html template package renders escaped version of html (unexpected) #26392

rybarix · 2018-07-15T14:58:41Z

Please answer these questions before submitting your issue. Thanks!

What version of Go are you using (`go version`)?

go version go1.10.3 linux/amd64

Does this issue reproduce with the latest release?

yes

What operating system and processor architecture are you using (`go env`)?

GOARCH="amd64"

What did you do?

// issue.go
package main
import (
	"html/template"
	"log"
	"net/http"
)

var templates = template.Must(template.ParseFiles("view_product.html"))
func RenderTemplate(w http.ResponseWriter, tmpl string, data interface{}) {
	err := templates.Execute(w, data)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
	}
}

func controller(w http.ResponseWriter, r *http.Request) {
	viewer.RenderTemplate(w, "view_product", nil)
}
func main() {
	http.HandleFunc("/", controller)
	log.Fatal(http.ListenAndServe(":8080", nil))
}

// view_product.html
<ul>
    <li>Hello</li>
</ul>

What did you expect to see?

interpreted html by browser:

Hello

What did you see instead?

escaped version:

<ul>
    <li>Hello</li>
</ul>

*But if we add <h1>Hello</h1> or div to 'view_product.html', browser renders correctly, (tested on chrome, firefox)

view_product.html -- working version which for some reason renders correctly

<h1>Hello</h1>
<ul>
    <li>Hello</li>
</ul>

There is unexpected behavior, which is not consistent.

The text was updated successfully, but these errors were encountered:

mvdan · 2018-07-15T15:20:55Z

Have you checked what output the html/template.Template renders to? Templates are simply templates - they do not know how a web browser will render them.

rybarix · 2018-07-15T15:24:05Z

but why adding h1 element resolve render issue.
PS Im new to golang.

earthboundkid · 2018-07-16T02:11:21Z

The issue is that the web browser doesn’t know that the page is HTML. You need to set the Content-Type header. Add w.Header().Set("Content-Type", "text/html"). See https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Type for more.

crvv · 2018-07-16T03:39:09Z

If you don't set Content-Type header. Go HTTP server will set it for you.
https://golang.org/pkg/net/http/#ResponseWriter

If the Header does not contain a Content-Type line, Write adds a Content-Type set to the result of passing the initial 512 bytes of written data to DetectContentType.

And DetectContentType thinks

<h1>Hello</h1>
<ul>
    <li>Hello</li>
</ul>

is text/html.

But

<ul>
    <li>Hello</li>
</ul>

is text/plain

I don't think this is a bug. HTML should start with <!DOCTYPE html>

rybarix · 2018-07-16T05:04:38Z

@crvv @carlmjohnson
thank you for explanation, that's enough to close this issue

rybarix closed this as completed Jul 16, 2018

golang locked and limited conversation to collaborators Jul 16, 2019

gopherbot added the FrozenDueToAge label Jul 16, 2019

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html template package renders escaped version of html (unexpected) #26392

html template package renders escaped version of html (unexpected) #26392

rybarix commented Jul 15, 2018 •

edited

mvdan commented Jul 15, 2018

rybarix commented Jul 15, 2018 •

edited

earthboundkid commented Jul 16, 2018 •

edited

crvv commented Jul 16, 2018

rybarix commented Jul 16, 2018 •

edited

html template package renders escaped version of html (unexpected) #26392

html template package renders escaped version of html (unexpected) #26392

Comments

rybarix commented Jul 15, 2018 • edited

What version of Go are you using (go version)?

Does this issue reproduce with the latest release?

What operating system and processor architecture are you using (go env)?

What did you do?

What did you expect to see?

What did you see instead?

mvdan commented Jul 15, 2018

rybarix commented Jul 15, 2018 • edited

earthboundkid commented Jul 16, 2018 • edited

crvv commented Jul 16, 2018

rybarix commented Jul 16, 2018 • edited

rybarix commented Jul 15, 2018 •

edited

What version of Go are you using (`go version`)?

What operating system and processor architecture are you using (`go env`)?

rybarix commented Jul 15, 2018 •

edited

earthboundkid commented Jul 16, 2018 •

edited

rybarix commented Jul 16, 2018 •

edited