Move all mail related codes from models to services/mailer (#7200)

* move all mail related codes from models to modules/mailer

* fix lint

* use DBContext instead Engine

* use WithContext not WithEngine

* Use DBContext instead of Engine

* don't use defer when sess.Close()

* move DBContext to context.go and add some methods

* move mailer from modules/ to services

* fix lint

* fix tests

* fix fmt

* add gitea copyright

* fix tests

* don't expose db functions

* make code clear

* add DefaultDBContext

* fix build

* fix bug

6 files changed, 838 insertions, 0 deletions

diff --git a/services/mailer/mail.go b/services/mailer/mail.go
new file mode 100644
index 0000000000..3f0a789dc4
--- /dev/null
+++ b/services/mailer/mail.go
@@ -0,0 +1,222 @@
+// Copyright 2016 The Gogs Authors. All rights reserved.
+// Copyright 2019 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package mailer
+
+import (
+	"bytes"
+	"fmt"
+	"html/template"
+	"path"
+
+	"code.gitea.io/gitea/models"
+	"code.gitea.io/gitea/modules/base"
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/markup"
+	"code.gitea.io/gitea/modules/markup/markdown"
+	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/timeutil"
+
+	"gopkg.in/gomail.v2"
+)
+
+const (
+	mailAuthActivate       base.TplName = "auth/activate"
+	mailAuthActivateEmail  base.TplName = "auth/activate_email"
+	mailAuthResetPassword  base.TplName = "auth/reset_passwd"
+	mailAuthRegisterNotify base.TplName = "auth/register_notify"
+
+	mailIssueComment base.TplName = "issue/comment"
+	mailIssueMention base.TplName = "issue/mention"
+
+	mailNotifyCollaborator base.TplName = "notify/collaborator"
+)
+
+var templates *template.Template
+
+// InitMailRender initializes the mail renderer
+func InitMailRender(tmpls *template.Template) {
+	templates = tmpls
+}
+
+// SendTestMail sends a test mail
+func SendTestMail(email string) error {
+	return gomail.Send(Sender, NewMessage([]string{email}, "Gitea Test Email!", "Gitea Test Email!").Message)
+}
+
+// SendUserMail sends a mail to the user
+func SendUserMail(language string, u *models.User, tpl base.TplName, code, subject, info string) {
+	data := map[string]interface{}{
+		"DisplayName":       u.DisplayName(),
+		"ActiveCodeLives":   timeutil.MinutesToFriendly(setting.Service.ActiveCodeLives, language),
+		"ResetPwdCodeLives": timeutil.MinutesToFriendly(setting.Service.ResetPwdCodeLives, language),
+		"Code":              code,
+	}
+
+	var content bytes.Buffer
+
+	if err := templates.ExecuteTemplate(&content, string(tpl), data); err != nil {
+		log.Error("Template: %v", err)
+		return
+	}
+
+	msg := NewMessage([]string{u.Email}, subject, content.String())
+	msg.Info = fmt.Sprintf("UID: %d, %s", u.ID, info)
+
+	SendAsync(msg)
+}
+
+// Locale represents an interface to translation
+type Locale interface {
+	Language() string
+	Tr(string, ...interface{}) string
+}
+
+// SendActivateAccountMail sends an activation mail to the user (new user registration)
+func SendActivateAccountMail(locale Locale, u *models.User) {
+	SendUserMail(locale.Language(), u, mailAuthActivate, u.GenerateActivateCode(), locale.Tr("mail.activate_account"), "activate account")
+}
+
+// SendResetPasswordMail sends a password reset mail to the user
+func SendResetPasswordMail(locale Locale, u *models.User) {
+	SendUserMail(locale.Language(), u, mailAuthResetPassword, u.GenerateActivateCode(), locale.Tr("mail.reset_password"), "recover account")
+}
+
+// SendActivateEmailMail sends confirmation email to confirm new email address
+func SendActivateEmailMail(locale Locale, u *models.User, email *models.EmailAddress) {
+	data := map[string]interface{}{
+		"DisplayName":     u.DisplayName(),
+		"ActiveCodeLives": timeutil.MinutesToFriendly(setting.Service.ActiveCodeLives, locale.Language()),
+		"Code":            u.GenerateEmailActivateCode(email.Email),
+		"Email":           email.Email,
+	}
+
+	var content bytes.Buffer
+
+	if err := templates.ExecuteTemplate(&content, string(mailAuthActivateEmail), data); err != nil {
+		log.Error("Template: %v", err)
+		return
+	}
+
+	msg := NewMessage([]string{email.Email}, locale.Tr("mail.activate_email"), content.String())
+	msg.Info = fmt.Sprintf("UID: %d, activate email", u.ID)
+
+	SendAsync(msg)
+}
+
+// SendRegisterNotifyMail triggers a notify e-mail by admin created a account.
+func SendRegisterNotifyMail(locale Locale, u *models.User) {
+	if setting.MailService == nil {
+		log.Warn("SendRegisterNotifyMail is being invoked but mail service hasn't been initialized")
+		return
+	}
+
+	data := map[string]interface{}{
+		"DisplayName": u.DisplayName(),
+		"Username":    u.Name,
+	}
+
+	var content bytes.Buffer
+
+	if err := templates.ExecuteTemplate(&content, string(mailAuthRegisterNotify), data); err != nil {
+		log.Error("Template: %v", err)
+		return
+	}
+
+	msg := NewMessage([]string{u.Email}, locale.Tr("mail.register_notify"), content.String())
+	msg.Info = fmt.Sprintf("UID: %d, registration notify", u.ID)
+
+	SendAsync(msg)
+}
+
+// SendCollaboratorMail sends mail notification to new collaborator.
+func SendCollaboratorMail(u, doer *models.User, repo *models.Repository) {
+	repoName := path.Join(repo.Owner.Name, repo.Name)
+	subject := fmt.Sprintf("%s added you to %s", doer.DisplayName(), repoName)
+
+	data := map[string]interface{}{
+		"Subject":  subject,
+		"RepoName": repoName,
+		"Link":     repo.HTMLURL(),
+	}
+
+	var content bytes.Buffer
+
+	if err := templates.ExecuteTemplate(&content, string(mailNotifyCollaborator), data); err != nil {
+		log.Error("Template: %v", err)
+		return
+	}
+
+	msg := NewMessage([]string{u.Email}, subject, content.String())
+	msg.Info = fmt.Sprintf("UID: %d, add collaborator", u.ID)
+
+	SendAsync(msg)
+}
+
+func composeTplData(subject, body, link string) map[string]interface{} {
+	data := make(map[string]interface{}, 10)
+	data["Subject"] = subject
+	data["Body"] = body
+	data["Link"] = link
+	return data
+}
+
+func composeIssueCommentMessage(issue *models.Issue, doer *models.User, content string, comment *models.Comment, tplName base.TplName, tos []string, info string) *Message {
+	var subject string
+	if comment != nil {
+		subject = "Re: " + mailSubject(issue)
+	} else {
+		subject = mailSubject(issue)
+	}
+	err := issue.LoadRepo()
+	if err != nil {
+		log.Error("LoadRepo: %v", err)
+	}
+	body := string(markup.RenderByType(markdown.MarkupName, []byte(content), issue.Repo.HTMLURL(), issue.Repo.ComposeMetas()))
+
+	var data = make(map[string]interface{}, 10)
+	if comment != nil {
+		data = composeTplData(subject, body, issue.HTMLURL()+"#"+comment.HashTag())
+	} else {
+		data = composeTplData(subject, body, issue.HTMLURL())
+	}
+	data["Doer"] = doer
+
+	var mailBody bytes.Buffer
+
+	if err := templates.ExecuteTemplate(&mailBody, string(tplName), data); err != nil {
+		log.Error("Template: %v", err)
+	}
+
+	msg := NewMessageFrom(tos, doer.DisplayName(), setting.MailService.FromEmail, subject, mailBody.String())
+	msg.Info = fmt.Sprintf("Subject: %s, %s", subject, info)
+
+	// Set Message-ID on first message so replies know what to reference
+	if comment == nil {
+		msg.SetHeader("Message-ID", "<"+issue.ReplyReference()+">")
+	} else {
+		msg.SetHeader("In-Reply-To", "<"+issue.ReplyReference()+">")
+		msg.SetHeader("References", "<"+issue.ReplyReference()+">")
+	}
+
+	return msg
+}
+
+// SendIssueCommentMail composes and sends issue comment emails to target receivers.
+func SendIssueCommentMail(issue *models.Issue, doer *models.User, content string, comment *models.Comment, tos []string) {
+	if len(tos) == 0 {
+		return
+	}
+
+	SendAsync(composeIssueCommentMessage(issue, doer, content, comment, mailIssueComment, tos, "issue comment"))
+}
+
+// SendIssueMentionMail composes and sends issue mention emails to target receivers.
+func SendIssueMentionMail(issue *models.Issue, doer *models.User, content string, comment *models.Comment, tos []string) {
+	if len(tos) == 0 {
+		return
+	}
+	SendAsync(composeIssueCommentMessage(issue, doer, content, comment, mailIssueMention, tos, "issue mention"))
+}
diff --git a/services/mailer/mail_comment.go b/services/mailer/mail_comment.go
new file mode 100644
index 0000000000..cb477f887b
--- /dev/null
+++ b/services/mailer/mail_comment.go
@@ -0,0 +1,47 @@
+// Copyright 2019 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package mailer
+
+import (
+	"fmt"
+
+	"code.gitea.io/gitea/models"
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/markup"
+)
+
+// MailParticipantsComment sends new comment emails to repository watchers
+// and mentioned people.
+func MailParticipantsComment(c *models.Comment, opType models.ActionType, issue *models.Issue) error {
+	return mailParticipantsComment(models.DefaultDBContext(), c, opType, issue)
+}
+
+func mailParticipantsComment(ctx models.DBContext, c *models.Comment, opType models.ActionType, issue *models.Issue) (err error) {
+	mentions := markup.FindAllMentions(c.Content)
+	if err = models.UpdateIssueMentions(ctx, c.IssueID, mentions); err != nil {
+		return fmt.Errorf("UpdateIssueMentions [%d]: %v", c.IssueID, err)
+	}
+
+	if len(c.Content) > 0 {
+		if err = mailIssueCommentToParticipants(issue, c.Poster, c.Content, c, mentions); err != nil {
+			log.Error("mailIssueCommentToParticipants: %v", err)
+		}
+	}
+
+	switch opType {
+	case models.ActionCloseIssue:
+		ct := fmt.Sprintf("Closed #%d.", issue.Index)
+		if err = mailIssueCommentToParticipants(issue, c.Poster, ct, c, mentions); err != nil {
+			log.Error("mailIssueCommentToParticipants: %v", err)
+		}
+	case models.ActionReopenIssue:
+		ct := fmt.Sprintf("Reopened #%d.", issue.Index)
+		if err = mailIssueCommentToParticipants(issue, c.Poster, ct, c, mentions); err != nil {
+			log.Error("mailIssueCommentToParticipants: %v", err)
+		}
+	}
+
+	return nil
+}
diff --git a/services/mailer/mail_issue.go b/services/mailer/mail_issue.go
new file mode 100644
index 0000000000..92d2c5a879
--- /dev/null
+++ b/services/mailer/mail_issue.go
@@ -0,0 +1,159 @@
+// Copyright 2019 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package mailer
+
+import (
+	"fmt"
+
+	"code.gitea.io/gitea/models"
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/markup"
+	"code.gitea.io/gitea/modules/setting"
+
+	"github.com/unknwon/com"
+)
+
+func mailSubject(issue *models.Issue) string {
+	return fmt.Sprintf("[%s] %s (#%d)", issue.Repo.FullName(), issue.Title, issue.Index)
+}
+
+// mailIssueCommentToParticipants can be used for both new issue creation and comment.
+// This function sends two list of emails:
+// 1. Repository watchers and users who are participated in comments.
+// 2. Users who are not in 1. but get mentioned in current issue/comment.
+func mailIssueCommentToParticipants(issue *models.Issue, doer *models.User, content string, comment *models.Comment, mentions []string) error {
+	if !setting.Service.EnableNotifyMail {
+		return nil
+	}
+
+	watchers, err := models.GetWatchers(issue.RepoID)
+	if err != nil {
+		return fmt.Errorf("getWatchers [repo_id: %d]: %v", issue.RepoID, err)
+	}
+	participants, err := models.GetParticipantsByIssueID(issue.ID)
+	if err != nil {
+		return fmt.Errorf("getParticipantsByIssueID [issue_id: %d]: %v", issue.ID, err)
+	}
+
+	// In case the issue poster is not watching the repository and is active,
+	// even if we have duplicated in watchers, can be safely filtered out.
+	err = issue.LoadPoster()
+	if err != nil {
+		return fmt.Errorf("GetUserByID [%d]: %v", issue.PosterID, err)
+	}
+	if issue.PosterID != doer.ID && issue.Poster.IsActive && !issue.Poster.ProhibitLogin {
+		participants = append(participants, issue.Poster)
+	}
+
+	// Assignees must receive any communications
+	assignees, err := models.GetAssigneesByIssue(issue)
+	if err != nil {
+		return err
+	}
+
+	for _, assignee := range assignees {
+		if assignee.ID != doer.ID {
+			participants = append(participants, assignee)
+		}
+	}
+
+	tos := make([]string, 0, len(watchers)) // List of email addresses.
+	names := make([]string, 0, len(watchers))
+	for i := range watchers {
+		if watchers[i].UserID == doer.ID {
+			continue
+		}
+
+		to, err := models.GetUserByID(watchers[i].UserID)
+		if err != nil {
+			return fmt.Errorf("GetUserByID [%d]: %v", watchers[i].UserID, err)
+		}
+		if to.IsOrganization() || to.EmailNotifications() != models.EmailNotificationsEnabled {
+			continue
+		}
+
+		tos = append(tos, to.Email)
+		names = append(names, to.Name)
+	}
+	for i := range participants {
+		if participants[i].ID == doer.ID ||
+			com.IsSliceContainsStr(names, participants[i].Name) ||
+			participants[i].EmailNotifications() != models.EmailNotificationsEnabled {
+			continue
+		}
+
+		tos = append(tos, participants[i].Email)
+		names = append(names, participants[i].Name)
+	}
+
+	if err := issue.LoadRepo(); err != nil {
+		return err
+	}
+
+	for _, to := range tos {
+		SendIssueCommentMail(issue, doer, content, comment, []string{to})
+	}
+
+	// Mail mentioned people and exclude watchers.
+	names = append(names, doer.Name)
+	tos = make([]string, 0, len(mentions)) // list of user names.
+	for i := range mentions {
+		if com.IsSliceContainsStr(names, mentions[i]) {
+			continue
+		}
+
+		tos = append(tos, mentions[i])
+	}
+
+	emails := models.GetUserEmailsByNames(tos)
+
+	for _, to := range emails {
+		SendIssueMentionMail(issue, doer, content, comment, []string{to})
+	}
+
+	return nil
+}
+
+// MailParticipants sends new issue thread created emails to repository watchers
+// and mentioned people.
+func MailParticipants(issue *models.Issue, doer *models.User, opType models.ActionType) error {
+	return mailParticipants(models.DefaultDBContext(), issue, doer, opType)
+}
+
+func mailParticipants(ctx models.DBContext, issue *models.Issue, doer *models.User, opType models.ActionType) (err error) {
+	mentions := markup.FindAllMentions(issue.Content)
+
+	if err = models.UpdateIssueMentions(ctx, issue.ID, mentions); err != nil {
+		return fmt.Errorf("UpdateIssueMentions [%d]: %v", issue.ID, err)
+	}
+
+	if len(issue.Content) > 0 {
+		if err = mailIssueCommentToParticipants(issue, doer, issue.Content, nil, mentions); err != nil {
+			log.Error("mailIssueCommentToParticipants: %v", err)
+		}
+	}
+
+	switch opType {
+	case models.ActionCreateIssue, models.ActionCreatePullRequest:
+		if len(issue.Content) == 0 {
+			ct := fmt.Sprintf("Created #%d.", issue.Index)
+			if err = mailIssueCommentToParticipants(issue, doer, ct, nil, mentions); err != nil {
+				log.Error("mailIssueCommentToParticipants: %v", err)
+			}
+		}
+	case models.ActionCloseIssue, models.ActionClosePullRequest:
+		ct := fmt.Sprintf("Closed #%d.", issue.Index)
+		if err = mailIssueCommentToParticipants(issue, doer, ct, nil, mentions); err != nil {
+			log.Error("mailIssueCommentToParticipants: %v", err)
+		}
+	case models.ActionReopenIssue, models.ActionReopenPullRequest:
+		ct := fmt.Sprintf("Reopened #%d.", issue.Index)
+		if err = mailIssueCommentToParticipants(issue, doer, ct, nil, mentions); err != nil {
+			log.Error("mailIssueCommentToParticipants: %v", err)
+		}
+	}
+
+	return nil
+}
diff --git a/services/mailer/mail_test.go b/services/mailer/mail_test.go
new file mode 100644
index 0000000000..c7a84d6b33
--- /dev/null
+++ b/services/mailer/mail_test.go
@@ -0,0 +1,91 @@
+// Copyright 2019 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package mailer
+
+import (
+	"html/template"
+	"testing"
+
+	"code.gitea.io/gitea/models"
+	"code.gitea.io/gitea/modules/setting"
+
+	"github.com/stretchr/testify/assert"
+)
+
+const tmpl = `
+<!DOCTYPE html>
+<html>
+<head>
+	<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
+	<title>{{.Subject}}</title>
+</head>
+
+<body>
+	<p>{{.Body}}</p>
+	<p>
+		---
+		<br>
+		<a href="{{.Link}}">View it on Gitea</a>.
+	</p>
+</body>
+</html>
+`
+
+func TestComposeIssueCommentMessage(t *testing.T) {
+	assert.NoError(t, models.PrepareTestDatabase())
+	var mailService = setting.Mailer{
+		From: "test@gitea.com",
+	}
+
+	setting.MailService = &mailService
+	setting.Domain = "localhost"
+
+	doer := models.AssertExistsAndLoadBean(t, &models.User{ID: 2}).(*models.User)
+	repo := models.AssertExistsAndLoadBean(t, &models.Repository{ID: 1, Owner: doer}).(*models.Repository)
+	issue := models.AssertExistsAndLoadBean(t, &models.Issue{ID: 1, Repo: repo, Poster: doer}).(*models.Issue)
+	comment := models.AssertExistsAndLoadBean(t, &models.Comment{ID: 2, Issue: issue}).(*models.Comment)
+
+	email := template.Must(template.New("issue/comment").Parse(tmpl))
+	InitMailRender(email)
+
+	tos := []string{"test@gitea.com", "test2@gitea.com"}
+	msg := composeIssueCommentMessage(issue, doer, "test body", comment, mailIssueComment, tos, "issue comment")
+
+	subject := msg.GetHeader("Subject")
+	inreplyTo := msg.GetHeader("In-Reply-To")
+	references := msg.GetHeader("References")
+
+	assert.Equal(t, subject[0], "Re: "+mailSubject(issue), "Comment reply subject should contain Re:")
+	assert.Equal(t, inreplyTo[0], "<user2/repo1/issues/1@localhost>", "In-Reply-To header doesn't match")
+	assert.Equal(t, references[0], "<user2/repo1/issues/1@localhost>", "References header doesn't match")
+}
+
+func TestComposeIssueMessage(t *testing.T) {
+	assert.NoError(t, models.PrepareTestDatabase())
+	var mailService = setting.Mailer{
+		From: "test@gitea.com",
+	}
+
+	setting.MailService = &mailService
+	setting.Domain = "localhost"
+
+	doer := models.AssertExistsAndLoadBean(t, &models.User{ID: 2}).(*models.User)
+	repo := models.AssertExistsAndLoadBean(t, &models.Repository{ID: 1, Owner: doer}).(*models.Repository)
+	issue := models.AssertExistsAndLoadBean(t, &models.Issue{ID: 1, Repo: repo, Poster: doer}).(*models.Issue)
+
+	email := template.Must(template.New("issue/comment").Parse(tmpl))
+	InitMailRender(email)
+
+	tos := []string{"test@gitea.com", "test2@gitea.com"}
+	msg := composeIssueCommentMessage(issue, doer, "test body", nil, mailIssueComment, tos, "issue create")
+
+	subject := msg.GetHeader("Subject")
+	messageID := msg.GetHeader("Message-ID")
+
+	assert.Equal(t, subject[0], mailSubject(issue), "Subject not equal to issue.mailSubject()")
+	assert.Nil(t, msg.GetHeader("In-Reply-To"))
+	assert.Nil(t, msg.GetHeader("References"))
+	assert.Equal(t, messageID[0], "<user2/repo1/issues/1@localhost>", "Message-ID header doesn't match")
+}
diff --git a/services/mailer/mailer.go b/services/mailer/mailer.go
new file mode 100644
index 0000000000..d19ae7b2f4
--- /dev/null
+++ b/services/mailer/mailer.go
@@ -0,0 +1,303 @@
+// Copyright 2014 The Gogs Authors. All rights reserved.
+// Copyright 2017 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package mailer
+
+import (
+	"bytes"
+	"crypto/tls"
+	"fmt"
+	"io"
+	"net"
+	"net/smtp"
+	"os"
+	"os/exec"
+	"strings"
+	"time"
+
+	"code.gitea.io/gitea/modules/base"
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/setting"
+
+	"github.com/jaytaylor/html2text"
+	"gopkg.in/gomail.v2"
+)
+
+// Message mail body and log info
+type Message struct {
+	Info string // Message information for log purpose.
+	*gomail.Message
+}
+
+// NewMessageFrom creates new mail message object with custom From header.
+func NewMessageFrom(to []string, fromDisplayName, fromAddress, subject, body string) *Message {
+	log.Trace("NewMessageFrom (body):\n%s", body)
+
+	msg := gomail.NewMessage()
+	msg.SetAddressHeader("From", fromAddress, fromDisplayName)
+	msg.SetHeader("To", to...)
+	if len(setting.MailService.SubjectPrefix) > 0 {
+		msg.SetHeader("Subject", setting.MailService.SubjectPrefix+" "+subject)
+	} else {
+		msg.SetHeader("Subject", subject)
+	}
+	msg.SetDateHeader("Date", time.Now())
+	msg.SetHeader("X-Auto-Response-Suppress", "All")
+
+	plainBody, err := html2text.FromString(body)
+	if err != nil || setting.MailService.SendAsPlainText {
+		if strings.Contains(base.TruncateString(body, 100), "<html>") {
+			log.Warn("Mail contains HTML but configured to send as plain text.")
+		}
+		msg.SetBody("text/plain", plainBody)
+	} else {
+		msg.SetBody("text/plain", plainBody)
+		msg.AddAlternative("text/html", body)
+	}
+
+	return &Message{
+		Message: msg,
+	}
+}
+
+// NewMessage creates new mail message object with default From header.
+func NewMessage(to []string, subject, body string) *Message {
+	return NewMessageFrom(to, setting.MailService.FromName, setting.MailService.FromEmail, subject, body)
+}
+
+type loginAuth struct {
+	username, password string
+}
+
+// LoginAuth SMTP AUTH LOGIN Auth Handler
+func LoginAuth(username, password string) smtp.Auth {
+	return &loginAuth{username, password}
+}
+
+// Start start SMTP login auth
+func (a *loginAuth) Start(server *smtp.ServerInfo) (string, []byte, error) {
+	return "LOGIN", []byte{}, nil
+}
+
+// Next next step of SMTP login auth
+func (a *loginAuth) Next(fromServer []byte, more bool) ([]byte, error) {
+	if more {
+		switch string(fromServer) {
+		case "Username:":
+			return []byte(a.username), nil
+		case "Password:":
+			return []byte(a.password), nil
+		default:
+			return nil, fmt.Errorf("unknown fromServer: %s", string(fromServer))
+		}
+	}
+	return nil, nil
+}
+
+// Sender SMTP mail sender
+type smtpSender struct {
+}
+
+// Send send email
+func (s *smtpSender) Send(from string, to []string, msg io.WriterTo) error {
+	opts := setting.MailService
+
+	host, port, err := net.SplitHostPort(opts.Host)
+	if err != nil {
+		return err
+	}
+
+	tlsconfig := &tls.Config{
+		InsecureSkipVerify: opts.SkipVerify,
+		ServerName:         host,
+	}
+
+	if opts.UseCertificate {
+		cert, err := tls.LoadX509KeyPair(opts.CertFile, opts.KeyFile)
+		if err != nil {
+			return err
+		}
+		tlsconfig.Certificates = []tls.Certificate{cert}
+	}
+
+	conn, err := net.Dial("tcp", net.JoinHostPort(host, port))
+	if err != nil {
+		return err
+	}
+	defer conn.Close()
+
+	isSecureConn := opts.IsTLSEnabled || (strings.HasSuffix(port, "465"))
+	// Start TLS directly if the port ends with 465 (SMTPS protocol)
+	if isSecureConn {
+		conn = tls.Client(conn, tlsconfig)
+	}
+
+	client, err := smtp.NewClient(conn, host)
+	if err != nil {
+		return fmt.Errorf("NewClient: %v", err)
+	}
+
+	if !opts.DisableHelo {
+		hostname := opts.HeloHostname
+		if len(hostname) == 0 {
+			hostname, err = os.Hostname()
+			if err != nil {
+				return err
+			}
+		}
+
+		if err = client.Hello(hostname); err != nil {
+			return fmt.Errorf("Hello: %v", err)
+		}
+	}
+
+	// If not using SMTPS, always use STARTTLS if available
+	hasStartTLS, _ := client.Extension("STARTTLS")
+	if !isSecureConn && hasStartTLS {
+		if err = client.StartTLS(tlsconfig); err != nil {
+			return fmt.Errorf("StartTLS: %v", err)
+		}
+	}
+
+	canAuth, options := client.Extension("AUTH")
+	if canAuth && len(opts.User) > 0 {
+		var auth smtp.Auth
+
+		if strings.Contains(options, "CRAM-MD5") {
+			auth = smtp.CRAMMD5Auth(opts.User, opts.Passwd)
+		} else if strings.Contains(options, "PLAIN") {
+			auth = smtp.PlainAuth("", opts.User, opts.Passwd, host)
+		} else if strings.Contains(options, "LOGIN") {
+			// Patch for AUTH LOGIN
+			auth = LoginAuth(opts.User, opts.Passwd)
+		}
+
+		if auth != nil {
+			if err = client.Auth(auth); err != nil {
+				return fmt.Errorf("Auth: %v", err)
+			}
+		}
+	}
+
+	if err = client.Mail(from); err != nil {
+		return fmt.Errorf("Mail: %v", err)
+	}
+
+	for _, rec := range to {
+		if err = client.Rcpt(rec); err != nil {
+			return fmt.Errorf("Rcpt: %v", err)
+		}
+	}
+
+	w, err := client.Data()
+	if err != nil {
+		return fmt.Errorf("Data: %v", err)
+	} else if _, err = msg.WriteTo(w); err != nil {
+		return fmt.Errorf("WriteTo: %v", err)
+	} else if err = w.Close(); err != nil {
+		return fmt.Errorf("Close: %v", err)
+	}
+
+	return client.Quit()
+}
+
+// Sender sendmail mail sender
+type sendmailSender struct {
+}
+
+// Send send email
+func (s *sendmailSender) Send(from string, to []string, msg io.WriterTo) error {
+	var err error
+	var closeError error
+	var waitError error
+
+	args := []string{"-F", from, "-i"}
+	args = append(args, setting.MailService.SendmailArgs...)
+	args = append(args, to...)
+	log.Trace("Sending with: %s %v", setting.MailService.SendmailPath, args)
+	cmd := exec.Command(setting.MailService.SendmailPath, args...)
+	pipe, err := cmd.StdinPipe()
+
+	if err != nil {
+		return err
+	}
+
+	if err = cmd.Start(); err != nil {
+		return err
+	}
+
+	_, err = msg.WriteTo(pipe)
+
+	// we MUST close the pipe or sendmail will hang waiting for more of the message
+	// Also we should wait on our sendmail command even if something fails
+	closeError = pipe.Close()
+	waitError = cmd.Wait()
+	if err != nil {
+		return err
+	} else if closeError != nil {
+		return closeError
+	} else {
+		return waitError
+	}
+}
+
+// Sender sendmail mail sender
+type dummySender struct {
+}
+
+// Send send email
+func (s *dummySender) Send(from string, to []string, msg io.WriterTo) error {
+	buf := bytes.Buffer{}
+	if _, err := msg.WriteTo(&buf); err != nil {
+		return err
+	}
+	log.Info("Mail From: %s To: %v Body: %s", from, to, buf.String())
+	return nil
+}
+
+func processMailQueue() {
+	for msg := range mailQueue {
+		log.Trace("New e-mail sending request %s: %s", msg.GetHeader("To"), msg.Info)
+		if err := gomail.Send(Sender, msg.Message); err != nil {
+			log.Error("Failed to send emails %s: %s - %v", msg.GetHeader("To"), msg.Info, err)
+		} else {
+			log.Trace("E-mails sent %s: %s", msg.GetHeader("To"), msg.Info)
+		}
+	}
+}
+
+var mailQueue chan *Message
+
+// Sender sender for sending mail synchronously
+var Sender gomail.Sender
+
+// NewContext start mail queue service
+func NewContext() {
+	// Need to check if mailQueue is nil because in during reinstall (user had installed
+	// before but swithed install lock off), this function will be called again
+	// while mail queue is already processing tasks, and produces a race condition.
+	if setting.MailService == nil || mailQueue != nil {
+		return
+	}
+
+	switch setting.MailService.MailerType {
+	case "smtp":
+		Sender = &smtpSender{}
+	case "sendmail":
+		Sender = &sendmailSender{}
+	case "dummy":
+		Sender = &dummySender{}
+	}
+
+	mailQueue = make(chan *Message, setting.MailService.QueueLength)
+	go processMailQueue()
+}
+
+// SendAsync send mail asynchronous
+func SendAsync(msg *Message) {
+	go func() {
+		mailQueue <- msg
+	}()
+}
diff --git a/services/mailer/main_test.go b/services/mailer/main_test.go
new file mode 100644
index 0000000000..bbd121024e
--- /dev/null
+++ b/services/mailer/main_test.go
@@ -0,0 +1,16 @@
+// Copyright 2019 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package mailer
+
+import (
+	"path/filepath"
+	"testing"
+
+	"code.gitea.io/gitea/models"
+)
+
+func TestMain(m *testing.M) {
+	models.MainTest(m, filepath.Join("..", ".."))
+}