v0.1.1: Added embeds/attachments

README.md

@@ -27,8 +27,8 @@ Some of the features of this library:
 * [X] RFC5322 compliant mail address validation
 * [X] Support for common mail header field generation (Message-ID, Date, Bulk-Precedence, etc.)
 * [X] Reusing the same SMTP connection to send multiple mails
+* [X] Support for attachments and inline embeds
 * [ ] Support for different encodings
-* [ ] Support for attachments
 
 ## Examples
 The packageis shipped with example code. Check it out on the packages 

client.go

@@ -83,6 +83,10 @@ var (
 	// ErrNoActiveConnection should be used when a method is used that requies a server connection
 	// but is not yet connected
 	ErrNoActiveConnection = errors.New("not connected to SMTP server")
+
+	// ErrServerNoUnencoded should be used when 8BIT encoding is selected for a message, but
+	// the server does not offer 8BITMIME mode
+	ErrServerNoUnencoded = errors.New("message is 8bit unencoded, but server does not support 8BITMIME")
 )
 
 // NewClient returns a new Session client object
@@ -281,6 +285,11 @@ func (c *Client) Send(ml ...*Msg) error {
 		return fmt.Errorf("failed to send mail: %w", err)
 	}
 	for _, m := range ml {
+		if m.encoding == NoEncoding {
+			if ok, _ := c.sc.Extension("8BITMIME"); !ok {
+				return ErrServerNoUnencoded
+			}
+		}
 		f, err := m.GetSender(false)
 		if err != nil {
 			return err

cmd/main.go

@@ -1,9 +1,9 @@
 package main
 
 import (
+	"flag"
 	"fmt"
 	"github.com/wneessen/go-mail"
-	"io"
 	"os"
 )
 
@@ -27,22 +27,34 @@ func main() {
 		fmt.Printf("failed to set TO address: %s", err)
 		os.Exit(1)
 	}
-	m.Subject("This is the Subject with Umlauts: üöäß")
-	m.SetHeader(mail.HeaderContentLang, "de", "en", "fr", "sp", "de", "en", "fr", "sp", "de", "en", "fr",
-		"sp", "de", "en", "fr", "sp")
-	m.SetHeader(mail.HeaderListUnsubscribePost, "üüüüüüüü", "aaaaääää", "ßßßßßßßßß", "XXXXXX", "ZZZZZ", "XXXXXXXX",
-		"äää äää", "YYYYYY", "XXXXXX", "ZZZZZ", "üäö´")
+	m.Subject("This is a mail with attachments")
 	m.SetMessageID()
 	m.SetDate()
 	m.SetBulk()
+	m.SetBodyString(mail.TypeTextPlain, "This should have an attachment.")
 
-	m.SetBodyWriter(mail.TypeTextPlain, func(fw io.Writer) error {
-		_, err := io.WriteString(fw, "This is a writer test")
-		return err
-	})
-	m.AddAlternativeString(mail.TypeTextHTML, "This is HTML content")
-	//m.Write(os.Stdout)
+	f, err := os.Open("/home/wneessen/certs.csv")
+	if err != nil {
+		fmt.Printf("failed to open file for reading: %s\n", err)
+		os.Exit(1)
+	}
+	defer func() {
+		if err := f.Close(); err != nil {
+			fmt.Printf("failed to close file: %s\n", err)
+			os.Exit(1)
+		}
+	}()
+	m.AttachReader("certs.csv", f, mail.WithFileName("test.txt"))
 
+	sendMail := flag.Bool("send", false, "wether to send mail or output to STDOUT")
+	flag.Parse()
+	if !*sendMail {
+		_, err := m.Write(os.Stdout)
+		if err != nil {
+			fmt.Printf("failed to write mail: %s\n", err)
+			os.Exit(1)
+		}
+	} else {
 		tu := os.Getenv("TEST_USER")
 		tp := os.Getenv("TEST_PASS")
 		c, err := mail.NewClient(th, mail.WithTLSPolicy(mail.TLSMandatory),
@@ -56,5 +68,5 @@ func main() {
 			fmt.Printf("failed to dial: %s\n", err)
 			os.Exit(1)
 		}
-
+	}
 }

file.go

@@ -0,0 +1,33 @@
+package mail
+
+import (
+	"io"
+	"net/textproto"
+)
+
+// FileOption returns a function that can be used for grouping File options
+type FileOption func(*File)
+
+// File is an attachment or embedded file of the Msg
+type File struct {
+	Name   string
+	Header textproto.MIMEHeader
+	Writer func(w io.Writer) error
+}
+
+// WithFileName sets the filename of the File
+func WithFileName(n string) FileOption {
+	return func(f *File) {
+		f.Name = n
+	}
+}
+
+// setHeader sets header fields to a File
+func (f *File) setHeader(h Header, v string) {
+	f.Header.Set(string(h), v)
+}
+
+func (f *File) getHeader(h Header) (string, bool) {
+	v := f.Header.Get(string(h))
+	return v, v != ""
+}

header.go

@@ -14,6 +14,9 @@ const (
 	// HeaderContentDisposition is the "Content-Disposition" header
 	HeaderContentDisposition Header = "Content-Disposition"
 
+	// HeaderContentID is the "Content-ID" header
+	HeaderContentID Header = "Content-ID"
+
 	// HeaderContentLang is the "Content-Language" header
 	HeaderContentLang Header = "Content-Language"
 

msg.go

@@ -9,6 +9,7 @@ import (
 	"mime"
 	"net/mail"
 	"os"
+	"path/filepath"
 	"time"
 )
 
@@ -45,17 +46,13 @@ type Msg struct {
 
 	// parts represent the different parts of the Msg
 	parts []*Part
-}
 
-// Part is a part of the Msg
-type Part struct {
-	w     func(io.Writer) error
-	ctype ContentType
-	enc   Encoding
-}
+	// attachments represent the different attachment File of the Msg
+	attachments []*File
 
-// PartOption returns a function that can be used for grouping Part options
-type PartOption func(*Part)
+	// embeds represent the different embedded File of the Msg
+	embeds []*File
+}
 
 // MsgOption returns a function that can be used for grouping Msg options
 type MsgOption func(*Msg)
@@ -372,7 +369,7 @@ func (m *Msg) SetBodyString(ct ContentType, b string, o ...PartOption) {
 
 // SetBodyWriter sets the body of the message.
 func (m *Msg) SetBodyWriter(ct ContentType, w func(io.Writer) error, o ...PartOption) {
-	p := m.NewPart(ct, o...)
+	p := m.newPart(ct, o...)
 	p.w = w
 	m.parts = []*Part{p}
 }
@@ -389,11 +386,31 @@ func (m *Msg) AddAlternativeString(ct ContentType, b string, o ...PartOption) {
 
 // AddAlternativeWriter sets the body of the message.
 func (m *Msg) AddAlternativeWriter(ct ContentType, w func(io.Writer) error, o ...PartOption) {
-	p := m.NewPart(ct, o...)
+	p := m.newPart(ct, o...)
 	p.w = w
 	m.parts = append(m.parts, p)
 }
 
+// AttachFile adds an attachment File to the Msg
+func (m *Msg) AttachFile(n string, o ...FileOption) {
+	m.attachments = m.appendFile(m.attachments, fileFromFS(n), o...)
+}
+
+// AttachReader adds an attachment File via io.Reader to the Msg
+func (m *Msg) AttachReader(n string, r io.Reader, o ...FileOption) {
+	m.attachments = m.appendFile(m.attachments, fileFromReader(n, r), o...)
+}
+
+// EmbedFile adds an embedded File to the Msg
+func (m *Msg) EmbedFile(n string, o ...FileOption) {
+	m.embeds = m.appendFile(m.embeds, fileFromFS(n), o...)
+}
+
+// EmbedReader adds an embedded File from an io.Reader to the Msg
+func (m *Msg) EmbedReader(n string, r io.Reader, o ...FileOption) {
+	m.embeds = m.appendFile(m.embeds, fileFromReader(n, r), o...)
+}
+
 // Write writes the formated Msg into a give io.Writer
 func (m *Msg) Write(w io.Writer) (int64, error) {
 	mw := &msgWriter{w: w}
@@ -401,8 +418,46 @@ func (m *Msg) Write(w io.Writer) (int64, error) {
 	return mw.n, mw.err
 }
 
-// NewPart returns a new Part for the Msg
-func (m *Msg) NewPart(ct ContentType, o ...PartOption) *Part {
+// appendFile adds a File to the Msg (as attachment or embed)
+func (m *Msg) appendFile(c []*File, f *File, o ...FileOption) []*File {
+	// Override defaults with optionally provided FileOption functions
+	for _, co := range o {
+		if co == nil {
+			continue
+		}
+		co(f)
+	}
+
+	if c == nil {
+		return []*File{f}
+	}
+
+	return append(c, f)
+}
+
+// encodeString encodes a string based on the configured message encoder and the corresponding
+// charset for the Msg
+func (m *Msg) encodeString(s string) string {
+	return m.encoder.Encode(string(m.charset), s)
+}
+
+// hasAlt returns true if the Msg has more than one part
+func (m *Msg) hasAlt() bool {
+	return len(m.parts) > 1
+}
+
+// hasMixed returns true if the Msg has mixed parts
+func (m *Msg) hasMixed() bool {
+	return (len(m.parts) > 0 && len(m.attachments) > 0) || len(m.attachments) > 1
+}
+
+// hasRelated returns true if the Msg has related parts
+func (m *Msg) hasRelated() bool {
+	return (len(m.parts) > 0 && len(m.embeds) > 0) || len(m.embeds) > 1
+}
+
+// newPart returns a new Part for the Msg
+func (m *Msg) newPart(ct ContentType, o ...PartOption) *Part {
 	p := &Part{
 		ctype: ct,
 		enc:   m.encoding,
@@ -419,23 +474,44 @@ func (m *Msg) NewPart(ct ContentType, o ...PartOption) *Part {
 	return p
 }
 
-// WithPartEncoding overrides the default Part encoding
-func WithPartEncoding(e Encoding) PartOption {
-	return func(p *Part) {
-		p.enc = e
-	}
-}
-
-// SetEncoding creates a new mime.WordEncoder based on the encoding setting of the message
-func (p *Part) SetEncoding(e Encoding) {
-	p.enc = e
-}
-
 // setEncoder creates a new mime.WordEncoder based on the encoding setting of the message
 func (m *Msg) setEncoder() {
 	m.encoder = getEncoder(m.encoding)
 }
 
+// fileFromFS returns a File pointer from a given file in the system's file system
+func fileFromFS(n string) *File {
+	return &File{
+		Name:   filepath.Base(n),
+		Header: make(map[string][]string),
+		Writer: func(w io.Writer) error {
+			h, err := os.Open(n)
+			if err != nil {
+				return err
+			}
+			if _, err := io.Copy(w, h); err != nil {
+				_ = h.Close()
+				return fmt.Errorf("failed to copy file to io.Writer: %w", err)
+			}
+			return h.Close()
+		},
+	}
+}
+
+// fileFromReader returns a File pointer from a given io.Reader
+func fileFromReader(n string, r io.Reader) *File {
+	return &File{
+		Name:   filepath.Base(n),
+		Header: make(map[string][]string),
+		Writer: func(w io.Writer) error {
+			if _, err := io.Copy(w, r); err != nil {
+				return err
+			}
+			return nil
+		},
+	}
+}
+
 // getEncoder creates a new mime.WordEncoder based on the encoding setting of the message
 func getEncoder(e Encoding) mime.WordEncoder {
 	switch e {
@@ -447,14 +523,3 @@ func getEncoder(e Encoding) mime.WordEncoder {
 		return mime.QEncoding
 	}
 }
-
-// encodeString encodes a string based on the configured message encoder and the corresponding
-// charset for the Msg
-func (m *Msg) encodeString(s string) string {
-	return m.encoder.Encode(string(m.charset), s)
-}
-
-// hasAlt returns true if the Msg has more than one part
-func (m *Msg) hasAlt() bool {
-	return len(m.parts) > 1
-}

msgwriter.go

@@ -4,9 +4,11 @@ import (
 	"encoding/base64"
 	"fmt"
 	"io"
+	"mime"
 	"mime/multipart"
 	"mime/quotedprintable"
 	"net/textproto"
+	"path/filepath"
 	"strings"
 )
 
@@ -55,16 +57,37 @@ func (mw *msgWriter) writeMsg(m *Msg) {
 	}
 	mw.writeHeader(HeaderMIMEVersion, string(m.mimever))
 
+	if m.hasMixed() {
+		mw.startMP("mixed", m.boundary)
+		mw.writeString("\r\n\r\n")
+	}
+	if m.hasRelated() {
+		mw.startMP("related", m.boundary)
+		mw.writeString("\r\n\r\n")
+	}
 	if m.hasAlt() {
 		mw.startMP(MIMEAlternative, m.boundary)
 		mw.writeString("\r\n\r\n")
 	}
+
 	for _, p := range m.parts {
 		mw.writePart(p, m.charset)
 	}
 	if m.hasAlt() {
 		mw.stopMP()
 	}
+
+	// Add embeds
+	mw.addFiles(m.embeds, false)
+	if m.hasRelated() {
+		mw.stopMP()
+	}
+
+	// Add attachments
+	mw.addFiles(m.attachments, true)
+	if m.hasMixed() {
+		mw.stopMP()
+	}
 }
 
 // startMP writes a multipart beginning
@@ -94,6 +117,47 @@ func (mw *msgWriter) stopMP() {
 	}
 }
 
+// addFiles adds the attachments/embeds file content to the mail body
+func (mw *msgWriter) addFiles(fl []*File, a bool) {
+	for _, f := range fl {
+		if _, ok := f.getHeader(HeaderContentType); !ok {
+			mt := mime.TypeByExtension(filepath.Ext(f.Name))
+			if mt == "" {
+				mt = "application/octet-stream"
+			}
+			f.setHeader(HeaderContentType, fmt.Sprintf(`%s; name="%s"`, mt, f.Name))
+		}
+
+		if _, ok := f.getHeader(HeaderContentTransferEnc); !ok {
+			f.setHeader(HeaderContentTransferEnc, string(EncodingB64))
+		}
+
+		if _, ok := f.getHeader(HeaderContentDisposition); !ok {
+			d := "inline"
+			if a {
+				d = "attachment"
+			}
+			f.setHeader(HeaderContentDisposition, fmt.Sprintf(`%s; filename="%s"`, d, f.Name))
+		}
+
+		if !a {
+			if _, ok := f.getHeader(HeaderContentID); !ok {
+				f.setHeader(HeaderContentID, fmt.Sprintf("<%s>", f.Name))
+			}
+		}
+		if mw.d == 0 {
+			for h, v := range f.Header {
+				mw.writeHeader(Header(h), v...)
+			}
+			mw.writeString("\r\n")
+		}
+		if mw.d > 0 {
+			mw.newPart(f.Header)
+		}
+		mw.writeBody(f.Writer, EncodingB64)
+	}
+}
+
 // newPart creates a new MIME multipart io.Writer and sets the partwriter to it
 func (mw *msgWriter) newPart(h map[string][]string) {
 	mw.pw, mw.err = mw.mpw[mw.d-1].CreatePart(h)

part.go

@@ -0,0 +1,25 @@
+package mail
+
+import "io"
+
+// PartOption returns a function that can be used for grouping Part options
+type PartOption func(*Part)
+
+// Part is a part of the Msg
+type Part struct {
+	ctype ContentType
+	enc   Encoding
+	w     func(io.Writer) error
+}
+
+// SetEncoding creates a new mime.WordEncoder based on the encoding setting of the message
+func (p *Part) SetEncoding(e Encoding) {
+	p.enc = e
+}
+
+// WithPartEncoding overrides the default Part encoding
+func WithPartEncoding(e Encoding) PartOption {
+	return func(p *Part) {
+		p.enc = e
+	}
+}