Golang : Download file example




Continuing from previous tutorial on how to use http.Get() function, in this tutorial, we will learn how to download/get file from another server via the http.Get() function and save the content into a file.

This program will

  • figure out the filename to be created based on the given URL

  • check if there is redirection and handle it

  • report the Get status

  • save the content to a file

  • print out the bytes downloaded.

downloadfile.go

 package main

 import (
 "fmt"
 "io"
 "net/http"
 "net/url"
 "os"
 "strings"
 )

 func main() {
 fmt.Println("Downloading file...")

 rawURL := "https://d1ohg4ss876yi2.cloudfront.net/golang-resize-image/big.jpg"

 fileURL, err := url.Parse(rawURL)

 if err != nil {
 panic(err)
 }

 path := fileURL.Path

 segments := strings.Split(path, "/")

 fileName := segments[2] // change the number to accommodate changes to the url.Path position 

 file, err := os.Create(fileName)

 if err != nil {
 fmt.Println(err)
 panic(err)
 }
 defer file.Close()

 check := http.Client{
 CheckRedirect: func(r *http.Request, via []*http.Request) error {
 r.URL.Opaque = r.URL.Path
 return nil
 },
 }

 resp, err := check.Get(rawURL) // add a filter to check redirect

 if err != nil {
 fmt.Println(err)
 panic(err)
 }
 defer resp.Body.Close()
 fmt.Println(resp.Status)

 size, err := io.Copy(file, resp.Body)

 if err != nil {
 panic(err)
 }

 fmt.Printf("%s with %v bytes downloaded", fileName, size)
 }

Output :

Downloading file...

200 OK

big.jpg with 150042 bytes downloaded

References :

Golang http.Get example

Get URI segments by number and assign as variable example

  See also : Golang : http.Get example





By Adam Ng

IF you gain some knowledge or the information here solved your programming problem. Please consider donating to the less fortunate or some charities that you like. Apart from donation, planting trees, volunteering or reducing your carbon footprint will be great too.


Advertisement