from simple_salesforce import Salesforce, SalesforceMalformedRequest
from argparse import ArgumentParser
from csv import DictWriter
from datetime import date
from pathlib import Path

production_instance = 'yourinstance.salesforce.com'

parser = ArgumentParser(description="Backs up all Salesforce objects to csv files")
parser.add_argument("username", help="User to authenticate as. Should be part of an 'integration_user' profile or some profile with no ip range restriction")
parser.add_argument("password", help="Password for the user")
parser.add_argument("security_token", help="Any API authenticating user needs to supply a security_token. You must log in as the user to get the security token from their profile")
parser.add_argument("instance", help="The instance to connect to")
parser.add_argument("datadir", help="The directory to store csv files in")
parser.add_argument("--objectNames", help="Space separated names of SalesForce objects or by default we backup all queryable objects", nargs='*')
args = parser.parse_args()

#create a subdirectory with todays date
datapath = Path(args.datadir) / date.today().isoformat() 
try:
  datapath.mkdir(parents=True) #in python 3.5 we can switch to using  exist_ok=True
except FileExistsError:
  pass

#log into salesforce
sf = Salesforce(username=args.username,password=args.password, security_token=args.security_token, sandbox=(production_instance!=args.instance), instance=args.instance)

#get a list of queryable object names we will need to backup
if args.objectNames:
  names = args.objectNames
else:
  #get a description of our global salesforce instance, see layout:
  # https://developer.salesforce.com/docs/atlas.en-us.api_rest.meta/api_rest/dome_describeGlobal.htm
  description = sf.describe()
  names = [obj['name'] for obj in description['sobjects'] if obj['queryable']]

#for every object we'll need all the fields it has that are exportable.
for name in names:
  salesforceObject = sf.__getattr__(name)
  # so get a list of the object fields for this object.
  fieldNames = [field['name'] for field in salesforceObject.describe()['fields']]
  # then build a SOQL query against that object and do a query_all
  try:
    results = sf.query_all( "SELECT " + ", ".join(fieldNames) + " FROM " + name  )['records']
  except SalesforceMalformedRequest as e:
    # ignore objects with rules about getting queried. 
    continue
  outputfile = datapath / (name+".csv")
  with outputfile.open(mode='w', encoding='utf_8_sig') as csvfile:
    writer = DictWriter(csvfile,fieldnames=fieldNames)
    writer.writeheader()
    for row in results:
      # each row has a strange attributes key we don't want
      row.pop('attributes',None)
      writer.writerow(row)
"""
This is free and unencumbered software released into the public domain.

Anyone is free to copy, modify, publish, use, compile, sell, or
distribute this software, either in source code form or as a compiled
binary, for any purpose, commercial or non-commercial, and by any
means.

In jurisdictions that recognize copyright laws, the author or authors
of this software dedicate any and all copyright interest in the
software to the public domain. We make this dedication for the benefit
of the public at large and to the detriment of our heirs and
successors. We intend this dedication to be an overt act of
relinquishment in perpetuity of all present and future rights to this
software under copyright law.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE.

For more information, please refer to <http://unlicense.org>
"""