ddns-updater/public_resolvers/base_resolver.go

package public_resolvers

import (
	"context"
	"fmt"
	"io"
	"net"
	"net/http"
)

type Doer interface {
	Do(*http.Request) (*http.Response, error)
}

type baseResolver struct {
	client Doer
	url    string
}

func (i baseResolver) ResolvePublicIp(ctx context.Context) (net.IP, error) {
	req, err := http.NewRequestWithContext(ctx, http.MethodGet, i.url, nil)
	if err != nil {
		return net.IP{}, fmt.Errorf("error creating ifconfig request: %w", err)
	}

	resp, err := i.client.Do(req)
	if err != nil {
		return net.IP{}, err
	}
	defer func() {
		_ = resp.Body.Close()
	}()

	if resp.StatusCode != http.StatusOK {
		return net.IP{}, fmt.Errorf("unexpected response code %d", resp.StatusCode)
	}

	ipText, err := io.ReadAll(resp.Body)
	if err != nil {
		return net.IP{}, fmt.Errorf("error reading body: %w", err)
	}

	return net.ParseIP(string(ipText)), nil
}