Overview
FastrAPI provides decorators for all standard HTTP methods. Each decorator registers a route handler for the specified path and HTTP method.
from fastrapi import FastrAPI
app = FastrAPI()
@app.get("/users")
def get_users():
return [{"id": 1, "name": "Alice"}]
@app.post("/users")
def create_user(data):
return {"id": 2, "name": data["name"]}
HTTP method decorators
@app.get()
Define a GET endpoint for retrieving data.
@app.get("/")
def home():
return {"message": "Hello World"}
@app.get("/items/{item_id}")
def get_item(item_id: int):
return {"item_id": item_id, "name": "Item name"}
Parameters
The URL path for the endpoint. Supports path parameters with {param_name} syntax
Returns
A decorator function that registers the route handler
@app.post()
Define a POST endpoint for creating resources or submitting data.
from pydantic import BaseModel
class User(BaseModel):
name: str
email: str
@app.post("/users")
def create_user(user: User):
return {
"id": 123,
"name": user.name,
"email": user.email
}
Parameters
The URL path for the endpoint
Returns
A decorator function that registers the route handler
@app.put()
Define a PUT endpoint for updating existing resources.
@app.put("/users/{user_id}")
def update_user(user_id: int, data):
return {
"id": user_id,
"name": data["name"],
"updated": True
}
Parameters
The URL path for the endpoint. Typically includes an ID parameter
Returns
A decorator function that registers the route handler
@app.delete()
Define a DELETE endpoint for removing resources.
@app.delete("/users/{user_id}")
def delete_user(user_id: int):
return {
"message": f"User {user_id} deleted",
"success": True
}
Parameters
The URL path for the endpoint. Typically includes an ID parameter
Returns
A decorator function that registers the route handler
@app.patch()
Define a PATCH endpoint for partial updates to resources.
@app.patch("/users/{user_id}")
def patch_user(user_id: int, data):
return {
"id": user_id,
"updated_fields": list(data.keys())
}
Parameters
The URL path for the endpoint
Returns
A decorator function that registers the route handler
@app.websocket()
Define a WebSocket endpoint for bidirectional communication.
@app.websocket("/ws")
async def websocket_endpoint(websocket):
await websocket.accept()
while True:
data = await websocket.receive_text()
await websocket.send_text(f"Echo: {data}")
Parameters
The URL path for the WebSocket endpoint. Must start with /
Returns
A decorator function that registers the WebSocket handler
Path parameters
All route decorators support path parameters using the {param_name} syntax.
@app.get("/users/{user_id}")
def get_user(user_id: int):
return {"user_id": user_id}
@app.get("/posts/{post_id}/comments/{comment_id}")
def get_comment(post_id: int, comment_id: int):
return {
"post_id": post_id,
"comment_id": comment_id
}
Query parameters
Query parameters are automatically extracted from the URL.
@app.get("/search")
def search(q: str, limit: int = 10):
return {
"query": q,
"limit": limit,
"results": []
}
# GET /search?q=python&limit=5
Request body
For POST, PUT, PATCH, and DELETE methods, the request body is automatically parsed and passed to your handler.
from pydantic import BaseModel
class Item(BaseModel):
name: str
price: float
description: str = None
@app.post("/items")
def create_item(item: Item):
return {
"name": item.name,
"price": item.price,
"description": item.description
}
Complete example
from fastrapi import FastrAPI
from pydantic import BaseModel
app = FastrAPI()
class User(BaseModel):
name: str
email: str
age: int
@app.get("/")
def root():
return {"message": "Welcome to the API"}
@app.get("/users")
def list_users():
return [{"id": 1, "name": "Alice"}, {"id": 2, "name": "Bob"}]
@app.get("/users/{user_id}")
def get_user(user_id: int):
return {"id": user_id, "name": "Alice"}
@app.post("/users")
def create_user(user: User):
return {
"id": 3,
"name": user.name,
"email": user.email,
"age": user.age
}
@app.put("/users/{user_id}")
def update_user(user_id: int, user: User):
return {
"id": user_id,
"name": user.name,
"email": user.email,
"age": user.age,
"updated": True
}
@app.delete("/users/{user_id}")
def delete_user(user_id: int):
return {"message": f"User {user_id} deleted"}
@app.patch("/users/{user_id}")
def patch_user(user_id: int, data):
return {"id": user_id, "updated_fields": list(data.keys())}
if __name__ == "__main__":
app.serve("127.0.0.1", 8080)