无法使用mongo-go-driver解码camelcase字段

Question

我正在使用这样的结构

type User struct {
    Username  string    `json: "username" bson: "username"`
    FirstName string    `json: "firstName" bson: "firstName"`
    LastName  string    `json: "lastName" bson: "lastName"`
    Email     string    `json: "email" bson: "email"`
    Gender    string    `json: "gender" bson: "gender"`
    Password  string    `json: "password" bson: "password"`
    Enabled   bool      `json: "enabled" bson: "enabled"`
    BirthDate time.Time `json: "birthDate" bson: "birthDate"`
    CreatedAt time.Time `json: "createdAt" bson: "createdAt"`
    UpdatedAt time.Time `json: "updatedAt" bson: "updatedAt"`
    collection *mongo.Collection
}

然后使用查询数据

func (u *User) FindByUsername(userName string) error {
    var ctx, _ = context.WithTimeout(context.Background(), 10*time.Second)
    filter := bson.M{"username": userName}
    err := u.collection.FindOne(ctx, filter).Decode(&u)
    return err
}

我得到的结果是

{"Username":"jbond","FirstName":"","LastName":"","Email":"[email protected]","Gender":"Male","Password":"","Enabled":true,"BirthDate":"0001-01-01T00:00:00Z","CreatedAt":"0001-01-01T00:00:00Z","UpdatedAt":"0001-01-01T00:00:00Z"}

除了驼峰式字段外，大多数数据都被填充，当我从控制台查询时，数据就在那里

> db.users.find().pretty()
{
    "_id" : ObjectId("xxxxxxxxxxxxxxxxxxxxxxxx"),
    "username" : "jbond",
    "firstName" : "James",
    "lastName" : "Bond",
    "email" : "[email protected]",
    "password" : "",
    "enabled" : true,
    "gender" : "Male",
    "birthDate" : {
        "type" : {
            "code" : "function Date() {\n    [native code]\n}"
        }
    },
    "createdAt" : {
        "type" : {
            "code" : "function Date() {\n    [native code]\n}"
        },
        "default" : {
            "code" : "function now() {\n    [native code]\n}"
        }
    },
    "updatedAt" : {
        "type" : {
            "code" : "function Date() {\n    [native code]\n}"
        },
        "default" : {
            "code" : "function now() {\n    [native code]\n}"
        }
    }
}

我不明白为什么一切都应该是小写的。或者我错过了什么？

Answer 1

不，它不是解码camel-case字段的失败。它无法解析struct标签。

根据doc：

按照惯例，标记字符串是可选的空格分隔的键：“值”对的串联。每个键都是一个非空字符串，由空格（U + 0020''），引号（U + 0022'“'）和冒号（U + 003A'：'）以外的非控制字符组成。每个值都被引用使用U + 0022'“'字符和Go字符串文字语法。

你应该删除json:和bson:之后的空格。