WTForms-JSON

0.3.5 · abandoned · verified Tue Apr 14

WTForms-JSON extends WTForms to provide convenient serialization and deserialization of form data to and from JSON, particularly useful for RESTful APIs. It allows forms to be populated directly from JSON payloads and validates them as usual. The latest version is 0.3.5, released in 2017. The project appears to be unmaintained.

Warnings

breaking WTForms-JSON has not been updated since 2017 and was last tested with WTForms 2.1. It is highly likely to have compatibility issues with modern WTForms 3.x+ and newer Python versions (3.8+).
Fix: For new projects, consider modern alternatives or manually handle JSON serialization/deserialization. If migrating, thoroughly test with your specific WTForms and Python versions.
gotcha The project is unmaintained. No new features, bug fixes, or security patches are expected. Relying on this library for new development is not recommended.
Fix: Evaluate actively maintained alternatives for JSON handling with WTForms or implement custom solutions.
gotcha To enable JSON processing for all WTForms forms, `wtforms_json.init_app()` must be called once at the start of your application. Failing to do so will mean forms do not gain the `.from_json()` method.
Fix: Ensure `init_app()` is called early in your application's lifecycle, typically during setup or configuration.
gotcha Error messages and validation behavior for JSON input might be less configurable or user-friendly compared to contemporary libraries or custom implementations.
Fix: Be prepared to implement custom error formatting or validation logic around WTForms-JSON if specific error structures are required for your API.

Install

pip install wtforms-json Install stable version

Imports

init_app
```
from wtforms_json import init_app
```
Call this once to enable JSON handling for WTForms.

Quickstart

Demonstrates initializing wtforms-json and populating a form with JSON data, followed by validation. It shows handling both valid and invalid JSON inputs.

from wtforms import Form, StringField, IntegerField
from wtforms.validators import DataRequired, NumberRange
from wtforms_json import init_app

# Initialize wtforms-json to extend WTForms functionality
init_app()

class UserProfileForm(Form):
    name = StringField('Name', validators=[DataRequired()])
    age = IntegerField('Age', validators=[NumberRange(min=0, max=120)])

# Example JSON data (e.g., from a request body)
valid_json_data = {'name': 'Jane Doe', 'age': 25}
invalid_json_data = {'name': '', 'age': 150} # Name missing, age out of range

print("--- Processing valid data ---")
form_valid = UserProfileForm()
form_valid.from_json(valid_json_data) # Populate form from JSON

if form_valid.validate():
    print(f"Form is valid. Data: {form_valid.data}")
else:
    print(f"Form errors: {form_valid.errors}")

print("\n--- Processing invalid data ---")
form_invalid = UserProfileForm()
form_invalid.from_json(invalid_json_data)

if form_invalid.validate():
    print(f"Form is valid. Data: {form_invalid.data}")
else:
    print(f"Form errors: {form_invalid.errors}")

view raw JSON →