dns-updater/ip/resolver/basic_http/service.go

package basic_http

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

type Service struct {
	ServiceName string
	Url         string
	Headers     http.Header
}

func (s Service) Name() string {
	return s.ServiceName
}

func (s Service) Lookup(ctx context.Context) (net.IP, error) {
	req, err := http.NewRequestWithContext(ctx, "GET", s.Url, nil)
	if err != nil {
		return nil, err
	}

	req.Header = s.Headers

	resp, err := http.DefaultClient.Do(req)
	if err != nil {
		return nil, err
	}

	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
		return nil, fmt.Errorf("HTTP Response: %s", resp.Status)
	}

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, err
	}

	// Trim spaces and stuff.
	ip_str := strings.TrimSpace(string(body))

	ip := net.ParseIP(ip_str)
	if ip == nil {
		err = fmt.Errorf("Failed to parse ip: %s", ip_str)
	}
	return ip, err
}