flask 完成简单查询请求处理，及跨域

文章大纲

• flask通用项目结构
• flask 简介
• 主体代码逻辑
• flask 跨域问题的处理
• flask 日志
• flask 微服务Flask-RESTful
• 启动服务命令

---

flask通用项目结构

| - projectName
	| - app  //程序包
		| - templates //jinjia2模板
		|- static //css,js 图片等静态文件
		| - main  //py程序包 ，可以有多个这种包，每个对应不同的功能
			| - __init__.py
			|- errors.py
			|- forms.py
			|- views.py
		|- __init__.py
		|- email.py //邮件处理程序
		|- models.py //数据库模型
	|- migrations //数据迁移文件夹
	| - tests  //单元测试
		|- __init__.py
		|- test*.py //单元测试程序，可以包含多个对应不同的功能点测试
	|- venv  //虚拟环境
	|- requirements.txt //列出了所有依赖包以及版本号，方便在其他位置生成相同的虚拟环境以及依赖
	|- config.py //全局配置文件，配置全局变量
	|- manage.py //启动程序

flask 简介

http://docs.jinkan.org/docs/flask/quickstart.html#a-minimal-application

主体代码逻辑

一个最简单的查询服务样例

#!/usr/bin/env python
# -*- encoding: utf-8 -*-
#-------------------------------------------------------------------------------
'''
@Author  :   {SEASON}
@License :   (C) Copyright 2013-2022, {OLD_IT_WANG}
@Contact :   {shiter@live.cn}
@Software:   PyCharm
@File    :
@Time    :   2019/4/25 14:57
@Desc    :

'''
#-------------------------------------------------------------------------------

import json
import random
import logging

from flask import Flask

from flask_sqlalchemy import SQLAlchemy
from flask import request,Response
from flask_cors import CORS

log_file_str = 'shuanghe_demo.log'
log_level = logging.INFO
app = Flask(__name__)
CORS(app)

app.config['SQLALCHEMY_DATABASE_URI'] = 'mysql+pymysql://username:password@ip:3306/database'
app.config['SQLALCHEMY_COMMIT_ON_TEARDOWN'] = True

db = SQLAlchemy(app)

english_chinese_dict = {'id':'身份证号',
'name':'姓名',
'sex':'性别',
'age':'年龄',
}

class neihuang_underwriting_search_result(db.Model):
    __tablename__ = 'neihuang_underwriting_search_result'

    id = db.Column(db.String(32),primary_key=True)
    name = db.Column(db.String(32))
    sex = db.Column(db.String(32))
    age = db.Column(db.String(32))

    def __repr__(self):
        return '<neihuang_underwriting_search_result %r>' % self.id

def convert_to_dict(obj):
    '''把Object对象转换成Dict对象'''
    result_dict = {}
    result_dict.update(obj.__dict__)
    result_dict.pop('_sa_instance_state', None)
    result_dict = random_value_of_labels(result_dict)
    return result_dict

def get_id_result(id):
    result = neihuang_underwriting_search_result.query.filter_by(id=id).one()

    result_dict = convert_to_dict(result)
    # result_list = database_name_conversion(result_dict)
    result_json = json.dumps(result_dict,ensure_ascii=False)
    return result_json

@app.route('/api/search',methods=['POST','GET'])
def search():

    #result_json  = get_id_result(id)
    if request.method == 'GET':
        user_id = json.loads(''.join(x for x in request.args))['id']
        print(user_id)
        app.logger.info(user_id + ' is search ING .......')
        result_json  = get_id_result(user_id)

    return Response(result_json)

if __name__ == '__main__':

    handler = logging.FileHandler(log_file_str, encoding='UTF-8')
    handler.setLevel(log_level)
    logging_format = logging.Formatter(
        '%(asctime)s - %(levelname)s - %(filename)s - %(funcName)s - %(lineno)s - %(message)s')
    handler.setFormatter(logging_format)
    app.logger.addHandler(handler)

    app.run(debug=True, host='0.0.0.0', port=18081)
    #放在这里是不对的
    # CORS(app, supports_credentials=True)

flask 跨域问题的处理

在处理跨域问题时候，应该把下列代码弄成全局的，也就是放

app = Flask(name)

cors = CORS(app)

否则跨域问题依然存在，报错信息为：

Access to XMLHttpRequest at ‘-----’ from origin ‘http://localhost:63342’ has been blocked by CORS policy: Response to preflight request doesn’t pass access control check: No ‘Access-Control-Allow-Origin’ header is present on the requested resource.

flask 日志

https://blog.csdn.net/iszhenyu/article/details/56846551

flask 微服务Flask-RESTful

写完了发现

https://flask-restful.readthedocs.io/en/latest/

启动服务命令

参考：https://www.cnblogs.com/zzyoucan/p/7764590.html

nohup command > myout.file 2>&1 &