ems/API/service.py

'''
Created on 24.10.2013

@author: Philipp Rauch
@version: 0.6
'''
# from sys import stderr
from datetime import datetime
from flask import Flask, jsonify, make_response, request, Response
from socket import gethostname
from Config.parser import config
from ems import ems
from buffer import Buffer

### LOAD CONFIG ###
c = config()
conf = c.readConf()

api_host = gethostname() if conf['flask_server'] == '0.0.0.0' else conf['flask_server']
api_url = 'http://%s:%s' % (api_host, conf['flask_port'])

#buf = Buffer()

class Request(object):
    '''
    request definition for buffer
    '''
    def __init__(self, path, time, req_id):
        self.content = path
        self.time = time
        self.id = req_id


def REST_start():
    api = REST()
    if conf['config_debug']:
        print 'REST-Thread:\t%s\n' % api
    api.app.run(host = conf['flask_server'],
                port = int(conf['flask_port']))
                #debug = conf['flask_debug']

class REST(object):

    def __init__(self):
        self.app = Flask(__name__)

        ### Start Buffer ###
        self.buf = Buffer()

        ### Start EMS thread ###
        self.EMS = ems(self.buf)
        self.EMS.start()

        if conf['config_debug']:
            print 'EMS-Thread:\t', self.EMS
            print '\tAPI-BUFFER:\t', self.buf

        ### ADD URL RULES ###
        self.app.error_handler_spec[None][400] = self.bad_reqest
        self.app.error_handler_spec[None][404] = self.not_found
        self.app.error_handler_spec[None][405] = self.not_allowed
        self.app.error_handler_spec[None][500] = self.server_error
        self.app.add_url_rule('/', 'get_root', self.get_root, methods = ['GET'])
        self.app.add_url_rule('/<path:path>', 'get_catch_all',
                              self.get_catch_all, methods = ['GET'])

    ########## ERROR Handler ##########
    def not_allowed(self, error):
        return make_response(jsonify( { 'error': '405 Not Allowed' } ), 405)

    def not_found(self, error):
        return make_response(jsonify( { 'error': '404 Not Found' } ), 404)

    def bad_reqest(self, error):
        return make_response(jsonify( { 'error': '400 Bad Reqest' } ), 400)

    def server_error(self, error):
        return make_response(jsonify( { 'error': '500 Internal Server Error' } ), 500)

    ##########  GET Handler  ##########
    def get_root(self):
        self.buf.set_href(Buffer.system, api_url)
        return jsonify( { 'system' : Buffer.system } )

    def get_catch_all(self, path):
        l = path.split('/')
        l.insert(0, Buffer.system)
        if '' == l[-1]:                     # if last element of list is empty
            del l[-1]                       # remove it
            out = self.buf.get_level(l)
        elif 'dyn' == l[-1]:
            args = request.args.to_dict(flat=False)     # returns a dictionary with a list of values for each key
                                                        # each value and each key is represented as a string
                                                        # to convert it to a dictionary use to_dict(flat=False)
                                                        # to_dict(flat=True) returns the key and the first item of the value list.
            out = self.buf.foo(l, args)
        elif 'point' == l[-1]:
            del l[-1]
            tmp = self.buf.get_point(l)
            return Response(tmp, content_type='text/json')
        else:
            #req = add_reqest(path)

            #while req not in Buffer.system['done']:
            #    pass

            #Buffer.system['done'].remove(req)
            out = self.buf.get_level(l)

        return jsonify( out )

    def add_reqest(self, path):
        '''
        build a request and add it to list
        '''
        notinlist = False
        time = datetime.now()
        req_id = Buffer._id
        tmp = Request(path, time, req_id)
        try:
            Buffer.system['0_request'].index(tmp)
        except ValueError:
            notinlist = True

        if notinlist:
            Buffer.system['0_request'].insert(0, tmp)
            return id
        else:
            return False