merged from gramsrv upstream

internal/updatecdn/client.go

@@ -0,0 +1,77 @@
+package updatecdn
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"strings"
+	"time"
+)
+
+type Resolver interface {
+	Resolve(ctx context.Context, req ResolveRequest) (*ResolvedUpdate, error)
+}
+
+type Client struct {
+	baseURL string
+	http    *http.Client
+}
+
+func NewClient(baseURL string, timeout time.Duration) (*Client, error) {
+	baseURL = strings.TrimRight(strings.TrimSpace(baseURL), "/")
+	parsed, err := url.Parse(baseURL)
+	if err != nil {
+		return nil, fmt.Errorf("parse update service URL: %w", err)
+	}
+	if (parsed.Scheme != "http" && parsed.Scheme != "https") || parsed.Hostname() == "" || parsed.User != nil || parsed.RawQuery != "" || parsed.Fragment != "" {
+		return nil, fmt.Errorf("update service URL must be an HTTP(S) base URL without credentials, query, or fragment")
+	}
+	if timeout <= 0 {
+		timeout = 2 * time.Second
+	}
+	return &Client{baseURL: baseURL, http: &http.Client{Timeout: timeout}}, nil
+}
+
+func (c *Client) Resolve(ctx context.Context, request ResolveRequest) (*ResolvedUpdate, error) {
+	u, err := url.Parse(c.baseURL + "/v1/resolve")
+	if err != nil {
+		return nil, err
+	}
+	query := u.Query()
+	query.Set("platform", request.Platform)
+	query.Set("channel", request.Channel)
+	query.Set("version", request.Version)
+	query.Set("source", request.Source)
+	query.Set("lang_code", request.LangCode)
+	u.RawQuery = query.Encode()
+
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, u.String(), nil)
+	if err != nil {
+		return nil, fmt.Errorf("build update resolve request: %w", err)
+	}
+	resp, err := c.http.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("resolve application update: %w", err)
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode == http.StatusNoContent {
+		return nil, nil
+	}
+	if resp.StatusCode != http.StatusOK {
+		_, _ = io.Copy(io.Discard, io.LimitReader(resp.Body, 4<<10))
+		return nil, fmt.Errorf("resolve application update: HTTP %d", resp.StatusCode)
+	}
+	var resolved ResolvedUpdate
+	decoder := json.NewDecoder(io.LimitReader(resp.Body, 256<<10))
+	decoder.DisallowUnknownFields()
+	if err := decoder.Decode(&resolved); err != nil {
+		return nil, fmt.Errorf("decode application update: %w", err)
+	}
+	if resolved.ID <= 0 || strings.TrimSpace(resolved.Version) == "" || strings.TrimSpace(resolved.Text) == "" {
+		return nil, fmt.Errorf("resolve application update: incomplete response")
+	}
+	return &resolved, nil
+}