life

controller执行后

c.RenderArgs["tagsJson"] = c.Json(tagService.GetTags(c.GetUserId()))
return c.RenderTemplate("note/note-dev.html")

 Controller:

type Controller struct {
	RenderArgs map[string]interface{} // Args passed to the template.
}

 返回 RenderTemplateResult 对象 

func (c *Controller) RenderTemplate(templatePath string) Result {

	// Get the Template.
	// 返回 GoTemplate{tmpl, loader}
	template, err := MainTemplateLoader.Template(templatePath)
	if err != nil {
		return c.RenderError(err)
	}

	return &RenderTemplateResult{
		Template:   template,
		RenderArgs: c.RenderArgs, // 把args给它
	}
}

result.go

// Action methods return this result to request a template be rendered.
type RenderTemplateResult struct {
	Template   Template
	RenderArgs map[string]interface{}
}
// 模仿这个方法
func (r *RenderTemplateResult) render(req *Request, resp *Response, wr io.Writer) {
	// 这里调用之
	err := r.Template.Render(wr, r.RenderArgs)
	if err == nil {
		return
	}
	//....
}
func (r *RenderTemplateResult) Apply(req *Request, resp *Response) {
	// Handle panics when rendering templates.
	defer func() {
		if err := recover(); err != nil {
			ERROR.Println(err)
			PlaintextErrorResult{fmt.Errorf("Template Execution Panic in %s:\n%s",
				r.Template.Name(), err)}.Apply(req, resp)
		}
	}()

	chunked := Config.BoolDefault("results.chunked", false)

	// If it's a HEAD request, throw away the bytes.
	out := io.Writer(resp.Out)
	if req.Method == "HEAD" {
		out = ioutil.Discard
	}

	// In a prod mode, write the status, render, and hope for the best.
	// (In a dev mode, always render to a temporary buffer first to avoid having
	// error pages distorted by HTML already written)
	if chunked && !DevMode {
		resp.WriteHeader(http.StatusOK, "text/html; charset=utf-8")
		r.render(req, resp, out) // 这里!!!
		return
	}

	// Render the template into a temporary buffer, to see if there was an error
	// rendering the template.  If not, then copy it into the response buffer.
	// Otherwise, template render errors may result in unpredictable HTML (and
	// would carry a 200 status code)
	var b bytes.Buffer
	r.render(req, resp, &b)
	if !chunked {
		resp.Out.Header().Set("Content-Length", strconv.Itoa(b.Len()))
	}
	resp.WriteHeader(http.StatusOK, "text/html; charset=utf-8")
	b.WriteTo(out)
}

revel / template.go 里有 MainTemplateLoader 类, Template类, 里面还有自定义模板函数

type Template interface {
	Name() string
	Content() []string
	Render(wr io.Writer, arg interface{}) error
}

// Adapter for Go Templates.
type GoTemplate strucst {
	*template.Template
	loader *TemplateLoader
}
// return a 'revel.Template' from Go's template.
func (gotmpl GoTemplate) Render(wr io.Writer, arg interface{}) error {
	return gotmpl.Execute(wr, arg)
}

---------------

OK, 

tpl := c.RenderTemplate("note/note-dev.html")
// 定义一个io.Writer, 可以是stringIoWriter? 写到string中
var b bytes.Buffer
tpl.Template.Render(b, tpl.RenderArgs)
fmt.Println(b.String())