/*
* jQuery File Upload Plugin GAE Go Example
* https://github.com/blueimp/jQuery-File-Upload
*
* Copyright 2011, Sebastian Tschan
* https://blueimp.net
*
* Licensed under the MIT license:
* http://www.opensource.org/licenses/MIT
*/
package app
import (
"bufio"
"bytes"
"encoding/json"
"fmt"
"github.com/disintegration/gift"
"golang.org/x/net/context"
"google.golang.org/appengine"
"google.golang.org/appengine/memcache"
"hash/crc32"
"image"
"image/gif"
"image/jpeg"
"image/png"
"io"
"log"
"mime/multipart"
"net/http"
"net/url"
"path/filepath"
"regexp"
"strings"
)
const (
WEBSITE = "https://blueimp.github.io/jQuery-File-Upload/"
MIN_FILE_SIZE = 1 // bytes
// Max file size is memcache limit (1MB) minus key size minus overhead:
MAX_FILE_SIZE = 999000 // bytes
IMAGE_TYPES = "image/(gif|p?jpeg|(x-)?png)"
ACCEPT_FILE_TYPES = IMAGE_TYPES
THUMB_MAX_WIDTH = 80
THUMB_MAX_HEIGHT = 80
EXPIRATION_TIME = 300 // seconds
// If empty, only allow redirects to the referer protocol+host.
// Set to a regexp string for custom pattern matching:
REDIRECT_ALLOW_TARGET = ""
)
var (
imageTypes = regexp.MustCompile(IMAGE_TYPES)
acceptFileTypes = regexp.MustCompile(ACCEPT_FILE_TYPES)
thumbSuffix = "." + fmt.Sprint(THUMB_MAX_WIDTH) + "x" +
fmt.Sprint(THUMB_MAX_HEIGHT)
)
func escape(s string) string {
return strings.Replace(url.QueryEscape(s), "+", "%20", -1)
}
func extractKey(r *http.Request) string {
// Use RequestURI instead of r.URL.Path, as we need the encoded form:
path := strings.Split(r.RequestURI, "?")[0]
// Also adjust double encoded slashes:
return strings.Replace(path[1:], "%252F", "%2F", -1)
}
func check(err error) {
if err != nil {
panic(err)
}
}
type FileInfo struct {
Key string `json:"-"`
ThumbnailKey string `json:"-"`
Url string `json:"url,omitempty"`
ThumbnailUrl string `json:"thumbnailUrl,omitempty"`
Name string `json:"name"`
Type string `json:"type"`
Size int64 `json:"size"`
Error string `json:"error,omitempty"`
DeleteUrl string `json:"deleteUrl,omitempty"`
DeleteType string `json:"deleteType,omitempty"`
}
func (fi *FileInfo) ValidateType() (valid bool) {
if acceptFileTypes.MatchString(fi.Type) {
return true
}
fi.Error = "Filetype not allowed"
return false
}
func (fi *FileInfo) ValidateSize() (valid bool) {
if fi.Size < MIN_FILE_SIZE {
fi.Error = "File is too small"
} else if fi.Size > MAX_FILE_SIZE {
fi.Error = "File is too big"
} else {
return true
}
return false
}
func (fi *FileInfo) CreateUrls(r *http.Request, c context.Context) {
u := &url.URL{
Scheme: r.URL.Scheme,
Host: appengine.DefaultVersionHostname(c),
Path: "/",
}
uString := u.String()
fi.Url = uString + fi.Key
fi.DeleteUrl = fi.Url
fi.DeleteType = "DELETE"
if fi.ThumbnailKey != "" {
fi.ThumbnailUrl = uString + fi.ThumbnailKey
}
}
func (fi *FileInfo) SetKey(checksum uint32) {
fi.Key = escape(string(fi.Type)) + "/" +
escape(fmt.Sprint(checksum)) + "/" +
escape(string(fi.Name))
}
func (fi *FileInfo) createThumb(buffer *bytes.Buffer, c context.Context) {
if imageTypes.MatchString(fi.Type) {
src, _, err := image.Decode(bytes.NewReader(buffer.Bytes()))
check(err)
filter := gift.New(gift.ResizeToFit(
THUMB_MAX_WIDTH,
THUMB_MAX_HEIGHT,
gift.LanczosResampling,
))
dst := image.NewNRGBA(filter.Bounds(src.Bounds()))
filter.Draw(dst, src)
buffer.Reset()
bWriter := bufio.NewWriter(buffer)
switch fi.Type {
case "image/jpeg", "image/pjpeg":
err = jpeg.Encode(bWriter, dst, nil)
case "image/gif":
err = gif.Encode(bWriter, dst, nil)
default:
err = png.Encode(bWriter, dst)
}
check(err)
bWriter.Flush()
thumbnailKey := fi.Key + thumbSuffix + filepath.Ext(fi.Name)
item := &memcache.Item{
Key: thumbnailKey,
Value: buffer.Bytes(),
}
err = memcache.Set(c, item)
check(err)
fi.ThumbnailKey = thumbnailKey
}
}
func handleUpload(r *http.Request, p *multipart.Part) (fi *FileInfo) {
fi = &FileInfo{
Name: p.FileName(),
Type: p.Header.Get("Content-Type"),
}
if !fi.ValidateType() {
return
}
defer func() {
if rec := recover(); rec != nil {
log.Println(rec)
fi.Error = rec.(error).Error()
}
}()
var buffer bytes.Buffer
hash := crc32.NewIEEE()
mw := io.MultiWriter(&buffer, hash)
lr := &io.LimitedReader{R: p, N: MAX_FILE_SIZE + 1}
_, err := io.Copy(mw, lr)
check(err)
fi.Size = MAX_FILE_SIZE + 1 - lr.N
if !fi.ValidateSize() {
return
}
fi.SetKey(hash.Sum32())
item := &memcache.Item{
Key: fi.Key,
Value: buffer.Bytes(),
}
context := appengine.NewContext(r)
err = memcache.Set(context, item)
check(err)
fi.createThumb(&buffer, context)
fi.CreateUrls(r, context)
return
}
func getFormValue(p *multipart.Part) string {
var b bytes.Buffer
io.CopyN(&b, p, int64(1<<20)) // Copy max: 1 MiB
return b.String()
}
func handleUploads(r *http.Request) (fileInfos []*FileInfo) {
fileInfos = make([]*FileInfo, 0)
mr, err := r.MultipartReader()
check(err)
r.Form, err = url.ParseQuery(r.URL.RawQuery)
check(err)
part, err := mr.NextPart()
for err == nil {
if name := part.FormName(); name != "" {
if part.FileName() != "" {
fileInfos = append(fileInfos, handleUpload(r, part))
} else {
r.Form[name] = append(r.Form[name], getFormValue(part))
}
}
part, err = mr.NextPart()
}
return
}
func validateRedirect(r *http.Request, redirect string) bool {
if redirect != "" {
var redirectAllowTarget *regexp.Regexp
if REDIRECT_ALLOW_TARGET != "" {
redirectAllowTarget = regexp.MustCompile(REDIRECT_ALLOW_TARGET)
} else {
referer := r.Referer()
if referer == "" {
return false
}
refererUrl, err := url.Parse(referer)
if err != nil {
return false
}
redirectAllowTarget = regexp.MustCompile("^" + regexp.QuoteMeta(
refererUrl.Scheme+"://"+refererUrl.Host+"/",
))
}
return redirectAllowTarget.MatchString(redirect)
}
return false
}
func get(w http.ResponseWriter, r *http.Request) {
if r.URL.Path == "/" {
http.Redirect(w, r, WEBSITE, http.StatusFound)
return
}
// Use RequestURI instead of r.URL.Path, as we need the encoded form:
key := extractKey(r)
parts := strings.Split(key, "/")
if len(parts) == 3 {
context := appengine.NewContext(r)
item, err := memcache.Get(context, key)
if err == nil {
w.Header().Add("X-Content-Type-Options", "nosniff")
contentType, _ := url.QueryUnescape(parts[0])
if !imageTypes.MatchString(contentType) {
contentType = "application/octet-stream"
}
w.Header().Add("Content-Type", contentType)
w.Header().Add(
"Cache-Control",
fmt.Sprintf("public,max-age=%d", EXPIRATION_TIME),
)
w.Write(item.Value)
return
}
}
http.Error(w, "404 Not Found", http.StatusNotFound)
}
func post(w http.ResponseWriter, r *http.Request) {
result := make(map[string][]*FileInfo, 1)
result["files"] = handleUploads(r)
b, err := json.Marshal(result)
check(err)
if redirect := r.FormValue("redirect"); validateRedirect(r, redirect) {
if strings.Contains(redirect, "%s") {
redirect = fmt.Sprintf(
redirect,
escape(string(b)),
)
}
http.Redirect(w, r, redirect, http.StatusFound)
return
}
w.Header().Set("Cache-Control", "no-cache")
jsonType := "application/json"
if strings.Index(r.Header.Get("Accept"), jsonType) != -1 {
w.Header().Set("Content-Type", jsonType)
}
fmt.Fprintln(w, string(b))
}
func delete(w http.ResponseWriter, r *http.Request) {
key := extractKey(r)
parts := strings.Split(key, "/")
if len(parts) == 3 {
result := make(map[string]bool, 1)
context := appengine.NewContext(r)
err := memcache.Delete(context, key)
if err == nil {
result[key] = true
contentType, _ := url.QueryUnescape(parts[0])
if imageTypes.MatchString(contentType) {
thumbnailKey := key + thumbSuffix + filepath.Ext(parts[2])
err := memcache.Delete(context, thumbnailKey)
if err == nil {
result[thumbnailKey] = true
}
}
}
w.Header().Set("Content-Type", "application/json")
b, err := json.Marshal(result)
check(err)
fmt.Fprintln(w, string(b))
} else {
http.Error(w, "405 Method not allowed", http.StatusMethodNotAllowed)
}
}
func handle(w http.ResponseWriter, r *http.Request) {
params, err := url.ParseQuery(r.URL.RawQuery)
check(err)
w.Header().Add("Access-Control-Allow-Origin", "*")
w.Header().Add(
"Access-Control-Allow-Methods",
"OPTIONS, HEAD, GET, POST, DELETE",
)
w.Header().Add(
"Access-Control-Allow-Headers",
"Content-Type, Content-Range, Content-Disposition",
)
switch r.Method {
case "OPTIONS", "HEAD":
return
case "GET":
get(w, r)
case "POST":
if len(params["_method"]) > 0 && params["_method"][0] == "DELETE" {
delete(w, r)
} else {
post(w, r)
}
case "DELETE":
delete(w, r)
default:
http.Error(w, "501 Not Implemented", http.StatusNotImplemented)
}
}
func init() {
http.HandleFunc("/", handle)
}
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