jsonargon 0.1.1

Serialization and deserialization of JSON objects from/into Python objects (with validation and remapping capabilities)

JSON Argon

https://gitlab.com/federico_pugliese/jsonargon

Serialization and deserialization of JSON objects from/into Python objects (with validation and remapping capabilities).

The underlying idea is to annotate a Python Class with metadata useful to serialize its objects into JSON strings and viceversa.

Main features and goals are:

• Concision
• JSON Validation
• Optional remapping of fields name
• Familiar interface

Installation

To get the latest stable version, just run

pip install jsonargon

or

pip install jsonargon==<version>

if you require a specific version.

Usage

Basic Usage

The basic requirement is to write the Python Class remapping your JSON.

from jsonargon.decorators import jsonclass
from jsonargon.fields.simple import Required, Nullable

@jsonclass
class Person:
    
    name: Required(str)
    age:  Nullable(int)
    

As simple as that. The name field is a required string, while the age is a non-required integer.

The Required type annotation will make sure that name is in your JSON string before deserializing it (a KeyError is thrown otherwise).

If you have your JSON string, you can easily remap it into a Python object of that class, after you get your JSON string somehow (probably something like {"name": "Jason Argonaut"}):

person = Person.from_json(your_json_string)

print(person.name)  # Jason Argonaut
print(person.age)   # None

You can also serialize your object into a JSON string.

person_json_string = person.to_json()

Advanced usage

JSON Argon also supports:

• Nested objects
• Lists and Dictionaries
• JSON-Python names remapping

Fields

Each field annotation support these parameters:

<field>(type: Any, json_name: str = None)

• type is a simple type like str, int, float or a Class
• json_name is an optional string representing the corresponding name in JSON

Field	Meaning	JSON
Required	A required, simple attribute	"name": "Jason"
Nullable	A nullable (None) simple attribute	As above, or "name": null or no attribute at all
RequiredList	A required (but maybe empty) list of objects of the specified type	"names": ["Argo", "Atalanta"], or "names": [] or "crew": [{"name": "Argo"}, {"name": "Atalanta"}]
NullableList	A nullable list of objects of the specified type	As above, or "names": null or no attribute at all
RequiredStringDict	A required (but maybe empty) dict of string -> objects of the specified type	"tags": {"scope": "dev"}, or "tags": {} or "documents": {"name": {"length":12}}
NullableStringDict	A required (but maybe empty) list of objects of the specified type	As above, or "tags": null or no attribute at all

You can find a complete example here (with the JSON below):

from jsonargon.decorators import jsonclass
from jsonargon.fields.simple import Required, Nullable
from jsonargon.fields.dict import RequiredStringDict
from jsonargon.fields.list import RequiredList

@jsonclass
class Size:
    
    length: Required(float)
    width:  Required(float)
    height: Nullable(float, "heigth")  # Correct a JSON typo


@jsonclass
class Member:

    name: Required(str)
    role: Nullable(str)
    

@jsonclass
class Ship:
    
    name: Required(str, "shipName")
    size: Required(Size)
    crew: RequiredList(Member, "members")
    attributes: RequiredStringDict(str)

To remap:

{
    "shipName": "Argo",
    "size": {
        "width": 45.4,
        "length": 34.2
    },
    "members": [
        {
            "name": "Atalanta"
        },
        {   
            "name": "Jason",
            "role": "leader"
        }
    ]
    "attributes": {
        "rarity": "mythological",
        "status": "destroyed"
    }
}

Origin of the name

There are several reasons behind the name of this library.

First of all, in Greek mythology, Jason was the leader of Argonauts.

Jason is quite similar to JSON pronunciation. He was the hero who defeated the monstrous dragon (often depicted as a giant snake - a clear reference to Python) that guarded the Golden Fleece.

Also, his ship was Argo, and the Argonauts his crew.

Argon, instead, is a noble gas. And with the same Class and style of a noble, this library aims to make you write a much cleaner code when dealing with JSON.

Make Jason proud of your code and join his crew of Argonauts.