Python graphql(FastAPI)

Python graphql(FastAPI)

GraphQL with Python and FastAPI: A Comprehensive Guide

In this article, we'll dive into the world of GraphQL and explore how to use it with Python and FastAPI, a modern web framework.

What is GraphQL?

GraphQL (Graph Query Language) is a query language for APIs. It allows clients to specify exactly what data they need from an API, which reduces network overhead and improves performance. GraphQL was created by Facebook and has since become popular among developers.

How does GraphQL work?

When a client sends a request to a GraphQL API, it includes a JSON payload that defines the query. The API then processes the query and returns the requested data in a JSON response.

GraphQL APIs typically have three types of queries:

Setting up GraphQL with Python and FastAPI

To get started, you'll need to install the necessary libraries:

Here's an example of how to set up a basic GraphQL API using FastAPI:

from fastapi import FastAPI
from pydantic import BaseModel
import graphene
app = FastAPI()
class Book(BaseModel):
title: str
author: str
class Books(graphene.ObjectType):
items = graphene.List(Book)
class Query(graphene.ObjectType):
books = graphene.List(Books)
class Mutation(graphene.Mutation.Object):
def init(self, book_title: str, book_author: str):
self.book = Book(title=book_title, author=book_author)
class CreateBook(Mutation):
class Arguments:
title = graphene.String(required=True)
author = graphene.String(required=True)
@classmethod
def mutate(cls, root, info, **kwargs):
return CreateBook(**kwargs)
app.add_route("/graphql", GraphQLView(schema=QueryType))

This code sets up a basic GraphQL API with three types of queries: books, book, and createBook. The books query returns a list of books, the book query retrieves a single book by ID, and the createBook mutation creates a new book.

Using GraphQL in your application

To use GraphQL in your application, you'll need to create a GraphQL schema that defines the types and fields available in your API. You can then use this schema to generate a GraphQL client library that allows you to query your API.

Here's an example of how to use GraphQL in a FastAPI application:

from fastapi import FastAPI
import graphene
app = FastAPI()
class Book(graphene.ObjectType):
title: str
author: str
class Books(graphene.ObjectType):
items = graphene.List(Book)
schema = graphene.Schema(query=Query, mutation=Mutation)
@app.get("/graphql")
async def graphql(request: Request):
query = request.query_params.get("query", None)
return await schema.execute(query)

This code sets up a GraphQL API that allows clients to send GraphQL queries and mutations to your application. The graphql route receives a GraphQL query as a GET parameter and executes it using the schema.execute() method.

Conclusion

In this article, we've explored the basics of GraphQL and how to use it with Python and FastAPI. We've set up a basic GraphQL API that allows clients to query and mutate data, and we've discussed how to use GraphQL in your application. With this knowledge, you're ready to start building powerful and scalable APIs using GraphQL!

Python GraphQL client

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