How to serialize SqlAlchemy result to JSON?

How to Serialize SqlAlchemy Result to JSON? 🐍💾🔃

If you've ever worked with SqlAlchemy, you might have found yourself in a situation where you need to serialize the query result into JSON format. Unfortunately, SqlAlchemy doesn't provide a built-in JSON serializer for its ORM objects. But fret not! In this blog post, we will explore some easy solutions to tackle this problem. Let's dive right in! 💪🏼

The Challenge 🤔

When attempting to serialize a SqlAlchemy query result using well-known methods like jsonpickle.encode or json.dumps, you may encounter the dreaded TypeError: <Product('3', 'some name', 'some desc')> is not JSON serializable error. This occurs because these methods struggle to serialize the actual SqlAlchemy ORM objects directly into JSON. 😱

Solution 1: Custom Serializer 🧪

One way to overcome this challenge is by implementing a custom serializer. Let's take a look at an example:

def serialize(obj):
    if isinstance(obj.__class__, DeclarativeMeta):
        # Handle SqlAlchemy ORM objects
        return obj.__dict__

    # Handle other non-serializable types if needed
    return None

The serialize function above detects if the object is an ORM object and returns its __dict__, which represents the object's attributes in a dictionary format. You can then use this function while serializing the query result using json.dumps:

import json

# Assuming 'items' is the result of a SqlAlchemy query
serialized_items = json.dumps(items, default=serialize)

Using this approach, you can now successfully serialize the query result to JSON!

Solution 2: Custom Mixin 🍳

Another approach is to utilize a custom mixin class that extends the functionality of SqlAlchemy's base model. Here's an example:

class JsonSerializableMixin(object):
    def to_json(self):
        return {column.name: getattr(self, column.name) for column in self.__table__.columns}

The to_json method above creates a dictionary mapping the column names to their corresponding values in the ORM object. You can then call this method on your ORM object to get the JSON representation:

# Assuming 'item' is a single ORM object
json_item = item.to_json()

This way, you can convert individual objects to JSON easily.

Bring on the JSON! 🚀

With these solutions in your arsenal, you can effortlessly serialize your SqlAlchemy query results into JSON format. Whether you opt for a custom serializer or a mixin class, the choice ultimately depends on your project requirements.

So go ahead, serialize those objects like a pro and unleash the power of JSON in your data-driven applications! 🎉

If you have any other tips, tricks, or alternative methods for serializing SqlAlchemy results to JSON, please share them in the comments below. Let's keep the conversation going! 💬✨