init

internal/client/client.go

@@ -0,0 +1,106 @@
+package client
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"time"
+)
+
+type Client struct {
+	baseURL string
+	http    *http.Client
+}
+
+func New(baseURL string) *Client {
+	return &Client{
+		baseURL: baseURL,
+		http:    &http.Client{Timeout: 10 * time.Second},
+	}
+}
+
+type listResponse struct {
+	Servers []string `json:"servers"`
+}
+
+type addRequest struct {
+	Address string `json:"address"`
+}
+
+type errorResponse struct {
+	Error string `json:"error"`
+}
+
+func (c *Client) List() ([]string, error) {
+	req, err := http.NewRequest(http.MethodGet, c.baseURL+"/dns", nil)
+	if err != nil {
+		return nil, err
+	}
+	resp, err := c.http.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, decodeError(resp)
+	}
+	var lr listResponse
+	if err := json.NewDecoder(resp.Body).Decode(&lr); err != nil {
+		return nil, fmt.Errorf("decode response: %w", err)
+	}
+	return lr.Servers, nil
+}
+
+func (c *Client) Add(addr string) error {
+	body, err := json.Marshal(addRequest{Address: addr})
+	if err != nil {
+		return err
+	}
+	req, err := http.NewRequest(http.MethodPost, c.baseURL+"/dns", bytes.NewReader(body))
+	if err != nil {
+		return err
+	}
+	req.Header.Set("Content-Type", "application/json")
+
+	resp, err := c.http.Do(req)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusCreated {
+		return decodeError(resp)
+	}
+	return nil
+}
+
+func (c *Client) Remove(addr string) error {
+	u := c.baseURL + "/dns/" + url.PathEscape(addr)
+	req, err := http.NewRequest(http.MethodDelete, u, nil)
+	if err != nil {
+		return err
+	}
+	resp, err := c.http.Do(req)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusNoContent {
+		return decodeError(resp)
+	}
+	return nil
+}
+
+func decodeError(resp *http.Response) error {
+	body, _ := io.ReadAll(resp.Body)
+	var er errorResponse
+	if json.Unmarshal(body, &er) == nil && er.Error != "" {
+		return fmt.Errorf("server returned %s: %s", resp.Status, er.Error)
+	}
+	return fmt.Errorf("server returned %s: %s", resp.Status, string(body))
+}