"""
This module provides functionality for parsing the string representations of
Bloomberg Open API Requests and Responses into equivalent JSON or dictionary
representations
"""
# A huge thank you to Paul McGuire who provided invaluable help working out
# the grammar for this. Discussion available at
# https://stackoverflow.com/questions/44144055/parsing-json-like-format-with-pyparsing/44172752#44172752
import json
import pyparsing as pp
def _parse(mystr):
LBRACE, RBRACE, EQUAL = map(pp.Suppress, "{}=")
field = pp.Word(pp.printables + ' ', excludeChars='[]=')
field.addParseAction(pp.tokenMap(str.rstrip))
string = pp.dblQuotedString().setParseAction(pp.removeQuotes)
number = pp.pyparsing_common.number()
date_expr = pp.Regex(r'\d\d\d\d-\d\d-\d\d')
time_expr = pp.Regex(r'\d\d:\d\d:\d\d\.\d\d\d')
nan = pp.Keyword('nan')
scalar_value = (string | date_expr | time_expr | number | nan)
list_marker = pp.Suppress("[]")
value_list = pp.Forward()
jobject = pp.Forward()
memberDef1 = pp.Group(field + EQUAL + scalar_value)
memberDef2 = pp.Group(field + EQUAL + jobject)
memberDef3 = pp.Group(field + list_marker + EQUAL + LBRACE + value_list +
RBRACE)
memberDef = memberDef1 | memberDef2 | memberDef3
value_list <<= (pp.delimitedList(scalar_value, ",") |
pp.ZeroOrMore(pp.Group(pp.Dict(memberDef2))))
value_list.setParseAction(lambda t: [pp.ParseResults(t[:])])
members = pp.OneOrMore(memberDef)
jobject <<= pp.Dict(LBRACE + pp.ZeroOrMore(memberDef) + RBRACE)
# force empty jobject to be a dict
jobject.setParseAction(lambda t: t or {})
parser = members
parser = pp.OneOrMore(pp.Group(pp.Dict(memberDef)))
return parser.parseString(mystr)
def to_dict_list(mystr):
"""
Translate a string representation of a Bloomberg Open API Request/Response
into a list of dictionaries.return
Parameters
----------
mystr: str
A string representation of one or more blpapi.request.Request or
blp.message.Message, these should be '\\n' seperated
"""
res = _parse(mystr)
dicts = []
for res_dict in res:
dicts.append(res_dict.asDict())
return dicts
def to_json(mystr):
"""
Translate a string representation of a Bloomberg Open API Request/Response
into a JSON string
Parameters
----------
mystr: str
A string representation of one or more blpapi.request.Request or
blp.message.Message, these should be '\\n' seperated
"""
dicts = to_dict_list(mystr)
json.dumps(dicts, indent=2)
