90 lines
2.6 KiB
Go
90 lines
2.6 KiB
Go
package metadata
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import (
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"bytes"
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"context"
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"encoding/json"
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"fmt"
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"io"
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"net/http"
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"net/url"
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"time"
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)
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const defaultTimeout = 10 * time.Second
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// newHTTPClient собирает http.Client с опциональным прокси и таймаутом.
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func newHTTPClient(proxy string, timeout time.Duration) (*http.Client, error) {
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if timeout <= 0 {
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timeout = defaultTimeout
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}
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transport := http.DefaultTransport
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if proxy != "" {
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u, err := url.Parse(proxy)
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if err != nil {
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return nil, fmt.Errorf("metadata: parse proxy %q: %w", proxy, err)
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}
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transport = &http.Transport{Proxy: http.ProxyURL(u)}
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}
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return &http.Client{Timeout: timeout, Transport: transport}, nil
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}
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const maxBody = 4 << 20 // 4 MiB — потолок на тело ответа
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// getJSON выполняет GET и декодирует JSON-ответ в out. headers — опц.
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// дополнительные заголовки (напр. Authorization).
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func getJSON(ctx context.Context, hc *http.Client, rawURL string, headers map[string]string, out any) error {
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req, err := http.NewRequestWithContext(ctx, http.MethodGet, rawURL, nil)
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if err != nil {
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return fmt.Errorf("metadata: build request: %w", err)
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}
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req.Header.Set("Accept", "application/json")
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for k, v := range headers {
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req.Header.Set(k, v)
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}
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return doJSON(hc, req, out)
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}
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// postJSON выполняет POST с JSON-телом и декодирует ответ.
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func postJSON(ctx context.Context, hc *http.Client, rawURL string, body, out any) error {
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payload, err := json.Marshal(body)
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if err != nil {
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return fmt.Errorf("metadata: marshal body: %w", err)
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}
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req, err := http.NewRequestWithContext(ctx, http.MethodPost, rawURL, bytes.NewReader(payload))
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if err != nil {
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return fmt.Errorf("metadata: build request: %w", err)
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}
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req.Header.Set("Content-Type", "application/json")
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req.Header.Set("Accept", "application/json")
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return doJSON(hc, req, out)
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}
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func doJSON(hc *http.Client, req *http.Request, out any) error {
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resp, err := hc.Do(req)
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if err != nil {
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return fmt.Errorf("metadata: request: %w", err)
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}
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defer func() { _ = resp.Body.Close() }()
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raw, err := io.ReadAll(io.LimitReader(resp.Body, maxBody))
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if err != nil {
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return fmt.Errorf("metadata: read body: %w", err)
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}
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if resp.StatusCode != http.StatusOK {
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return fmt.Errorf("metadata: status %d: %s", resp.StatusCode, snippet(raw))
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}
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if err := json.Unmarshal(raw, out); err != nil {
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return fmt.Errorf("metadata: decode: %w (body: %s)", err, snippet(raw))
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}
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return nil
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}
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func snippet(b []byte) string {
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const max = 200
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if len(b) > max {
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return string(b[:max]) + "…"
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}
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return string(b)
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}
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