from psycopg2.pool import SimpleConnectionPool
import gevent_psycopg2

gevent_psycopg2.monkey_patch()

class BaseHandler(web.RequestHandler):

    @property
    def db(self):
        if not hasattr(self.application, 'pgpool'):
            self.application.pgpool = SimpleConnectionPool(minconn=1, maxconn=20,host='localhost', database='database', user='postgres',
                password='password', port=5432)

        if not hasattr(self, '_db'):
            self._db = self.application.pgpool.getconn()
        return self._db

    def set_status(self, status_code):
        '''
        解决因为数据库操作错误导致的全局500错误
        '''
        if status_code == 500:
            self.db.rollback()
        super(BaseHandler, self).set_status(status_code)

        def get(self):
            cur = self.db.cursor()
        cur.execute('select * from articles')
        self.write(str(cur.fetchall()))

    def on_finish(self):
        self.application.pgpool.putconn(self.db)#将数据库连接放回连接池中
        del self._db