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代码
package main
import (
"html/template"
"io"
"io/ioutil"
"log"
"net/http"
"os"
"path"
"runtime/debug"
"strings"
)
const (
ListDir = 0x0001
UploadDir = "./uploads"
TemplateDir = "./views"
)
var templates = make(map[string]*template.Template)
func init() {
fileInfoArr, err := ioutil.ReadDir(TemplateDir)
check(err)
var templateName, templatePath string
for _, fileInfo := range fileInfoArr {
templateName = fileInfo.Name()
if ext := path.Ext(templateName); ext != ".html" {
continue
}
tmpl := strings.Split(templateName,".")[0]
templatePath = TemplateDir + "/" + 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, tmpl string, locals map[string]interface{}) {
err := templates[tmpl].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 := os.Create(UploadDir + "/" + 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) {
imageId := r.FormValue("id")
imagePath := UploadDir + "/" + 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{})
var 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 err, ok := recover().(error); ok {
http.Error(w, err.Error(), http.StatusInternalServerError)
log.Printf("WARN: panic in %v - %v\n", fn, err)
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())
}
}
list.html
<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>List</title>
</head>
<body>
<ol>
{{range $.images}}
<li><a href="/view?id={{.|urlquery}}">{{.|html}}</a></li>
{{end}}
</ol>
</body>
</html>
upload.html
<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>Upload</title>
</head>
<body>
<form method="POST" action="/upload" enctype="multipart/form-data">
Choose an image to upload: <input name="image" type="file"/>
<input type="submit" value="Upload"/>
</form>
</body>
</html>