flask blueprint one blueprint inside another

Creating a Flask API Project with Multiple Blueprints

This post is part one of a three-part series that will walk you through setting up a Flask API project, adding a React frontend to the project, and then adding some data visualization to the React frontend.

In this first part, we'll focus on creating a Flask API project with multiple blueprints. A blueprint in Flask is a way to organize your application into smaller, reusable components. We'll explore how to create a single blueprint and then nest another blueprint inside it.

What are Blueprints?

Before diving into the code, let's briefly discuss what blueprints are and why we need them. A blueprint is essentially a module that defines a set of URLs and views for your Flask application. In other words, a blueprint is responsible for handling HTTP requests and responses.

Flask provides an `APIBlueprint` class that makes it easy to create blueprints with additional web API support. The `APIBlueprint` class inherits from the standard Flask `Blueprint` class, so you can use all of its features, such as routing and URL building.

Creating a Single Blueprint

Let's start by creating a single blueprint for our Flask API project. Here's an example:

```

from apiflask import APIBlueprint

bp = APIBlueprint('foo', __name__, tag='Foo')

```

In this example, we're creating a blueprint named 'foo' and specifying its package name as the current module (`__name__`). We're also setting the tag for our blueprint to 'Foo'.

Nesting Blueprints

Now that we have a single blueprint created, let's see how we can nest another blueprint inside it. To do this, we'll create a new blueprint and pass our existing blueprint as the parent:

```

from apiflask import APIBlueprint

parent_bp = APIBlueprint('foo', __name__, tag='Foo')

child_bp = APIBlueprint('bar', parent_bp, tag='Bar')

```

In this example, we're creating a child blueprint named 'bar' and specifying its parent as the 'foo' blueprint. We're also setting the tag for our child blueprint to 'Bar'.

By nesting blueprints, we can create a hierarchical structure for our application that makes it easier to organize and reuse code.

In this first part of the series, we've covered how to create a Flask API project with multiple blueprints. We've seen how to create a single blueprint and nest another blueprint inside it. In the next part of the series, we'll explore how to add a React frontend to our Flask API project.

Flask blueprint one blueprint inside another