decode: refactor file decoding into config package

config/decode.go

@@ -0,0 +1,56 @@
+package config
+
+import (
+	"bytes"
+	"compress/gzip"
+	"encoding/base64"
+	"fmt"
+)
+
+func DecodeBase64Content(content string) ([]byte, error) {
+	output, err := base64.StdEncoding.DecodeString(content)
+
+	if err != nil {
+		return nil, fmt.Errorf("Unable to decode base64: %q", err)
+	}
+
+	return output, nil
+}
+
+func DecodeGzipContent(content string) ([]byte, error) {
+	gzr, err := gzip.NewReader(bytes.NewReader([]byte(content)))
+
+	if err != nil {
+		return nil, fmt.Errorf("Unable to decode gzip: %q", err)
+	}
+	defer gzr.Close()
+
+	buf := new(bytes.Buffer)
+	buf.ReadFrom(gzr)
+
+	return buf.Bytes(), nil
+}
+
+func DecodeContent(content string, encoding string) ([]byte, error) {
+	switch encoding {
+	case "":
+		return []byte(content), nil
+
+	case "b64", "base64":
+		return DecodeBase64Content(content)
+
+	case "gz", "gzip":
+		return DecodeGzipContent(content)
+
+	case "gz+base64", "gzip+base64", "gz+b64", "gzip+b64":
+		gz, err := DecodeBase64Content(content)
+
+		if err != nil {
+			return nil, err
+		}
+
+		return DecodeGzipContent(string(gz))
+	}
+
+	return nil, fmt.Errorf("Unsupported encoding %q", encoding)
+}