Go语言Mgo库中结构体字段的灵活持久化控制

package main

import (
    "crypto/sha1"
    "encoding/base64"
    "fmt"
    "log" // 使用log代替fmt.Println处理错误
    "gopkg.in/mgo.v2" // 推荐使用gopkg.in/mgo.v2
)

type Person struct {
    Name        string
    SSN         string // 此字段包含敏感信息，不应直接存入DB
    HashedSSN   string
}

func main() {
    bob := Person{"Bob", "fake_ssn_123", ""}

    // 计算SSN的哈希值
    hasher := sha1.New()
    hasher.Write([]byte(bob.SSN))
    sha := base64.URLEncoding.EncodeToString(hasher.Sum(nil))
    bob.HashedSSN = sha

    // 连接MongoDB
    mgoSession, err := mgo.Dial("mongodb://localhost:27017") // 使用完整URI
    if err != nil {
        log.Fatalf("mongo_config#initMongoSessions : Could not dial to mgoSession: %v", err)
    }
    defer mgoSession.Close() // 确保会话关闭

    // 获取数据库和集合
    c := mgoSession.DB("test").C("person")

    // 插入数据
    err = c.Insert(bob)
    if err != nil {
        log.Fatalf("Failed to insert person: %v", err)
    }
    fmt.Println("Person inserted successfully (without field tag). Check your DB to see SSN is stored.")
}

package main

import (
    "crypto/sha1"
    "encoding/base64"
    "fmt"
    "log"
    "gopkg.in/mgo.v2"
)

type Person struct {
    Name        string
    SSN         string `bson:"-"` // 添加此标签，mgo将忽略此字段
    HashedSSN   string
}

func main() {
    bob := Person{"Bob", "fake_ssn_123", ""}

    // 计算SSN的哈希值
    hasher := sha1.New()
    hasher.Write([]byte(bob.SSN))
    sha := base64.URLEncoding.EncodeToString(hasher.Sum(nil))
    bob.HashedSSN = sha

    // 连接MongoDB
    mgoSession, err := mgo.Dial("mongodb://localhost:27017")
    if err != nil {
        log.Fatalf("mongo_config#initMongoSessions : Could not dial to mgoSession: %v", err)
    }
    defer mgoSession.Close()

    // 获取数据库和集合
    c := mgoSession.DB("test").C("person")

    // 插入数据
    err = c.Insert(bob)
    if err != nil {
        log.Fatalf("Failed to insert person: %v", err)
    }
    fmt.Println("Person inserted successfully (with bson:\"-\" tag). Check your DB to confirm SSN is NOT stored.")

    // 验证：从数据库读取并打印
    var retrievedPerson Person
    err = c.Find(nil).One(&retrievedPerson) // 查找并读取第一个文档
    if err != nil {
        log.Fatalf("Failed to retrieve person: %v", err)
    }
    fmt.Printf("Retrieved Person: %+v\n", retrievedPerson)
    // 注意：retrievedPerson.SSN 将会是空字符串，因为在反序列化时也被忽略了
}