Go template.ExecuteTemplate include html

Question

I have followed this tutorial: http://golang.org/doc/articles/wiki/final.go and have slightly modified it for my needs/wants. The problem is I would like to support HTML in

Answer 1

Here's an approach that doesn't require any changes to your existing structs, and a very minimal, additive change to your templates:

Change these lines:

var (
    templates = template.Must(template.ParseFiles("tmpl/edit.html", "tmpl/view.html"))
)

to this (include a funcmap with a function that will output un-escaped HTML):

var templates = template.Must(template.New("main").Funcs(template.FuncMap{
    "safeHTML": func(b []byte) template.HTML {
        return template.HTML(b)
    },
}).ParseFiles("tmpl/edit.html", "tmpl/view.html"))

And then just change your template HTML from this:

<div>{{printf "%s" .Body}}</div>

to this (use your new function):

<div>{{ .Body | safeHTML }}</div>

Much easier!

Answer 2

I created a custom function for the template as follows:

func noescape(str string) template.HTML {
    return template.HTML(str)
}

var fn = template.FuncMap{
    "noescape": noescape,
}

Then on your template:

{{ noescape $x.Body }}

Answer 3

Convert your []byte or string to type template.HTML (documented here)

p.Body = template.HTML(s) // where s is a string or []byte

Then, in your template, just:

{{.Body}}

It will be printed without escaping.

EDIT

In order to be able to include HTML in you page's body you need to change the Page type declaration:

type Page struct {
    Title string
    Body  template.HTML
}

then assign to it.

Answer 4

In my case (where I am populating a view struct with a list of Activity), I had to change the property Message string to Message template.HTML. Then, when setting the property value I can call activity.Message = template.HTML("The <b>HTML</b>").

Answer 5

For clarification and a much simpler way of passing HTML to template, see

https://groups.google.com/forum/#!topic/golang-nuts/8L4eDkr5Q84

Just create your HTML string via go and pass it into your template, e.g.:

Sout := ""
.
.

    Sout += fmt.Sprintf(`<tr><td>%s<td align=center>%.2f<td>%s<td>%s<td>%s<td>%s<td align=center>%d<td align=center>%d
                    <td align=center>%d`, AccountID, amount, remissiondetails, created, begins, ends,
                    freePDFs, freeinformants, freeSDQs)

.
.
    render(w, "templates/Waivers.html", map[string]interface{}{ "Body":template.HTML(Sout), })

Answer 6

Take a look at the template.HTML type. It can be used to encapsulate a known safe fragment of HTML (like the output from Markdown). The "html/template" package will not escape this this type.

type Page struct {
    Title string
    Body template.HTML
}

page := &Page{
    Title: "Example",
    Body:  template.HTML(blackfriday.MarkdownCommon([]byte("foo bar")),
}

I usually write my own func Markdown(text string) html.Template method that calls blackfriday with the appropriate config and does some type conversions. Another alternative might be also to register a "html" func in the template parser, that allows you to output any value without any escaping by doing something like {{html .MySafeStr}}. The code might look like:

var tmpl = template.Must(template.New("").Funcs(template.FuncMap{
    "html": func(value interface{}) template.HTML {
        return template.HTML(fmt.Sprint(value))
    },
}).ParseFiles("file1.html", "file2.html"))