```go
package main
import (
"html/template"
"io"
"io/ioutil"
"log"
"net/http"
"os"
"path"
"runtime/debug"
)
const (
ListDir = 0x0001
UPLOAD_DIR = "./uploads"
TEMPLATE_DIR = "./views"
)
var templates = make(map[string]*template.Template)
func init() {
fileInfoArr, err := ioutil.ReadDir(TEMPLATE_DIR)
check(err)
var templateName, templatePath, tmpl string
for _, fileInfo := range fileInfoArr {
templateName = fileInfo.Name()
if ext := path.Ext(templateName); ext != ".html" {
continue
}
templatePath = TEMPLATE_DIR + "/" + templateName
log.Println("Loading template:", templatePath)
t := template.Must(template.ParseFiles(templatePath))
templates[tmpl] = t
}
}
func check(err error) {
if err != nil {
panic(err)
}
}
func renderHtml(w http.ResponseWriter, templ string, locals map[string]interface{}) {
err := templates[templ].Execute(w, locals)
check(err)
}
func isExists(path string) bool {
_, err := os.Stat(path)
if err == nil {
return true
}
return os.IsExist(err)
}
func uploadHandler(w http.ResponseWriter, r *http.Request) {
if r.Method == "GET" {
renderHtml(w, "upload", nil)
}
if r.Method == "POST" {
f, h, err := r.FormFile("image")
check(err)
filename := h.Filename
defer f.Close()
t, err := ioutil.TempFile(UPLOAD_DIR, filename)
check(err)
defer t.Close()
_, err = io.Copy(t, f)
check(err)
http.Redirect(w, r, "/view?id="+filename, http.StatusFound)
}
}
func viewHandler(w http.ResponseWriter, r *http.Request) {
var imageId, imagePath string
imageId = r.FormValue("id")
imagePath = UPLOAD_DIR + "/" + imageId
if exists := isExists(imagePath); !exists {
http.NotFound(w, r)
return
}
w.Header().Set("Content-Type", "image")
http.ServeFile(w, r, imagePath)
}
func listHandler(w http.ResponseWriter, r *http.Request) {
fileInfoArr, err := ioutil.ReadDir("./uploads")
check(err)
locals := make(map[string]interface{})
images := []string{}
for _, fileInfo := range fileInfoArr {
images = append(images, fileInfo.Name())
}
locals["images"] = images
renderHtml(w, "list", locals)
}
func safeHandler(fn http.HandlerFunc) http.HandlerFunc {
return func(w http.ResponseWriter, r *http.Request) {
defer func() {
if e, ok := recover().(error); ok {
http.Error(w, err.Error(), http.StatusInternalServerError)
//或者输出自定义的50x错误页面
//w.WriteHeader(http.StatusInternalServerError)
//renderHtml(w,"error",e)
//logging
log.Println("WARN:panic in %v. - %v", fn, e)
log.Println(string(debug.Stack()))
}
}()
fn(w, r)
}
}
func staticDirHandler(mux *http.ServeMux, prefix string, staticDir string, flags int) {
mux.HandleFunc(prefix, func(w http.ResponseWriter, r *http.Request) {
file := staticDir + r.URL.Path[len(prefix)-1:]
if (flags & ListDir) == 0 {
if exists := isExists(file); !exists {
http.NotFound(w, r)
return
}
}
http.ServeFile(w, r, file)
})
}
func main() {
mux := http.NewServeMux()
staticDirHandler(mux, "/assets", "./public", 0)
mux.HandleFunc("/", safeHandler(listHandler))
mux.HandleFunc("/view", safeHandler(viewHandler))
mux.HandleFunc("/upload", safeHandler(uploadHandler))
err := http.ListenAndServe(":8080", mux)
if err != nil {
log.Fatal("ListenAndServe: ", err.Error())
}
}
```
undefined: err in err.Error
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