Raise exception (or not) when a JSON response with errorCode is received

[femtotrader]

Hello,

I think most of json.loads(...) should be replaced by self.parse_response(...)

def parse_response_without_exception(self, *args, **kwargs):
    response = json.loads(*args, **kwargs)
    return(response)

def parse_response_with_exception(self, *args, **kwargs):
    response = json.loads(*args, **kwargs)
    if 'errorCode' in response:
        raise(Exception(response['errorCode']))
    return(response)

so if an error message is returned it will raise an exception so it can be catch (or not)

if you want to keep current behaviour you should set inside __init__

self.parse_response = self.parse_response_without_exception

Moreover it will also allow user to easily monkey pach this code to redefine this parse_response
function.
I personally prefer to return Bunch object instead of dict so my own parse_response looks like

from bunch import Bunch, bunchify

 def parse_response_with_exception(self, *args, **kwargs):
    response = json.loads(*args, **kwargs)
    if 'errorCode' in response:
        raise(Exception(response['errorCode']))
    return(bunchify(response))

Kind regards

Femto

[lewisbarber]

Hi Femto,

Thank you for raising these issues. If you would like to fork the code, make the updates and submit a pull request I would be happy to accept them into the library (following successful testing).

Thanks,
Lewis

[femtotrader]

Hi Lewis,

I will submit a PR when I will have some free time (because I know Subversion but I'm not a Git user).
My PR will also try to fix docstring and some minor details to have a more "pythonic" code.

For example

class IGService:

    D_BASE_URL = {
        'live': 'https://api.ig.com/gateway/deal',
        'demo': 'https://demo-api.ig.com/gateway/deal'
    }

    def __init__(self, username, password, api_key, acc_type="live"):
        """Constructor, calls the method required to connect to the API (accepts acc_type = LIVE or DEMO)"""

        ....

        try:
            self.BASE_URL = self.D_BASE_URL[acc_type.lower()]
        except:
            raise(Exception("Invalid account type specified, please provide LIVE or DEMO."))

is more pythonic than

class IGService:

    ...

    BASE_URL = 'https://api.ig.com/gateway/deal'
    BASE_URL_DEMO = 'https://demo-api.ig.com/gateway/deal'

    # Constructor, calls the method required to connect to the API (accepts acc_type = LIVE or DEMO)
    def __init__(self, username, password, api_key, acc_type="LIVE"):

        if acc_type != "DEMO" and acc_type != "LIVE":
            print "Error: Invalid account type specified, please provide LIVE or DEMO."
        return

        if acc_type == "DEMO":
            self.BASE_URL = self.BASE_URL_DEMO

4 spaces indentation is also better according PEP8.
https://www.python.org/dev/peps/pep-0008

I also think that you should use Pandas library and that some methods should return a DataFrame instead of a dict. For example

def fetch_accounts(self):

    response = requests.get(self.BASE_URL + '/accounts', headers=self.LOGGED_IN_HEADERS)

    return json.loads(response.text)

should be

    import pandas as pd

def fetch_accounts(self):
    raw_response = requests.get(self.BASE_URL + '/accounts', headers=self.LOGGED_IN_HEADERS)
    response = self.parse_response(raw_response.text)
    df = pd.DataFrame(response['accounts'])
    return(df)

many other methods like this should return DataFrame, it will be much easier for user to read ouputs (and also compute mean, max, sort, ...)

fetch_account_activity_by_period, fetch_transaction_history_by_type_and_period, fetch_open_positions, fetch_all_watchlists, fetch_watchlist_markets are some method which could return DataFrame

Kind regards