render.go

// Package pongo2gin is a template renderer that can be used with the Gin
// web framework https://github.com/gin-gonic/gin it uses the Pongo2 template
// library https://github.com/flosch/pongo2
package pongo2gin

import (
	"github.com/flosch/pongo2/v5"
	"github.com/gin-gonic/gin"
	"github.com/gin-gonic/gin/render"

	"net/http"
)

// RenderOptions is used to configure the renderer.
type RenderOptions struct {
	Fs            http.FileSystem
	ContentType   string
	AlwaysNoCache bool
	BaseDir       string
}

// Pongo2Render is a custom Gin template renderer using Pongo2.
type Pongo2Render struct {
	Options  *RenderOptions
	Template *pongo2.Template
	Context  pongo2.Context
}

// New creates a new Pongo2Render instance with custom Options.
func New(options RenderOptions) *Pongo2Render {
	return &Pongo2Render{
		Options: &options,
	}
}

// Default creates a Pongo2Render instance with default options.

// Instance should return a new Pongo2Render struct per request and prepare
// the template by either loading it from disk or using pongo2's cache.
func (p Pongo2Render) Instance(name string, data interface{}) render.Render {
	var template *pongo2.Template

	var fsLoader *pongo2.HttpFilesystemLoader
	if p.Options.Fs != nil {
		fsLoader = pongo2.MustNewHttpFileSystemLoader(p.Options.Fs, p.Options.BaseDir)

	} else {
		panic(" you should specified fs options")
	}
	set := pongo2.NewSet("", fsLoader)

	// always read template files from disk if in debug mode, use cache otherwise.
	if gin.Mode() == "debug" || p.Options.AlwaysNoCache == true {
		template = pongo2.Must(set.FromFile(name))
	} else {
		template = pongo2.Must(set.FromCache(name))
	}

	return Pongo2Render{
		Template: template,
		Context:  data.(pongo2.Context),
		Options:  p.Options,
	}
}

// 渲染模板和字符串
func (p Pongo2Render) RenderStringWithTemplateAndData(name string, data interface{}) (string, error) {
	var template *pongo2.Template

	var fsLoader *pongo2.HttpFilesystemLoader
	if p.Options.Fs != nil {
		fsLoader = pongo2.MustNewHttpFileSystemLoader(p.Options.Fs, p.Options.BaseDir)

	} else {
		panic(" you should specified fs options")
	}
	set := pongo2.NewSet("", fsLoader)

	// always read template files from disk if in debug mode, use cache otherwise.
	if gin.Mode() == "debug" || p.Options.AlwaysNoCache == true {
		template = pongo2.Must(set.FromFile(name))
	} else {
		template = pongo2.Must(set.FromCache(name))
	}
	outStr, err := template.Execute(data.(pongo2.Context))
	return outStr, err
}

// Render should render the template to the response.
func (p Pongo2Render) Render(w http.ResponseWriter) error {
	p.WriteContentType(w)
	err := p.Template.ExecuteWriter(p.Context, w)
	return err
}

// WriteContentType should add the Content-Type header to the response
// when not set yet.
func (p Pongo2Render) WriteContentType(w http.ResponseWriter) {
	header := w.Header()
	if val := header["Content-Type"]; len(val) == 0 {
		header["Content-Type"] = []string{p.Options.ContentType}
	}
}