psycopg2.errors.InFailedSqlTransaction：当前事务被中止，命令被忽略，直到事务块结束

Question

我写了一个scrapy程序来从一个站点抓取数据，如果我抓取到一个json文件或csv文件，这个程序会成功抓取，当我尝试抓取我的postgres数据库时出现问题，下图显示了我收到的错误, 如何修复错误：

def process_item(self, item, spider):
    """Save deals in the database.
    This method is called for every item pipeline component.
    """
    self.cur.execute("insert into Deals (Name,Deal_Url,Image_Url,Old_Price,Special_Price,Final_Price) values(%s,%s,%s,%s,%s,%s)",(item['Name'],item['Product_URL'],item['Image_URL'],item['Old_Price'],item['Special_Price'],item['Final_Price']))
    self.connection.commit()
    return item

Answer 1

当事务中的操作失败时，您需要回滚，除了修复恶意操作（可能试图访问item不存在的任何值）之外，您还可以将插入语句包装在 try/except 块中：

def process_item(self, item, spider):
    """Save deals in the database.
    This method is called for every item pipeline component.
    """

    try:
        self.cur.execute("insert into Deals (Name,Deal_Url,Image_Url,Old_Price,Special_Price,Final_Price) values(%s,%s,%s,%s,%s,%s)",(item['Name'],item['Product_URL'],item['Image_URL'],item['Old_Price'],item['Special_Price'],item['Final_Price']))
        self.connection.commit()
    except:
        self.connection.rollback()
    return item