added pkg/filecli/

pkg/filecli/getfile.go

@@ -0,0 +1,53 @@
+package filecli
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"net/http"
+	"strconv"
+)
+
+func (cli *Client) GetFile(ctx context.Context, rawpath string, writer io.Writer) (bool, error) {
+	var err error
+	var exist bool
+
+	ref, err :=ParsePath(rawpath)
+	if err != nil {
+		return exist, err
+	}
+	uri := ref.File()
+
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, uri, nil)
+	if err != nil {
+		return exist, err
+	}
+	req.Header.Set("User-Agent", cli.userAgent)
+	req.Header.Set("Accept", "*/*")
+	resp, err := cli.httpClient.Do(req)
+	if err != nil {
+		return exist, err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode == http.StatusNotFound {
+		return exist, err
+	}
+	if resp.StatusCode != http.StatusOK {
+		err := fmt.Errorf("Unexpected response code %s", resp.Status)
+		return exist, err
+	}
+	contentLength := resp.Header.Get("Content-Length")
+	blobSize, err := strconv.ParseInt(contentLength, 10, 64)
+	if err != nil {
+		return exist, err
+	}
+
+	recSize, err := Copy(ctx, writer, resp.Body)
+	if blobSize != recSize {
+		err := fmt.Errorf("Mismatch declared and actual body size, %d and %d", blobSize, recSize)
+		return exist, err
+	}
+	exist = true
+	return exist, err
+}