Add attachments support to composer

Closes: https://todo.sr.ht/~sircmpwn/koushin/13

plugins/base/handlers.go

@@ -270,7 +270,13 @@ func handleCompose(ectx echo.Context) error {
 		msg.Text = ctx.FormValue("text")
 		msg.InReplyTo = ctx.FormValue("in_reply_to")
 
-		err := ctx.Session.DoSMTP(func(c *smtp.Client) error {
+		form, err := ctx.MultipartForm()
+		if err != nil {
+			return fmt.Errorf("failed to get multipart form: %v", err)
+		}
+		msg.Attachments = form.File["attachments"]
+
+		err = ctx.Session.DoSMTP(func(c *smtp.Client) error {
 			return sendMessage(c, &msg)
 		})
 		if err != nil {

plugins/base/public/compose.html

@@ -8,14 +8,14 @@
 
 <h2>Compose new message</h2>
 
-<form method="post" action="">
+<form method="post" action="" enctype="multipart/form-data">
 	<input type="hidden" name="in_reply_to" value="{{.Message.InReplyTo}}">
 
 	<label for="from">From:</label>
-	<input type="email" name="from" id="from" value="{{.Message.From}}">
+	<input type="email" name="from" id="from" required value="{{.Message.From}}">
 	<br><br>
 	<label for="to">To:</label>
-	<input type="email" name="to" id="to" multiple value="{{.Message.ToString}}">
+	<input type="email" name="to" id="to" multiple required value="{{.Message.ToString}}">
 	<br><br>
 	<label for="subject">Subject:</label>
 	<input type="text" name="subject" id="subject" value="{{.Message.Subject}}">
@@ -23,6 +23,9 @@
 	<label for="text">Body:</label><br>
 	<textarea name="text" id="text" cols="80" rows="20">{{.Message.Text}}</textarea>
 	<br><br>
+	<label for="attachments">Attachments:</label>
+	<input type="file" name="attachments" id="attachments" multiple>
+	<br><br>
 	<input type="submit" value="Send">
 </form>
 

plugins/base/smtp.go

@@ -4,6 +4,7 @@ import (
 	"bufio"
 	"fmt"
 	"io"
+	"mime/multipart"
 	"strings"
 	"time"
 
@@ -26,17 +27,49 @@ func quote(r io.Reader) (string, error) {
 }
 
 type OutgoingMessage struct {
-	From      string
-	To        []string
-	Subject   string
-	InReplyTo string
-	Text      string
+	From        string
+	To          []string
+	Subject     string
+	InReplyTo   string
+	Text        string
+	Attachments []*multipart.FileHeader
 }
 
 func (msg *OutgoingMessage) ToString() string {
 	return strings.Join(msg.To, ", ")
 }
 
+func writeAttachment(mw *mail.Writer, att *multipart.FileHeader) error {
+	var h mail.AttachmentHeader
+	h.Set("Content-Type", att.Header.Get("Content-Type"))
+	h.SetFilename(att.Filename)
+
+	aw, err := mw.CreateAttachment(h)
+	if err != nil {
+		return fmt.Errorf("failed to create attachment: %v", err)
+	}
+	defer aw.Close()
+
+	f, err := att.Open()
+	if err != nil {
+		return fmt.Errorf("failed to open attachment: %v", err)
+	}
+	defer f.Close()
+
+	if _, err := io.Copy(aw, f); err != nil {
+		return fmt.Errorf("failed to write attachment: %v", err)
+	}
+
+	if err := f.Close(); err != nil {
+		return fmt.Errorf("failed to close attachment: %v", err)
+	}
+	if err := aw.Close(); err != nil {
+		return fmt.Errorf("failed to close attachment writer: %v", err)
+	}
+
+	return nil
+}
+
 func (msg *OutgoingMessage) WriteTo(w io.Writer) error {
 	from := []*mail.Address{{"", msg.From}}
 
@@ -78,6 +111,12 @@ func (msg *OutgoingMessage) WriteTo(w io.Writer) error {
 		return fmt.Errorf("failed to close text part: %v", err)
 	}
 
+	for _, att := range msg.Attachments {
+		if err := writeAttachment(mw, att); err != nil {
+			return err
+		}
+	}
+
 	if err := mw.Close(); err != nil {
 		return fmt.Errorf("failed to close mail writer: %v", err)
 	}