Build a Simple Flask Mock Server to Simulate APIs Quickly

Function Goals

Start a local HTTP service

Support GET and POST requests

Customizable response content (JSON or text)

Configurable URL paths and response data

Support delayed responses to simulate network latency

Install Flask

pip install flask

Example: Simple Mock Server (mock_server.py)

from flask import Flask, request, jsonify
import time

app = Flask(__name__)

# Mock data
MOCK_DATA = {
    "/api/login": {
        "success": True,
        "message": "登录成功",
        "data": {"token": "abc123xyz"}
    },
    "/api/user/profile": {
        "id": 1,
        "name": "张三",
        "email": "[email protected]"
    },
    "/api/users": [
        {"id": 1, "name": "Alice"},
        {"id": 2, "name": "Bob"}
    ]
}

DELAY = 0.5  # seconds

@app.before_request
def before_request():
    """Log each request"""
    print(f"[请求] {request.method} {request.path}")

@app.after_request
def after_request(response):
    """Add artificial delay after each response"""
    time.sleep(DELAY)
    return response

@app.route('/', methods=["GET", "POST"])
def mock_api(endpoint):
    """General mock endpoint"""
    full_path = f"/{endpoint}"
    if full_path in MOCK_DATA:
        return jsonify(MOCK_DATA[full_path])
    else:
        return jsonify({"error": "接口未定义", "path": full_path}), 404

if __name__ == "__main__":
    print("Mock Server 正在运行，监听地址: http://localhost:5000")
    app.run(host="0.0.0.0", port=5000, debug=True)

Example explanation:

How to Test This Mock Server?

Method 1: Browser – Open http://localhost:5000/api/login in a browser.

Method 2: Postman or curl – Run curl -X GET http://localhost:5000/api/users.

Method 3: Python requests script – Use the following script:

import requests
url = "http://localhost:5000/api/login"
response = requests.get(url)
print("状态码:", response.status_code)
print("响应内容:", response.json())

Advanced: Load MOCK Data from File

import json
import os

MOCK_FILE = "mock_data.json"
if os.path.exists(MOCK_FILE):
    with open(MOCK_FILE, "r", encoding="utf-8") as f:
        MOCK_DATA = json.load(f)
else:
    MOCK_DATA = {}

Example mock_data.json content:

{
  "/api/login": {
    "success": true,
    "token": "abc123xyz"
  },
  "/api/logout": {
    "message": "登出成功"
  }
}