Initial commit.

configuration/configuration.go

@@ -0,0 +1,61 @@
+package configuration
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+var errCfg = errors.New("configuration")
+
+// Config is a configuration controlling structure.
+type Config struct {
+	RSS     *RSS     `json:"rss"`
+	Outputs *Outputs `json:"outputs"`
+}
+
+// New creates new configuration controller.
+func New(path string) (*Config, error) {
+	cfg := &Config{}
+
+	// Get configuration file real path.
+	userHomeDir, err := os.UserHomeDir()
+	if err != nil {
+		return nil, fmt.Errorf("%w: parse configuration file: get real path: get user home dir: %w", errCfg, err)
+	}
+
+	path = strings.Replace(path, "~", userHomeDir, 1)
+
+	absPath, err := filepath.Abs(path)
+	if err != nil {
+		return nil, fmt.Errorf("%w: parse configuration file: get real path: get absolute path: %w", errCfg, err)
+	}
+
+	cfgFileData, err := os.ReadFile(absPath)
+	if err != nil {
+		return nil, fmt.Errorf("%w: parse configuration file: read file: %w", errCfg, err)
+	}
+
+	if err := json.Unmarshal(cfgFileData, cfg); err != nil {
+		return nil, fmt.Errorf("%w: parse configuration file: %w", errCfg, err)
+	}
+
+	// Validate configuration.
+	if err := cfg.Validate(); err != nil {
+		return nil, fmt.Errorf("%w: %w", errCfg, err)
+	}
+
+	return cfg, nil
+}
+
+// Validate validates app configuration.
+func (c *Config) Validate() error {
+	if err := c.RSS.Validate(); err != nil {
+		return fmt.Errorf("validate configuration: %w", err)
+	}
+
+	return nil
+}