我在使用新手Go编程时遇到问题,例如:无效的内存地址或nil指针取消引用
有时我可以解决问题,但这使我感到困惑。这是处理程序级别的代码,我尝试实现### p.repo.UpdateProfile()和r.body解码中的数据
//UpdateProfile handler
func (p *Profile) UpdateProfile(w http.ResponseWriter, r *http.Request) {
var (
errForm models.ErrorForm
resp models.Response
respError models.ErrorResponse
errField models.ErrField
data *models.EditProfile
)
userid := r.Context().Value(viper.GetString("token.userid"))
errDecode := json.NewDecoder(r.Body).Decode(&data)
errPayload := p.repo.UpdateProfile(r.Context(), data, userid)
if errPayload.Error() == "username_exist" {
respError.Message = "username already taken"
respError.Status = 422
lib.ResJSON(w, respError.Status, respError)
return
}
lib.Catch(errPayload)
resp.Data = ""
resp.Message = "Success"
resp.Status = 200
lib.ResJSON(w, resp.Status, resp)
}
func (m *mysqlProfileRepo) UpdateProfile(ctx context.Context, p *models.EditProfile, userid interface{}) error {
query := ""
var checkexist int
row1, err1 := m.Conn.QueryContext(ctx, query, p.Username)
if err1 != nil {
return err1
}
for row1.Next() {
if errSc1 := row1.Scan(&checkexist); errSc1 != nil {
return errors.New("error_scan_db")
}
}
if checkexist != 0 {
return errors.New("username_exist")
}
query1 := ""
query2 := ""
stmts := []*lib.PipelineStmt{
lib.NewPipelineStmt(query1, p.Image, p.Location, p.Link, p.Bio, p.Birthday, userid),
lib.NewPipelineStmt(query2, p.Username, p.Fullname, userid),
}
errTrx := lib.WithTransaction(m.Conn, func(tx lib.Transaction) error {
_, errRunPipe := lib.RunPipeline(tx, stmts...)
return errRunPipe
})
if errTrx != nil {
return errTrx
}
return nil
}
panic: runtime error: invalid memory address or nil pointer dereference
2019/07/21 13:27:36 goroutine 8 [running]:
runtime/debug.Stack(0xc00028e100, 0x16b1a20, 0xc000094040)
/usr/local/Cellar/go/1.12.6/libexec/src/runtime/debug/stack.go:24 +0x9d
github.com/go-chi/chi/middleware.Recoverer.func1.1(0xc00028e100, 0x16b6be0, 0xc000256280)
/Users/rizaldinurmuhammad/go/src/github.com/go-chi/chi/middleware/recoverer.go:25 +0x9c
panic(0x155e7a0, 0x1a66a10)
/usr/local/Cellar/go/1.12.6/libexec/src/runtime/panic.go:522 +0x1b5
audioo_api/handler.(*Profile).UpdateProfile(0xc000020030, 0x16b6be0, 0xc000256280, 0xc00028e200)
/Users/rizaldinurmuhammad/go/src/audioo_api/handler/profile.go:73 +0x524
net/http.HandlerFunc.ServeHTTP(0xc000020050, 0x16b6be0, 0xc000256280, 0xc00028e200)
/usr/local/Cellar/go/1.12.6/libexec/src/net/http/server.go:1995 +0x44
audioo_api/lib/mid.Authenticate.func1.1(0x16b6be0, 0xc000256280, 0xc00028e100)
/Users/rizaldinurmuhammad/go/src/audioo_api/lib/mid/auth.go:48 +0x71e
net/http.HandlerFunc.ServeHTTP(0xc00000e0a0, 0x16b6be0, 0xc000256280, 0xc00028e100)
/usr/local/Cellar/go/1.12.6/libexec/src/net/http/server.go:1995 +0x44
github.com/go-chi/chi.(*ChainHandler).ServeHTTP(0xc000066140, 0x16b6be0, 0xc000256280, 0xc00028e100)
/Users/rizaldinurmuhammad/go/src/github.com/go-chi/chi/chain.go:31 +0x52
github.com/go-chi/chi.(*Mux).routeHTTP(0xc0000a5f80, 0x16b6be0, 0xc000256280, 0xc00028e100)
/Users/rizaldinurmuhammad/go/src/github.com/go-chi/chi/mux.go:425 +0x27f
net/http.HandlerFunc.ServeHTTP(0xc000020040, 0x16b6be0, 0xc000256280, 0xc00028e100)
/usr/local/Cellar/go/1.12.6/libexec/src/net/http/server.go:1995 +0x44
github.com/go-chi/chi.(*Mux).ServeHTTP(0xc0000a5f80, 0x16b6be0, 0xc000256280, 0xc00028e100)
/Users/rizaldinurmuhammad/go/src/github.com/go-chi/chi/mux.go:70 +0x451
github.com/go-chi/chi.(*Mux).Mount.func1(0x16b6be0, 0xc000256280, 0xc00028e100)
/Users/rizaldinurmuhammad/go/src/github.com/go-chi/chi/mux.go:292 +0x127
net/http.HandlerFunc.ServeHTTP(0xc00000e0e0, 0x16b6be0, 0xc000256280, 0xc00028e100)
/usr/local/Cellar/go/1.12.6/libexec/src/net/http/server.go:1995 +0x44
github.com/go-chi/chi.(*Mux).routeHTTP(0xc0000a59e0, 0x16b6be0, 0xc000256280, 0xc00028e100)
/Users/rizaldinurmuhammad/go/src/github.com/go-chi/chi/mux.go:425 +0x27f
net/http.HandlerFunc.ServeHTTP(0xc0001db880, 0x16b6be0, 0xc000256280, 0xc00028e100)
/usr/local/Cellar/go/1.12.6/libexec/src/net/http/server.go:1995 +0x44
github.com/go-chi/chi.(*Mux).ServeHTTP(0xc0000a59e0, 0x16b6be0, 0xc000256280, 0xc00028e100)
/Users/rizaldinurmuhammad/go/src/github.com/go-chi/chi/mux.go:70 +0x451
github.com/go-chi/chi.(*Mux).Mount.func1(0x16b6be0, 0xc000256280, 0xc00028e100)
/Users/rizaldinurmuhammad/go/src/github.com/go-chi/chi/mux.go:292 +0x127
net/http.HandlerFunc.ServeHTTP(0xc00000e180, 0x16b6be0, 0xc000256280, 0xc00028e100)
/usr/local/Cellar/go/1.12.6/libexec/src/net/http/server.go:1995 +0x44
github.com/go-chi/chi.(*Mux).routeHTTP(0xc0000a5920, 0x16b6be0, 0xc000256280, 0xc00028e100)
/Users/rizaldinurmuhammad/go/src/github.com/go-chi/chi/mux.go:425 +0x27f
net/http.HandlerFunc.ServeHTTP(0xc000020090, 0x16b6be0, 0xc000256280, 0xc00028e100)
/usr/local/Cellar/go/1.12.6/libexec/src/net/http/server.go:1995 +0x44
audioo_api/lib/mid.Limit.func1(0x16b6be0, 0xc000256280, 0xc00028e100)
/Users/rizaldinurmuhammad/go/src/audioo_api/lib/mid/limit.go:79 +0xe5
net/http.HandlerFunc.ServeHTTP(0xc00000e1a0, 0x16b6be0, 0xc000256280, 0xc00028e100)
/usr/local/Cellar/go/1.12.6/libexec/src/net/http/server.go:1995 +0x44
github.com/go-chi/cors.(*Cors).Handler.func1(0x16b6be0, 0xc000256280, 0xc00028e100)
/Users/rizaldinurmuhammad/go/src/github.com/go-chi/cors/cors.go:201 +0x1a4
net/http.HandlerFunc.ServeHTTP(0xc00000e1c0, 0x16b6be0, 0xc000256280, 0xc00028e100)
/usr/local/Cellar/go/1.12.6/libexec/src/net/http/server.go:1995 +0x44
github.com/go-chi/chi/middleware.Recoverer.func1(0x16b6be0, 0xc000256280, 0xc00028e100)
/Users/rizaldinurmuhammad/go/src/github.com/go-chi/chi/middleware/recoverer.go:35 +0x9f
net/http.HandlerFunc.ServeHTTP(0xc00000e1e0, 0x16b6be0, 0xc000256280, 0xc00028e100)
/usr/local/Cellar/go/1.12.6/libexec/src/net/http/server.go:1995 +0x44
github.com/go-chi/chi/middleware.RedirectSlashes.func1(0x16b6be0, 0xc000256280, 0xc00028e100)
/Users/rizaldinurmuhammad/go/src/github.com/go-chi/chi/middleware/strip.go:53 +0x202
net/http.HandlerFunc.ServeHTTP(0xc00000e200, 0x16b6be0, 0xc000256280, 0xc00028e100)
/usr/local/Cellar/go/1.12.6/libexec/src/net/http/server.go:1995 +0x44
github.com/go-chi/chi/middleware.(*Compressor).Handler.func1.1(0x1f69180, 0xc000256240, 0xc00028e100)
/Users/rizaldinurmuhammad/go/src/github.com/go-chi/chi/middleware/compress.go:190 +0x254
net/http.HandlerFunc.ServeHTTP(0xc00000e2c0, 0x1f69180, 0xc000256240, 0xc00028e100)
/usr/local/Cellar/go/1.12.6/libexec/src/net/http/server.go:1995 +0x44
github.com/go-chi/chi/middleware.RequestLogger.func1.1(0x16b78a0, 0xc000226000, 0xc00028e000)
/Users/rizaldinurmuhammad/go/src/github.com/go-chi/chi/middleware/logger.go:46 +0x291
net/http.HandlerFunc.ServeHTTP(0xc00009a210, 0x16b78a0, 0xc000226000, 0xc00028e000)
/usr/local/Cellar/go/1.12.6/libexec/src/net/http/server.go:1995 +0x44
github.com/go-chi/chi.(*Mux).ServeHTTP(0xc0000a5920, 0x16b78a0, 0xc000226000, 0xc000154000)
/Users/rizaldinurmuhammad/go/src/github.com/go-chi/chi/mux.go:82 +0x294
net/http.serverHandler.ServeHTTP(0xc00009c410, 0x16b78a0, 0xc000226000, 0xc000154000)
/usr/local/Cellar/go/1.12.6/libexec/src/net/http/server.go:2774 +0xa8
net/http.(*conn).serve(0xc0002ce640, 0x16b8aa0, 0xc000067340)
/usr/local/Cellar/go/1.12.6/libexec/src/net/http/server.go:1878 +0x851
created by net/http.(*Server).Serve
/usr/local/Cellar/go/1.12.6/libexec/src/net/http/server.go:2884 +0x2f4
我想知道这个问题与r.body有关,但我不知道该如何解决
根据Body io.ReadCloser的软件包文档:
对于客户端请求,nil主体表示该请求没有主体,例如GET请求。对于服务器请求,请求正文始终为非零。
您说的是服务器,因此它始终为非零,因此错误发生在Decode
调用中,您将指针传递给nil指针。
data
是一个nil
指针,&data
是一个指针的nil
指针。
如果数据是非接口类型,则解决方案,除非models
软件包明确禁止new(EditProfile)
:
data = new(models.EditProfile)
errDecode := json.NewDecoder(r.Body).Decode(data)
如果data是接口,请先为其分配一个实值,然后再次传递而无需引用Decode
:errDecode := json.NewDecoder(r.Body).Decode(data)
在后一种情况下,还要仔细检查是否声明了正确的类型*models.EditProfile
。
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我来说两句