Golang邮件程序中出现无效内存地址或空指针引用错误

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我正在使用 https://github.com/kataras/go-mailer 和 https://github.com/gin-gonic/gin

我不知何故收到此错误：

[gin] 2022/02/19 - 13:23:24 | 500 |   10.211394ms |             ::1 | post     "/new-code?userid=kiddo&email=pog_champ_email!"
error occuredcontext deadline exceeded

2022/02/19 13:23:35 [recovery] 2022/02/19 - 13:23:35 panic recovered:
post /new-code?userid=kiddo&email=hi_email_here? http/1.1
host: localhost:8080
accept: */*
accept-encoding: gzip, deflate, br
connection: keep-alive
content-length: 0
postman-token: 07942c52-c661-46e9-a4c0-4eeb3c5bb6d1
user-agent: postmanruntime/7.28.4


runtime error: invalid memory address or nil pointer dereference
/usr/local/go/src/runtime/panic.go:221 (0x104a406)
        panicmem: panic(memoryerror)
/usr/local/go/src/runtime/signal_unix.go:735 (0x104a3d6)
        sigpanic: panicmem()
/users/gaurish/desktop/coding/sayheytome-emails/main.go:73 (0x169bfc7)
        main.func1: "code":    insert.insertedid,
/users/gaurish/go/pkg/mod/github.com/gin-gonic/[email protected]/context.go:168 (0x14da441)
        (*context).next: c.handlers[c.index](c)
/users/gaurish/go/pkg/mod/github.com/gin-gonic/[email protected]/recovery.go:99 (0x14da42c)
        customrecoverywithwriter.func1: c.next()
/users/gaurish/go/pkg/mod/github.com/gin-gonic/[email protected]/context.go:168 (0x14d96a6)
        (*context).next: c.handlers[c.index](c)
/users/gaurish/go/pkg/mod/github.com/gin-gonic/[email protected]/logger.go:241 (0x14d9689)
        loggerwithconfig.func1: c.next()
/users/gaurish/go/pkg/mod/github.com/gin-gonic/[email protected]/context.go:168 (0x14d8bf0)
        (*context).next: c.handlers[c.index](c)
/users/gaurish/go/pkg/mod/github.com/gin-gonic/[email protected]/gin.go:555 (0x14d8858)
        (*engine).handlehttprequest: c.next()
/users/gaurish/go/pkg/mod/github.com/gin-gonic/[email protected]/gin.go:511 (0x14d8391)
        (*engine).servehttp: engine.handlehttprequest(c)
/usr/local/go/src/net/http/server.go:2879 (0x12c393a)
        serverhandler.servehttp: handler.servehttp(rw, req)
/usr/local/go/src/net/http/server.go:1930 (0x12befe7)
        (*conn).serve: serverhandler{c.server}.servehttp(w, w.req)
/usr/local/go/src/runtime/asm_amd64.s:1581 (0x1065040)
        goexit: byte    $0x90   // nop

[gin] 2022/02/19 - 13:23:35 | 500 |    3.428745ms |             ::1 | post     "/new-code?userid=kiddo&email=i_had_email_here_kekw?"

这里是邮件程序代码：https://sourceb.in/25i37egif8（这是 500 行 html）

这是路由器代码：

package main

import (
    "context"
    "fmt"
    "time"

    "github.com/gin-gonic/gin"
    "go.mongodb.org/mongo-driver/bson"
    "go.mongodb.org/mongo-driver/mongo"
    "go.mongodb.org/mongo-driver/mongo/options"
    "go.mongodb.org/mongo-driver/mongo/readpref"
)

func ping(client *mongo.Client, ctx context.Context) error {
    if err := client.Ping(ctx, readpref.Primary()); err != nil {
        return err
    }
    fmt.Println("[MONGODB] Connected Successfully")
    return nil
}

func connect(uri string) (*mongo.Client, context.Context,
    context.CancelFunc, error) {
    ctx, cancel := context.WithTimeout(context.Background(),
        30*time.Second)
    client, err := mongo.Connect(ctx, options.Client().ApplyURI(uri))
    return client, ctx, cancel, err
}

func close(client *mongo.Client, ctx context.Context,
    cancel context.CancelFunc) {
    defer cancel()
    defer func() {
        if err := client.Disconnect(ctx); err != nil {
            panic(err)
        }
    }()
}

func main() {
    r := gin.Default()
    client, ctx, cancel, err := connect("MONGODB>>>>>>")
    if err != nil {
        panic(err)
    }
    defer close(client, ctx, cancel)
    ping(client, ctx)
    Database := client.Database("codes")
    CodesCollection := Database.Collection("Codes")
    r.POST("/new-code", func(c *gin.Context) {
        email := c.Query("email")
        Insert, err := CodesCollection.InsertOne(ctx, bson.D{
            {
                Key:   "userid",
                Value: c.Query("userid"),
            },
            {
                Key:   "used",
                Value: false,
            },
            {
                Key:   "expired",
                Value: time.Now().Add(time.Hour * 6).Unix(),
            },
        })
        if err != nil {
            fmt.Print("Error Occured")
            fmt.Print(err.Error())
        }
        c.JSON(200, gin.H{
            "success": true,
            "code":    Insert.InsertedID,
        })
        EmailUrl := "https://example.com"
        SendMail(email, EmailUrl)
    })
    r.Run()
}

我应该做什么？我正在使用邮递员，这似乎不是问题，直到昨天我只是在没有邮件系统的情况下使用它并且它工作正常，所以可能根本不会是 mongodb 问题。

正确答案

由于某种原因，此处的行返回错误。所以 insert 是 nil。

insert, err := codescollection.insertone(...)

这就是为什么当您在此处调用 insert.insertedid 时，

c.json(200, gin.h{
            "success": true,
            "code":    insert.insertedid,
        })

对 insert.insertedid 的调用因 nil 指针引用异常而发生恐慌。

要修复此问题，请将 return 添加到您的错误处理代码片段以进一步停止执行：

if err != nil {
            fmt.Print("Error Occured")
            fmt.Print(err.Error())
            return
        }

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