Reconstruct source files from a webpack-made sourceMap

webpack_source_reconstruct.py

#!/usr/bin/env python3

import json
import os
import sys

def main():
    if len(sys.argv) != 2:
        print("Usage: webpack_source_reconstruct.py /path/to/source.map")
        sys.exit(1)

    sourcemap = os.path.abspath(sys.argv[1])
    if not os.path.isfile(sourcemap):
        print("Sourcemap is not file")
        sys.exit(1)

    try:
        with open(sourcemap, 'r') as f:
            sourcemap = json.load(f)
            if 'sourcesContent' not in sourcemap or len(sourcemap['sourcesContent']) == 0:
                print("Sourcemap does not contain content.")
                sys.exit(2)

            idx = 0
            if 'sources' in sourcemap:
                lsources = len(sourcemap['sources'])
                lcontent = len(sourcemap['sourcesContent'])
                if lsources != lcontent:
                    print("Warning: sources and sourcesContent do not agree, filenames may be wrong")

                for source in sourcemap['sources']:
                    filename = source.replace("webpack://", "")
                    filename = filename.replace("/", "-").replace("\\", "-")
                    if filename[0] == '.':
                        filename = filename[1:]

                    if not os.path.isdir("output/"):
                        os.mkdir("output/", 0o755)

                    try:
                        content = sourcemap['sourcesContent'][idx]
                        idx += 1
                        print("Writing %s" % filename)
                        with open("output/"+filename, 'w') as sf:
                            sf.write(content)
                    except IndexError:
                        print("Reached end of sourcesContent, finishing incompletely")
                        sys.exit(1)

    except:
        raise
        print("Sourcemap failed to parse.")
        sys.exit(2)

if __name__ == "__main__":
    main()