feat: add gzip and ungzip functions

crypto.go

@@ -2,6 +2,7 @@ package sprig
 
 import (
 	"bytes"
+	"compress/gzip"
 	"crypto"
 	"crypto/aes"
 	"crypto/cipher"
@@ -651,3 +652,37 @@ 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

@@ -422,3 +422,10 @@ 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

@@ -22,8 +22,7 @@ import (
 //
 // Use this to pass the functions into the template engine:
 //
-// 	tpl := template.New("foo").Funcs(sprig.FuncMap()))
-//
+//	tpl := template.New("foo").Funcs(sprig.FuncMap()))
 func FuncMap() template.FuncMap {
 	return HtmlFuncMap()
 }
@@ -336,20 +335,22 @@ var genericMap = map[string]interface{}{
 	"mustChunk":   mustChunk,
 
 	// Crypto:
-	"bcrypt":            bcrypt,
-	"htpasswd":          htpasswd,
-	"genPrivateKey":     generatePrivateKey,
-	"derivePassword":    derivePassword,
-	"buildCustomCert":   buildCustomCertificate,
-	"genCA":             generateCertificateAuthority,
-	"genCAWithKey":      generateCertificateAuthorityWithPEMKey,
-	"genSelfSignedCert": generateSelfSignedCertificate,
+	"bcrypt":                   bcrypt,
+	"htpasswd":                 htpasswd,
+	"genPrivateKey":            generatePrivateKey,
+	"derivePassword":           derivePassword,
+	"buildCustomCert":          buildCustomCertificate,
+	"genCA":                    generateCertificateAuthority,
+	"genCAWithKey":             generateCertificateAuthorityWithPEMKey,
+	"genSelfSignedCert":        generateSelfSignedCertificate,
 	"genSelfSignedCertWithKey": generateSelfSignedCertificateWithPEMKey,
-	"genSignedCert":     generateSignedCertificate,
-	"genSignedCertWithKey": generateSignedCertificateWithPEMKey,
-	"encryptAES":        encryptAES,
-	"decryptAES":        decryptAES,
-	"randBytes":         randBytes,
+	"genSignedCert":            generateSignedCertificate,
+	"genSignedCertWithKey":     generateSignedCertificateWithPEMKey,
+	"encryptAES":               encryptAES,
+	"decryptAES":               decryptAES,
+	"randBytes":                randBytes,
+	"gzip":                     gzipCompress,
+	"ungzip":                   gzipDecompress,
 
 	// UUIDs:
 	"uuidv4": uuidv4,