2017-02-01 09:01
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I am returing all rows of a table as json to the variable pdata and unmarshaling it into an interface object. I have an instance of the user struct which I would like to pass along with the unmarshalled json data to the render function and access it using field arguments {{.fieldname}} in the html template.

if uuid != "" {
    pdata, err := getProduct()
    if err != nil {

    type Prdata struct {
        Puid     string `json:"puid"`
        Pname    string `json:"pname"`
        Quantity string `json:"quantity"`
        Price    string `json:"price"`
        Image    string `json:"image"`

    // Obj:= make(map[Prdata]string)

    var Pr Prdata

    err = json.Unmarshal(pdata , &Pr)
    if err != nil {


    render(w, "internal", Pr)

fmt.Println(string(pdata)) gives this output


I have only been successful to unmarshal the data into an interface{} object. Trying to make maps with keys of the type interface{} and values of type string but it throws the error:

"json: cannot unmarshal array into Go value of type map[interface {}]string"

The render function takes an argument of the type interface{}

func render(w http.ResponseWriter, name string, data interface{})

fmt.Println(Pr) gives this output:

[map[quantity:100 image:1Appleiphone7.jpeg pname:iphone7 price:70000 puid:d6742e4e-2ad6-43c5-97f4-e8a7b00684e2]]

u is an instance of struct User

var u = &User{}

type User struct {
    Uuid     string            
    Username string           
    Password string           
    Fname    string            
    Email    string            

I can see the output on the html page using the pipeline {{.}}. However I am not able to access any data using the fieldname.

There must be a way of doing this. But I am not sure how?

When I pass of a json of the type below, I am able to pass it to the struct type and reference it by the key values using pipelines in my template.

    str := `{
    "image": "1Appleiphone7.jpeg",
    "pname": "iphone7",
    "price": "70000",
    "puid": "d6742e4e-2ad6-43c5-97f4-e8a7b00684e2",
    "quantity": "100"

unmarshal function

err = json.Unmarshal([]byte(str), &Pr)

The difference in the json data of the DB record pdata and the one above str is in the use of backticks "`". It seems that though the json data shows key value pairs, it is actually a json array and not a json object. Is there a way to get around this?

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2条回答 默认 最新

  • douliexu5623 2017-02-04 09:36

    I am posting a working example of unmarshalling json as bytes into a struct type which then can be referenced using the {{.}} in the template.

    package main

    import (
    type Usrdata struct {
        Uuid  string
        Fname string
    type Prdata struct {
        Puid     string `json:"puid"`
        Pname    string `json:"pname"`
        Quantity string `json:"quantity"`
        Price    string `json:"price"`
        Image    string `json:"image"`
    type Data struct {
        U Usrdata
        P []Prdata
    func main() {
        Ur := Usrdata{Uuid: "xyz", Fname: "Somename"}
        Pr := make([]Prdata, 0)
        var Dt Data
        Dt.U = Ur
        pdata := `[{"image":"1Appleiphone7.jpeg","pname":"iphone7","price":"70000","puid":"d6742e4e-2ad6-43c5-97f4-e8a7b00684e2","quantity":"100"}]`
        err := json.Unmarshal([]byte(pdata), &Pr)
        if err != nil {
        Dt.P = Pr
    解决 无用
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