feat: add parser option to parse raw content

encode.go

@@ -24,6 +24,7 @@ const (
 	te7Bit transferEncoding = iota
 	teQuoted
 	teBase64
+	teRaw
 )
 
 const (
@@ -194,6 +195,10 @@ func (p *Part) encodeContent(b *bufio.Writer, cte transferEncoding) (err error)
 		return p.encodeContentFromReader(b)
 	}
 
+	if p.parser != nil && p.parser.rawContent {
+		cte = teRaw
+	}
+
 	switch cte {
 	case teBase64:
 		enc := base64.StdEncoding

options.go

@@ -51,3 +51,15 @@ func (o maxStoredPartErrorsOption) apply(p *Parser) {
 	max := int(o)
 	p.maxStoredPartErrors = &max
 }
+
+// RawContent if set to true will not try to decode the CTE and return the raw part content.
+// Otherwise, will try to automatically decode the CTE.
+func RawContent(a bool) Option {
+	return rawContentOption(a)
+}
+
+type rawContentOption bool
+
+func (o rawContentOption) apply(p *Parser) {
+	p.rawContent = bool(o)
+}

parser.go

@@ -20,6 +20,7 @@ type Parser struct {
 	multipartWOBoundaryAsSinglePart bool
 	readPartErrorPolicy             ReadPartErrorPolicy
 	skipMalformedParts              bool
+	rawContent                      bool
 }
 
 // defaultParser is a Parser with default configuration.

part.go

@@ -277,7 +277,10 @@ func (p *Part) decodeContent(r io.Reader, readPartErrorPolicy ReadPartErrorPolic
 	// b64cleaner aggregates errors, must maintain a reference to it to get them later.
 	var b64cleaner *coding.Base64Cleaner
 	// Build content decoding reader.
-	encoding := header.Get(hnContentEncoding)
+	encoding := ""
+	if p.parser != nil && !p.parser.rawContent {
+		encoding = header.Get(hnContentEncoding)
+	}
 	validEncoding := true
 	switch strings.ToLower(encoding) {
 	case cteQuotedPrintable: