template

README

template

Use both "text/template" & "html/template" together under a common umbrella.

background

Shall be written another day :-)

package docu

Package template implements the interface common to the standard packages "text/template" and "html/template" as type Template.

Thus, it exploits the fact, that

  package `html/template` provides the same interface as package `text/template`
  and should be used instead of `text/template` whenever the output is HTML
  as it automatically secures HTML output against certain attacks.

as said in go doc text/template and go doc html/template.

All methods and all package level functions are forewarded.

Instead of a single New(name) this package unsurprisingly provides two constructors:

• template.Text(name) &

• template.HTML(name).

Note: The package level functions ParseFiles & ParseGlob became

• ParseTextFiles / ParseHTMLfile resp.

• ParseTextGlob / ParseHTMLglob.

Thus, the exported type Template represents the template used, be it html or text.

Also the type FuncMap is forwarded.

Note: Clients in need to access any other type

• such as ExecError (from "text/template") or

• data types such as HTML, CSS, JS and friends

• as well as Error and ErrorCode (from "html/template")

are requested to use the respective standard package directly for access to the error and data types.

For example escape_test.go uses

  import( data "html/template" )

and refers to

  data.HTML, data.CSS, data.JS ...

later.

Implementation notes

• doc.go just documents the package (as quoted above) for go doc github.com/GoLangsam/template
• template.go defines the interface type Template (and the convenient wrapper Must and the ubiquous type FuncMap)
• forward.go forwards package level functions. It'is simply taken from "html/template" as noted inside.
• wrapTemplateText.go and wrapTemplateHTML.go define respective (private) implementation types, foreward the methods (if need) and the Parse... functions. Intentionally they are as similar possible.

Examples and test

All *_test.go files from both standard packages are used! (Except as noted below.)

Adjusted are just things such as:

• package declarations
  • template => template_test
  • in order to avoid spurious bug: duplicate flag definition debug
• imports
  • "text/template" resp. "html/template" => "github.com/GoLangsam/template"
• references to type Template
  • *Template => Template
• constructors
  • New => Text resp. HTML
• the global Parse-functions
  • template.Parse... => template.ParseText... resp. template.ParseHTML...
• data types from "html/template"
  • imported as data, and types used accordingly, e.g.
  • template.HTML => data.HTML
• few portions are deactivated / commented, as they require internals of the underlying package
  • css_test.go, html_test.go, js_test.go url_test.go and from "html/template" are entirely omitted for same reason
• misspellings: Cincinatti => Cincinnati
  • in order to make Go Report Card more happy :-)

As of now, no additional tests are provided. The author could not think of anything reasonable yet.

Your suggestions, remarks, questions and/or contributions are welcome ;-)

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Documentation

Overview

Package template implements the interface common to the standard packages "text/template" and "html/template" as type Template.

Thus, it exploits the fact, that

package html/template provides the same interface as package text/template
and should be used instead of text/template whenever the output is HTML
as it automatically secures HTML output against certain attacks.

as said in go doc text/template and go doc html/template.

All methods and all package level functions are forewarded.

Instead of a single New(name) this package unsurprisingly provides two constructors:

- template.Text(name) &

- template.HTML(name).

Note: The package level functions ParseFiles & ParseGlob became

- ParseTextFiles / ParseHTMLfile resp.

- ParseTextGlob / ParseHTMLglob.

Thus, the exported type Template represents the template used, be it html or text.

Also the type FuncMap is forwarded.

Note: Clients in need to access any other type

- such as ExecError (from "text/template") or

- data types such as HTML, CSS, JS and friends

- as well as Error and ErrorCode (from "html/template")

are requested to use the respective standard package directly for access to the error and data types.

For example escape_test.go uses

import( data "html/template" )

and refers to

data.HTML, data.CSS, data.JS ...

later.

Index

• func HTMLEscape(w io.Writer, b []byte)
• func HTMLEscapeString(s string) string
• func HTMLEscaper(args ...interface{}) string
• func IsTrue(val interface{}) (truth, ok bool)
• func JSEscape(w io.Writer, b []byte)
• func JSEscapeString(s string) string
• func JSEscaper(args ...interface{}) string
• func URLQueryEscaper(args ...interface{}) string
• type FuncMap
• type Template
  • func HTML(Name string) Template
  • func Must(t Template, err error) Template
  • func ParseHTMLfiles(filenames ...string) (Template, error)
  • func ParseHTMLglob(pattern string) (Template, error)
  • func ParseTextFiles(filenames ...string) (Template, error)
  • func ParseTextGlob(pattern string) (Template, error)
  • func Text(Name string) Template

Examples

• HTML
• HTML (Autoescaping)
• HTML (Block)
• HTML (Escape)
• Template (Autoescaping)
• Template (Block)
• Template (Escape)
• Template (Func)
• Template (Glob)
• Template (Helpers)
• Template (Html)
• Template (Parsefiles)
• Template (Share)
• Template (Text)
• Text (Block)
• Text (Text)

Functions

func HTMLEscape

func HTMLEscape(w io.Writer, b []byte)

HTMLEscape writes to w the escaped HTML equivalent of the plain text data b.

func HTMLEscapeString

func HTMLEscapeString(s string) string

HTMLEscapeString returns the escaped HTML equivalent of the plain text data s.

func HTMLEscaper

func HTMLEscaper(args ...interface{}) string

HTMLEscaper returns the escaped HTML equivalent of the textual representation of its arguments.

func IsTrue

func IsTrue(val interface{}) (truth, ok bool)

IsTrue reports whether the value is 'true', in the sense of not the zero of its type, and whether the value has a meaningful truth value. This is the definition of truth used by if and other such actions.

func JSEscape

func JSEscape(w io.Writer, b []byte)

JSEscape writes to w the escaped JavaScript equivalent of the plain text data b.

func JSEscapeString

func JSEscapeString(s string) string

JSEscapeString returns the escaped JavaScript equivalent of the plain text data s.

func JSEscaper

func JSEscaper(args ...interface{}) string

JSEscaper returns the escaped JavaScript equivalent of the textual representation of its arguments.

func URLQueryEscaper

func URLQueryEscaper(args ...interface{}) string

URLQueryEscaper returns the escaped value of the textual representation of its arguments in a form suitable for embedding in a URL query.

Types

type FuncMap

type FuncMap map[string]interface{}

FuncMap is the type of the map defining the mapping from names to functions. Each function must have either a single return value, or two return values of which the second has type error. In that case, if the second (error) return value evaluates to non-nil during execution, execution terminates and Execute returns that error.

When template execution invokes a function with an argument list, that list must be assignable to the function's parameter types. Functions meant to apply to arguments of arbitrary type can use parameters of type interface{} or of type reflect.Value. Similarly, functions meant to return a result of arbitrary type can return interface{} or reflect.Value.

type Template

type Template interface {
	AddParseTree(name string, tree *parse.Tree) (Template, error)
	Clone() (Template, error)
	DefinedTemplates() string
	Delims(left, right string) Template
	Execute(wr io.Writer, data interface{}) error
	ExecuteTemplate(wr io.Writer, name string, data interface{}) error
	Funcs(funcMap map[string]interface{}) Template
	Lookup(name string) Template
	Name() string
	New(name string) Template
	Option(opt ...string) Template
	Parse(text string) (Template, error)
	ParseFiles(filenames ...string) (Template, error)
	ParseGlob(pattern string) (Template, error)
	Templates() []Template
}

Template represents the template used (html or text).

For documentation of these methods please refer to the respective underlying standard package, e.g. `go doc text/template Parse` or `go doc html/template ExecuteTemplate`.

Example (Autoescaping)

package main

import (
	"log"
	"os"

	"github.com/GoLangsam/template"
)

func main() {
	check := func(err error) {
		if err != nil {
			log.Fatal(err)
		}
	}
	t, err := template.HTML("foo").Parse(`{{define "T"}}Hello, {{.}}!{{end}}`)
	check(err)
	err = t.ExecuteTemplate(os.Stdout, "T", "<script>alert('you have been pwned')</script>")
	check(err)
}

Output:

Hello, <script>alert('you have been pwned')</script>!

Example (Block)

package main

import (
	"log"
	"os"
	"strings"

	"github.com/GoLangsam/template"
)

func main() {
	const (
		master  = `Names:{{block "list" .}}{{"\n"}}{{range .}}{{println "-" .}}{{end}}{{end}}`
		overlay = `{{define "list"}} {{join . ", "}}{{end}} `
	)
	var (
		funcs     = template.FuncMap{"join": strings.Join}
		guardians = []string{"Gamora", "Groot", "Nebula", "Rocket", "Star-Lord"}
	)
	masterTmpl, err := template.HTML("master").Funcs(funcs).Parse(master)
	if err != nil {
		log.Fatal(err)
	}
	overlayTmpl, err := template.Must(masterTmpl.Clone()).Parse(overlay)
	if err != nil {
		log.Fatal(err)
	}
	if err := masterTmpl.Execute(os.Stdout, guardians); err != nil {
		log.Fatal(err)
	}
	if err := overlayTmpl.Execute(os.Stdout, guardians); err != nil {
		log.Fatal(err)
	}
}

Output:

Names:
- Gamora
- Groot
- Nebula
- Rocket
- Star-Lord
Names: Gamora, Groot, Nebula, Rocket, Star-Lord

Example (Escape)

package main

import (
	"fmt"

	"os"

	"github.com/GoLangsam/template"
)

func main() {
	const s = `"Fran & Freddie's Diner" <tasty@example.com>`
	v := []interface{}{`"Fran & Freddie's Diner"`, ' ', `<tasty@example.com>`}

	fmt.Println(template.HTMLEscapeString(s))
	template.HTMLEscape(os.Stdout, []byte(s))
	fmt.Fprintln(os.Stdout, "")
	fmt.Println(template.HTMLEscaper(v...))

	fmt.Println(template.JSEscapeString(s))
	template.JSEscape(os.Stdout, []byte(s))
	fmt.Fprintln(os.Stdout, "")
	fmt.Println(template.JSEscaper(v...))

	fmt.Println(template.URLQueryEscaper(v...))

}

Output:

"Fran & Freddie's Diner" <tasty@example.com>
"Fran & Freddie's Diner" <tasty@example.com>
"Fran & Freddie's Diner"32<tasty@example.com>
\"Fran & Freddie\'s Diner\" \x3Ctasty@example.com\x3E
\"Fran & Freddie\'s Diner\" \x3Ctasty@example.com\x3E
\"Fran & Freddie\'s Diner\"32\x3Ctasty@example.com\x3E
%22Fran+%26+Freddie%27s+Diner%2232%3Ctasty%40example.com%3E

Example (Func)

This example demonstrates a custom function to process template text. It installs the strings.Title function and uses it to Make Title Text Look Good In Our Template's Output.

package main

import (
	"log"
	"os"
	"strings"

	"github.com/GoLangsam/template"
)

func main() {
	// First we create a FuncMap with which to register the function.
	funcMap := template.FuncMap{
		// The name "title" is what the function will be called in the template text.
		"title": strings.Title,
	}

	// A simple template definition to test our function.
	// We print the input text several ways:
	// - the original
	// - title-cased
	// - title-cased and then printed with %q
	// - printed with %q and then title-cased.
	const templateText = `
Input: {{printf "%q" .}}
Output 0: {{title .}}
Output 1: {{title . | printf "%q"}}
Output 2: {{printf "%q" . | title}}
`

	// Create a template, add the function map, and parse the text.
	tmpl, err := template.Text("titleTest").Funcs(funcMap).Parse(templateText)
	if err != nil {
		log.Fatalf("parsing: %s", err)
	}

	// Run the template to verify the output.
	err = tmpl.Execute(os.Stdout, "the go programming language")
	if err != nil {
		log.Fatalf("execution: %s", err)
	}

}

Output:

Input: "the go programming language"
Output 0: The Go Programming Language
Output 1: "The Go Programming Language"
Output 2: "The Go Programming Language"

Example (Glob)

Here we demonstrate loading a set of templates from a directory.

package main

import (
	"io"
	"io/ioutil"
	"log"
	"os"
	"path/filepath"

	"github.com/GoLangsam/template"
)

// templateFile defines the contents of a template to be stored in a file, for testing.
type templateFile struct {
	name     string
	contents string
}

func createTestDir(files []templateFile) string {
	dir, err := ioutil.TempDir("", "template")
	if err != nil {
		log.Fatal(err)
	}
	for _, file := range files {
		f, err := os.Create(filepath.Join(dir, file.name))
		if err != nil {
			log.Fatal(err)
		}
		defer f.Close()
		_, err = io.WriteString(f, file.contents)
		if err != nil {
			log.Fatal(err)
		}
	}
	return dir
}

func main() {
	// Here we create a temporary directory and populate it with our sample
	// template definition files; usually the template files would already
	// exist in some location known to the program.
	dir := createTestDir([]templateFile{
		// T0.tmpl is a plain template file that just invokes T1.
		{"T0.tmpl", `T0 invokes T1: ({{template "T1"}})`},
		// T1.tmpl defines a template, T1 that invokes T2.
		{"T1.tmpl", `{{define "T1"}}T1 invokes T2: ({{template "T2"}}){{end}}`},
		// T2.tmpl defines a template T2.
		{"T2.tmpl", `{{define "T2"}}This is T2{{end}}`},
	})
	// Clean up after the test; another quirk of running as an example.
	defer os.RemoveAll(dir)

	// pattern is the glob pattern used to find all the template files.
	pattern := filepath.Join(dir, "*.tmpl")

	// Here starts the example proper.
	// T0.tmpl is the first name matched, so it becomes the starting template,
	// the value returned by ParseGlob.
	tmpl := template.Must(template.ParseHTMLglob(pattern))

	err := tmpl.Execute(os.Stdout, nil)
	if err != nil {
		log.Fatalf("template execution: %s", err)
	}
}

Output:

T0 invokes T1: (T1 invokes T2: (This is T2))

Example (Helpers)

This example demonstrates one way to share some templates and use them in different contexts. In this variant we add multiple driver templates by hand to an existing bundle of templates.

package main

import (
	"io"
	"io/ioutil"
	"log"
	"os"
	"path/filepath"

	"github.com/GoLangsam/template"
)

// templateFile defines the contents of a template to be stored in a file, for testing.
type templateFile struct {
	name     string
	contents string
}

func createTestDir(files []templateFile) string {
	dir, err := ioutil.TempDir("", "template")
	if err != nil {
		log.Fatal(err)
	}
	for _, file := range files {
		f, err := os.Create(filepath.Join(dir, file.name))
		if err != nil {
			log.Fatal(err)
		}
		defer f.Close()
		_, err = io.WriteString(f, file.contents)
		if err != nil {
			log.Fatal(err)
		}
	}
	return dir
}

func main() {
	// Here we create a temporary directory and populate it with our sample
	// template definition files; usually the template files would already
	// exist in some location known to the program.
	dir := createTestDir([]templateFile{
		// T1.tmpl defines a template, T1 that invokes T2.
		{"T1.tmpl", `{{define "T1"}}T1 invokes T2: ({{template "T2"}}){{end}}`},
		// T2.tmpl defines a template T2.
		{"T2.tmpl", `{{define "T2"}}This is T2{{end}}`},
	})
	// Clean up after the test; another quirk of running as an example.
	defer os.RemoveAll(dir)

	// pattern is the glob pattern used to find all the template files.
	pattern := filepath.Join(dir, "*.tmpl")

	// Here starts the example proper.
	// Load the helpers.
	templates := template.Must(template.ParseHTMLglob(pattern))
	// Add one driver template to the bunch; we do this with an explicit template definition.
	_, err := templates.Parse("{{define `driver1`}}Driver 1 calls T1: ({{template `T1`}})\n{{end}}")
	if err != nil {
		log.Fatal("parsing driver1: ", err)
	}
	// Add another driver template.
	_, err = templates.Parse("{{define `driver2`}}Driver 2 calls T2: ({{template `T2`}})\n{{end}}")
	if err != nil {
		log.Fatal("parsing driver2: ", err)
	}
	// We load all the templates before execution. This package does not require
	// that behavior but html/template's escaping does, so it's a good habit.
	err = templates.ExecuteTemplate(os.Stdout, "driver1", nil)
	if err != nil {
		log.Fatalf("driver1 execution: %s", err)
	}
	err = templates.ExecuteTemplate(os.Stdout, "driver2", nil)
	if err != nil {
		log.Fatalf("driver2 execution: %s", err)
	}
}

Output:

Driver 1 calls T1: (T1 invokes T2: (This is T2))
Driver 2 calls T2: (This is T2)

Example (Html)

package main

import (
	"log"
	"os"

	"github.com/GoLangsam/template"
)

func main() {
	const tpl = `
<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title>{{.Title}}</title>
	</head>
	<body>
		{{range .Items}}<div>{{ . }}</div>{{else}}<div><strong>no rows</strong></div>{{end}}
	</body>
</html>`

	check := func(err error) {
		if err != nil {
			log.Fatal(err)
		}
	}
	t, err := template.HTML("webpage").Parse(tpl)
	check(err)

	data := struct {
		Title string
		Items []string
	}{
		Title: "My page",
		Items: []string{
			"My photos",
			"My blog",
		},
	}

	err = t.Execute(os.Stdout, data)
	check(err)

	noItems := struct {
		Title string
		Items []string
	}{
		Title: "My another page",
		Items: []string{},
	}

	err = t.Execute(os.Stdout, noItems)
	check(err)

}

Output:

<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title>My page</title>
	</head>
	<body>
		<div>My photos</div><div>My blog</div>
	</body>
</html>
<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title>My another page</title>
	</head>
	<body>
		<div><strong>no rows</strong></div>
	</body>
</html>

Example (Parsefiles)

Here we demonstrate loading a set of templates from files in different directories

package main

import (
	"io"
	"io/ioutil"
	"log"
	"os"
	"path/filepath"

	"github.com/GoLangsam/template"
)

// templateFile defines the contents of a template to be stored in a file, for testing.
type templateFile struct {
	name     string
	contents string
}

func createTestDir(files []templateFile) string {
	dir, err := ioutil.TempDir("", "template")
	if err != nil {
		log.Fatal(err)
	}
	for _, file := range files {
		f, err := os.Create(filepath.Join(dir, file.name))
		if err != nil {
			log.Fatal(err)
		}
		defer f.Close()
		_, err = io.WriteString(f, file.contents)
		if err != nil {
			log.Fatal(err)
		}
	}
	return dir
}

func main() {
	// Here we create different temporary directories and populate them with our sample
	// template definition files; usually the template files would already
	// exist in some location known to the program.
	dir1 := createTestDir([]templateFile{
		// T1.tmpl is a plain template file that just invokes T2.
		{"T1.tmpl", `T1 invokes T2: ({{template "T2"}})`},
	})

	dir2 := createTestDir([]templateFile{
		// T2.tmpl defines a template T2.
		{"T2.tmpl", `{{define "T2"}}This is T2{{end}}`},
	})

	// Clean up after the test; another quirk of running as an example.
	defer func(dirs ...string) {
		for _, dir := range dirs {
			os.RemoveAll(dir)
		}
	}(dir1, dir2)

	// Here starts the example proper.
	// Let's just parse only dir1/T0 and dir2/T2
	paths := []string{
		filepath.Join(dir1, "T1.tmpl"),
		filepath.Join(dir2, "T2.tmpl"),
	}
	tmpl := template.Must(template.ParseHTMLfiles(paths...))

	err := tmpl.Execute(os.Stdout, nil)
	if err != nil {
		log.Fatalf("template execution: %s", err)
	}
}

Output:

T1 invokes T2: (This is T2)

Example (Share)

This example demonstrates how to use one group of driver templates with distinct sets of helper templates.

package main

import (
	"io"
	"io/ioutil"
	"log"
	"os"
	"path/filepath"

	"github.com/GoLangsam/template"
)

// templateFile defines the contents of a template to be stored in a file, for testing.
type templateFile struct {
	name     string
	contents string
}

func createTestDir(files []templateFile) string {
	dir, err := ioutil.TempDir("", "template")
	if err != nil {
		log.Fatal(err)
	}
	for _, file := range files {
		f, err := os.Create(filepath.Join(dir, file.name))
		if err != nil {
			log.Fatal(err)
		}
		defer f.Close()
		_, err = io.WriteString(f, file.contents)
		if err != nil {
			log.Fatal(err)
		}
	}
	return dir
}

func main() {
	// Here we create a temporary directory and populate it with our sample
	// template definition files; usually the template files would already
	// exist in some location known to the program.
	dir := createTestDir([]templateFile{
		// T0.tmpl is a plain template file that just invokes T1.
		{"T0.tmpl", "T0 ({{.}} version) invokes T1: ({{template `T1`}})\n"},
		// T1.tmpl defines a template, T1 that invokes T2. Note T2 is not defined
		{"T1.tmpl", `{{define "T1"}}T1 invokes T2: ({{template "T2"}}){{end}}`},
	})
	// Clean up after the test; another quirk of running as an example.
	defer os.RemoveAll(dir)

	// pattern is the glob pattern used to find all the template files.
	pattern := filepath.Join(dir, "*.tmpl")

	// Here starts the example proper.
	// Load the drivers.
	drivers := template.Must(template.HTML("T0.tmpl").ParseGlob(pattern))

	// We must define an implementation of the T2 template. First we clone
	// the drivers, then add a definition of T2 to the template name space.

	// 1. Clone the helper set to create a new name space from which to run them.
	first, err := drivers.Clone()
	if err != nil {
		log.Fatal("cloning helpers: ", err)
	}
	// 2. Define T2, version A, and parse it.
	_, err = first.Parse("{{define `T2`}}T2, version A{{end}}")
	if err != nil {
		log.Fatal("parsing T2: ", err)
	}

	// Now repeat the whole thing, using a different version of T2.
	// 1. Clone the drivers.
	second, err := drivers.Clone()
	if err != nil {
		log.Fatal("cloning drivers: ", err)
	}
	// 2. Define T2, version B, and parse it.
	_, err = second.Parse("{{define `T2`}}T2, version B{{end}}")
	if err != nil {
		log.Fatal("parsing T2: ", err)
	}

	// Execute the templates in the reverse order to verify the
	// first is unaffected by the second.
	err = second.ExecuteTemplate(os.Stdout, "T0.tmpl", "second")
	if err != nil {
		log.Fatalf("second execution: %s", err)
	}
	err = first.ExecuteTemplate(os.Stdout, "T0.tmpl", "first")
	if err != nil {
		log.Fatalf("first: execution: %s", err)
	}

}

Output:

T0 (second version) invokes T1: (T1 invokes T2: (T2, version B))
T0 (first version) invokes T1: (T1 invokes T2: (T2, version A))

Example (Text)

package main

import (
	"log"
	"os"

	"github.com/GoLangsam/template"
)

func main() {
	// Define a template.
	const letter = `
Dear {{.Name}},
{{if .Attended}}
It was a pleasure to see you at the wedding.
{{- else}}
It is a shame you couldn't make it to the wedding.
{{- end}}
{{with .Gift -}}
Thank you for the lovely {{.}}.
{{end}}
Best wishes,
Josie
`

	// Prepare some data to insert into the template.
	type Recipient struct {
		Name, Gift string
		Attended   bool
	}
	var recipients = []Recipient{
		{"Aunt Mildred", "bone china tea set", true},
		{"Uncle John", "moleskin pants", false},
		{"Cousin Rodney", "", false},
	}

	// Create a new template and parse the letter into it.
	t := template.Must(template.Text("letter").Parse(letter))

	// Execute the template for each recipient.
	for _, r := range recipients {
		err := t.Execute(os.Stdout, r)
		if err != nil {
			log.Println("executing template:", err)
		}
	}

}

Output:

Dear Aunt Mildred,

It was a pleasure to see you at the wedding.
Thank you for the lovely bone china tea set.

Best wishes,
Josie

Dear Uncle John,

It is a shame you couldn't make it to the wedding.
Thank you for the lovely moleskin pants.

Best wishes,
Josie

Dear Cousin Rodney,

It is a shame you couldn't make it to the wedding.

Best wishes,
Josie

func HTML

func HTML(Name string) Template

HTML returns a new "html/template" Template

Example

package main

import (
	"log"
	"os"

	"github.com/GoLangsam/template"
)

func main() {
	const tpl = `
<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title>{{.Title}}</title>
	</head>
	<body>
		{{range .Items}}<div>{{ . }}</div>{{else}}<div><strong>no rows</strong></div>{{end}}
	</body>
</html>`

	check := func(err error) {
		if err != nil {
			log.Fatal(err)
		}
	}
	t, err := template.HTML("webpage").Parse(tpl)
	check(err)

	data := struct {
		Title string
		Items []string
	}{
		Title: "My page",
		Items: []string{
			"My photos",
			"My blog",
		},
	}

	err = t.Execute(os.Stdout, data)
	check(err)

	noItems := struct {
		Title string
		Items []string
	}{
		Title: "My another page",
		Items: []string{},
	}

	err = t.Execute(os.Stdout, noItems)
	check(err)

}

Output:

<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title>My page</title>
	</head>
	<body>
		<div>My photos</div><div>My blog</div>
	</body>
</html>
<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title>My another page</title>
	</head>
	<body>
		<div><strong>no rows</strong></div>
	</body>
</html>

Example (Autoescaping)

package main

import (
	"log"
	"os"

	"github.com/GoLangsam/template"
)

func main() {
	check := func(err error) {
		if err != nil {
			log.Fatal(err)
		}
	}
	t, err := template.HTML("foo").Parse(`{{define "T"}}Hello, {{.}}!{{end}}`)
	check(err)
	err = t.ExecuteTemplate(os.Stdout, "T", "<script>alert('you have been pwned')</script>")
	check(err)
}

Output:

Hello, <script>alert('you have been pwned')</script>!

Example (Block)

package main

import (
	"log"
	"os"
	"strings"

	"github.com/GoLangsam/template"
)

func main() {
	const (
		master  = `Names:{{block "list" .}}{{"\n"}}{{range .}}{{println "-" .}}{{end}}{{end}}`
		overlay = `{{define "list"}} {{join . ", "}}{{end}} `
	)
	var (
		funcs     = template.FuncMap{"join": strings.Join}
		guardians = []string{"Gamora", "Groot", "Nebula", "Rocket", "Star-Lord"}
	)
	masterTmpl, err := template.HTML("master").Funcs(funcs).Parse(master)
	if err != nil {
		log.Fatal(err)
	}
	overlayTmpl, err := template.Must(masterTmpl.Clone()).Parse(overlay)
	if err != nil {
		log.Fatal(err)
	}
	if err := masterTmpl.Execute(os.Stdout, guardians); err != nil {
		log.Fatal(err)
	}
	if err := overlayTmpl.Execute(os.Stdout, guardians); err != nil {
		log.Fatal(err)
	}
}

Output:

Names:
- Gamora
- Groot
- Nebula
- Rocket
- Star-Lord
Names: Gamora, Groot, Nebula, Rocket, Star-Lord

Example (Escape)

package main

import (
	"fmt"

	"os"

	"github.com/GoLangsam/template"
)

func main() {
	const s = `"Fran & Freddie's Diner" <tasty@example.com>`
	v := []interface{}{`"Fran & Freddie's Diner"`, ' ', `<tasty@example.com>`}

	fmt.Println(template.HTMLEscapeString(s))
	template.HTMLEscape(os.Stdout, []byte(s))
	fmt.Fprintln(os.Stdout, "")
	fmt.Println(template.HTMLEscaper(v...))

	fmt.Println(template.JSEscapeString(s))
	template.JSEscape(os.Stdout, []byte(s))
	fmt.Fprintln(os.Stdout, "")
	fmt.Println(template.JSEscaper(v...))

	fmt.Println(template.URLQueryEscaper(v...))

}

Output:

"Fran & Freddie's Diner" <tasty@example.com>
"Fran & Freddie's Diner" <tasty@example.com>
"Fran & Freddie's Diner"32<tasty@example.com>
\"Fran & Freddie\'s Diner\" \x3Ctasty@example.com\x3E
\"Fran & Freddie\'s Diner\" \x3Ctasty@example.com\x3E
\"Fran & Freddie\'s Diner\"32\x3Ctasty@example.com\x3E
%22Fran+%26+Freddie%27s+Diner%2232%3Ctasty%40example.com%3E

func Must

func Must(t Template, err error) Template

Must is a helper that wraps a call to a function returning (Template, error) and panics if the error is non-nil. It is intended for use in variable initializations such as

var t = template.Must(template.NewText|HtmlTemplate("name").Parse("text"))

func ParseHTMLfiles

func ParseHTMLfiles(filenames ...string) (Template, error)

ParseHTMLfiles wraps html/template.ParseFiles

func ParseHTMLglob

func ParseHTMLglob(pattern string) (Template, error)

ParseHTMLglob wraps html/template.ParseGlob

func ParseTextFiles

func ParseTextFiles(filenames ...string) (Template, error)

ParseTextFiles wraps text/template.ParseFiles

func ParseTextGlob

func ParseTextGlob(pattern string) (Template, error)

ParseTextGlob wraps text/template.ParseGlob

func Text

func Text(Name string) Template

Text returns a new "text/template" Template

Example (Block)

package main

import (
	"log"
	"os"
	"strings"

	"github.com/GoLangsam/template"
)

func main() {
	const (
		master  = `Names:{{block "list" .}}{{"\n"}}{{range .}}{{println "-" .}}{{end}}{{end}}`
		overlay = `{{define "list"}} {{join . ", "}}{{end}} `
	)
	var (
		funcs     = template.FuncMap{"join": strings.Join}
		guardians = []string{"Gamora", "Groot", "Nebula", "Rocket", "Star-Lord"}
	)
	masterTmpl, err := template.Text("master").Funcs(funcs).Parse(master)
	if err != nil {
		log.Fatal(err)
	}
	overlayTmpl, err := template.Must(masterTmpl.Clone()).Parse(overlay)
	if err != nil {
		log.Fatal(err)
	}
	if err := masterTmpl.Execute(os.Stdout, guardians); err != nil {
		log.Fatal(err)
	}
	if err := overlayTmpl.Execute(os.Stdout, guardians); err != nil {
		log.Fatal(err)
	}
}

Output:

Names:
- Gamora
- Groot
- Nebula
- Rocket
- Star-Lord
Names: Gamora, Groot, Nebula, Rocket, Star-Lord

Example (Text)

package main

import (
	"log"
	"os"

	"github.com/GoLangsam/template"
)

func main() {
	// Define a template.
	const letter = `
Dear {{.Name}},
{{if .Attended}}
It was a pleasure to see you at the wedding.
{{- else}}
It is a shame you couldn't make it to the wedding.
{{- end}}
{{with .Gift -}}
Thank you for the lovely {{.}}.
{{end}}
Best wishes,
Josie
`

	// Prepare some data to insert into the template.
	type Recipient struct {
		Name, Gift string
		Attended   bool
	}
	var recipients = []Recipient{
		{"Aunt Mildred", "bone china tea set", true},
		{"Uncle John", "moleskin pants", false},
		{"Cousin Rodney", "", false},
	}

	// Create a new template and parse the letter into it.
	t := template.Must(template.Text("letter").Parse(letter))

	// Execute the template for each recipient.
	for _, r := range recipients {
		err := t.Execute(os.Stdout, r)
		if err != nil {
			log.Println("executing template:", err)
		}
	}

}

Output:

Dear Aunt Mildred,

It was a pleasure to see you at the wedding.
Thank you for the lovely bone china tea set.

Best wishes,
Josie

Dear Uncle John,

It is a shame you couldn't make it to the wedding.
Thank you for the lovely moleskin pants.

Best wishes,
Josie

Dear Cousin Rodney,

It is a shame you couldn't make it to the wedding.

Best wishes,
Josie