如何在单个函数golang中从不同文件解码两个不同的结构？

Question

I want to decode the two different struct for saving the data into the collection. but it gives error.

The two struct are given below these two files are in the folder named models.

User.go

type User struct {
 Id                         int         `json:"id" bson:"_id,omitempty"`
 FirstName                  string      `json:"first_name,omitempty" bson:"first_name,omitempty"`
 LastName                   string      `json:"last_name,omitempty" bson:"last_name,omitempty"`
 EmailId                    string      `json:"email_id,omitempty" bson:"email_id,omitempty"`
 Password                   string      `json:"password,omitempty" bson:"password,omitempty"`
 PhoneNumber                string      `json:"phone_number,omitempty" bson:"phone_number,omitempty"`
 AltPhoneNumber             string      `json:"alt_phone_number" bson:"alt_phone_number"`
 Gender                     string      `json:"gender,omitempty" bson:"gender,omitempty"`
 Note                       string      `json:"note,omitempty" bson:"note,omitempty"`
}

Provider.go

type Provider struct {
 Id                      int                `json:"id" bson:"_id,omitempty"`
 Uid                     int                `json:"uid" bson:"uid,omitempty"`
 Speed                   string             `json:"speed,omitempty" bson:"speed,omitempty"`
 ProviderCategory        string             `json:"provider_category,omitempty" bson:"provider_category,omitempty"`
 Priority                int                `json:"priority,omitempty" bson:"priority,omitempty"`
}

The code I tried to decode them

import (
    "encoding/json"
    "go-training/models"
    "github.com/gin-gonic/gin"
    "fmt"
)

var provider models.Provider
var user models.User

func SaveProvider(c *gin.Context) {
    response := ResponseController{}
    //decode the struct
    providerErr := json.NewDecoder(c.Request.Body).Decode(&provider)
    fmt.Println(providerErr) //Output:- nil
    userErr := json.NewDecoder(c.Request.Body).Decode(&user)
    fmt.Println(userErr) //output:- EOF
    if userErr != nil {
        fmt.Println("data is not properly formatted")
    }
    if providerErr != nil {
        fmt.Printl?("data is not properly formatted")
    }
}

Data entered in the json form-

{
 "Id":1,
 "Uid":1,
 "speed":"new",
 "provider_category":"WL",
 "priority":1,
 "first_name":"puneet",
 "last_name":"jindal",
 "email_id":"[e-mail]",
 "password":"poiuytrewq",
 "phone_number":"9876543210",
 "alt_phone_number":"9876543210",
 "gender":"male",
 "note":"phase 7"
}    

Error:- EOF

How can I solve this problem? Can anyone help me? Thank you.

Answer 1

The code in the question does not work because the first decoder reads the entire request body. The second decoder starts at EOF.

The fix is to slurp up the body to a byte slice and unmarshal twice from that slice:

// slurp up the body.  p is a []byte
p, err := ioutil.ReadAll(c.Request.Body)
if err != nil {
   // handler error
}

var provider models.Provider
if err := json.Unmarshal(p, &provider); err != nil {
    // handle error
}

var user models.User
if err := json.Unmarshal(p, &user); err != nil {
     // handle error
}