refactor: move function into web package

pkg/web/web.go

@@ -3,6 +3,10 @@ package web
 
 import (
 	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
 	"time"
 )
 
@@ -20,3 +24,29 @@ func ReadJSON(url string, target interface{}) error {
 	defer res.Body.Close()
 	return json.NewDecoder(res.Body).Decode(target)
 }
+
+// GetFile downloads a file and saves it to a filepath
+func GetFile(filepath string, url string) (err error) {
+	out, err := os.Create(filepath)
+	if err != nil {
+		return err
+	}
+	defer out.Close()
+
+	resp, err := http.Get(url)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return fmt.Errorf("bad status: %s", resp.Status)
+	}
+
+	_, err = io.Copy(out, resp.Body)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}