53 lines
1.2 KiB
Go
53 lines
1.2 KiB
Go
|
package ip
|
||
|
|
|
||
|
|
import (
|
||
|
|
"bytes"
|
||
|
|
"context"
|
||
|
|
"fmt"
|
||
|
|
"io"
|
||
|
|
"net"
|
||
|
|
"net/http"
|
||
|
|
)
|
||
|
|
|
||
|
|
const ifconfigURL = "https://ifconfig.me"
|
||
|
|
const httpMaxRead = 100
|
||
|
|
|
||
|
|
// TODO: use a struct, but a baseHTTPClient inside it to perform unit tests
|
||
|
|
type Getter interface {
|
||
|
|
GetCurrentPublicIP(ctx context.Context) (net.IP, error)
|
||
|
|
}
|
||
|
|
|
||
|
|
type concreteIPGetter struct {
|
||
|
|
}
|
||
|
|
|
||
|
|
func (c *concreteIPGetter) GetCurrentPublicIP(ctx context.Context) (net.IP, error) {
|
||
|
|
req, err := http.NewRequestWithContext(ctx, http.MethodGet, ifconfigURL, nil)
|
||
|
|
if err != nil {
|
||
|
|
return nil, fmt.Errorf("failed to prepare public IP request: %w", err)
|
||
|
|
}
|
||
|
|
resp, err := http.DefaultClient.Do(req)
|
||
|
|
if err != nil {
|
||
|
|
return nil, fmt.Errorf("failed to get current IP from ifconfig: %w", err)
|
||
|
|
}
|
||
|
|
|
||
|
|
if resp.ContentLength > httpMaxRead {
|
||
|
|
return nil, fmt.Errorf("response too big: %d/%d", resp.ContentLength, httpMaxRead)
|
||
|
|
}
|
||
|
|
|
||
|
|
buf := bytes.NewBuffer([]byte{})
|
||
|
|
if _, err := io.CopyN(buf, resp.Body, resp.ContentLength); err != nil {
|
||
|
|
return nil, fmt.Errorf("error parsing body: %w", err)
|
||
|
|
}
|
||
|
|
|
||
|
|
content := string(buf.Bytes())
|
||
|
|
res := net.ParseIP(content)
|
||
|
|
if res == nil {
|
||
|
|
return nil, fmt.Errorf("got an invalid public IP %q", content)
|
||
|
|
}
|
||
|
|
return res, nil
|
||
|
|
}
|
||
|
|
|
||
|
|
func New() *concreteIPGetter {
|
||
|
|
return &concreteIPGetter{}
|
||
|
|
}
|