wsgi_api.py

# This file is part of DQXServer - (C) Copyright 2014, Paul Vauterin, Ben Jeffery, Alistair Miles <info@cggh.org>
# This program is free software licensed under the GNU Affero General Public License.
# You can find a copy of this license in LICENSE in the top directory of the source code or at <http://opensource.org/licenses/AGPL-3.0>

from urlparse import parse_qs
import importlib
import simplejson
import os
import traceback

import DQXUtils
import DQXDbTools
import responders
from responders import uploadfile

# import customresponders

# Try to import all custom modules
customRespondersPath = os.path.join(os.path.dirname(__file__), 'customresponders')
for dirname in os.listdir(customRespondersPath):
    tryModulePath = os.path.join(customRespondersPath, dirname)
    if os.path.isdir(tryModulePath):
        importlib.import_module('customresponders.' + dirname)


def application(environ, start_response):
    request_data = dict((k,v[0]) for k,v in parse_qs(environ['QUERY_STRING']).items())
    if 'datatype' not in request_data:
        DQXUtils.LogServer('--> request does not contain datatype')
        start_response('404 NOT FOUND', [('Content-Type', 'text/plain')])
        yield 'Not found: request does not contain datatype'
        return

    request_type = request_data['datatype']

    tm = DQXUtils.Timer()

    if request_type == 'custom':
        request_custommodule = request_data['respmodule']
        request_customid = request_data['respid']
        responder = importlib.import_module('customresponders.' + request_custommodule + '.' + request_customid)
    else:
        try:
            #Fetch the handler by request type, using some introspection magic in responders/__init__.py
            responder = getattr(responders, request_type)
        except AttributeError:
            raise Exception("Unknown request {0}".format(request_type))


    request_data['environ'] = environ
    response = request_data
    try:
        try:
            response = responder.response(request_data)
            status = '200 OK'
        except DQXDbTools.CredentialException as e:
            print('CREDENTIAL EXCEPTION: '+str(e))
            response['Error'] = 'Credential problem: ' + str(e)
            #Really should be 403 - but I think the JS will break as it expects 200
            #status = '403 Forbidden'
            status = '200 OK'
        except DQXDbTools.Timeout as e:
            status = '504 Gateway Timeout'

        #Check for a custom response (eg in downloadtable)
        if 'handler' in dir(responder):
            for item in responder.handler(start_response, response):
                yield item

        else:
        #Default is to respond with JSON
            del response['environ']
            response = simplejson.dumps(response, use_decimal=True)
            response_headers = [('Content-type', 'application/json'),
                                ('Access-Control-Allow-Origin','*'),
                                ('Content-Length', str(len(response)))]
            start_response(status, response_headers)
            yield response
    except Exception as e:
        start_response('500 Server Error', [])
        traceback.print_exc()
        yield str(e)


    DQXUtils.LogServer('Responded to {0} in wall={1}s cpu={2}s'.format(request_type, tm.Elapsed(),tm.ElapsedCPU()))