Golang : Test file read write permission example
Problem :
You need to test if a file has the correct write or read permission before performing write or read operation. How to do that?
Solution :
Use os.OpenFile()
function and check the error with os.IsPermission() to see if a file has permission denied error.
For example :
To test if a file has write permission : (do not run this program as root or super user)
package main
import (
"fmt"
"os"
)
func main() {
fileName := "file.txt"
file, err := os.OpenFile(fileName, os.O_WRONLY, 0666)
if err != nil {
if os.IsPermission(err) {
fmt.Println("Unable to write to ", fileName)
fmt.Println(err)
os.Exit(1)
}
}
file.Close()
}
To test if a file has read permission : (do not run this program as root or super user)
package main
import (
"fmt"
"os"
)
func main() {
fileName := "file.txt"
file, err = os.OpenFile(fileName, os.O_RDONLY, 0666)
if err != nil {
if os.IsPermission(err) {
fmt.Println("Unable to read from ", fileName)
fmt.Println(err)
os.Exit(1)
}
}
file.Close()
}
References :
https://golang.org/pkg/os/#IsPermission
https://www.socketloop.com/tutorials/golang-check-if-a-file-exist-or-not
See also : Golang : Get file permission
By Adam Ng
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