Handle n != 0 && err != nil

main.go

@@ -241,38 +241,28 @@ func main() {
 	writer := bufio.NewWriter(file)
 	defer writer.Flush()
 	reader := bufio.NewReader(response.Body)
-	contentLengthString := ""
-	if response.ContentLength >= 0 {
-		contentLengthString = FormatBytes(float64(response.ContentLength))
-	}
 	lastOutputLength := 0
 	bytesDownloaded := 0
 	toWrite := make([]byte, 1024*1024)
 	for {
-		output := fmt.Sprintf("%s downloaded", FormatBytes(float64(bytesDownloaded)))
-		if response.ContentLength >= 0 {
-			output = fmt.Sprintf("%s out of %s downloaded (%.2f%%)", FormatBytes(float64(bytesDownloaded)), contentLengthString, float64(bytesDownloaded)/float64(response.ContentLength)*100.0)
-		}
-		fmt.Print(output)
-		for i := 0; i < lastOutputLength-len(output); i++ {
-			fmt.Print(" ")
-		}
-		lastOutputLength = len(output)
-		fmt.Print("\r")
+		lastOutputLength = PrintStatus(float64(bytesDownloaded), float64(response.ContentLength), lastOutputLength)
 		n, err := reader.Read(toWrite)
-		if n == 0 && errors.Is(err, io.EOF) {
+		if n > 0 {
+			_, writeErr := writer.Write(toWrite[:n])
+			if writeErr != nil {
+				fmt.Fprintf(os.Stderr, "Failed to write response: %s\n", writeErr)
+				os.Exit(1)
+			}
+			bytesDownloaded += n
+			lastOutputLength = PrintStatus(float64(bytesDownloaded), float64(response.ContentLength), lastOutputLength)
+		}
+		if errors.Is(err, io.EOF) {
 			break
 		}
 		if err != nil {
 			fmt.Fprintf(os.Stderr, "Failed to read response: %s\n", err)
 			os.Exit(1)
 		}
-		_, err = writer.Write(toWrite[:n])
-		if err != nil {
-			fmt.Fprintf(os.Stderr, "Failed to write response: %s\n", err)
-			os.Exit(1)
-		}
-		bytesDownloaded += n
 	}
 	fmt.Println()
 }

utils.go

@@ -295,3 +295,17 @@ func GetExtension(mimeType string) (string, error) {
 	fmt.Println(exts)
 	return exts[0], nil
 }
+
+func PrintStatus(bytesDownloaded, contentLength float64, lastOutputLength int) int {
+	output := fmt.Sprintf("%s downloaded", FormatBytes(bytesDownloaded))
+	if contentLength >= 0 {
+		contentLengthString := FormatBytes(contentLength)
+		output = fmt.Sprintf("%s out of %s downloaded (%.2f%%)", FormatBytes(bytesDownloaded), contentLengthString, bytesDownloaded/contentLength*100.0)
+	}
+	fmt.Print(output)
+	for i := 0; i < lastOutputLength-len(output); i++ {
+		fmt.Print(" ")
+	}
+	fmt.Print("\r")
+	return len(output)
+}