gin/render/render.go

128 lines
2.8 KiB
Go

// Copyright 2014 Manu Martinez-Almeida. All rights reserved.
// Use of this source code is governed by a MIT style
// license that can be found in the LICENSE file.
package render
import (
"encoding/json"
"encoding/xml"
"fmt"
"html/template"
"net/http"
)
type (
Render interface {
Render(http.ResponseWriter, int, ...interface{}) error
}
jsonRender struct{}
indentedJSON struct{}
xmlRender struct{}
plainTextRender struct{}
htmlPlainRender struct{}
redirectRender struct{}
HTMLRender struct {
Template *template.Template
}
)
var (
JSON = jsonRender{}
IndentedJSON = indentedJSON{}
XML = xmlRender{}
HTMLPlain = htmlPlainRender{}
Plain = plainTextRender{}
Redirect = redirectRender{}
)
func (_ redirectRender) Render(w http.ResponseWriter, code int, data ...interface{}) error {
w.Header().Set("Location", data[0].(string))
w.WriteHeader(code)
return nil
}
func (_ jsonRender) Render(w http.ResponseWriter, code int, data ...interface{}) error {
WriteHeader(w, code, "application/json")
return json.NewEncoder(w).Encode(data[0])
}
func (_ indentedJSON) Render(w http.ResponseWriter, code int, data ...interface{}) error {
WriteHeader(w, code, "application/json")
jsonData, err := json.MarshalIndent(data[0], "", " ")
if err != nil {
return err
}
_, err = w.Write(jsonData)
return err
}
func (_ xmlRender) Render(w http.ResponseWriter, code int, data ...interface{}) error {
WriteHeader(w, code, "application/xml")
return xml.NewEncoder(w).Encode(data[0])
}
func (_ plainTextRender) Render(w http.ResponseWriter, code int, data ...interface{}) (err error) {
WriteHeader(w, code, "text/plain")
format := data[0].(string)
args := data[1].([]interface{})
if len(args) > 0 {
_, err = fmt.Fprintf(w, format, args...)
} else {
_, err = w.Write([]byte(format))
}
return
}
func (_ htmlPlainRender) Render(w http.ResponseWriter, code int, data ...interface{}) (err error) {
WriteHeader(w, code, "text/html")
format := data[0].(string)
args := data[1].([]interface{})
if len(args) > 0 {
_, err = fmt.Fprintf(w, format, args...)
} else {
_, err = w.Write([]byte(format))
}
return
}
func (html HTMLRender) Render(w http.ResponseWriter, code int, data ...interface{}) error {
WriteHeader(w, code, "text/html")
file := data[0].(string)
args := data[1]
return html.Template.ExecuteTemplate(w, file, args)
}
func WriteHeader(w http.ResponseWriter, code int, contentType string) {
contentType = joinStrings(contentType, "; charset=utf-8")
w.Header().Set("Content-Type", contentType)
w.WriteHeader(code)
}
func joinStrings(a ...string) string {
if len(a) == 0 {
return ""
}
if len(a) == 1 {
return a[0]
}
n := 0
for i := 0; i < len(a); i++ {
n += len(a[i])
}
b := make([]byte, n)
n = 0
for _, s := range a {
n += copy(b[n:], s)
}
return string(b)
}