"""********************************************************************************
web_service.py
DAE Tools: pyDAE module, www.daetools.com
Copyright (C) Dragan Nikolic
***********************************************************************************
DAE Tools is free software; you can redistribute it and/or modify it under the
terms of the GNU General Public License version 3 as published by the Free Software
Foundation. DAE Tools is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with the
DAE Tools software; if not, see <http://www.gnu.org/licenses/>.
********************************************************************************"""
import os, sys, json, traceback, cgi
import uuid, zipfile, cgitb, hashlib, threading
import wsgiref.simple_server
from daetools.pyDAE import *
try:
# python 3
import http.client as http_client
from urllib.parse import urlparse
except ImportError:
# python 2
import httplib as http_client
from urlparse import urlparse
# cgi traceback
#logdir = os.path.join(os.path.expanduser('~'), 'daetools_ws')
#cgitb.enable(display = 0, logdir = logdir, format = 'html')
[docs]class BadRequest(RuntimeError):
"""Results in: 400 Bad Request response"""
pass
[docs]class ServerError(RuntimeError):
"""Results in: 500 Internal Server Error response"""
pass
[docs]class daeWebService(object):
"""The base class for web applications/web services.
Performs the low level tasks such as parsing the query to get its arguments
and sending responses with results to the clients."""
def __init__(self):
self.noHTTPRequests = 0
self.activeObjects = {}
self.httpServer = None
[docs] @staticmethod
def startWebService(application, address, port, serveForever = False):
"""Start the web application."""
http_port = int(port)
http_address = str(address)
httpd = wsgiref.simple_server.make_server(http_address, http_port, application, handler_class=NoLoggingWSGIRequestHandler)
application.httpServer = httpd
if serveForever:
# Serve even if there is no active clients.
httpd.serve_forever(poll_interval = 5.0)
else:
# Serve as long as the function keepRunning returns True.
# keepRunning will return False if all clients freed their objects and exited.
while application.keepRunning():
httpd.handle_request()
[docs] @staticmethod
def tryConnectWebService(address, port, timeout = 10):
"""Try to connect to the above server (timeout is 10s).
If successful, the server has successfully been started
and the subsequent clients can connect to it."""
c = http_client.HTTPConnection(address, port, timeout)
[docs] def keepRunning(self):
"""Server will stop if at least one request has been processed and no activeObjects exist
(all active objects finished with the simulation).
Therefore, the server can serve multiple clients but will shutdown after all objects
freed their resources and the number of active objects goes to zero."""
return len(self.activeObjects) > 0 or self.noHTTPRequests == 0
[docs] def getQueryArguments(self, environ):
"""Returns the query arguments' values as a dictionary object.
Can process both GET and POST requests (double check this)."""
arguments = cgi.FieldStorage(fp = environ['wsgi.input'], environ = environ)
pathInfo = environ['PATH_INFO']
return pathInfo, arguments
[docs] def jsonBadRequest(self, reason, start_response, simulationID):
"""Returns the bad request error status to the client.
The argument reason is a string with the exception description.
It is not a fatal error, thus DO NOT delete the current object identified by its simulationID."""
if simulationID and simulationID in self.activeObjects:
del self.activeObjects[simulationID]
obj = {'Status': 'Error',
'Reason': reason,
'Result': None}
return self._sendResponse_json(obj, '400 Bad Request', start_response)
[docs] def jsonError(self, reason, start_response, simulationID):
"""Returns the error status to the client.
The argument reason is a string with the exception description.
In case of errors always deletes the current object identified by its simulationID."""
if simulationID and simulationID in self.activeObjects:
del self.activeObjects[simulationID]
obj = {'Status': 'Error',
'Reason': reason,
'Result': None}
return self._sendResponse_json(obj, '500 Internal Server Error', start_response)
[docs] def jsonSuccess(self, start_response):
"""Returns the success status to the client and no results."""
obj = {'Status': 'Success',
'Reason': None,
'Result': None}
return self._sendResponse_json(obj, '200 OK', start_response)
[docs] def jsonResult(self, result, start_response):
"""Returns the success status and the data to the client."""
obj = {'Status': 'Success',
'Reason': None,
'Result': result}
return self._sendResponse_json(obj, '200 OK', start_response)
def _sendResponse_json(self, obj, status, start_response):
"""Low level function that sends the HTTP response in JSON format.
The argument obj contains the data to be sent as JSON message."""
json_b = json.dumps(obj, indent = 2).encode() # default is utf-8
start_response(status, [('Access-Control-Allow-Origin', '*'),
('Access-Control-Allow-Methods', 'POST, GET, OPTIONS'),
('Content-type', 'application/json'),
('Content-Length', str(len(json_b)))])
return [json_b]
def _sendResponse_html(self, html_content, status, start_response):
"""Low level function that sends the HTTP response in HTML format.
The argument html_content contains the HTML message."""
html_b = html_content.encode() # default is utf-8
start_response(status, [('Access-Control-Allow-Origin', '*'),
('Access-Control-Allow-Methods', 'POST, GET, OPTIONS'),
('Content-type', 'text/html'),
('Content-Length', str(len(html_b)))])
return [html_b]
def _sendFile(self, filePath, contentType, start_response):
"""Low level function that sends a file as the HTTP response.
The argument html_content contains the HTML message."""
try:
f = open(filePath, 'rb')
content = f.read()
filename = os.path.basename(filePath)
content_len = len(content)
start_response('200 OK', [('Access-Control-Allow-Origin', '*'),
('Access-Control-Allow-Methods', 'POST, GET, OPTIONS'),
('Content-type', contentType),
('Content-Disposition', 'attachment; filename=%s' % filename),
('Content-Length', str(content_len))])
finally:
f.close()
return [content]
[docs]class NoLoggingWSGIRequestHandler(wsgiref.simple_server.WSGIRequestHandler):
"""Request handler that suppresses logging to the stderr."""
[docs] def log_message(self, format, *args):
pass
