Golang BoltDB删除似乎不工作的密钥

Question

go版本CentOS 7，go版本go1.17.7 linux/amd64 64

这个问题可能会导致对BoltDB工作方式的误解，或者我有一个bug，或者有一个问题。我以前使用过BoltDB，并取得了很好的效果。不过，我并没有明确地找出这个问题。我看到的是，我尝试从桶中删除一个键，并且在active db.Update中删除密钥及其值，但是在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。

我使用一个BoltDB桶来存储与创建新帐户的电子邮件地址相关的临时令牌。希望立即整理和清理旧数据(过期的令牌、误用的令牌等)。相当标准的东西。临时令牌的结构是(键是临时令牌，10位随机字符串)：

(临时令牌是桶键)

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”。这将创建对REST服务的调用，该调用将在临时令牌表中创建一个条目，如下所示：

"BpLnfgDsc2“=> foo@bar.com，1645650084

该服务发送电子邮件给具有临时令牌嵌入的URL，该链接将用户带到允许他们输入电子邮件地址(再次验证)和新密码(两次)的表单。然后，点击Submit就会从web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
}

我正在用一个超时令牌(4)进行测试，所以当它遇到超时令牌时，它想要从桶中删除这个现在无效的令牌。

在A位置，它打印:第一个Get调用令牌BpLnfgDsc2是{"emailaddress":"foo@bar.com"，"tokenexpirytime":1645650084}

在我将代码放在执行.Get的B位置，它打印出来(看起来要删除)：在DB关闭(4)之前，删除之后，令牌BpLnfgDsc2是

在C位置，它打印(看起来是返回)：在DB关闭后，令牌BpLnfgDsc2是{"emailaddress":"foo@bar.com"，"tokenexpirytime":1645650084}

任何内容都不返回错误。我已经重复了很多次，把fmt.Printfs放在任何地方，看看到底是怎么回事。结果是一样的，关键似乎没有被删除。在此之后，我将对DB文件进行'vi -b‘，而键，值仍然存在。运行后，它仍然看到关键的值在那里。我很困惑，任何建议都会很感激的。

更新: Put/Get/Delete/Get的基本螺栓功能按照此测试代码工作(应该是显而易见的)：

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：

令牌的值："foo“是"{"emailaddress":"foo@bar.com"，"tokenexpirytime":1234567890}”就在把它放在那里之后

值:删除后的"foo“是"”。

所以，不知道为什么其他代码不能工作。好像delete使用的是不同的键，但是其他代码的键是相同的。

Answer 1

我认为具有非零返回值的db.Update的行为是这里的混乱。根据医生们

在闭包中，您有一个一致的数据库视图。通过在结束时返回零来提交事务。还可以通过返回错误在任何时候回滚事务。

您将返回一个错误：

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

这意味着该db.Update(中的所有操作都回滚。这可以在简单的示例中通过一个小的更改(return fmt.Errorf("RETURNING ERROR HERE"))来复制：

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())
    }
}

现在的产出是：

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内容相匹配。修复相对简单--如果您希望提交更改，请不要返回错误。