Python Serialization and Deserialization in Flask SQLAlchemy

Serialization: Serialization is the process of converting complex data structures or objects into a specific format (like Json or xml like http) that will be used for store or save state of objects and it helps to send data over a network and facilitate communication between client and server in a web application. In python, commonly used libraries for serialization are Json, Marshmallow, etc.…

In python, web framework like Flask Restful Api with SQLAlchemy serialization is process of converting python objects (like model instance) into a specific format like (Json) which can be easily sent over internet. When client makes a request to API, the response is often serialized before it will send back to client.

In order to serialize data in Flask RESTful API first we need to

• Defining models in SQLAlchemy: First we should define data models which is a structure of database tables by using SQLAlchemy. Example, I am making a Book app here I use User and Book models.

• Creating Schemas: Next, create serialization schemas. These schemas define our data to be converted to and from Json like format which helps in serializing and deserializing data for our models.

here the to_dict method is used for serialization. It converts the schema object back into a dictionary. and from_dict method is used for deserialization. It takes a dictionary as input and creates an instance of the schema.

• Using Schema in Flask: Next in flask routes we use schema to serialize data before sending it as response. We use schema for handling request (i.e.) when we fetch data from database using SQLAlchemy we use this schema to convert into Json like format.

• Deserialization: If API allows client to send data using POST request to create or update resources, we use this schema to deserialize data back into python object
• Returning response to client: At last, when sending data back to client, Flask will convert python dictionary into appropriate format based on ‘Content-Type’ of request.

Summary: Serialization is used for converting complex data into format suitable for storage that can be transmit data over internet which used for communication between client making request and response is done serialize format from server.

Importance: The are importance of serialization in modern programming is Flexibility by allowing schemas to adapt changes in data structure, Data Consistency which ensures data stored in consistent and standardized format, Data Validation by ensuring data meets expected format, Security, Communication between networks, Code maintainability and code organization ability.

Conclusion: Thus serialization allows us to work with standard JSON files. JSON is a widely used format for data exchange and it is very convenient. human-readable and language-independent, and it’s lighter than XML. Using the JSON module we can serialize and deserialize several standard Python types like bool, dict, int, float, list, string, tuple, none etc. The JSON module and XML are a good choice if we want to interoperability among different languages.