
        
        :param method: if specified, response to specified methods
        '''
        self.routeevent(path, statichttp(container)(routinemethod), container, host, vhost, method)
    def routeargs(self, path, routinemethod, container = None, host = None, vhost = None, method = [b'POST'],
                  tostr = True, matchargs = (), fileargs=(), queryargs=(), cookieargs=(), sessionargs=(),
                  csrfcheck = False, csrfarg = '_csrf', formlimit = 67108864):
        '''
        Convenient way to route a processor with arguments. Automatically parse arguments and pass them to
        the corresponding handler arguments. If required arguments are missing, HttpInputException is thrown which
        creates a 400 Bad Request response. If optional arguments are missing, they are replaced with default values
        just as normal Python call does. If handler accepts keyword arguments, extra arguments are sent
        with kwargs. If not, they are safely ignored.
        
        :param path: path to match, can be a regular expression
        
        :param routinemethod: factory function routinemethod(env, arga, argb, argc...). env is an Environment
                object. form or querystring arguments 'arga', 'argb', 'argc' are passed to arga, argb, argc.
        
        :param container: routine container
        
        :param host: if specified, only response to request to specified host
        
        :param vhost: if specified, only response to request to specified vhost.
                      If not specified, response to dispatcher default vhost.
        
        :param method: methods allowed. With POST method, arguments are extracted from form by default;
                        With GET or HEAD method, arguments are extracted from querystring(args).
        
        :param tostr: In Python3, convert bytes to str before sending arguments to handler.
        
        :param matchargs: Instead of using form or args, extract arguments from path match.
                        matchargs is a sequence of matcher group names. If specified a group name
                        by number, the argument is used as positional arguments; if specified a group
                        name by name(str), the argument is used as a keyword argument.
        
        :param fileargs: Instead of using form or args, extract specified arguments from files.
        
        :param queryargs: Instead of using form, extract specified arguments from args. Notice that when
                          GET is allowed, the arguments are always extracted from args by default.
        
        :param cookieargs: Instead of using form or args, extract specified arguments from cookies.
        
        :param sessionargs: Instead of using form or args, extract specified arguments from session.
                            Notice that if sessionargs is not empty, env.sessionstart() is called,
                            so vlcp.service.utils.session.Session module must be loaded.
                
        :param csrfcheck: If True, check <csrfarg> in input arguments against <csrfarg> in session.
                          Notice that csrfcheck=True cause env.sessionstart() to be called, so
                          vlcp.service.utils.session.Session module must be loaded.
        
        :param csrfarg: argument name to check, default to "_csrf"
         
        :param formlimit: limit on parseform, default to 64MB. None to no limit.
        
        For example, if using::
        
           async def handler(env, target, arga, argb, argc):
              ...
           
           dispatcher.routeargs(b'/do/(.*)', handler, matchargs=(1,), queryargs=('argc'))
        
        And there is a HTTP POST::
        
           POST /do/mytarget?argc=1 HTTP/1.1
           Host: ...
           ...
        
           arga=test&argb=test2
        
        then handler accepts arguments: target="mytarget", arga="test", argb="test2", argc="1"
        '''
        code = routinemethod.__code__
        if code.co_flags & 0x08:
            haskwargs = True
        else:
            haskwargs = False
        # Remove argument env
        arguments = code.co_varnames[1:code.co_argcount]
        if hasattr(routinemethod, '__self__') and routinemethod.__self__:
            # First argument is self, remove an extra argument
            arguments=arguments[1:]
        # Optional arguments
        if hasattr(routinemethod, '__defaults__') and routinemethod.__defaults__:
            requires = arguments[:-len(routinemethod.__defaults__)]
        else:
            requires = arguments[:]
        async def handler(env):
            if tostr:
                def _str(s):
                    if not isinstance(s, str):
                        return s.decode(env.encoding)
                    else:
                        return s
            else:
                def _str(s):
                    return s
            if tostr:
                env.argstostr()
                env.cookietostr()
            if env.method == b'POST':
                await env.parseform(formlimit, tostr)
                argfrom = env.form
            else:
                # Ignore input
                env.form = {}
                env.files = {}
                argfrom = env.args
            args = []
            kwargs = dict(argfrom)
            def discard(k):
                if k in kwargs:
                    del kwargs[k]
            def extract(k, source):
                if k in source:
                    kwargs[k] = source[k]
                else:
                    discard(k)
            try:
                ps = 0
                for ma in matchargs:
                    v = _str(env.path_match.group(ma))
                    if v is not None:
                        if isinstance(ma, str):
                            kwargs[ma] = v
                        else:
                            args.append(v)
                            ps += 1
                    else:
                        if isinstance(ma, str):
                            discard(ma)
                        else:
                            if ps < len(arguments):
                                discard(arguments[ps])
                            ps += 1
                for fa in fileargs:
                    extract(fa, env.files)
                if env.method == b'POST':
                    for qa in queryargs:
                        extract(qa, env.args)
                for ca in cookieargs:
                    extract(ca, env.cookies)
                # CSRF check is done before session arguments to prevent check against session self
                if csrfcheck:
                    if csrfarg not in kwargs:
                        raise HttpInputException('CSRF check failed')
                    await env.sessionstart()
                    if env.session.vars[csrfarg] != kwargs[csrfarg]:
                        raise HttpInputException('CSRF check failed')
                if sessionargs:
                    await env.sessionstart()
                    for sa in sessionargs:
                        extract(sa, env.session.vars)
                # Check required arguments
                for k in requires[ps:]:
                    if k not in kwargs:
                        raise HttpInputException('Argument "' + k + '" is required')
                # Remove positional arguments
                for k in requires[:ps]:
                    if k in kwargs:
                        del kwargs[k]
                if not haskwargs:
                    # Remove extra parameters
                    validargs = arguments[ps:]
                    kwargs = dict((k,v) for (k,v) in kwargs.items() if k in validargs)
                r = routinemethod(env, *args, **kwargs)
            except KeyError as exc:
                raise HttpInputException('Missing argument: ' + str(exc))
            except Exception as exc:
                raise HttpInputException(str(exc))
            if r:
                return await r
        self.route(path, handler, container, host, vhost, method)
    class _EncodedMatch(object):
        "Hacker for match.expand"
        def __init__(self, innerobj):
            self.__innerobj = innerobj
        def __getattr__(self, key):
            return getattr(self.__innerobj, key)
        def group(self, index = 0):
            return quote_from_bytes(self.__innerobj.group(index)).encode('ascii')
    @classmethod
    def expand(cls, match, expand):
        """
        If use expand directly, the url-decoded context will be decoded again, which create a security
        issue. Hack expand to quote the text before expanding
        """
        return re._expand(match.re, cls._EncodedMatch(match), expand)
    def rewrite(self, path, expand, newmethod = None, host = None, vhost = None, method = [b'GET', b'HEAD'], keepquery = True):
        "Automatically rewrite a request to another location"
        async def func(env):
            newpath = self.expand(env.path_match, expand)
            if keepquery and getattr(env, 'querystring', None):
                if b'?' in newpath:
                    newpath += b'&' + env.querystring
                else:
                    newpath += b'?' + env.querystring
            await env.rewrite(newpath, newmethod)
        self.route(path, func)
    def redirect(self, path, expand, status = 302, host = None, vhost = None, method = [b'GET', b'HEAD'], keepquery = True):
        "Automatically redirect a request to another location"
        async def func(env):
            newpath = self.expand(env.path_match, expand)
            if keepquery and getattr(env, 'querystring', None):
                if b'?' in newpath:
                    newpath += b'&' + env.querystring
                else:
                    newpath += b'?' + env.querystring
            await env.redirect(newpath, status)
        self.route(path, func)

class HttpHandler(RoutineContainer):
    logger = logging.getLogger(__name__ + '.HttpHandler')
    def __init__(self, scheduler=None, daemon=False, vhost = ''):
        RoutineContainer.__init__(self, scheduler=scheduler, daemon=daemon)
        self.dispatcher = Dispatcher(scheduler, daemon, vhost)
    @staticmethod
    def route(path, host = None, vhost = None, method = [b'GET', b'HEAD']):
        def decorator(func):
            func.routemode = 'route'
            func.route_path = path
            func.route_host = host
            func.route_vhost = vhost
            func.route_method = method
            func.route_kwargs = {}
            return func
        return decorator
    @staticmethod
    def routeevent(path, host = None, vhost = None, method = [b'GET', b'HEAD']):
        def decorator(func):
            func.routemode = 'routeevent'
            func.route_path = path
            func.route_host = host
            func.route_vhost = vhost
            func.route_method = method
            func.route_kwargs = {}
            return func
        return decorator
    @staticmethod
    def routeargs(path, host = None, vhost = None, method = [b'POST'], **kwargs):
        "For extra arguments, see Dispatcher.routeargs. They must be specified by keyword arguments"
        def decorator(func):
            func.routemode = 'routeargs'
            func.route_path = path
            func.route_host = host
            func.route_vhost = vhost
            func.route_method = method
            func.route_kwargs = kwargs
            return func
        return decorator
    def start(self, asyncStart=False):
        for key in dir(self):
            val = getattr(self, key)
            if hasattr(val, '__func__') and hasattr(val.__func__, 'routemode'):
                getattr(self.dispatcher, val.__func__.routemode)(val.__func__.route_path,
                                                               val,
                                                               self,
                                                               val.__func__.route_host,
                                                               val.__func__.route_vhost,
                                                               val.__func__.route_method,
                                                               **val.__func__.route_kwargs)
        if hasattr(self, 'rewrites'):
            for rw in self.rewrites:
                if len(rw) > 2:
                    self.dispatcher.rewrite(rw[0], rw[1], **rw[2])
                else:
                    self.dispatcher.rewrite(rw[0], rw[1])
        if hasattr(self, 'redirects'):
            for rw in self.redirects:
                if len(rw) > 2:
                    self.dispatcher.redirect(rw[0], rw[1], **rw[2])
                else:
                    self.dispatcher.redirect(rw[0], rw[1])
    def close(self):
        self.dispatcher.close()