Random and Popular Recipes

Introduction: Enhancing User Experience with Dynamic Recipes

Welcome back! So far, you’ve learned how to build API endpoints that let users retrieve recipes, search by ingredients, and view recipe steps. These features are essential for any recipe app, but sometimes users want a little more excitement or guidance. For example, what if someone can’t decide what to cook and wants a random suggestion? Or maybe they want to see the most popular recipes based on ratings from other users. In this lesson, you’ll learn how to add two new features to your cooking helper API: An endpoint that returns a random recipe An endpoint that returns the most popular recipes based on user ratings These features make your app more interactive and helpful, giving users new ways to discover recipes.

Quick Recall: Retrieving and Filtering Recipes

Before we dive in, let’s quickly remind ourselves how we’ve been working with recipes so far. Previously, you built endpoints to: List all recipes with pagination (so users don’t get overwhelmed by too many results at once) Retrieve a single recipe by its ID Search for recipes by ingredients All of these endpoints use Flask for routing and SQLAlchemy to interact with the database. You’ve also learned how to format JSON responses so that the data is easy to use in any app. Now, let’s build on these skills to add dynamic selection features.

Building the Random Recipe Endpoint

Let’s start by creating an endpoint that returns a random recipe. This is useful for users who want to try something new or can’t decide what to cook.

Step 1: Setting Up the Route

First, we need to define a new route in our Flask app. We’ll use the @routes.route decorator to create a GET endpoint at /api/recipes/random . Python @routes.route('/api/recipes/random', methods=['GET']) def get_random_recipe(): # Implementation will go here This sets up the endpoint, but it doesn’t do anything yet.

Step 2: Selecting a Random Recipe

To select a random recipe from the database, we use SQLAlchemy ’s order_by(func.random()) method. This tells the database to shuffle the recipes and pick the first one. Python recipe = Recipe.query.order_by(func.random()).first() Recipe.query starts a query for all recipes. .order_by(func.random()) shuffles the order randomly. .first() picks the first recipe from the shuffled list. If there are no recipes in the database, recipe will be None .

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Python

if not recipe:
    return jsonify({'error': 'No recipes found'}), 404

return jsonify({
    'id': recipe.id,
    'name': recipe.name,
    'ingredients': [i.name for i in recipe.ingredients],
    'steps': recipe.steps
}), 200

Python

@routes.route('/api/recipes/random', methods=['GET'])
def get_random_recipe():
    recipe = Recipe.query.order_by(func.random()).first()

    if not recipe:
        return jsonify({'error': 'No recipes found'}), 404

    return jsonify({
        'id': recipe.id,
        'name': recipe.name,
        'ingredients': [i.name for i in recipe.ingredients],
        'steps': recipe.steps
    }), 200

JSON

{
  "id": 3,
  "name": "Spaghetti Carbonara",
  "ingredients": ["spaghetti", "eggs", "bacon", "parmesan"],
  "steps": "Boil pasta\nCook bacon\nMix eggs and cheese\nCombine all"
}

Python

@routes.route('/api/recipes/popular', methods=['GET'])
def get_popular_recipes():
    # Implementation will go here

Python

subquery = (
    db.session.query(
        Review.recipe_id,
        func.avg(Review.rating).label('avg_rating')
    )
    .group_by(Review.recipe_id)
    .subquery()
)

Python

recipes = (
    db.session.query(Recipe, subquery.c.avg_rating)
    .join(subquery, Recipe.id == subquery.c.recipe_id)
    .order_by(subquery.c.avg_rating.desc())
    .limit(10)
    .all()
)

Python

result = [{
    'id': recipe.id,
    'name': recipe.name,
    'ingredients': [i.name for i in recipe.ingredients],
    'steps': recipe.steps,
    'average_rating': round(avg_rating, 2)
} for recipe, avg_rating in recipes]

return jsonify(result), 200

Python

@routes.route('/api/recipes/popular', methods=['GET'])
def get_popular_recipes():
    subquery = (
        db.session.query(
            Review.recipe_id,
            func.avg(Review.rating).label('avg_rating')
        )
        .group_by(Review.recipe_id)
        .subquery()
    )

    recipes = (
        db.session.query(Recipe, subquery.c.avg_rating)
        .join(subquery, Recipe.id == subquery.c.recipe_id)
        .order_by(subquery.c.avg_rating.desc())
        .limit(10)
        .all()
    )

    result = [{
        'id': recipe.id,
        'name': recipe.name,
        'ingredients': [i.name for i in recipe.ingredients],
        'steps': recipe.steps,
        'average_rating': round(avg_rating, 2)
    } for recipe, avg_rating in recipes]

    return jsonify(result), 200

JSON

[
  {
    "id": 2,
    "name": "Chicken Alfredo",
    "ingredients": ["chicken", "pasta", "cream", "parmesan"],
    "steps": "Cook chicken\nBoil pasta\nMake sauce\nCombine all",
    "average_rating": 4.75
  },
  {
    "id": 5,
    "name": "Vegetable Stir Fry",
    "ingredients": ["broccoli", "carrots", "soy sauce", "rice"],
    "steps": "Chop veggies\nStir fry\nAdd sauce\nServe with rice",
    "average_rating": 4.5
  }
]

Introduction: Enhancing User Experience with Dynamic Recipes

Quick Recall: Retrieving and Filtering Recipes

Building the Random Recipe Endpoint

Step 1: Setting Up the Route

Step 2: Selecting a Random Recipe

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Step 3: Returning the Recipe as JSON

Full Example

Building the Popular Recipes Endpoint

Step 1: Setting Up the Route

Step 2: Calculating Average Ratings

Step 3: Joining Recipes with Ratings and Sorting

Step 4: Formatting the Output

Full Example

Summary and What’s Next