Golang BoltDB 删除键似乎不起作用

Question

CentOS 7,Githubboltdb/bolt版本1.3.1,go版本go1.17.7linux/amd64

这个issue可能是对BoltDB工作原理的误解，也可能是我有bug，也可能是有问题。我以前用过 BoltDB，并且取得了很好的效果。虽然，我没有明确地寻找这个问题。我所看到的是，我尝试从存储桶中删除一个键，键及其值在活动 db.Update 中被删除，但在 db.Update 结束后它仍然存在。寻找可能发生的事情的任何解释。看来这个功能不可能被破坏。

我正在使用 BoltDB 存储桶来存储与用于创建新帐户的电子邮件地址关联的临时令牌。想要整洁并立即清理旧数据（过期的令牌、误用的令牌等）。很标准的东西。临时token的结构为（key为临时token，10位随机字符串）：

（临时令牌是Bucket key）

type tempTokenStruct struct {

EmailAddress        string   `json:"emailaddress"`        // Email Address to be changed 

TokenExpiryTime     int64    `json:"tokenexpirytime"`     // Expiry Time for token in Epoch time

}

用户在 Web 表单中输入电子邮件地址并点击 'submit'。这会创建对 REST 服务的调用，该服务会在临时令牌 table 中创建一个条目，例如：

"BpLnfgDsc2" => foo@bar.com, 1645650084

该服务通过电子邮件发送 URL，其中嵌入了临时令牌，link 将用户带到一个表单，允许他们输入他们的电子邮件地址（再次验证）和新的密码（两次）。点击提交然后会导致从网络处理程序中调用以下代码：

func checkTokenValid(emailAddress string, tempToken string) error {
var tempTokenData tempTokenStruct
var tempTokenBytes []byte

tempTokenBytes = []byte(tempToken)

db, err := bolt.Open(USER_DB_NAME, 0644, nil)

if err != nil {
    return err
}

defer db.Close()

err = db.Update(func(tx *bolt.Tx) error {
    tempTokenBucket := tx.Bucket([]byte("temptokens"))

    // The bucket hasn't been created, so there are no stored tokens
    if tempTokenBucket == nil {
        return errors.New("Not Authorized (1): Please request a new password new/change email from the login page.")
    }

    // There is no matching token stored in the bucket, so this is an invalid request
    tempTokenJSON := tempTokenBucket.Get(tempTokenBytes)

    //[I've put a printf here: A]

    if tempTokenJSON == nil {
        return errors.New("Not Authorized (2): Please request a new password new/change email from the login page.")
    }

    jsonConvertErr := json.Unmarshal(tempTokenJSON, &tempTokenData)

    if jsonConvertErr != nil {
        tempTokenBucket.Delete(tempTokenBytes)
        return errors.New("Not Authorized (3): Please request a new password new/change email from the login page.")
    }

    // Check to see if the time is expired, if so, remove the key and indicate error
    if tempTokenData.TokenExpiryTime < time.Now().Unix() {
        tempTokenBucket.Delete(tempTokenBytes)

        //[I've put a printf here: B]

        return errors.New("Not Authorized (4): Please request a new password new/change email from the login page.")
    }

    // Check to see if the email addresses match
    if emailAddress != tempTokenData.EmailAddress {
        tempTokenBucket.Delete(tempTokenBytes)
        return errors.New("Not Authorized (5): Please request a new password new/change email from the login page.")
    }

    tempTokenBucket.Delete(tempTokenBytes)
    return nil
})

// This is test code to see if the key was in fact deleted
db.Update(func(tx *bolt.Tx) error {
    tempTokenBucket := tx.Bucket([]byte("temptokens"))
    tempTokenJSON := tempTokenBucket.Get(tempTokenBytes)

    // [I've put a printf here: C]

    return nil
})

return err
}

我正在使用超时令牌 (4) 进行测试，所以我的想法是，当它遇到那个超时令牌时，它想要从存储桶中删除这个现在无效的令牌。

在A位置，打印：首先获取呼叫令牌 BpLnfgDsc2 是 {"emailaddress":"foo@bar.com","tokenexpirytime":1645650084}

在B位置我放了一个代码，做了一个.Get，它打印出来（看起来被删除了）： DB Close前(4)，删除后token BpLnfgDsc2为

在C位置，它打印（看起来是回来了）：数据库关闭后，令牌 BpLnfgDsc2 为 {"emailaddress":"foo@bar.com","tokenexpirytime":1645650084}

没有返回任何错误。我已经重复了很多次，将 fmt.Printfs 放在各处以查看发生了什么。结果是一样的，密钥似乎没有被删除。坐下后，我 'vi -b' 数据库文件，键，值仍然存在。运行坐下后，它仍然在那里看到键值。我很困惑，任何指点将不胜感激。

更新：Put/Get/Delete/Get 的基本螺栓功能按照此测试代码工作（应该很明显）：

package main

import "fmt"
import "encoding/json"
import "github.com/boltdb/bolt"

type tempTokenStruct struct {
EmailAddress        string   `json:"emailaddress"`        // Email Address to be changed (Temporary Token is the DB key)
TokenExpiryTime     int64    `json:"tokenexpirytime"`     // Expiry Time for token in Epoch time
}


func main() {
    var tempToken tempTokenStruct

    tempToken.EmailAddress = "foo@bar.com"
    tempToken.TokenExpiryTime = 1234567890

    tempTokenDataJSON, jsonMarshalError := json.Marshal(tempToken)

    if jsonMarshalError != nil {
            fmt.Printf("JSON Marshal Error: %s\n", jsonMarshalError.Error())
            return
    }

    tempTokenKey := []byte("foo")

db, err := bolt.Open("test.db", 0644, nil)

if err != nil {
            fmt.Printf("Error opening Database\n")
    return
}

defer db.Close()

// Put a key in the table
err = db.Update(func(tx *bolt.Tx) error {
    tempTokenBucket, err := tx.CreateBucketIfNotExists([]byte("temptokens"))

    if err != nil {
        return err
    }

    dbPutError := tempTokenBucket.Put(tempTokenKey, []byte(tempTokenDataJSON))

    return dbPutError
})

    if err != nil {
            fmt.Printf("Error putting key value pair into table: %s\n", err.Error())
    }

    // Check if the key/value is there after putting it in
err = db.Update(func(tx *bolt.Tx) error {
    tempTokenBucket, err := tx.CreateBucketIfNotExists([]byte("temptokens"))

    if err != nil {
        return err
    }

    valueGet := tempTokenBucket.Get(tempTokenKey)

            fmt.Printf("Value for Token: \"%s\" is \"%s\" just after putting it in there\n", tempTokenKey, valueGet)

    return nil
})

    // Delete that key from the table
err = db.Update(func(tx *bolt.Tx) error {
    tempTokenBucket, err := tx.CreateBucketIfNotExists([]byte("temptokens"))

    if err != nil {
        return err
    }

    dbDeleteError := tempTokenBucket.Delete(tempTokenKey)

    return dbDeleteError
})

    if err != nil {
            fmt.Printf("Error Deleting key from bucket: %s\n", err.Error())
    }

    // Check if the key/value is there after deleting it
err = db.Update(func(tx *bolt.Tx) error {
    tempTokenBucket, err := tx.CreateBucketIfNotExists([]byte("temptokens"))

    if err != nil {
        return err
    }

    valueGet := tempTokenBucket.Get(tempTokenKey)

            fmt.Printf("Value for Token: \"%s\" is \"%s\" after the delete\n", tempTokenKey, valueGet)

    return nil
})

    if err != nil {
            fmt.Printf("Error getting key from table: %s\n", err.Error())
    }
}

打印出来：

令牌的价值：“foo”是“{“emailaddress”：“foo@bar.com”，“tokenexpirytime”：1234567890}“刚把它放在那里

令牌值：“foo”在删除后为“”

所以，不确定为什么其他代码不起作用。几乎就像删除使用不同的键一样，但键在其他代码中是相同的。

Answer 1

我认为 db.Update 与 non-nil return 值的行为是这里的混淆。根据 the docs

Inside the closure, you have a consistent view of the database. You commit the transaction by returning nil at the end. You can also rollback the transaction at any point by returning an error.

您 return 出错了：

return errors.New("Not Authorized (4): Please request a new password new/change email from the login page.")

这意味着 db.Update( 中的所有操作都被回滚。这可以在您的简单示例中复制，只需稍作更改 (return fmt.Errorf("RETURNING ERROR HERE")):

package main

import "fmt"
import "encoding/json"
import "github.com/boltdb/bolt"

type tempTokenStruct struct {
    EmailAddress    string `json:"emailaddress"`    // Email Address to be changed (Temporary Token is the DB key)
    TokenExpiryTime int64  `json:"tokenexpirytime"` // Expiry Time for token in Epoch time
}

func main() {
    var tempToken tempTokenStruct
    tempToken.EmailAddress = "foo@bar.com"
    tempToken.TokenExpiryTime = 1234567890

    tempTokenDataJSON, jsonMarshalError := json.Marshal(tempToken)
    if jsonMarshalError != nil {
        fmt.Printf("JSON Marshal Error: %s\n", jsonMarshalError.Error())
        return
    }
    tempTokenKey := []byte("foo")
    db, err := bolt.Open("test.db", 0644, nil)
    if err != nil {
        fmt.Printf("Error opening Database\n")
        return
    }
    defer db.Close()

    // Put a key in the table
    err = db.Update(func(tx *bolt.Tx) error {
        tempTokenBucket, err := tx.CreateBucketIfNotExists([]byte("temptokens"))

        if err != nil {
            return err
        }

        dbPutError := tempTokenBucket.Put(tempTokenKey, []byte(tempTokenDataJSON))

        return dbPutError
    })

    if err != nil {
        fmt.Printf("Error putting key value pair into table: %s\n", err.Error())
    }

    // Check if the key/value is there after putting it in
    err = db.Update(func(tx *bolt.Tx) error {
        tempTokenBucket, err := tx.CreateBucketIfNotExists([]byte("temptokens"))

        if err != nil {
            return err
        }

        valueGet := tempTokenBucket.Get(tempTokenKey)

        fmt.Printf("Value for Token: \"%s\" is \"%s\" just after putting it in there\n", tempTokenKey, valueGet)

        return nil
    })

    // Delete that key from the table
    err = db.Update(func(tx *bolt.Tx) error {
        tempTokenBucket, err := tx.CreateBucketIfNotExists([]byte("temptokens"))

        if err != nil {
            return err
        }
        tempTokenBucket.Delete(tempTokenKey)
        return fmt.Errorf("RETURNING ERROR HERE")  // CHANGED HERE
    })

    if err != nil {
        fmt.Printf("Error Deleting key from bucket: %s\n", err.Error())
    }

    // Check if the key/value is there after deleting it
    err = db.Update(func(tx *bolt.Tx) error {
        tempTokenBucket, err := tx.CreateBucketIfNotExists([]byte("temptokens"))
        if err != nil {
            return err
        }
        valueGet := tempTokenBucket.Get(tempTokenKey)
        fmt.Printf("Value for Token: \"%s\" is \"%s\" after the delete\n", tempTokenKey, valueGet)
        return nil
    })

    if err != nil {
        fmt.Printf("Error getting key from table: %s\n", err.Error())
    }
}

现在的输出是：

Value for Token: "foo" is "{"emailaddress":"foo@bar.com","tokenexpirytime":1234567890}" just after putting it in there
Error Deleting key from bucket: RETURNING ERROR HERE
Value for Token: "foo" is "{"emailaddress":"foo@bar.com","tokenexpirytime":1234567890}" after the delete

这似乎与您在主代码中看到的相符。修复相对简单 - 如果您想要提交更改，请不要 return 错误。

Golang BoltDB 删除键似乎不起作用

Golang BoltDB Delete Key Seemingly Not Working

go

bucket

boltdb