encode.py

from nmssavetool import writeFile, compress
import json #standard, no package required
import sys #only if we pass command line arguments
from urllib.request import urlopen # only in case we want to fetch the mapping from github

def reverse_mapping(fl, mapdata):
    #creates a data structure for compressing a hg file, reversing the mapping of a json file
    mapping = dict()
    for i in mapdata.get("Mapping"):
        mapping[i.get("Value")]=i.get("Key")  
    #wrap the mapping in a hook for custom parsing
    def hookwithmapping(obj):
        mappedobj = dict()
        try:
            for i in obj:
                mappedobj[mapping[i]] = obj[i]
            return mappedobj
        except:
            return obj
    #then extract the data structure using our custom hook to apply the name mapping:
    return json.load(fl, object_hook=hookwithmapping)

if __name__ == "__main__":
    if len(sys.argv) != 2:
        print("usage: python encode.py <the json file to encode>")
    else:
        fn = sys.argv[1]
        if fn[-5:] != '.json':        
            print("usage: python encode.py <the json file to encode> - argument must end with .json!")
        else:
            print("attempt to encode file:", fn)
            #mapdata = json.load(open("sample/mapping.json")) # load the name mapping from a local copy or from github
            mapdata = json.load(urlopen("https://github.com/monkeyman192/MBINCompiler/releases/latest/download/mapping.json"))
            #apply the reverse mapping while loading the json save data, and encode the result as a json ansi bytearray
            savedata = reverse_mapping(open(fn, "r", encoding="ansi"), mapdata)
            savebytes = json.dumps(savedata, separators=(',', ':')).encode("ansi")
            #compress the result to a hg file using nmssavetool.py by Robert Maupin:
            writeFile(fn.replace("json", "hg"), compress(savebytes))
            print("Done. A hg file of the same name was (over)written.")