Flask-API

3.1 · deprecated · verified Thu Apr 16

Flask-API provides tools for building browsable web APIs on top of Flask, offering features like content negotiation and a custom renderer system. While it reached version 3.1, it is now largely unmaintained. Developers starting new projects are strongly advised to use more actively maintained alternatives like Flask-RESTX or Flask-Smorest.

Common errors

```
ModuleNotFoundError: No module named 'flask_api'
```
cause The `flask-api` package has not been installed in your Python environment.

fix Run `pip install flask-api` to install the library.
```
AttributeError: 'FlaskAPI' object has no attribute 'json_encoder'
```
cause This error often occurs when running `flask-api` with newer versions of Flask (e.g., Flask 2.x+), which have changed internal attributes like `json_encoder`. `flask-api` has not been updated to reflect these changes.

fix Upgrade to an actively maintained Flask API framework like Flask-RESTX or Flask-Smorest, or downgrade your Flask version to one compatible with `flask-api` (e.g., Flask 1.x).
```
ValueError: View function did not return a response tuple (response, status_code, headers)
```
cause While Flask-API aims for simplified returns, mixing standard Flask view return types (e.g., a simple string or an `int`) with Flask-API's expected dictionary/object returns can lead to this error if the rendering pipeline isn't correctly configured or a custom renderer isn't handling the type.

fix Ensure your view functions return dictionaries, `flask.Response` objects, or a tuple compatible with Flask-API's rendering system. For example, `return {'status': 'ok'}` is preferred over `return 'ok'` directly if not using a custom renderer for strings.

Warnings

breaking The `flask-api` library is unmaintained and will not receive updates for new Flask versions or critical security patches. Using it in new projects or with modern Flask versions (2.x+) is highly discouraged.
Fix: Migrate to actively maintained alternatives such as Flask-RESTX (a fork of Flask-RESTful), Flask-Smorest, or simply use plain Flask for API development.
gotcha Flask-API's content negotiation and renderer system might conflict with or behave unexpectedly when combined with modern Flask features or other API extensions. Its approach to response rendering can be less flexible than newer solutions.
Fix: If you must use Flask-API, thoroughly test response types and content negotiation. For better control and flexibility, consider alternatives that offer clearer separation of concerns for rendering.
deprecated The project is explicitly marked as unmaintained by its original developers, with the recommendation to use other libraries for new development. Expect no new features, bug fixes, or compatibility updates.
Fix: Avoid using `flask-api` for new development. For existing projects, consider a migration strategy to a supported library.

Install

pip install flask-api Install Flask-API

Imports

FlaskAPI
```
from flask_api import FlaskAPI
```

APIException

from flask_api.exceptions import APIException

status
```
from flask_api import status
```

Quickstart

A basic Flask-API application demonstrating content negotiation and custom error handling using APIException. When run, it provides a browsable API for the root path and a specific item lookup.

from flask_api import FlaskAPI
from flask_api.exceptions import APIException
from flask_api import status

app = FlaskAPI(__name__)

@app.route('/')
def hello_world():
    return {"message": "Hello, World!"}

@app.route('/items/<int:item_id>/')
def get_item(item_id):
    items = {
        1: {'name': 'Apple', 'price': 1.00},
        2: {'name': 'Banana', 'price': 0.50}
    }
    try:
        return items[item_id]
    except KeyError:
        raise APIException('Item not found', status_code=status.HTTP_404_NOT_FOUND)

if __name__ == '__main__':
    app.run(debug=True)

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