POST Query Parameters in FastAPI
Last Updated :
08 Dec, 2023
FastAPI is a powerful and efficient Python web framework for building APIs with ease. For most of the applications getting data from a user is done through a POST request and this is a common task for developers is consume query parameters from POST requests. In this article, we’ll explore the concepts behind this process and provide practical examples to illustrate how it’s done.
Query Parameters in FastAPI
Below are the key concepts related to this:
- POST Requests: Post requests are mainly used for sending data to the server. Before delving into consuming query parameters, it’s essential to grasp the basics of POST requests. In FastAPI, POST requests are commonly used for submitting data to the server.
- Query Parameters in POST Requests: In traditional GET requests query parameters are part of the URL, but in a POST request, query parameters are typically sent in the request body. FastAPI simplifies this process, allowing developers to access these parameters effortlessly. In FastAPI, there is a request object in every endpoint that has info about all query parameters sent by the user, so we can use that request object and extract info from that object.
- FastAPI’s Request Object: In FastAPI there is a Request object that encapsulates the incoming HTTP request. This object includes all the necessary information about the request, making it easy to extract query parameters. we can extract all info from this request object and use them in our application as needed.
Consume Query Parameters from POST in FastAPI
In this example, we created a FastAPI app, and defined “/submit_data” as an API endpoint that accepts a POST request from a user and simply returns the username and age parameter of this POST request to the user as a response.
app.py: Here we can note that we had accessed the POST request parameter named “username” and “age“. In the below code, we can see that in FastAPI there is a request object which contains info about the POST request, we can acceess that object and get required from POST request. Below is the code example which done what we mentioned above with proper comments to understand.
Python3
from fastapi import FastAPI, HTTPException, Request
app = FastAPI()
@app.post("/submit_data")
async def submit_data(request: Request):
try:
data = await request.json()
if "username" not in data or "age" not in data:
raise HTTPException(
status_code=422, detail="Incomplete data provided")
username = data["username"]
age = data["age"]
return {"message": "User data submitted successfully!",
"user_data": {"username": username, "age": age}}
except HTTPException as e:
raise e
except Exception as e:
raise HTTPException(
status_code=500, detail=f"An error occurred: {str(e)}")
if __name__ == "__main__":
import uvicorn
uvicorn.run(app, host="127.0.0.1", port=8000)
|
Run the Code
We can run this code as we run simple python file. server will start on the “http://127.0.0.1:8000” (localhost). we can test this code by sending Post request to the endpoint “/submit_data“. Here, we had used a Postman to test API endpoints.
Output
Case 1: Sending both username and age as parameter in POST request
Here we can se that username and age passed in request body, we got proper response from server with message “User data submitted successfully!“.
Case 2: Any one info missing (either username or age)
Here in this case we don’t send some info(either username or age) so as mentiond in our code’s try block if both field are not there we simply raise a error “Incomplete data provided”.
So this is how we can consume a query parameter from a POST request in fastAPI. we can simply convert the request object into JSON format and then we can use it, as required.
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