Merge pull request #172 from wneessen/feature/171_implement-per-part-charsets

Add Charset support for message parts

msg.go

@@ -1141,6 +1141,7 @@ func (m *Msg) hasPGPType() bool {
 func (m *Msg) newPart(ct ContentType, o ...PartOption) *Part {
 	p := &Part{
 		ctype: ct,
+		cset:  m.charset,
 		enc:   m.encoding,
 	}
 

msgwriter.go

@@ -245,7 +245,11 @@ func (mw *msgWriter) newPart(h map[string][]string) {
 
 // writePart writes the corresponding part to the Msg body
 func (mw *msgWriter) writePart(p *Part, cs Charset) {
-	ct := fmt.Sprintf("%s; charset=%s", p.ctype, cs)
+	pcs := p.cset
+	if pcs.String() == "" {
+		pcs = cs
+	}
+	ct := fmt.Sprintf("%s; charset=%s", p.ctype, pcs)
 	cte := p.enc.String()
 	if mw.d == 0 {
 		mw.writeHeader(HeaderContentType, ct)

msgwriter_test.go

@@ -53,6 +53,7 @@ func TestMsgWriter_writeMsg(t *testing.T) {
 	m.SetDateWithValue(now)
 	m.SetMessageIDWithValue("message@id.com")
 	m.SetBodyString(TypeTextPlain, "This is the body")
+	m.AddAlternativeString(TypeTextHTML, "This is the alternative body")
 	buf := bytes.Buffer{}
 	mw := &msgWriter{w: &buf, c: CharsetUTF8, en: mime.QEncoding}
 	mw.writeMsg(m)
@@ -95,6 +96,26 @@ func TestMsgWriter_writeMsg(t *testing.T) {
 	if !strings.Contains(ms, "\r\n\r\nThis is the body") {
 		ea = append(ea, "Message body")
 	}
+
+	pl := m.GetParts()
+	if len(pl) <= 0 {
+		t.Errorf("expected multiple parts but got none")
+		return
+	}
+	if len(pl) == 2 {
+		ap := pl[1]
+		ap.SetCharset(CharsetISO88591)
+	}
+	buf.Reset()
+	mw.writeMsg(m)
+	ms = buf.String()
+	if !strings.Contains(ms, "\r\n\r\nThis is the alternative body") {
+		ea = append(ea, "Message alternative body")
+	}
+	if !strings.Contains(ms, `Content-Type: text/html; charset=ISO-8859-1`) {
+		ea = append(ea, "alternative body charset")
+	}
+
 	if len(ea) > 0 {
 		em := "writeMsg() failed. The following errors occurred:\n"
 		for e := range ea {

part.go

@@ -15,6 +15,7 @@ type PartOption func(*Part)
 // Part is a part of the Msg
 type Part struct {
 	ctype ContentType
+	cset  Charset
 	desc  string
 	enc   Encoding
 	del   bool
@@ -30,6 +31,11 @@ func (p *Part) GetContent() ([]byte, error) {
 	return b.Bytes(), nil
 }
 
+// GetCharset returns the currently set Charset of the Part
+func (p *Part) GetCharset() Charset {
+	return p.cset
+}
+
 // GetContentType returns the currently set ContentType of the Part
 func (p *Part) GetContentType() ContentType {
 	return p.ctype
@@ -61,6 +67,11 @@ func (p *Part) SetContentType(c ContentType) {
 	p.ctype = c
 }
 
+// SetCharset overrides the Charset of the Part
+func (p *Part) SetCharset(c Charset) {
+	p.cset = c
+}
+
 // SetEncoding creates a new mime.WordEncoder based on the encoding setting of the message
 func (p *Part) SetEncoding(e Encoding) {
 	p.enc = e
@@ -82,6 +93,13 @@ func (p *Part) Delete() {
 	p.del = true
 }
 
+// WithPartCharset overrides the default Part charset
+func WithPartCharset(c Charset) PartOption {
+	return func(p *Part) {
+		p.cset = c
+	}
+}
+
 // WithPartEncoding overrides the default Part encoding
 func WithPartEncoding(e Encoding) PartOption {
 	return func(p *Part) {

part_test.go

@@ -45,6 +45,33 @@ func TestPartEncoding(t *testing.T) {
 	}
 }
 
+// TestWithPartCharset tests the WithPartCharset method
+func TestWithPartCharset(t *testing.T) {
+	tests := []struct {
+		name string
+		cs   Charset
+		want string
+	}{
+		{"Part charset: UTF-8", CharsetUTF8, "UTF-8"},
+		{"Part charset: ISO-8859-1", CharsetISO88591, "ISO-8859-1"},
+		{"Part charset: empty", "", ""},
+	}
+	for _, tt := range tests {
+		m := NewMsg()
+		t.Run(tt.name, func(t *testing.T) {
+			part := m.newPart(TypeTextPlain, WithPartCharset(tt.cs), nil)
+			if part == nil {
+				t.Errorf("newPart() WithPartCharset() failed: no part returned")
+				return
+			}
+			if part.cset.String() != tt.want {
+				t.Errorf("newPart() WithPartCharset() failed: expected charset: %s, got: %s",
+					tt.want, part.cset.String())
+			}
+		})
+	}
+}
+
 // TestPart_WithPartContentDescription tests the WithPartContentDescription method
 func TestPart_WithPartContentDescription(t *testing.T) {
 	tests := []struct {
@@ -320,3 +347,32 @@ func getPartList(m *Msg) ([]*Part, error) {
 	}
 	return pl, nil
 }
+
+// TestPart_SetCharset tests Part.SetCharset method
+func TestPart_SetCharset(t *testing.T) {
+	tests := []struct {
+		name string
+		cs   Charset
+		want string
+	}{
+		{"Charset: UTF-8", CharsetUTF8, "UTF-8"},
+		{"Charset: ISO-8859-1", CharsetISO88591, "ISO-8859-1"},
+		{"Charset: empty", "", ""},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			m := NewMsg()
+			m.SetBodyString(TypeTextPlain, "This is a test with ümläutß")
+			pl, err := getPartList(m)
+			if err != nil {
+				t.Errorf("failed: %s", err)
+				return
+			}
+			pl[0].SetCharset(tt.cs)
+			cs := pl[0].GetCharset()
+			if string(cs) != tt.want {
+				t.Errorf("SetCharset failed. Got: %s, expected: %s", string(cs), tt.want)
+			}
+		})
+	}
+}