feat: add gzip and ungzip functions

crypto.go

@@ -2,6 +2,7 @@ package sprig
 
 import (
 	"bytes"
+	"compress/gzip"
 	"crypto"
 	"crypto/aes"
 	"crypto/cipher"
@@ -657,3 +658,37 @@ func decryptAES(password string, crypt64 string) (string, error) {
 
 	return string(decrypted[:len(decrypted)-int(decrypted[len(decrypted)-1])]), nil
 }
+
+func gzipCompress(input string) (string, error) {
+	var buffer bytes.Buffer
+	gzipWriter := gzip.NewWriter(&buffer)
+	_, err := gzipWriter.Write([]byte(input))
+	if err != nil {
+		return "", err
+	}
+
+	if err := gzipWriter.Close(); err != nil {
+		return "", err
+	}
+
+	return buffer.String(), nil
+}
+
+func gzipDecompress(input string) (string, error) {
+	gzipReader, err := gzip.NewReader(bytes.NewReader([]byte(input)))
+	if err != nil {
+		return "", err
+	}
+
+	var buffer bytes.Buffer
+	_, err = buffer.ReadFrom(gzipReader)
+	if err != nil {
+		return "", err
+	}
+
+	if err := gzipReader.Close(); err != nil {
+		return "", err
+	}
+
+	return buffer.String(), nil
+}

crypto_test.go

@@ -430,3 +430,10 @@ func TestEncryptDecryptAES(t *testing.T) {
 		t.Error(err)
 	}
 }
+
+func TestCompressDecompressGzip(t *testing.T) {
+	tpl := `{{"plaintext" | gzip | ungzip }}`
+	if err := runt(tpl, "plaintext"); err != nil {
+		t.Error(err)
+	}
+}

functions.go

@@ -353,6 +353,8 @@ var genericMap = map[string]interface{}{
 	"encryptAES":               encryptAES,
 	"decryptAES":               decryptAES,
 	"randBytes":                randBytes,
+	"gzip":                     gzipCompress,
+	"ungzip":                   gzipDecompress,
 
 	// UUIDs:
 	"uuidv4": uuidv4,