services.py

#-*- coding:utf-8 -*-
import re
from xml.parsers.expat import ExpatError
import xml.sax.saxutils

import requests
import xmltodict

from requests import Request, Session
import logging 

log = logging.getLogger(__name__) 





from . import api, errors, settings

### CONFIG ###






# enspired by http://stackoverflow.com/questions/30259452/proper-way-to-consume-data-from-restful-api-in-django
# def get_books(year, author):
#     url = 'http://api.example.com/books' 
#     params = {'year': year, 'author': author}
#     r = requests.get('http://api.example.com/books', params)
#     books = r.json()
#     books_list = {'books':books['results']}

# xml = """<?xml version='1.0' encoding='utf-8'?>
# <a>б</a>"""
# headers = {'Content-Type': 'application/xml'} # set what your server accepts
# print requests.post('http://httpbin.org/post', data=xml, headers=headers).text

context = {
	'account_name': settings.ACCOUNT_NAME,
}

def get_keys(keys_list, obj):
	"""
		Returns obj with keys_list 
		And obj with all other keys (if any)
	"""

	new_obj = {}
	for key in keys_list:
		if key in obj:
			new_obj[key] = obj[key]
			del obj[key]

	return new_obj,obj

def tune_dict(method, xml_params):
	"""
		Changes dict to conform Invoicexpress API 
	"""
	# import pdb
	# pdb.set_trace()
	if 'items' in xml_params:
		if 'item' in xml_params['items']:
			if type(xml_params['items']['item']) == type([]) :
				xml_params['items']['@type'] = 'array'

	if method == 'invoice-receipts.email-document' :
		if 'body' in xml_params:
			xml_params['body'] = xml.sax.saxutils.escape( xml_params['body'] ) 
	return xml_params




def ask_api(method, xml_params={}):
	""" this function will do all  requests 
		to Invocexpress API

	:param action: 			api call name (e.g. users.accouts , invoices.get)
	:param xml_params: 	params, that should specified in xml body long list of additional arguments;
	

	:returns:		API answer as python dict 
	"""

	action = api.method[method]

	# find all params in brackets
	url  = action['url']
	keys_in_url = re.findall('\{(.[^\}]+)\}',url)

			
	# sort parameters into 2 groups xml parameters
	# and url parameters
	addr_params, xml_params = get_keys(keys_in_url, xml_params)
	addr_params['account-name'] = settings.ACCOUNT_NAME

	# now compile urls using settings
	url = action['url'].format(**addr_params)
	
	out = []
	for key in xml_params.keys():
		if key[-2:]=='[]':
			out  += [ key+"="+x for x in xml_params.pop(key) ]

	if len(out) > 0 :
		url = url+'?'+'&'.join(out)
		

	if 'url_params' in action:
		url_params, xml_params = get_keys(action['url_params'],xml_params)
	else:
		url_params = {}

	headers = {'Content-Type': 'application/xml; charset=utf-8'}
	url_params['api_key'] = settings.API_KEY

	request_args = {}
	if xml_params != {} :

		if not ('root_tag_name' in action) :
			raise errors.WrongParams ('This call must have root_tag_name') 

		# need to "tune" dict due to API 
		xml_params = tune_dict(method, xml_params)
 		# wrap xml_params in root_tag
		xml_params = { action['root_tag_name'] : xml_params }
		request_args['data'] = xmltodict.unparse(xml_params).encode('utf8')
		
	print url
	print headers
	print url_params
	print request_args
	#TODO: use one session for many requests
	s = Session()
	req = Request( action['method'],
		url = url,
	    headers=headers,
	    params = url_params,
	    **request_args
	)
	prepared = req.prepare()
	# TODO: connection error handling
	resp = s.send(prepared)

	print resp

	if resp.status_code == 200 or resp.status_code==201:
		try :
			out  = xmltodict.parse(resp.text)
			if len( out.keys() ) > 1:
				raise errors.ApiUnimplemented('Have more then 1 key')
			out = out [ out.keys()[0] ]
		except ExpatError:
			out = resp.text
		return out
	elif resp.status_code == 202:
		return 202
	else : 
		error_message = str(resp.status_code)+': '+resp.text
		
		if resp.status_code == 404:
			raise errors.Error404(error_message)	
		else :
			raise errors.ApiCallError(error_message)


# TODO: remove items special handling