Go File Upload Handler

Handle multipart file uploads in Go with size limits, MIME type validation, unique filename generation, streaming to disk without buffering entire file, and.

Go File Upload

Code

snippet 
package main

import (
  "fmt"
  "io"
  "net/http"
  "os"
  "time"
)

func uploadHandler(w http.ResponseWriter, r *http.Request) {
  r.ParseMultipartForm(10 << 20)
  file, header, err := r.FormFile("file")
  if err != nil {
    http.Error(w, "No file", http.StatusBadRequest)
    return
  }
  defer file.Close()
  dst, _ := os.Create(fmt.Sprintf("uploads/%d-%s", time.Now().Unix(), header.Filename))
  defer dst.Close()
  io.Copy(dst, file)
  fmt.Fprintf(w, `{"path":"%s","size":%d}`, dst.Name(), header.Size)
}