gogo-templates

Golang template - how to render templates?

One layout template with three children templates.

layout.html

<html>
  <body>
    {{template "tags"}}

    {{template "content"}}

    {{template "comment"}}
  </body>
</html>

tags.html

{{define "tags"}}
<div>
    {{.Name}}
<div>
{{end}}

content.html

{{define "content"}}
<div>
   <p>{{.Title}}</p>
   <p>{{.Content}}</p>
</div>
{{end}}

comment.html

{{define "tags"}}
<div>
    {{.Note}}
</div>
{{end}}

gocode

type Tags struct {
   Id int
   Name string
}

type Content struct {
   Id int
   Title string
   Content string
}

type Comment struct {
   Id int
   Note string
}


func main() {
    tags := &Tags{"Id":1, "Name":"golang"}
    Content := &Content{"Id":9, "Title":"Hello", "Content":"World!"}
    Comment := &Comment{"Id":2, "Note":"Good Day!"}
}

I am confused that how to render each children template and combine the result to layout output.

Thanks.

Solution

  • 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 <name> <arg>}} 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 = `<html>
  <body>
    {{template "tags" .Tags}}

    {{template "content" .Content}}

    {{template "comment" .Comment}}
  </body>
</html>`

var tags = `{{define "tags"}}
<div>
    {{.Name}}
<div>
{{end}}`

var content = `{{define "content"}}
<div>
   <p>{{.Title}}</p>
   <p>{{.Content}}</p>
</div>
{{end}}`

var comment = `{{define "comment"}}
<div>
    {{.Note}}
</div>
{{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)
}