43 lines
975 B
Go
43 lines
975 B
Go
package platform
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import (
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"context"
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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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)
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// Download fetches url into destPath atomically (temp file + rename) with
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// the given file mode. Any non-2xx response returns an error and leaves
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// no file behind.
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func Download(ctx context.Context, url, destPath string, mode os.FileMode) 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 err
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}
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resp, err := http.DefaultClient.Do(req)
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if err != nil {
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return err
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}
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defer resp.Body.Close()
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if resp.StatusCode < 200 || resp.StatusCode >= 300 {
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return fmt.Errorf("download %s: http %d", url, resp.StatusCode)
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}
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tmp := destPath + ".tmp"
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f, err := os.OpenFile(tmp, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, mode)
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if err != nil {
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return err
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}
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if _, err := io.Copy(f, resp.Body); err != nil {
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f.Close()
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os.Remove(tmp)
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return err
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}
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if err := f.Close(); err != nil {
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os.Remove(tmp)
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return err
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}
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return os.Rename(tmp, destPath)
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}
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