// GoToSocial // Copyright (C) GoToSocial Authors admin@gotosocial.org // SPDX-License-Identifier: AGPL-3.0-or-later // // This program is free software: you can redistribute it and/or modify // it under the terms of the GNU Affero General Public License as published by // the Free Software Foundation, either version 3 of the License, or // (at your option) any later version. // // This program is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU Affero General Public License for more details. // // You should have received a copy of the GNU Affero General Public License // along with this program. If not, see <http://www.gnu.org/licenses/>. package email import ( "bytes" "errors" "fmt" "net/smtp" "os" "path/filepath" "strings" "text/template" "time" "github.com/google/uuid" "github.com/superseriousbusiness/gotosocial/internal/config" "github.com/superseriousbusiness/gotosocial/internal/gtserror" ) func (s *sender) sendTemplate(template string, subject string, data any, toAddresses ...string) error { buf := &bytes.Buffer{} if err := s.template.ExecuteTemplate(buf, template, data); err != nil { return err } msg, err := assembleMessage(subject, buf.String(), s.from, s.msgIDHost, toAddresses...) if err != nil { return err } if err := smtp.SendMail(s.hostAddress, s.auth, s.from, toAddresses, msg); err != nil { return gtserror.SetSMTP(err) } return nil } func loadTemplates(templateBaseDir string) (*template.Template, error) { if !filepath.IsAbs(templateBaseDir) { cwd, err := os.Getwd() if err != nil { return nil, fmt.Errorf("error getting current working directory: %s", err) } templateBaseDir = filepath.Join(cwd, templateBaseDir) } // look for all templates that start with 'email_' return template.ParseGlob(filepath.Join(templateBaseDir, "email_*")) } // assembleMessage assembles a valid email message following: // - https://datatracker.ietf.org/doc/html/rfc2822 // - https://pkg.go.dev/net/smtp#SendMail func assembleMessage(mailSubject string, mailBody string, mailFrom string, msgIDHost string, mailTo ...string) ([]byte, error) { if strings.ContainsAny(mailSubject, "\r\n") { return nil, errors.New("email subject must not contain newline characters") } if strings.ContainsAny(mailFrom, "\r\n") { return nil, errors.New("email from address must not contain newline characters") } for _, to := range mailTo { if strings.ContainsAny(to, "\r\n") { return nil, errors.New("email to address must not contain newline characters") } } // Normalize the message body to use CRLF line endings const CRLF = "\r\n" mailBody = strings.ReplaceAll(mailBody, CRLF, "\n") mailBody = strings.ReplaceAll(mailBody, "\n", CRLF) msg := bytes.Buffer{} switch { case len(mailTo) == 1: // Address email directly to the one recipient. msg.WriteString("To: " + mailTo[0] + CRLF) case config.GetSMTPDiscloseRecipients(): // Simply address To all recipients. msg.WriteString("To: " + strings.Join(mailTo, ", ") + CRLF) default: // Address To anonymous group. // // Email will be sent to all recipients but we shouldn't include Bcc header. // // From the smtp.SendMail function: 'Sending "Bcc" messages is accomplished by // including an email address in the to parameter but not including it in the // msg headers.' msg.WriteString("To: Undisclosed Recipients:;" + CRLF) } msg.WriteString("Date: " + time.Now().Format(time.RFC822Z) + CRLF) msg.WriteString("From: " + mailFrom + CRLF) msg.WriteString("Message-ID: <" + uuid.New().String() + "@" + msgIDHost + ">" + CRLF) msg.WriteString("Subject: " + mailSubject + CRLF) msg.WriteString("MIME-Version: 1.0" + CRLF) msg.WriteString("Content-Transfer-Encoding: 8bit" + CRLF) msg.WriteString("Content-Type: text/plain; charset=\"UTF-8\"" + CRLF) msg.WriteString(CRLF) msg.WriteString(mailBody) msg.WriteString(CRLF) return msg.Bytes(), nil }