用装饰器实现flask异常处理

前言

刚好最近了解了python装饰器，就在工作中用实践了一把，避免写很多重复的代码，在有多个路由的情况下效果显而易见。本文纯属一个学渣的探索历程，请以此小例子为参考，在工作中尽情发挥，可能flask本身有别的更好的实现，但是本人flask小白，如有更好的实现方法还请批评指正。python装饰器基础及多装饰器的运行顺序解析可参考https://www.jianshu.com/p/4043735e839e

实例代码

# coding: utf-8
import numpy as np
import os
import time
import datetime
from flask import Flask, request, jsonify, Response, abort
import json
import uuid
from functools import wraps
app = Flask(__name__)
app.config['JSON_AS_ASCII'] = False
#异常处理装饰函数
def decorator(fun):
    @wraps(fun)
    def wrapper(*args, **kwargs):
        try:
            try_result = fun(*args, **kwargs)
            return try_result
        except KeyError as e:
            error_warning = {'error_warning': 'A key error has occurred. Please check if the keys of the uploaded json are correct.'}
            return jsonify(error_warning)
        except TypeError as e:
            error_warning = {'error_warning': 'A type error has occurred. Please check if the uploaded json data type is correct.'}
            return jsonify(error_warning)
        except Exception as e:
            error_warning = {'error_warning':repr(e)}
            return jsonify(error_warning)
    return wrapper
#定义路由
@app.route('/assign', methods=['GET', 'POST'])
@decorator
def assignment():
    data = {'flags': 'haha', 'corpus': 'hello'}
    setsd = {}
    setsd['label'] = data['flag']
    results = setsd
    return jsonify(results)
@app.route('/', methods=['GET', 'POST'])
@decorator
def sayhi():
      return 'hellow world'
  
# 捕获404错误       
@app.errorhandler(404)
def errors(error): 
    return jsonify(repr(error))
    
@decorator
def run_app():
    app.run(debug=True, host = *****, port = 5000)
    return 'web服务启动了'

if __name__ == '__main__':
    service = run_app()
    print (service)

总结：

这样实现避免在每个路由下面都写一个try...except的代码块，代码的复用还是挺重要的，请大家都要坚持少写重复代码。此外flask中的用户登录验证、表单验证等都可用装饰器实现。表单验证逻辑可参考此篇文章https://www.jianshu.com/p/2aabc4b3db4c谢谢！