#coding:utf-8

from flask import Flask
from werkzeug.routing import BaseConverter

#定义正则转换器的类
class RegexConverter(BaseConverter):
    def __init__(self,url_map,*items):
        super(RegexConverter, self).__init__(url_map)
        self.regex=items[0]

app = Flask(__name__)
#实例化
app.url_map.converters['regex']=RegexConverter

@app.route('/user/<regex("([a-z]|[A-Z]){4}"):username>', methods=['POST', 'GET'])
def user(username):
    return 'Hello,%s' % username

if __name__ == '__main__':
    app.run(debug=True)