golang http server provides file download function

Introduction to the

Go (also known as Golang) is a statically strongly typed, compiled, concurrent, and garbage collection programming language developed by Google.

Robert Griesemer, Rob Parker (Rob Pike) and Ken Thompson (Ken Thompson) began designing Go in September 2007, and later Ian Lance Taylor and Russ Cox joined the project. Go is based on the Inferno operating system. Go was officially announced as an open source project in November 2009 and was implemented on the Linux and Mac OS X platforms, followed by the Windows system. In 2016, Go was chosen as the "TIOBE Language of the Year 2016" by software evaluation company TIOBE. Currently, Go releases a level 2 version every six months (that is, upgrading from ES32en.x to ES34en.y).

go is golang the full name is golang or go for short

golang implements http server to provide file download function, the specific code is as follows:

func FileDownload(w http.ResponseWriter, r *http.Request) {
  filename := get_filename_from_request(r)

  file, _ := os.Open(filename)
  defer file.Close()

  fileHeader := make([]byte, 512)
  file.Read(fileHeader)

  fileStat, _ := file.Stat()

  w.Header().Set("Content-Disposition", "attachment; filename=" + filename)
  w.Header().Set("Content-Type", http.DetectContentType(fileHeader))
  w.Header().Set("Content-Length", strconv.FormatInt(fileStat.Size(), 10))

  file.Seek(0, 0)
  io.Copy(w, file)

  return
}

ps: Take a look at golang's simplest, http server

Simple hello world

package main
import (
 "fmt"
 "io"
 "net/http"
)
func main() {
 http.HandleFunc("/", helloWorld)
 e:=http.ListenAndServe(":8888",nil)
 if e!=nil{
 fmt.Println(e.Error())
 }
}
func helloWorld(w http.ResponseWriter, r *http.Request) {
 str:="Hello World"
 n,e:=io.WriteString(w, str)
 if e!=nil{
 fmt.Println(e.Error())
 } else {
 fmt.Println(n," " ,len(str))
 }
}

conclusion

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