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// Copyright 2019 GoAdmin Core Team. All rights reserved.
// Use of this source code is governed by a Apache-2.0 style
// license that can be found in the LICENSE file.
package file
import (
"fmt"
"io"
"mime/multipart"
"os"
"path"
"sync"
"github.com/GoAdminGroup/go-admin/plugins/admin/modules"
)
// Uploader is a file uploader which contains the method Upload.
type Uploader interface {
Upload(*multipart.Form) error
}
// UploaderGenerator is a function return an Uploader.
type UploaderGenerator func() Uploader
var uploaderList = map[string]UploaderGenerator{
"local": GetLocalFileUploader,
}
var upMu sync.Mutex
// AddUploader makes a uploader generator available by the provided theme name.
// If Add is called twice with the same name or if uploader is nil,
// it panics.
func AddUploader(name string, up UploaderGenerator) {
upMu.Lock()
defer upMu.Unlock()
if up == nil {
panic("uploader generator is nil")
}
if _, dup := uploaderList[name]; dup {
panic("add uploader generator twice " + name)
}
uploaderList[name] = up
}
// GetFileEngine return the Uploader of given name.
func GetFileEngine(name string) Uploader {
if up, ok := uploaderList[name]; ok {
return up()
}
panic("wrong uploader name")
}
// UploadFun is a function to process the uploading logic.
type UploadFun func(*multipart.FileHeader, string) (string, error)
// Upload receive the return value of given UploadFun and put them into the form.
func Upload(c UploadFun, form *multipart.Form) error {
var (
suffix string
filename string
)
for k := range form.File {
for _, fileObj := range form.File[k] {
suffix = path.Ext(fileObj.Filename)
filename = modules.Uuid() + suffix
pathStr, err := c(fileObj, filename)
if err != nil {
return err
}
form.Value[k] = append(form.Value[k], pathStr)
form.Value[k+"_size"] = append(form.Value[k+"_size"], fmt.Sprintf("%d", fileObj.Size))
}
}
return nil
}
// SaveMultipartFile used in a local Uploader which help to save file in the local path.
func SaveMultipartFile(fh *multipart.FileHeader, path string) error {
f, err := fh.Open()
if err != nil {
return err
}
if ff, ok := f.(*os.File); ok {
// Windows can't rename files that are opened.
if err := f.Close(); err != nil {
return err
}
// If renaming fails we try the normal copying method.
// Renaming could fail if the files are on different devices.
if os.Rename(ff.Name(), path) == nil {
return nil
}
// Reopen f for the code below.
f, err = fh.Open()
if err != nil {
return err
}
}
defer func() {
if err2 := f.Close(); err2 != nil {
err = err2
}
}()
ff, err := os.Create(path)
if err != nil {
return err
}
defer func() {
if err2 := ff.Close(); err2 != nil {
err = err2
}
}()
_, err = copyZeroAlloc(ff, f)
return err
}
func copyZeroAlloc(w io.Writer, r io.Reader) (int64, error) {
buf := copyBufPool.Get().([]byte)
n, err := io.CopyBuffer(w, r, buf)
copyBufPool.Put(buf)
return n, err
}
var copyBufPool = sync.Pool{
New: func() interface{} {
return make([]byte, 4096)
},
}
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