StreamJSON

Write objects or arrays to a JSON file using a stream. Useful for when you don't want to read large amounts of data in memory, for example when you need to save large amounts of data from a database to a single JSON file.

Read objects from a JSON file using a stream. Does not require loading the whole JSON file in memory.

Install

pip install streamjson

How to write to JSON file

Fetch data from a database or anywhere else and send to a JSON file. The send function takes in a dictionary or a list. A new file with the given name will be created, the root of the JSON file is an array by default.

from streamjson import StreamJSONWriter

persons = [{'id': '0001', 'first_name': 'John', 'last_name': 'Doe'},
           {'id': '0002', 'first_name': 'Jane', 'last_name': 'Doe'}]

with StreamJSONWriter('persons.json', indent=2) as writer:
    for person in persons:
        writer.send(person)

persons.json:

[
  {
    "id": "0001",
    "first_name": "John",
    "last_name": "Doe"
  },
  {
    "id": "0002",
    "first_name": "Jane",
    "last_name": "Doe"
  }
]

How to read from JSON file

The reader will stream each object from the JSON file.

from streamjson import StreamJSONReader

with StreamJSONReader('persons.json') as reader:
    for obj in reader.find():
        print(obj)