Golang template - how to render templates?

Question

One layout template with three children templates.

layout.html

  
    {{template \"tags\"}}

    {{template \"content\"}}

          


        

Answer 1

As always, the doc is a good place to start.

I wrote a working example on the playground

To explain a bit:

1. You don't need strings in struct literals: &Tags{Id: 1}, not &Tags{"Id":1}
2. You can only pass a single object to your template to execute, which will dispatch objects to each subtemplate as you require in the {{template }} instruction. I used a ad-hoc Page struct, but a map[string]interface{} would do if you prefer.
3. You need to parse each template (I used strings in the Playground, but ParseFiles would do if you have your html files already)
4. I used os.Stdout to execute it, but you should obviously replace that by the corresponding ResponseWriter

And the whole code:

package main

import "fmt"
import "html/template"
import "os"

var page = `
  
    {{template "tags" .Tags}}

    {{template "content" .Content}}

    {{template "comment" .Comment}}
  
`

var tags = `{{define "tags"}}

    {{.Name}}

{{end}}`

var content = `{{define "content"}}

   
{{.Title}}
   
{{.Content}}

{{end}}`

var comment = `{{define "comment"}}

    {{.Note}}

{{end}}`

type Tags struct {
   Id int
   Name string
}

type Content struct {
   Id int
   Title string
   Content string
}

type Comment struct {
   Id int
   Note string
}

type Page struct {
    Tags *Tags
    Content *Content
    Comment *Comment
}

func main() {
    pagedata := &Page{Tags:&Tags{Id:1, Name:"golang"},
                      Content: &Content{Id:9, Title:"Hello", Content:"World!"},
                      Comment: &Comment{Id:2, Note:"Good Day!"}}
    tmpl := template.New("page")
    var err error
    if tmpl, err = tmpl.Parse(page); err != nil {
        fmt.Println(err)
    }
    if tmpl, err = tmpl.Parse(tags); err != nil {
        fmt.Println(err)
    }
    if tmpl, err = tmpl.Parse(comment); err != nil {
        fmt.Println(err)
    }
    if tmpl, err = tmpl.Parse(content); err != nil {
        fmt.Println(err)
    }
    tmpl.Execute(os.Stdout, pagedata)
}