microWebSrv.py

"""
The MIT License (MIT)
Copyright © 2018 Jean-Christophe Bos & HC² (www.hc2.fr)
"""


from json import loads, dumps
from os import stat
from _thread import start_new_thread
import socket
import gc
import re

try:
    from .microWebTemplate import MicroWebTemplate
except:
    pass

try:
    from .microWebSocket import MicroWebSocket
except:
    pass


class MicroWebSrvRoute:
    def __init__(self, route, method, func, routeArgNames, routeRegex):
        self.route = route
        self.method = method
        self.func = func
        self.routeArgNames = routeArgNames
        self.routeRegex = routeRegex


class MicroWebSrv:

    # ============================================================================
    # ===( Constants )============================================================
    # ============================================================================

    _indexPages = [
        "index.pyhtml",
        "index.html",
        "index.htm",
        "default.pyhtml",
        "default.html",
        "default.htm"
    ]

    _mimeTypes = {
        ".txt": "text/plain",
        ".htm": "text/html",
        ".html": "text/html",
        ".css": "text/css",
        ".csv": "text/csv",
        ".js": "application/javascript",
        ".xml": "application/xml",
        ".xhtml": "application/xhtml+xml",
        ".json": "application/json",
        ".zip": "application/zip",
        ".pdf": "application/pdf",
        ".jpg": "image/jpeg",
        ".jpeg": "image/jpeg",
        ".png": "image/png",
        ".gif": "image/gif",
        ".svg": "image/svg+xml",
        ".ico": "image/x-icon"
    }

    _html_escape_chars = {
        "&": "&",
        '"': """,
        "'": "'",
        ">": ">",
        "<": "&lt;"
    }

    _pyhtmlPagesExt = '.pyhtml'

    # ============================================================================
    # ===( Class globals  )=======================================================
    # ============================================================================

    _docoratedRouteHandlers = []

    # ============================================================================
    # ===( Utils  )===============================================================
    # ============================================================================

    @classmethod
    def route(cls, url, method='GET'):
        """ Adds a route handler function to the routing list """
        def route_decorator(func):
            item = (url, method, func)
            cls._docoratedRouteHandlers.append(item)
            return func
        return route_decorator

    # ----------------------------------------------------------------------------

    @staticmethod
    def HTMLEscape(s):
        return ''.join(MicroWebSrv._html_escape_chars.get(c, c) for c in s)

    # ----------------------------------------------------------------------------

    @staticmethod
    def _tryAllocByteArray(size):
        for x in range(10):
            try:
                gc.collect()
                return bytearray(size)
            except:
                pass
        return None

    # ----------------------------------------------------------------------------

    @staticmethod
    def _tryStartThread(func, args=()):
        for x in range(10):
            try:
                gc.collect()
                start_new_thread(func, args)
                return True
            except:
                global _mwsrv_thread_id
                try:
                    _mwsrv_thread_id += 1
                except:
                    _mwsrv_thread_id = 0
                try:
                    start_new_thread('MWSRV_THREAD_%s' %
                                     _mwsrv_thread_id, func, args)
                    return True
                except:
                    pass
        return False

    # ----------------------------------------------------------------------------

    @staticmethod
    def _unquote(s):
        r = s.split('%')
        for i in range(1, len(r)):
            s = r[i]
            try:
                r[i] = chr(int(s[:2], 16)) + s[2:]
            except:
                r[i] = '%' + s
        return ''.join(r)

    # ----------------------------------------------------------------------------

    @staticmethod
    def _unquote_plus(s):
        return MicroWebSrv._unquote(s.replace('+', ' '))

    # ----------------------------------------------------------------------------

    @staticmethod
    def _fileExists(path):
        try:
            stat(path)
            return True
        except:
            return False

    # ----------------------------------------------------------------------------

    @staticmethod
    def _isPyHTMLFile(filename):
        return filename.lower().endswith(MicroWebSrv._pyhtmlPagesExt)

    # ============================================================================
    # ===( Constructor )==========================================================
    # ============================================================================

    def __init__(self,
                 routeHandlers=[],
                 port=80,
                 bindIP='0.0.0.0',
                 webPath="/flash/www"):

        self._srvAddr = (bindIP, port)
        self._webPath = webPath
        self._notFoundUrl = None
        self._started = False

        self.MaxWebSocketRecvLen = 1024
        self.WebSocketThreaded = True
        self.AcceptWebSocketCallback = None

        self._routeHandlers = []
        routeHandlers += self._docoratedRouteHandlers
        for route, method, func in routeHandlers:
            routeParts = route.split('/')
            # -> ['', 'users', '<uID>', 'addresses', '<addrID>', 'test', '<anotherID>']
            routeArgNames = []
            routeRegex = ''
            for s in routeParts:
                if s.startswith('<') and s.endswith('>'):
                    routeArgNames.append(s[1:-1])
                    routeRegex += '/(\\w*)'
                elif s:
                    routeRegex += '/' + s
            routeRegex += '$'
            # -> '/users/(\w*)/addresses/(\w*)/test/(\w*)$'
            routeRegex = re.compile(routeRegex)

            self._routeHandlers.append(MicroWebSrvRoute(
                route, method, func, routeArgNames, routeRegex))

    # ============================================================================
    # ===( Server Process )=======================================================
    # ============================================================================

    def _serverProcess(self):
        self._started = True
        while True:
            try:
                client, cliAddr = self._server.accept()
            except:
                break
            self._client(self, client, cliAddr)
        self._started = False

    # ============================================================================
    # ===( Functions )============================================================
    # ============================================================================

    def Start(self, threaded=True):
        if not self._started:
            self._server = socket.socket(socket.AF_INET, socket.SOCK_STREAM, socket.IPPROTO_TCP)
            self._server.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
            self._server.bind(self._srvAddr)
            self._server.listen(1)
            if threaded:
                MicroWebSrv._tryStartThread(self._serverProcess)
            else:
                self._serverProcess()

    # ----------------------------------------------------------------------------

    def Stop(self):
        if self._started:
            self._server.close()

    # ----------------------------------------------------------------------------

    def IsStarted(self):
        return self._started

    # ----------------------------------------------------------------------------

    def SetNotFoundPageUrl(self, url=None):
        self._notFoundUrl = url

    # ----------------------------------------------------------------------------

    def GetMimeTypeFromFilename(self, filename):
        filename = filename.lower()
        for ext in self._mimeTypes:
            if filename.endswith(ext):
                return self._mimeTypes[ext]
        return None

    # ----------------------------------------------------------------------------

    def GetRouteHandler(self, resUrl, method):
        if self._routeHandlers:
            #resUrl = resUrl.upper()
            if resUrl.endswith('/'):
                resUrl = resUrl[:-1]
            method = method.upper()
            for rh in self._routeHandlers:
                if rh.method == method:
                    m = rh.routeRegex.match(resUrl)
                    if m:   # found matching route?
                        if rh.routeArgNames:
                            routeArgs = {}
                            for i, name in enumerate(rh.routeArgNames):
                                value = m.group(i+1)
                                try:
                                    value = int(value)
                                except:
                                    pass
                                routeArgs[name] = value
                            return (rh.func, routeArgs)
                        else:
                            return (rh.func, None)
        return (None, None)

    # ----------------------------------------------------------------------------

    def _physPathFromURLPath(self, urlPath):
        if urlPath == '/':
            for idxPage in self._indexPages:
                physPath = self._webPath + '/' + idxPage
                if MicroWebSrv._fileExists(physPath):
                    return physPath
        else:
            physPath = self._webPath + urlPath
            if MicroWebSrv._fileExists(physPath):
                return physPath
        return None

    # ============================================================================
    # ===( Class Client  )========================================================
    # ============================================================================

    class _client:

        # ------------------------------------------------------------------------

        def __init__(self, microWebSrv, socket, addr):
            socket.settimeout(2)
            self._microWebSrv = microWebSrv
            self._socket = socket
            self._addr = addr
            self._method = None
            self._path = None
            self._httpVer = None
            self._resPath = "/"
            self._queryString = ""
            self._queryParams = {}
            self._headers = {}
            self._contentType = None
            self._contentLength = 0

            if hasattr(socket, 'readline'):   # MicroPython
                self._socketfile = self._socket
            else:   # CPython
                self._socketfile = self._socket.makefile('rwb')

            self._processRequest()

        # ------------------------------------------------------------------------

        def _processRequest(self):
            try:
                response = MicroWebSrv._response(self)
                if self._parseFirstLine(response):
                    if self._parseHeader(response):
                        upg = self._getConnUpgrade()
                        if not upg:
                            routeHandler, routeArgs = self._microWebSrv.GetRouteHandler(
                                self._resPath, self._method)
                            if routeHandler:
                                if routeArgs is not None:
                                    routeHandler(self, response, routeArgs)
                                else:
                                    routeHandler(self, response)
                            elif self._method.upper() == "GET":
                                filepath = self._microWebSrv._physPathFromURLPath(
                                    self._resPath)
                                if filepath:
                                    if MicroWebSrv._isPyHTMLFile(filepath):
                                        response.WriteResponsePyHTMLFile(
                                            filepath)
                                    else:
                                        contentType = self._microWebSrv.GetMimeTypeFromFilename(
                                            filepath)
                                        if contentType:
                                            response.WriteResponseFile(
                                                filepath, contentType)
                                        else:
                                            response.WriteResponseForbidden()
                                else:
                                    response.WriteResponseNotFound()
                            else:
                                response.WriteResponseMethodNotAllowed()
                        elif upg == 'websocket' and 'MicroWebSocket' in globals() \
                                and self._microWebSrv.AcceptWebSocketCallback:
                            MicroWebSocket(socket=self._socket, httpClient=self,
                                           httpResponse=response, maxRecvLen=self._microWebSrv.MaxWebSocketRecvLen,
                                           threaded=self._microWebSrv.WebSocketThreaded,
                                           acceptCallback=self._microWebSrv.AcceptWebSocketCallback)
                            return
                        else:
                            response.WriteResponseNotImplemented()
                    else:
                        response.WriteResponseBadRequest()
            except:
                response.WriteResponseInternalServerError()
            try:
                if self._socketfile is not self._socket:
                    self._socketfile.close()
                self._socket.close()
            except:
                pass

        # ------------------------------------------------------------------------

        def _parseFirstLine(self, response):
            try:
                elements = self._socketfile.readline().decode().strip().split()
                if len(elements) == 3:
                    self._method = elements[0].upper()
                    self._path = elements[1]
                    self._httpVer = elements[2].upper()
                    elements = self._path.split('?', 1)
                    if len(elements) > 0:
                        self._resPath = MicroWebSrv._unquote_plus(elements[0])
                        if len(elements) > 1:
                            self._queryString = elements[1]
                            elements = self._queryString.split('&')
                            for s in elements:
                                param = s.split('=', 1)
                                if len(param) > 0:
                                    value = MicroWebSrv._unquote(
                                        param[1]) if len(param) > 1 else ''
                                    self._queryParams[MicroWebSrv._unquote(
                                        param[0])] = value
                    return True
            except:
                pass
            return False

        # ------------------------------------------------------------------------

        def _parseHeader(self, response):
            while True:
                elements = self._socketfile.readline().decode().strip().split(':', 1)
                if len(elements) == 2:
                    self._headers[elements[0].strip()] = elements[1].strip()
                elif len(elements) == 1 and len(elements[0]) == 0:
                    if self._method == 'POST':
                        self._contentType = self._headers.get(
                            "Content-Type", None)
                        self._contentLength = int(
                            self._headers.get("Content-Length", 0))
                    return True
                else:
                    return False

        # ------------------------------------------------------------------------

        def _getConnUpgrade(self):
            if 'upgrade' in self._headers.get('Connection', '').lower():
                return self._headers.get('Upgrade', '').lower()
            return None

        # ------------------------------------------------------------------------

        def GetServer(self):
            return self._microWebSrv

        # ------------------------------------------------------------------------

        def GetAddr(self):
            return self._addr

        # ------------------------------------------------------------------------

        def GetIPAddr(self):
            return self._addr[0]

        # ------------------------------------------------------------------------

        def GetPort(self):
            return self._addr[1]

        # ------------------------------------------------------------------------

        def GetRequestMethod(self):
            return self._method

        # ------------------------------------------------------------------------

        def GetRequestTotalPath(self):
            return self._path

        # ------------------------------------------------------------------------

        def GetRequestPath(self):
            return self._resPath

        # ------------------------------------------------------------------------

        def GetRequestQueryString(self):
            return self._queryString

        # ------------------------------------------------------------------------

        def GetRequestQueryParams(self):
            return self._queryParams

        # ------------------------------------------------------------------------

        def GetRequestHeaders(self):
            return self._headers

        # ------------------------------------------------------------------------

        def GetRequestContentType(self):
            return self._contentType

        # ------------------------------------------------------------------------

        def GetRequestContentLength(self):
            return self._contentLength

        # ------------------------------------------------------------------------

        def ReadRequestContent(self, size=None):
            self._socket.setblocking(False)
            b = None
            try:
                if not size:
                    b = self._socketfile.read(self._contentLength)
                elif size > 0:
                    b = self._socketfile.read(size)
            except:
                pass
            self._socket.setblocking(True)
            return b if b else b''

        # ------------------------------------------------------------------------

        def ReadRequestPostedFormData(self):
            res = {}
            data = self.ReadRequestContent()
            if len(data) > 0:
                elements = data.decode().split('&')
                for s in elements:
                    param = s.split('=', 1)
                    if len(param) > 0:
                        value = MicroWebSrv._unquote(
                            param[1]) if len(param) > 1 else ''
                        res[MicroWebSrv._unquote(param[0])] = value
            return res

        # ------------------------------------------------------------------------

        def ReadRequestContentAsJSON(self):
            try:
                return loads(self.ReadRequestContent())
            except:
                return None

    # ============================================================================
    # ===( Class Response  )======================================================
    # ============================================================================

    class _response:

        # ------------------------------------------------------------------------

        def __init__(self, client):
            self._client = client

        # ------------------------------------------------------------------------

        def _write(self, data):
            if type(data) == str:
                data = data.encode()
            return self._client._socketfile.write(data)

        # ------------------------------------------------------------------------

        def _writeFirstLine(self, code):
            reason = self._responseCodes.get(code, ('Unknown reason', ))[0]
            self._write("HTTP/1.1 %s %s\r\n" % (code, reason))

        # ------------------------------------------------------------------------

        def _writeHeader(self, name, value):
            self._write("%s: %s\r\n" % (name, value))

        # ------------------------------------------------------------------------

        def _writeContentTypeHeader(self, contentType, charset=None):
            if contentType:
                ct = contentType \
                    + (("; charset=%s" % charset) if charset else "")
            else:
                ct = "application/octet-stream"
            self._writeHeader("Content-Type", ct)

        # ------------------------------------------------------------------------

        def _writeServerHeader(self):
            self._writeHeader("Server", "MicroWebSrv by JC`zic")

        # ------------------------------------------------------------------------

        def _writeEndHeader(self):
            self._write("\r\n")

        # ------------------------------------------------------------------------

        def _writeBeforeContent(self, code, headers, contentType, contentCharset, contentLength):
            self._writeFirstLine(code)
            if isinstance(headers, dict):
                for header in headers:
                    self._writeHeader(header, headers[header])
            if contentLength > 0:
                self._writeContentTypeHeader(contentType, contentCharset)
                self._writeHeader("Content-Length", contentLength)
            self._writeServerHeader()
            self._writeHeader("Connection", "close")
            self._writeEndHeader()

        # ------------------------------------------------------------------------

        def WriteSwitchProto(self, upgrade, headers=None):
            self._writeFirstLine(101)
            self._writeHeader("Connection", "Upgrade")
            self._writeHeader("Upgrade",    upgrade)
            if isinstance(headers, dict):
                for header in headers:
                    self._writeHeader(header, headers[header])
            self._writeServerHeader()
            self._writeEndHeader()
            if self._client._socketfile is not self._client._socket:
                self._client._socketfile.flush()   # CPython needs flush to continue protocol

        # ------------------------------------------------------------------------

        def WriteResponse(self, code, headers, contentType, contentCharset, content):
            try:
                contentLength = len(content) if content else 0
                self._writeBeforeContent(
                    code, headers, contentType, contentCharset, contentLength)
                if contentLength > 0:
                    self._write(content)
                return True
            except:
                return False

        # ------------------------------------------------------------------------

        def WriteResponsePyHTMLFile(self, filepath, headers=None, vars=None):
            if 'MicroWebTemplate' in globals():
                with open(filepath, 'r') as file:
                    code = file.read()
                mWebTmpl = MicroWebTemplate(
                    code, escapeStrFunc=MicroWebSrv.HTMLEscape, filepath=filepath)
                try:
                    tmplResult = mWebTmpl.Execute(None, vars)
                    return self.WriteResponse(200, headers, "text/html", "UTF-8", tmplResult)
                except Exception as ex:
                    return self.WriteResponse(500,
                                              None,
                                              "text/html",
                                              "UTF-8",
                                              self._execErrCtnTmpl % {
                                                  'module': 'PyHTML',
                                                  'message': str(ex)
                                              })
            return self.WriteResponseNotImplemented()

        # ------------------------------------------------------------------------

        def WriteResponseFile(self, filepath, contentType=None, headers=None):
            try:
                size = stat(filepath)[6]
                if size > 0:
                    with open(filepath, 'rb') as file:
                        self._writeBeforeContent(
                            200, headers, contentType, None, size)
                        buf = MicroWebSrv._tryAllocByteArray(1024)
                        if buf:
                            while size > 0:
                                x = file.readinto(buf)
                                if x < len(buf):
                                    buf = memoryview(buf)[:x]
                                self._write(buf)
                                size -= x
                            return True
                        self.WriteResponseInternalServerError()
                        return False
            except:
                pass
            self.WriteResponseNotFound()
            return False

        # ------------------------------------------------------------------------

        def WriteResponseFileAttachment(self, filepath, attachmentName, headers=None):
            if not isinstance(headers, dict):
                headers = {}
            headers["Content-Disposition"] = "attachment; filename=\"%s\"" % attachmentName
            return self.WriteResponseFile(filepath, None, headers)

        # ------------------------------------------------------------------------

        def WriteResponseOk(self, headers=None, contentType=None, contentCharset=None, content=None):
            return self.WriteResponse(200, headers, contentType, contentCharset, content)

        # ------------------------------------------------------------------------

        def WriteResponseJSONOk(self, obj=None, headers=None):
            return self.WriteResponse(200, headers, "application/json", "UTF-8", dumps(obj))

        # ------------------------------------------------------------------------

        def WriteResponseRedirect(self, location):
            headers = {"Location": location}
            return self.WriteResponse(302, headers, None, None, None)

        # ------------------------------------------------------------------------

        def WriteResponseError(self, code):
            responseCode = self._responseCodes.get(
                code, ('Unknown reason', ''))
            return self.WriteResponse(code,
                                      None,
                                      "text/html",
                                      "UTF-8",
                                      self._errCtnTmpl % {
                                          'code': code,
                                          'reason': responseCode[0],
                                          'message': responseCode[1]
                                      })

        # ------------------------------------------------------------------------

        def WriteResponseJSONError(self, code, obj=None):
            return self.WriteResponse(code,
                                      None,
                                      "application/json",
                                      "UTF-8",
                                      dumps(obj if obj else {}))

        # ------------------------------------------------------------------------

        def WriteResponseBadRequest(self):
            return self.WriteResponseError(400)

        # ------------------------------------------------------------------------

        def WriteResponseForbidden(self):
            return self.WriteResponseError(403)

        # ------------------------------------------------------------------------

        def WriteResponseNotFound(self):
            if self._client._microWebSrv._notFoundUrl:
                self.WriteResponseRedirect(
                    self._client._microWebSrv._notFoundUrl)
            else:
                return self.WriteResponseError(404)

        # ------------------------------------------------------------------------

        def WriteResponseMethodNotAllowed(self):
            return self.WriteResponseError(405)

        # ------------------------------------------------------------------------

        def WriteResponseInternalServerError(self):
            return self.WriteResponseError(500)

        # ------------------------------------------------------------------------

        def WriteResponseNotImplemented(self):
            return self.WriteResponseError(501)

        # ------------------------------------------------------------------------

        def FlashMessage(self, messageText, messageStyle=''):
            if 'MicroWebTemplate' in globals():
                MicroWebTemplate.MESSAGE_TEXT = messageText
                MicroWebTemplate.MESSAGE_STYLE = messageStyle

        # ------------------------------------------------------------------------

        _errCtnTmpl = """\
        <html>
            <head>
                <title>Error</title>
            </head>
            <body>
                <h1>%(code)d %(reason)s</h1>
                %(message)s
            </body>
        </html>
        """

        # ------------------------------------------------------------------------

        _execErrCtnTmpl = """\
        <html>
            <head>
                <title>Page execution error</title>
            </head>
            <body>
                <h1>%(module)s page execution error</h1>
                %(message)s
            </body>
        </html>
        """

        # ------------------------------------------------------------------------

        _responseCodes = {
            100: ('Continue', 'Request received, please continue'),
            101: ('Switching Protocols',
                  'Switching to new protocol; obey Upgrade header'),

            200: ('OK', 'Request fulfilled, document follows'),
            201: ('Created', 'Document created, URL follows'),
            202: ('Accepted',
                  'Request accepted, processing continues off-line'),
            203: ('Non-Authoritative Information', 'Request fulfilled from cache'),
            204: ('No Content', 'Request fulfilled, nothing follows'),
            205: ('Reset Content', 'Clear input form for further input.'),
            206: ('Partial Content', 'Partial content follows.'),

            300: ('Multiple Choices',
                  'Object has several resources -- see URI list'),
            301: ('Moved Permanently', 'Object moved permanently -- see URI list'),
            302: ('Found', 'Object moved temporarily -- see URI list'),
            303: ('See Other', 'Object moved -- see Method and URL list'),
            304: ('Not Modified',
                  'Document has not changed since given time'),
            305: ('Use Proxy',
                  'You must use proxy specified in Location to access this '
                  'resource.'),
            307: ('Temporary Redirect',
                  'Object moved temporarily -- see URI list'),

            400: ('Bad Request',
                  'Bad request syntax or unsupported method'),
            401: ('Unauthorized',
                  'No permission -- see authorization schemes'),
            402: ('Payment Required',
                  'No payment -- see charging schemes'),
            403: ('Forbidden',
                  'Request forbidden -- authorization will not help'),
            404: ('Not Found', 'Nothing matches the given URI'),
            405: ('Method Not Allowed',
                  'Specified method is invalid for this resource.'),
            406: ('Not Acceptable', 'URI not available in preferred format.'),
            407: ('Proxy Authentication Required', 'You must authenticate with '
                  'this proxy before proceeding.'),
            408: ('Request Timeout', 'Request timed out; try again later.'),
            409: ('Conflict', 'Request conflict.'),
            410: ('Gone',
                  'URI no longer exists and has been permanently removed.'),
            411: ('Length Required', 'Client must specify Content-Length.'),
            412: ('Precondition Failed', 'Precondition in headers is false.'),
            413: ('Request Entity Too Large', 'Entity is too large.'),
            414: ('Request-URI Too Long', 'URI is too long.'),
            415: ('Unsupported Media Type', 'Entity body in unsupported format.'),
            416: ('Requested Range Not Satisfiable',
                  'Cannot satisfy request range.'),
            417: ('Expectation Failed',
                  'Expect condition could not be satisfied.'),

            500: ('Internal Server Error', 'Server got itself in trouble'),
            501: ('Not Implemented',
                  'Server does not support this operation'),
            502: ('Bad Gateway', 'Invalid responses from another server/proxy.'),
            503: ('Service Unavailable',
                  'The server cannot process the request due to a high load'),
            504: ('Gateway Timeout',
                  'The gateway server did not receive a timely response'),
            505: ('HTTP Version Not Supported', 'Cannot fulfill request.'),
        }

    # ============================================================================
    # ============================================================================
    # ============================================================================