02 August 2016   0 comments   Python


Mind that age!

This blog post is 4 years old! Most likely, its content is outdated. Especially if it's technical.

Last week I made a little library called json-schema-reducer. It's a simple function that takes a JSON Schema and dict (or a JSON string or a .json file path), and makes a new dict that only contains the keys listed in the JSON Schema.

This is handy if you have a JSON Schema which dictates what you can/want to share/publish/save, but you have a data structure that contains keys and values you don't want to share/publish/save.

I built this because there are a couple of projects that can turn data structures into models from a JSON Schema but none that have the ability to reduce stuff from a data structure. Here's an example:

Sample JSON Schema (schema.json)

    "type": "object", 
    "$schema": "http://json-schema.org/draft-04/schema#", 
    "title": "Sample JSON Schema", 
    "required": [
    "properties": {
        "name": {
            "type": "string"
        "sex": {
            "type": "string"
        "title": {
            "type": "string"

Sample data structure (sample.json)

    "name": "Peter",
    "sex": "male",
    "email": "peterbe@example.com",


>>> from json_schema_reducer import make_reduced_dict
>>> make_reduced_dict('schema.json', 'sample.json')
{'name': 'Peter', 'sex': 'male'}  # Note! No "email" key

The project works in Python 2 and Python 3. See tests.

Also, the function tries to be convenient in that it can accept either a dict, a JSON string or path to a .json file.


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