If you access servers remotely over SSH connections, you are bound to have come across scp. It is what you use to upload files to these remote servers.
If you want to programmatically upload files like scp over an SSH connection to a remote server using Go, then you can use an ssh.Client:
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| // Error handling omitted for brevity.
func uploadFile(sshClient *ssh.Client, filename string, mode os.FileMode, size int64, r io.Reader) {
// Set up a new SSH session.
sess, _ := sshClient.NewSession()
defer sess.Close()
// Write the file's metadata and contents to the stdin pipe.
w, _ := sess.StdinPipe()
go func() {
defer w.Close()
// Write "C{mode} {size} {filename}\n"
fmt.Fprintf(w, "C%#o %d %s\n", mode, size, path.Base(filename))
// Write the file's contents.
io.Copy(w, r)
// End with a null byte.
fmt.Fprint(w, "\x00")
}()
sess.Stdout = os.Stdout
sess.Stderr = os.Stderr
// Run `scp -t {filename}` on the server-side.
sess.Run(fmt.Sprintf("scp -t %s", filename))
}
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You can use this function like so:
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| // Connect to the remote server over SSH.
c, _ := ssh.Dial("tcp", "carrot.local:22", &ssh.ClientConfig{
User: "hjr265",
Auth: []ssh.AuthMethod{
ssh.PasswordCallback(func() (string, error) { return "KeyboardCat", nil }),
},
HostKeyCallback: ssh.InsecureIgnoreHostKey(),
})
// Upload the file.
f, _ := os.Open("hello.txt")
fi, _ := f.Stat()
uploadFile(c, fi.Name(), 0644, fi.Size(), f)
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