Handlebars support - Embrace the feature request https://github.com/kataras/iris/issues/239

render/template/engine/handlebars/handlebars.go

@@ -0,0 +1,110 @@
+// Package handlebars the HandlebarsEngine's functionality
+package handlebars
+
+import (
+	"fmt"
+	"io"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"strings"
+	"sync"
+
+	"github.com/aymerick/raymond"
+	"github.com/kataras/iris/config"
+)
+
+type (
+	// Engine the Handlebars engine
+	Engine struct {
+		Config        *config.Template
+		templateCache map[string]*raymond.Template
+		mu            sync.Mutex
+	}
+)
+
+// New creates and returns the Handlebars template engine
+func New(c config.Template) *Engine {
+	s := &Engine{Config: &c, templateCache: make(map[string]*raymond.Template, 0)}
+	return s
+}
+
+// BuildTemplates builds the handlebars templates
+func (e *Engine) BuildTemplates() error {
+	if e.Config.Extensions == nil || len(e.Config.Extensions) == 0 {
+		e.Config.Extensions = []string{".html"}
+	}
+
+	// register the global helpers
+	if e.Config.Handlebars.Helpers != nil {
+		raymond.RegisterHelpers(e.Config.Handlebars.Helpers)
+	}
+	var templateErr error
+
+	dir := e.Config.Directory
+	filepath.Walk(dir, func(path string, info os.FileInfo, err error) error {
+		if info == nil || info.IsDir() {
+			return nil
+		}
+
+		rel, err := filepath.Rel(dir, path)
+		if err != nil {
+			return err
+		}
+
+		ext := ""
+		if strings.Index(rel, ".") != -1 {
+			ext = filepath.Ext(rel)
+		}
+
+		for _, extension := range e.Config.Extensions {
+			if ext == extension {
+
+				buf, err := ioutil.ReadFile(path)
+				contents := string(buf)
+
+				if err != nil {
+					templateErr = err
+					break
+				}
+
+				name := filepath.ToSlash(rel)
+
+				tmpl, err := raymond.Parse(contents)
+				if err != nil {
+					templateErr = err
+					continue
+				}
+				e.mu.Lock()
+				e.templateCache[name] = tmpl
+				e.mu.Unlock()
+
+				break
+			}
+		}
+		return nil
+	})
+	return templateErr
+
+}
+func (e *Engine) fromCache(relativeName string) *raymond.Template {
+	e.mu.Lock()
+	tmpl, ok := e.templateCache[relativeName]
+	if ok {
+		e.mu.Unlock()
+		return tmpl
+	}
+	e.mu.Unlock()
+	return nil
+}
+
+// ExecuteWriter executes a templates and write its results to the out writer
+func (e *Engine) ExecuteWriter(out io.Writer, name string, binding interface{}, layout string) error {
+	if tmpl := e.fromCache(name); tmpl != nil {
+		res, err := tmpl.Exec(binding)
+		_, err = fmt.Fprint(out, res)
+		return err
+	}
+
+	return fmt.Errorf("[IRIS TEMPLATES] Template with name %s doesn't exists in the dir %s", name, e.Config.Directory)
+}