lib.py

import itertools
import json
import re
from typing import List


def group(_input):
    d = list(itertools.chain(*list(map(lambda x: list(x.items()), _input))))
    _s = [[a, [c for _, c in b]] for a, b in itertools.groupby(sorted(d, key=lambda x: x[0]), key=lambda x: x[0])]
    return {a: group(b) if all(isinstance(i, dict) for i in b) else list(itertools.chain(*b)) for a, b in _s}


def fix_values(dic):
    for k, v in dic.items():
        if isinstance(v, list):
            dic[k] = ''.join(v)
        else:
            fix_values(v)
    return dic


def trim(s):
    """clear all white characters"""
    return re.sub(r'\s', '', s)


def build_query(items, indent=2):
    """
    transform a tree into grqphql query string
    """
    dic = build_dict(items)
    return re.sub(r'["\s]', '', json.dumps(dic, indent=indent))[1:-1]


def build_dict(items):
    """
    transform a list of conditions into dictionary
    """
    dicts = []
    for item in items:
        json_str = '{' + re.sub(r'([$\w]+)', r'"\1"', item) + '}'
        dic = json.loads(json_str)
        dicts.append(dic)
    dic = group(dicts)
    return fix_values(dic)

test_build_query.py

from django.test import TestCase

from  .lib import build_dict, build_query, trim


class TestBuildQuery(TestCase):
    def test_build_dict(self):
        items = [
            'aa:{bb:{cc:{f3:{_op3:$f3}}}}',  # 1
            'aa:{bb:{f2:{_op2:$f2}}}',  # 2
            'aa:{dd:{f4:{_op4:$f4}}}',  # 3
            'aa:{bb:{f1:{_op1:$f1}}}',  # 1
        ]
        expected = {
            'aa': {
                'bb': {
                    'cc': {
                        'f3': {
                            '_op3': '$f3'
                        }
                    },
                    'f1': {
                        '_op1': '$f1'
                    },
                    'f2': {
                        '_op2': '$f2'
                    },
                },
                'dd': {
                    'f4': {
                        '_op4': '$f4'
                    }
                }
            }
        }
        assert build_dict(items) == expected

    def test_build_query(self):
        items = [
            'aa:{bb:{cc:{f3:{_op3:$f3}}}}',  # 1
            'aa:{bb:{f2:{_op2:$f2}}}',  # 2
            'aa:{dd:{f4:{_op4:$f4}}}',  # 3
            'aa:{bb:{f1:{_op1:$f1}}}',  # 1
        ]
        expected = '''
            aa: {
                bb: {
                    cc: {f3: {_op3: $f3}},
                    f1: {_op1: $f1},
                    f2: {_op2: $f2}
                },
                dd: {f4: {_op4: $f4}}
            }
            '''
        assert build_query(items) == trim(expected)