接上篇：一文掌握异步web框架FastAPI（四）-****博客

目录

七、中间件

 15、测试环境中间件

16、访问速率限制中间件，即限制每个IP特定时间内的请求数（基于内存，生产上要使用数据库）

        1）限制单ip访问速率

        2）增加限制单ip并发（跟上面的一样，也是限制每个IP特定时间内的请求数，另一种写法）

        3）增加封禁IP

17. 请求体解析中间件

18. 自定义认证中间件

19. 重试机制中间件

20. 请求频率统计中间件（各个接口的访问次数）

21. 路径重写中间件

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七、中间件

 15、测试环境中间件

这个中间件用于识别请求是否来自于测试环境，并采取相应的措施，如禁用缓存或跳过某些安全检查。

from fastapi import FastAPI, Request, HTTPException
from fastapi.responses import JSONResponse
import os
import logging

# 配置日志
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)
app = FastAPI()


@app.middleware("http")
async def test_environment_middleware(request: Request, call_next):
    try:
        # 检查环境变量
        test_environment_enabled = os.getenv("TEST_ENVIRONMENT_ENABLED", "false").lower() == "true"
        if "X-Test-Environment" in request.headers and request.headers["X-Test-Environment"].lower() == "true":
            if test_environment_enabled:
                logger.info("Test environment header detected. Enabling test environment specific logic.")
                # 测试环境特有的处理
                # 例如：设置数据库连接为测试数据库、开启调试模式等
                pass
            else:
                logger.warning("Test environment header detected, but TEST_ENVIRONMENT_ENABLED is not set to true.")
                return JSONResponse({"message": "Test environment not enabled"}, status_code=403)
        response = await call_next(request)
        return response
    except Exception as e:
        logger.error(f"Error in test_environment_middleware: {str(e)}")
        return JSONResponse({"message": "Internal server error"}, status_code=500)


@app.get("/")
async def root():
    return {"message": "Hello World"}


if __name__ == "__main__":
    import uvicorn

    uvicorn.run(app, host="0.0.0.0", port=8000)

请求：

import requests

# FastAPI应用的URL
url = "http://127.0.0.1:8000/"
# 发送GET请求到根路径，并包含测试环境头部
response = requests.get(url, headers={"X-Test-Environment": "true"})
# 打印响应状态码和内容
print(f"Status Code: {response.status_code}")
print(f"Response Content: {response.json()}")

本地未启用测试环境：

16、访问速率限制中间件，即限制每个IP特定时间内的请求数（基于内存，生产上要使用数据库）

        1）限制单ip访问速率

from fastapi import FastAPI, Request
from fastapi.responses import JSONResponse
import time
from collections import defaultdict
import logging

app = FastAPI()
# 初始化rate_limits字典
rate_limits = defaultdict(list)
# 配置日志
logging.basicConfig(level=logging.DEBUG)
logger = logging.getLogger(__name__)


# 定义中间件
@app.middleware("http")
async def rate_limit_middleware(request: Request, call_next):
    ip = request.headers.get("X-Forwarded-For", request.client.host).split(",")[0].strip()
    now = time.time()
    # 移除旧的请求时间戳
    rate_limits[ip] = [t for t in rate_limits[ip] if t > now - 60]
    # 检查速率限制
    if len(rate_limits[ip]) >= 10:  # 限制为每分钟10个请求
        logger.debug(f"Rate limit exceeded for IP: {ip}")
        return JSONResponse(
            status_code=429,
            content={"detail": "Too Many Requests"}
        )
    # 添加当前请求的时间戳
    rate_limits[ip].append(now)
    # 继续处理请求
    response = await call_next(request)
    return response


# 定义路由
@app.get("/")
async def root():
    return {"message": "Hello World"}


# 启动应用
if __name__ == "__main__":
    import uvicorn

    uvicorn.run(app, host="0.0.0.0", port=8000, log_level="debug")

请求：

import requests
import time

# FastAPI应用的URL
url = "http://127.0.0.1:8000/"
# 用于测试的IP地址
ip = "127.0.0.1"
# 设置请求头，模拟X-Forwarded-For
headers = {
    "X-Forwarded-For": ip
}


# 发送多个请求以测试速率限制
def test_rate_limit():
    for i in range(15):
        try:
            response = requests.get(url, headers=headers)
            print(f"Request {i + 1}: Status Code: {response.status_code}")
            if response.status_code == 429:
                print(f"Request {i + 1}: {response.json()}")
        except Exception as e:
            print(f"Request {i + 1}: Error: {e}")
        time.sleep(1)  # 等待1秒