Init: lab4 done

utils/urlFile.go

@@ -0,0 +1,48 @@
+package utils
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+)
+
+func LoadUrls(filename string) ([]string, error) {
+	file, err := os.OpenFile(filename, os.O_RDONLY, 0644)
+	if err != nil {
+		if errors.Is(err, os.ErrNotExist) {
+			return []string{}, nil
+		}
+		return nil, fmt.Errorf("failed to open file, %w", err)
+	}
+
+	b, err := io.ReadAll(file)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read file, %w", err)
+	}
+
+	var res []string
+	if err := json.Unmarshal(b, &res); err != nil {
+		return nil, fmt.Errorf("failed to unmarshal from json, %w", err)
+	}
+
+	return res, nil
+}
+
+func SaveUrls(filename string, urls []string) error {
+	file, err := os.OpenFile(filename, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0644)
+	if err != nil {
+		return fmt.Errorf("failed to open file, %w", err)
+	}
+
+	b, err := json.Marshal(urls)
+	if err != nil {
+		return fmt.Errorf("failed to marshal to json, %w", err)
+	}
+
+	if _, err := file.Write(b); err != nil {
+		return fmt.Errorf("failed to write to file, %w", err)
+	}
+	return nil
+}