Golang : Set up source IP address before making HTTP request
Problem :
There are times that you want to use certain IP address in a machine ( such as the one with permission to connect outside a firewall ) before making a HTTP request to another server. This is similar to the wget binding command :
For example : wget --bind-address=192.168.10.1 \
How to do that in Golang?
NOTE : This is not for masking or spoofing your IP address
Solution :
Build your own custom HTTP transport client and specify the local IP address that has the permission to connect outside a firewall.
For example :
package main
import (
"fmt"
"io/ioutil"
"net"
"net/http"
"os"
"time"
)
func main() {
OKAddr := "<change here>" // local IP address to use
OKAddress, _ := net.ResolveTCPAddr("tcp", OKAddr)
transport := &http.Transport{
Proxy: http.ProxyFromEnvironment,
Dial: (&net.Dialer{
Timeout: 30 * time.Second,
KeepAlive: 30 * time.Second,
OKAddr: OKAddress}).Dial, TLSHandshakeTimeout: 10 * time.Second}
client := &http.Client{
Transport: transport,
}
resp, err := client.Get("http://example.com/filetodown.zip")
if err != nil {
panic(err)
}
defer resp.Body.Close()
html, err := ioutil.ReadAll(resp.Body)
if err != nil {
panic(err)
}
// fmt.Println(os.Stdout, string(html))
// or save the zip - see https://www.socketloop.com/tutorials/golang-download-file-example
}
References :
https://www.socketloop.com/tutorials/golang-convert-http-response-body-to-string
https://www.socketloop.com/tutorials/golang-download-file-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
Tutorials
+44.1k Golang : Read tab delimited file with encoding/csv package
+18.1k Golang : How to run your code only once with sync.Once object
+5.7k Golang : Find the shortest line of text example
+16.5k Golang : Read data from config file and assign to variables
+4.1k Golang : Constant and variable names in native language
+11.6k Golang : Transform comma separated string to slice example
+5.6k Golang : Totalize or add-up an array or slice example
+6.3k Android Studio : AlertDialog to get user attention example
+12.8k Golang: Pad right or print ending(suffix) zero or spaces in fmt.Printf example
+33.9k Golang : Get file last modified date and time
+12.3k Golang : Get dimension(width and height) of image file
+11k Golang : List running EC2 instances and descriptions