Use Protobuf With Fastapi

Protocol buffers, also known as Protobuf, are a popular data serialization format used for communication between services. They are efficient, easy to use, and language-agnostic. In this article, we will look at how to use Protobuf with FastAPI, a modern, high-performance web framework for building APIs with Python.

First, let’s start by installing the necessary dependencies. You will need to install fastapi, google-protobuf, and grpcio. You can do this by running the following command:

pip install fastapi google-protobuf grpcio

Next, you will need to define your Protobuf message. You can do this by creating a .proto file and defining your message using the Protobuf syntax. For example:

syntax = "proto3";

message User {
  string name = 1;
  int32 age = 2;
  string email = 3;
}

Once you have defined your message, you will need to compile it using the protoc compiler. This will generate Python code that you can use to encode and decode your message. You can do this by running the following command:

protoc -I=. --python_out=. path/to/your_message.proto

Now that you have compiled your message, you can use it in your FastAPI application. First, you will need to create a FastAPI application and define an endpoint that accepts a Protobuf message. You can do this by using the Body and PROTOBUF parameters from FastAPI’s pydantic module:

from fastapi import FastAPI
from pydantic import BaseModel, PROTOBUF
from path.to.your_message_pb2 import User  # import the generated Protobuf message

app = FastAPI()

class UserRequest(BaseModel):
    user: PROTOBUF(User)

@app.post("/users")
def create_user(request: UserRequest):
    user = request.user
    # do something with the user object
    return {"message": "success"}

Now, when you send a POST request to the /users endpoint with a Protobuf-encoded message as the request body, FastAPI will automatically decode it and pass the resulting User object to the endpoint handler.

The PROTOBUF parameter is used to specify that the request body is encoded using Protobuf. The User class is the compiled Protobuf message that you generated earlier using the protoc compiler.

Protobuf is a powerful and efficient tool for communication between services, and FastAPI makes it easy to use in your Python applications. With just a few lines of code, you can add Protobuf support to your FastAPI application and start using it to efficiently transfer data between services.