Golang ファイルアップロードで異なるエンコードされたファイル名を処理するにはどうすればよいですか?

import "mime/multipart"
import "fmt"

func handleFileUpload(r *http.Request) {
    r.ParseMultipartForm(32 << 20) // 设置最大上传大小为 32 MB

    file, _, err := r.FormFile("file")
    if err != nil {
        fmt.Println(err)
        return
    }
    defer file.Close()

    fname := r.Form.Get("file")
    fnameDec, err := mime.ParseMediaType(fname)
    if err != nil {
        fmt.Println(err)
        return
    }

    fmt.Println("Original filename:", fname)
    fmt.Println("Decoded filename:", fnameDec.Filename)
}

import "net/url"
import "fmt"

func handleFileUpload(r *http.Request) {
    r.ParseMultipartForm(32 << 20)

    file, _, err := r.FormFile("file")
    if err != nil {
        fmt.Println(err)
        return
    }
    defer file.Close()

    fname := r.Form.Get("file")
    fnameDec, err := url.PathUnescape(fname)
    if err != nil {
        fmt.Println(err)
        return
    }

    fmt.Println("Original filename:", fname)
    fmt.Println("Decoded filename:", fnameDec)
}

package main

import (
    "fmt"
    "net/http"
    "mime/multipart"
    "url"
)

func handleFileUpload(w http.ResponseWriter, r *http.Request) {
    r.ParseMultipartForm(32 << 20)

    file, _, err := r.FormFile("file")
    if err != nil {
        fmt.Fprintln(w, "Error parsing multipart form:", err)
        return
    }
    defer file.Close()

    fname := r.Form.Get("file")
    fnameDec, err := mime.ParseMediaType(fname)
    if err != nil {
        fmt.Fprintf(w, "Error parsing MIME header: %s", err)
        return
    }

    fmt.Fprintf(w, "Original filename: %s\n", fname)
    fmt.Fprintf(w, "Decoded filename (mime.Header): %s\n", fnameDec.Filename)

    fnameDec, err = url.PathUnescape(fname)
    if err != nil {
        fmt.Fprintf(w, "Error unencoding URL: %s", err)
        return
    }
    fmt.Fprintf(w, "Decoded filename (URL): %s", fnameDec)
}

func main() {
    http.HandleFunc("/upload", handleFileUpload)
    http.ListenAndServe(":8080", nil)
}