go 文件上传 

package main

import (
    "fmt"
    "io"
    "io/ioutil"
    "log"
    "net/http"
    "os"
    "reflect"
)

const (
    UPLOAD_DIR = "./uploads"
)

func uploadHandler(w http.ResponseWriter, r *http.Request) {
    if r.Method == "GET" {
        io.WriteString(w, "<html><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></html>")
        return
    }

    if r.Method == "POST" {
        f, h, err := r.FormFile("image")
        if err != nil {
            http.Error(w, err.Error(), http.StatusInternalServerError)
            return
        }
        filename := h.Filename
        fmt.Println("filename:", filename)

        defer f.Close() //文件流句柄

        t, err := os.Create(UPLOAD_DIR + "/" + filename)
        fmt.Println("filepath:", UPLOAD_DIR+"/"+filename)

        if err != nil {
            http.Error(w, err.Error(), http.StatusInternalServerError)
            return
        }

        defer t.Close() //关闭临时文件句柄

        if _, err := io.Copy(t, f); err != nil {
            http.Error(w, err.Error(), http.StatusInternalServerError)
            return
        }
        http.Redirect(w, r, "/view?id="+filename, http.StatusFound)
    }
}

func viewHandler(w http.ResponseWriter, r *http.Request) {
    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响应头输出格式
    http.ServeFile(w, r, imagePath)
}

func isExists(path string) bool {
    _, err := os.Stat(path)
    if err == nil {
        return true
    }
    return os.IsExist(err)
}

func listHandler(w http.ResponseWriter, r *http.Request) {
    fileInfoArr, err := ioutil.ReadDir("./uploads")
    if err != nil {
        http.Error(w, err.Error(), http.StatusInternalServerError)
        return
    }
    var listHtml string
    for _, fileInfo := range fileInfoArr {
        imgid := fileInfo.Name
        fmt.Println("type:", reflect.TypeOf(imgid))
        listHtml += "<li><a href=\"/view?id=" + imgid() + "\">" + imgid() + "</a></li>"
    }
    io.WriteString(w, "<html><body><ol>"+listHtml+"</ol></body></html>")
}

func init() { //main函数之前执行
    fmt.Println("init-----")
}

func safeHandler(fn http.HandlerFunc) http.HandlerFunc { //异常的处理
    return func(w http.ResponseWriter, r *http.Request) {
        defer func() {
            if e, ok := recover().(error); ok {
                http.Error(w, err.Error(), http.StatusInternalServerError)
                log.Println("WARN: panic in %v - %v", fn, e)
                log.Println(string(debug.Stack()))
            }
        }()
        fn(w, r)
    }
}

//处理静态资源
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)
    http.HandleFunc("/", safeHandler(listHandler))
    http.HandleFunc("/view", safeHandler(viewHandler))
    http.HandleFunc("/upload", safeHandler(uploadHandler))
    err := http.ListenAndServe(":8080", nil)
    if err != nil {
        log.Fatal("ListenAndServe: ", err.Error())
    }
}

 

posted @ 2018-02-27 12:13  无天666  阅读(754)  评论(0)    收藏  举报