GraphQL_example_python.py

from flask import Flask, request
from graphene import ObjectType, String, Schema, List, Field




'''
Pre-requesities: python3 -m pip install graphene flask

USAGE: open Postman and create new QraphQL request then paste this url: http://localhost:5000/graphql and these Queries ... 

- to get all the books:
query {
    books {
        title
        author
    }
}

- to get one book by id:
query {
    bookById (id: "123") {
        title
        author
    }
}

- to get all the products:
query {
    products{
        title
        author
    }
}
'''
app = Flask(__name__)

# Define a DTO
class Item(ObjectType):
    title = String()
    author = String()

# Define a query class
class Query(ObjectType):
    products = List(Item)
    books = List(Item)
    bookById = Field(Item, id=String())


    
    def resolve_products(self, info):
        # Return a list of products
        return [
            Item(title="product 1", author="Author 1"),
            Item(title="product 2", author="Author 2"),
            Item(title="product 3", author="Author 3")
        ]
        
    def resolve_books(self, info):
        # Return a list of books
        return [
            Item(title="Book 1", author="Author 1"),
            Item(title="Book 2", author="Author 2"),
            Item(title="Book 3", author="Author 3")
        ]
        
    def resolve_bookById(self, info, id):
        return Item(title=f"Book {id}", author=f"Author {id}")


# Create a schema
schema = Schema(query=Query)

# Define the GraphQL endpoint
@app.route("/graphql", methods=["POST"])
def graphql():
    # Get the GraphQL query from the request body
    query = request.get_json()["query"]

    # Execute the query
    result = schema.execute(query)

    # Return the query result
    return {"data": result.data}

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