![FastAPI Tutorial](/fastapi/images/fastapi-mini-logo.jpg)
- FastAPI Tutorial
- FastAPI - Home
- FastAPI - Introduction
- FastAPI - Hello World
- FastAPI - OpenAPI
- FastAPI - Uvicorn
- FastAPI - Type Hints
- FastAPI - IDE Support
- FastAPI - Rest Architecture
- FastAPI - Path Parameters
- FastAPI - Query Parameters
- FastAPI - Parameter Validation
- FastAPI - Pydantic
- FastAPI - Request Body
- FastAPI - Templates
- FastAPI - Static Files
- FastAPI - HTML Form Templates
- FastAPI - Accessing Form Data
- FastAPI - Uploading Files
- FastAPI - Cookie Parameters
- FastAPI - Header Parameters
- FastAPI - Response Model
- FastAPI - Nested Models
- FastAPI - Dependencies
- FastAPI - CORS
- FastAPI - Crud Operations
- FastAPI - SQL Databases
- FastAPI - Using MongoDB
- FastAPI - Using GraphQL
- FastAPI - Websockets
- FastAPI - FastAPI Event Handlers
- FastAPI - Mounting A Sub-App
- FastAPI - Middleware
- FastAPI - Mounting Flast App
- FastAPI - Deployment
- FastAPI Useful Resources
- FastAPI - Quick Guide
- FastAPI - Useful Resources
- FastAPI - Discussion
FastAPI - Header Parameters
In order to read the values of an HTTP header that is a part of the client request, import the Header object from the FastAPI library, and declare a parameter of Header type in the operation function definition. The name of the parameter should match with the HTTP header converted in camel_case.
In the following example, the "accept-language" header is to be retrieved. Since Python doesn’t allow "-" (dash) in the name of identifier, it is replaced by "_" (underscore)
from typing import Optional from fastapi import FastAPI, Header app = FastAPI() @app.get("/headers/") async def read_header(accept_language: Optional[str] = Header(None)): return {"Accept-Language": accept_language}
As the following Swagger documentation shows, the retrieved header is shown as the response body.
![FastAPI Header Parameters](/fastapi/images/header1.jpg)
You can push custom as well as predefined headers in the response object. The operation function should have a parameter of Response type. In order to set a custom header, its name should be prefixed with "X". In the following case, a custom header called "X-Web-Framework" and a predefined header “Content-Language" is added along with the response of the operation function.
from fastapi import FastAPI from fastapi.responses import JSONResponse app = FastAPI() @app.get("/rspheader/") def set_rsp_headers(): content = {"message": "Hello World"} headers = {"X-Web-Framework": "FastAPI", "Content-Language": "en-US"} return JSONResponse(content=content, headers=headers)
The newly added headers will appear in the response header section of the documentation.
![FastAPI Header Parameters](/fastapi/images/header2.jpg)
To Continue Learning Please Login