json_helper.py

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# Copyright 2017 Mycroft AI Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
import json


def merge_dict(base, delta):
    """
        Recursively merging configuration dictionaries.

        Args:
            base:  Target for merge
            delta: Dictionary to merge into base
    """

    for k, dv in delta.items():
        bv = base.get(k)
        if isinstance(dv, dict) and isinstance(bv, dict):
            merge_dict(bv, dv)
        else:
            base[k] = dv


def load_commented_json(filename):
    """ Loads an JSON file, ignoring comments

    Supports a trivial extension to the JSON file format.  Allow comments
    to be embedded within the JSON, requiring that a comment be on an
    independent line starting with '//' or '#'.

    NOTE: A file created with these style comments will break strict JSON
          parsers.  This is similar to but lighter-weight than "human json"
          proposed at https://hjson.org

    Args:
        filename (str):  path to the commented JSON file

    Returns:
        obj: decoded Python object
    """
    with open(filename) as f:
        contents = f.read()

    return json.loads(uncomment_json(contents))


def uncomment_json(commented_json_str):
    """ Removes comments from a JSON string.

    Supporting a trivial extension to the JSON format.  Allow comments
    to be embedded within the JSON, requiring that a comment be on an
    independent line starting with '//' or '#'.

    Example...
       {
         // comment
         'name' : 'value'
       }

    Args:
        commented_json_str (str):  a JSON string

    Returns:
        str: uncommented, legal JSON
    """
    lines = commented_json_str.splitlines()
    # remove all comment lines, starting with // or #
    nocomment = []
    for line in lines:
        stripped = line.lstrip()
        if stripped.startswith("//") or stripped.startswith("#"):
            continue
        nocomment.append(line)

    return " ".join(nocomment)