71 lines
1.6 KiB
Go
71 lines
1.6 KiB
Go
package rpm
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import (
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"context"
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"crypto/sha256"
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"encoding/hex"
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"fmt"
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"io"
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"net/http"
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"os"
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"path/filepath"
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)
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func verifyChecksum(data []byte, expected string) error {
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sum := sha256.Sum256(data)
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got := hex.EncodeToString(sum[:])
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if got != expected {
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return fmt.Errorf("checksum mismatch: got %s, want %s", got, expected)
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}
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return nil
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}
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// DownloadAndVerify fetches url into destPath atomically (temp file + rename),
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// verifies the SHA256 checksum if checksumType is "sha256", and returns bytes written.
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func DownloadAndVerify(ctx context.Context, httpClient *http.Client, url, destPath, checksumType, expectedChecksum string) (int64, error) {
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req, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
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if err != nil {
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return 0, err
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}
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resp, err := httpClient.Do(req)
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if err != nil {
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return 0, err
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}
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defer resp.Body.Close()
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if resp.StatusCode != http.StatusOK {
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return 0, fmt.Errorf("HTTP %d for %s", resp.StatusCode, url)
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}
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tmpPath := destPath + ".tmp"
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if err := os.MkdirAll(filepath.Dir(tmpPath), 0o755); err != nil {
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return 0, err
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}
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f, err := os.Create(tmpPath)
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if err != nil {
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return 0, err
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}
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h := sha256.New()
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n, err := io.Copy(io.MultiWriter(f, h), resp.Body)
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f.Close()
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if err != nil {
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os.Remove(tmpPath)
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return 0, err
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}
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if checksumType == "sha256" && expectedChecksum != "" {
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got := hex.EncodeToString(h.Sum(nil))
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if got != expectedChecksum {
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os.Remove(tmpPath)
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return 0, fmt.Errorf("checksum mismatch for %s: got %s, want %s", url, got, expectedChecksum)
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}
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}
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if err := os.Rename(tmpPath, destPath); err != nil {
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os.Remove(tmpPath)
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return 0, err
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}
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return n, nil
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}
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