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使用 Python 快速创建 API

Barbara Streisand

发布： 2024-10-23 20:07:02

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“使用 FastAPI 在 5 分钟内创建 API。FastAPI 是一个现代的高性能 Python 框架，可以轻松构建强大的 Web 应用程序。”

安装
使用 pip 安装 FastAPI 和 uvicorn（ASGI 服务器）：

pip install fastapi uvicorn
pip install fastapi

让我们创建我们的 API

打开记事本并粘贴以下内容，将文件另存为data.json（我们将使用POST方法向该文件添加数据，并使用GET方法检索记录

data.json

[
   {
      "name": "John",
      "age": 25
   },
   {  "name": "Smith",
      "age": 27
   }
]

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现在创建一个新的 python 文件，将其命名为 app.py 并粘贴以下代码

# This section imports necessary modules and classes from the FastAPI library and Python's standard library. It imports FastAPI for creating the web application, HTTPException for raising HTTP exceptions, List for type hints, and json for working with JSON data.

from fastapi import FastAPI, HTTPException
from typing import List
import json

# This creates an instance of the FastAPI class, which will be the main application instance for handling HTTP requests.
app = FastAPI()

# This block reads the content of the "data.json" file using a context manager (with statement) and loads the JSON data into the initial_data variable.
with open("data.json", "r") as file:
    initial_data = json.load(file)

# This line initializes the data variable with the loaded JSON data, effectively creating a list of dictionaries containing user information.
data = initial_data

# This decorator (@app.get(...)) defines a GET endpoint at the "/users" URL. It uses the get_users function to handle the request. The response_model parameter specifies the expected response model, which is a list of dictionaries in this case.
@app.get("/users", response_model=List[dict])
async def get_users():
    return data

# This decorator (@app.post(...)) defines a POST endpoint at the "/users" URL. It uses the create_user function to handle the request. The response_model parameter specifies the expected response model, which is a single dictionary in this case.
# The create_user function attempts to append the received user dictionary to the data list. If successful, it constructs a response dictionary indicating the success. If an exception occurs during the attempt (e.g., due to invalid data), it constructs a response dictionary indicating an error.
@app.post("/users", response_model=dict)
async def create_user(user: dict):
    try:
        data.append(user)
        response_data = {"message": "User created successfully", "user": user}
    except:
        response_data = {"message": "Error creating user", "user": user}
    return response_data

# This function uses a context manager to open the "data.json" file in write mode and then uses json.dump to write the contents of the data list back to the file, formatting it with an indentation of 4 spaces.
def save_data():
    with open("data.json", "w") as file:
        json.dump(data, file, indent=4)

# This decorator (@app.on_event(...)) defines a function that will be executed when the FastAPI application is shutting down. In this case, it calls the save_data function to save the data back to the JSON file before the application exits.
@app.on_event("shutdown")
async def shutdown_event():
    save_data()

# This block checks if the script is being run directly (not imported as a module). If it is, it uses the uvicorn.run function to start the FastAPI application on host "0.0.0.0" and port 8000. This is how you launch the application using the Uvicorn ASGI server.
if __name__ == "__main__":
    import uvicorn
    uvicorn.run(app, host="0.0.0.0", port=8000)

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运行app.py，Uvicorn服务器将启动一个新进程来处理传入的HTTP请求。服务器启动并运行后，打开 Postman，使用 URL 创建一个新的 GET 请求：http://0.0.0.0:8000/users，然后单击发送

Create API’s in inutes with Python