sql - Can I use gorilla schema with an sql.NullString?

Question

I am using gorilla schema to populate a struct based on a user's form submission. My struct contains sql.NullString and I am currently getting the following error:

schema: converter not found for sql.NullString

How can I use sql.NullString in a struct that I want to populate with gorilla schema?

Answer 1

我创建了一个要点（https://gist.github.com/carbocation/51b55297702c7d30d3ef），它展示了解决此问题的一种方法。您需要为schema.Converter以下四种类型中的每一种创建一个：sql.NullString、sql.NullBool、sql.NullInt64 和 sql.NullFloat64。

sql.NullString 的示例：

import "database/sql"
import "reflect"

func ConvertSQLNullString(value string) reflect.Value {
    v := sql.NullString{}
    if err := v.Scan(value); err != nil {
        return reflect.Value{}
    }

    return reflect.ValueOf(v)
}

然后将其注册到您的*schema.Decoder（通常是全局包，在本例中名为d）：

import "database/sql"

nullString := sql.NullString{}
d.RegisterConverter(nullString, ConvertSQLNullString)