Add support for incoming emails

.drone.yml

@@ -230,6 +230,10 @@ services:
       MINIO_ACCESS_KEY: 123456
       MINIO_SECRET_KEY: 12345678
 
+  - name: smtpimap
+    image: tabascoterrier/docker-imap-devel:latest
+    pull: always
+
 steps:
   - name: fetch-tags
     image: docker:git

docs/content/doc/advanced/config-cheat-sheet.en-us.md

@@ -743,6 +743,20 @@ and
 - `SEND_BUFFER_LEN`: **100**: Buffer length of mailing queue. **DEPRECATED** use `LENGTH` in `[queue.mailer]`
 - `SEND_AS_PLAIN_TEXT`: **false**: Send mails only in plain text, without HTML alternative.
 
+## Incoming Email (`incoming_email`)
+
+- `ENABLED`: **false**: Enable handling of incoming emails.
+- `REPLY_TO_ADDRESS`: **\<empty\>**: # The email address including the %{token} placeholder that will be replaced per user/action. Example: `incoming+%{token}@example.com`. The placeholder must appear in the user part of the address (before the `@`).
+- `HOST`: **\<empty\>**: IMAP server host.
+- `PORT`: **\<empty\>**: IMAP server port.
+- `USERNAME`: **\<empty\>**: Username of the receiving account.
+- `PASSWORD`: **\<empty\>**: Password of the receiving account.
+- `USE_TLS`: **false**: Whether the IMAP server uses TLS.
+- `SKIP_TLS_VERIFY`: **false**: If set to `true`, completely ignores server certificate validation errors. This option is unsafe.
+- `MAILBOX`: **INBOX**: The mailbox name where incoming mail will end up.
+- `DELETE_HANDLED_MESSAGE`: **true**: Whether handled messages should be deleted from the mailbox.
+- `MAXIMUM_MESSAGE_SIZE`: **0**: Maximum size of a message to handle. Bigger messages are ignored.
+
 ## Cache (`cache`)
 
 - `ENABLED`: **true**: Enable the cache.

docs/content/doc/features/comparison.en-us.md

@@ -106,7 +106,7 @@ _Symbols used in table:_
 | Issue search                  | ✓                                                   | ✘    | ✓         | ✓         | ✓         | ✓         | ✘            |
 | Global issue search           | [/](https://github.com/go-gitea/gitea/issues/2434)  | ✘    | ✓         | ✓         | ✓         | ✓         | ✘            |
 | Issue dependency              | ✓                                                   | ✘    | ✘         | ✘         | ✘         | ✘         | ✘            |
-| Create issue via email        | [✘](https://github.com/go-gitea/gitea/issues/6226)  | ✘    | ✘         | ✘         | ✓         | ✓         | ✘            |
+| Create issue via email        | [✘](https://github.com/go-gitea/gitea/issues/6226)  | ✘    | ✘         | ✓         | ✓         | ✓         | ✘            |
 | Service Desk                  | [✘](https://github.com/go-gitea/gitea/issues/6219)  | ✘    | ✘         | ✓         | ✓         | ✘         | ✘            |
 
 ## Pull/Merge requests

docs/content/doc/features/comparison.zh-cn.md

@@ -92,7 +92,7 @@ _表格中的符号含义:_
 | 工单搜索            | ✓                                                  | ✘                                             | ✓         | ✓                                                                       | ✓         | ✓              | ✘            |
 | 工单全局搜索        | [✘](https://github.com/go-gitea/gitea/issues/2434) | ✘                                             | ✓         | ✓                                                                       | ✓         | ✓              | ✘            |
 | 工单依赖关系        | ✓                                                  | ✘                                             | ✘         | ✘                                                                       | ✘         | ✘              | ✘            |
-| 通过 Email 创建工单 | [✘](https://github.com/go-gitea/gitea/issues/6226) | [✘](https://github.com/gogs/gogs/issues/2602) | ✘         | ✘                                                                       | ✓         | ✓              | ✘            |
+| 通过 Email 创建工单 | [✘](https://github.com/go-gitea/gitea/issues/6226) | [✘](https://github.com/gogs/gogs/issues/2602) | ✘         | ✓                                                                       | ✓         | ✓              | ✘            |
 | 服务台              | [✘](https://github.com/go-gitea/gitea/issues/6219) | ✘                                             | ✘         | [✓](https://gitlab.com/groups/gitlab-org/-/epics/3103)                  | ✓         | ✘              | ✘            |
 
 #### Pull/Merge requests

docs/content/doc/features/comparison.zh-tw.md

@@ -93,7 +93,7 @@ menu:
 | 問題搜尋             | ✓                                                  | ✘                                             | ✓         | ✓                                                                       | ✓         | ✓         | ✘            |
 | 全域問題搜尋         | [✘](https://github.com/go-gitea/gitea/issues/2434) | ✘                                             | ✓         | ✓                                                                       | ✓         | ✓         | ✘            |
 | 問題相依             | ✓                                                  | ✘                                             | ✘         | ✘                                                                       | ✘         | ✘         | ✘            |
-| 從電子郵件建立問題   | [✘](https://github.com/go-gitea/gitea/issues/6226) | [✘](https://github.com/gogs/gogs/issues/2602) | ✘         | ✘                                                                       | ✓         | ✓         | ✘            |
+| 從電子郵件建立問題   | [✘](https://github.com/go-gitea/gitea/issues/6226) | [✘](https://github.com/gogs/gogs/issues/2602) | ✘         | ✓                                                                       | ✓         | ✓         | ✘            |
 | 服務台               | [✘](https://github.com/go-gitea/gitea/issues/6219) | ✘                                             | ✘         | [✓](https://gitlab.com/groups/gitlab-org/-/epics/3103)                  | ✓         | ✘         | ✘            |
 
 ## 拉取/合併請求

docs/content/doc/usage/incoming-email.en-us.md

@@ -0,0 +1,47 @@
+---
+date: "2022-12-01T00:00:00+00:00"
+title: "Incoming Email"
+slug: "incoming-email"
+draft: false
+toc: false
+menu:
+  sidebar:
+    parent: "usage"
+    name: "Incoming Email"
+    weight: 13
+    identifier: "incoming-email"
+---
+
+# Incoming Email
+
+Gitea supports the execution of several actions through incoming mails. This page describes how to set this up.
+
+**Table of Contents**
+
+{{< toc >}}
+
+## Requirements
+
+Handling incoming email messages requires an IMAP-enabled email account.
+The recommended strategy is to use [email sub-addressing](https://en.wikipedia.org/wiki/Email_address#Sub-addressing) but a catch-all mailbox does work too.
+The receiving email address contains a user/action specific token which tells Gitea which action should be performed.
+This token is expected in the `To` and `Delivered-To` header fields.
+
+Gitea tries to detect automatic responses to skip and the email server should be configured to reduce the incoming noise too (spam, newsletter).
+
+## Configuration
+
+To activate the handling of incoming email messages you have to configure the `incoming_email` section in the configuration file.
+
+The `REPLY_TO_ADDRESS` contains the address an email client will respond to.
+This address needs to contain the `%{token}` placeholder which will be replaced with a token describing the user/action.
+This placeholder must only appear once in the address and must be in the user part of the address (before the `@`).
+
+An example using email sub-addressing may look like this: `incoming+%{token}@example.com`
+
+If a catch-all mailbox is used, the placeholder may be used anywhere in the user part of the address: `incoming+%{token}@example.com`, `incoming_%{token}@example.com`, `%{token}@example.com`
+
+## Security
+
+Be careful when choosing the domain used for receiving incoming email.
+It's recommended receiving incoming email on a subdomain, such as `incoming.example.com` to prevent potential security problems with other services running on `example.com`.

go.mod

@@ -159,8 +159,13 @@ require (
 	github.com/cpuguy83/go-md2man/v2 v2.0.2 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f // indirect
+	github.com/dimiro1/reply v0.0.0-20200315094148-d0136a4c9e21 // indirect
 	github.com/dlclark/regexp2 v1.7.0 // indirect
 	github.com/dsnet/compress v0.0.2-0.20210315054119-f66993602bf5 // indirect
+	github.com/emersion/go-imap v1.2.1 // indirect
+	github.com/emersion/go-message v0.16.0 // indirect
+	github.com/emersion/go-sasl v0.0.0-20200509203442-7bfe0ed36a21 // indirect
+	github.com/emersion/go-textwrapper v0.0.0-20200911093747-65d896831594 // indirect
 	github.com/envoyproxy/go-control-plane v0.10.2-0.20220325020618-49ff273808a1 // indirect
 	github.com/envoyproxy/protoc-gen-validate v0.6.2 // indirect
 	github.com/felixge/httpsnoop v1.0.3 // indirect

go.sum

@@ -389,11 +389,14 @@ github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f h1:lO4WD4F/r
 github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f/go.mod h1:cuUVRXasLTGF7a8hSLbxyZXjz+1KgoB3wDUb6vlszIc=
 github.com/dgryski/go-sip13 v0.0.0-20181026042036-e10d5fee7954/go.mod h1:vAd38F8PWV+bWy6jNmig1y/TA+kYO4g3RSRF0IAv0no=
 github.com/dimchansky/utfbom v1.1.0/go.mod h1:rO41eb7gLfo8SF1jd9F8HplJm1Fewwi4mQvIirEdv+8=
+github.com/dimiro1/reply v0.0.0-20200315094148-d0136a4c9e21 h1:PdsjTl0Cg+ZJgOx/CFV5NNgO1ThTreqdgKYiDCMHJwA=
+github.com/dimiro1/reply v0.0.0-20200315094148-d0136a4c9e21/go.mod h1:xJvkyD6Y2rZapGvPJLYo9dyx1s5dxBEDPa8T3YTuOk0=
 github.com/djherbis/buffer v1.1.0/go.mod h1:VwN8VdFkMY0DCALdY8o00d3IZ6Amz/UNVMWcSaJT44o=
 github.com/djherbis/buffer v1.2.0 h1:PH5Dd2ss0C7CRRhQCZ2u7MssF+No9ide8Ye71nPHcrQ=
 github.com/djherbis/buffer v1.2.0/go.mod h1:fjnebbZjCUpPinBRD+TDwXSOeNQ7fPQWLfGQqiAiUyE=
 github.com/djherbis/nio/v3 v3.0.1 h1:6wxhnuppteMa6RHA4L81Dq7ThkZH8SwnDzXDYy95vB4=
 github.com/djherbis/nio/v3 v3.0.1/go.mod h1:Ng4h80pbZFMla1yKzm61cF0tqqilXZYrogmWgZxOcmg=
+github.com/dlclark/regexp2 v1.2.0/go.mod h1:2pZnwuY/m+8K6iRw6wQdMtk+rH5tNGR1i55kozfMjCc=
 github.com/dlclark/regexp2 v1.4.0/go.mod h1:2pZnwuY/m+8K6iRw6wQdMtk+rH5tNGR1i55kozfMjCc=
 github.com/dlclark/regexp2 v1.7.0 h1:7lJfhqlPssTb1WQx4yvTHN0uElPEv52sbaECrAQxjAo=
 github.com/dlclark/regexp2 v1.7.0/go.mod h1:DHkYz0B9wPfa6wondMfaivmHpzrQ3v9q8cnmRbL6yW8=
@@ -415,6 +418,15 @@ github.com/editorconfig/editorconfig-core-go/v2 v2.4.5 h1:kTcVMyCvFGQmTk0S5+R7GF
 github.com/editorconfig/editorconfig-core-go/v2 v2.4.5/go.mod h1:rDB5UUleQsOI1HLbojaBmDNR8oUUe31InmNDTVzcDHY=
 github.com/edsrzf/mmap-go v1.0.0/go.mod h1:YO35OhQPt3KJa3ryjFM5Bs14WD66h8eGKpfaBNrHW5M=
 github.com/elazarl/go-bindata-assetfs v1.0.1/go.mod h1:v+YaWX3bdea5J/mo8dSETolEo7R71Vk1u8bnjau5yw4=
+github.com/emersion/go-imap v1.2.1 h1:+s9ZjMEjOB8NzZMVTM3cCenz2JrQIGGo5j1df19WjTA=
+github.com/emersion/go-imap v1.2.1/go.mod h1:Qlx1FSx2FTxjnjWpIlVNEuX+ylerZQNFE5NsmKFSejY=
+github.com/emersion/go-message v0.15.0/go.mod h1:wQUEfE+38+7EW8p8aZ96ptg6bAb1iwdgej19uXASlE4=
+github.com/emersion/go-message v0.16.0 h1:uZLz8ClLv3V5fSFF/fFdW9jXjrZkXIpE1Fn8fKx7pO4=
+github.com/emersion/go-message v0.16.0/go.mod h1:pDJDgf/xeUIF+eicT6B/hPX/ZbEorKkUMPOxrPVG2eQ=
+github.com/emersion/go-sasl v0.0.0-20200509203442-7bfe0ed36a21 h1:OJyUGMJTzHTd1XQp98QTaHernxMYzRaOasRir9hUlFQ=
+github.com/emersion/go-sasl v0.0.0-20200509203442-7bfe0ed36a21/go.mod h1:iL2twTeMvZnrg54ZoPDNfJaJaqy0xIQFuBdrLsmspwQ=
+github.com/emersion/go-textwrapper v0.0.0-20200911093747-65d896831594 h1:IbFBtwoTQyw0fIM5xv1HF+Y+3ZijDR839WMulgxCcUY=
+github.com/emersion/go-textwrapper v0.0.0-20200911093747-65d896831594/go.mod h1:aqO8z8wPrjkscevZJFVE1wXJrLpC5LtJG7fqLOsPb2U=
 github.com/emirpasic/gods v1.12.0/go.mod h1:YfzfFFoVP/catgzJb4IKIqXjX78Ha8FMSDh3ymbK86o=
 github.com/emirpasic/gods v1.18.1 h1:FXtiHYKDGKCW2KzwZKx0iC0PQmdlorYgdFG9jPXJ1Bc=
 github.com/emirpasic/gods v1.18.1/go.mod h1:8tpGGwCnJ5H4r6BWwaV6OrWmMoPhUl5jm/FMNAnJvWQ=

models/unittest/testdb.go

@@ -106,6 +106,8 @@ func MainTest(m *testing.M, testOpts *TestOptions) {
 
 	setting.Git.HomePath = filepath.Join(setting.AppDataPath, "home")
 
+	setting.IncomingEmail.ReplyToAddress = "incoming+%{token}@localhost"
+
 	if err = storage.Init(); err != nil {
 		fatalTestError("storage.Init: %v\n", err)
 	}

modules/setting/incoming_email.go

@@ -0,0 +1,72 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package setting
+
+import (
+	"fmt"
+	"net/mail"
+	"strings"
+
+	"code.gitea.io/gitea/modules/log"
+)
+
+var IncomingEmail = struct {
+	Enabled              bool
+	ReplyToAddress       string
+	TokenPlaceholder     string `ini:"-"`
+	Host                 string
+	Port                 int
+	UseTLS               bool `ini:"USE_TLS"`
+	SkipTLSVerify        bool `ini:"SKIP_TLS_VERIFY"`
+	Username             string
+	Password             string
+	Mailbox              string
+	DeleteHandledMessage bool
+	MaximumMessageSize   uint32
+}{
+	Mailbox:              "INBOX",
+	DeleteHandledMessage: true,
+	TokenPlaceholder:     "%{token}",
+}
+
+func newIncomingEmail() {
+	if err := Cfg.Section("incoming_email").MapTo(&IncomingEmail); err != nil {
+		log.Fatal("Unable to map [incoming_email] section on to IncomingEmail. Error: %v", err)
+	}
+
+	if !IncomingEmail.Enabled {
+		return
+	}
+
+	if err := checkReplyToAddress(IncomingEmail.ReplyToAddress); err != nil {
+		log.Fatal("Invalid incoming_mail.REPLY_TO_ADDRESS (%s): %v", IncomingEmail.ReplyToAddress, err)
+	}
+}
+
+func checkReplyToAddress(address string) error {
+	parsed, err := mail.ParseAddress(IncomingEmail.ReplyToAddress)
+	if err != nil {
+		return err
+	}
+
+	if parsed.Name != "" {
+		return fmt.Errorf("name must not be set")
+	}
+
+	c := strings.Count(IncomingEmail.ReplyToAddress, IncomingEmail.TokenPlaceholder)
+	switch c {
+	case 0:
+		return fmt.Errorf("%s must appear in the user part of the address (before the @)", IncomingEmail.TokenPlaceholder)
+	case 1:
+	default:
+		return fmt.Errorf("%s must appear only once", IncomingEmail.TokenPlaceholder)
+	}
+
+	parts := strings.Split(IncomingEmail.ReplyToAddress, "@")
+	if !strings.Contains(parts[0], IncomingEmail.TokenPlaceholder) {
+		return fmt.Errorf("%s must appear in the user part of the address (before the @)", IncomingEmail.TokenPlaceholder)
+	}
+
+	return nil
+}

modules/setting/setting.go

@@ -1331,6 +1331,7 @@ func NewServices() {
 	newSessionService()
 	newCORSService()
 	newMailService()
+	newIncomingEmail()
 	newRegisterMailService()
 	newNotifyMailService()
 	newProxyService()

modules/util/pack.go

@@ -0,0 +1,33 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package util
+
+import (
+	"bytes"
+	"encoding/gob"
+)
+
+// PackData uses gob to encode the given data in sequence
+func PackData(data ...interface{}) ([]byte, error) {
+	var buf bytes.Buffer
+	enc := gob.NewEncoder(&buf)
+	for _, datum := range data {
+		if err := enc.Encode(datum); err != nil {
+			return nil, err
+		}
+	}
+	return buf.Bytes(), nil
+}
+
+// UnpackData uses gob to decode the given data in sequence
+func UnpackData(buf []byte, data ...interface{}) error {
+	r := bytes.NewReader(buf)
+	enc := gob.NewDecoder(r)
+	for _, datum := range data {
+		if err := enc.Decode(datum); err != nil {
+			return err
+		}
+	}
+	return nil
+}

modules/util/pack_test.go

@@ -0,0 +1,28 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package util
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestPackAndUnpackData(t *testing.T) {
+	s := "string"
+	i := int64(4)
+	f := float32(4.1)
+
+	var s2 string
+	var i2 int64
+	var f2 float32
+
+	data, err := PackData(s, i, f)
+	assert.NoError(t, err)
+
+	assert.NoError(t, UnpackData(data, &s2, &i2, &f2))
+	assert.NoError(t, UnpackData(data, &s2))
+	assert.Error(t, UnpackData(data, &i2))
+	assert.Error(t, UnpackData(data, &s2, &f2))
+}

routers/init.go

@@ -40,6 +40,7 @@ import (
 	"code.gitea.io/gitea/services/automerge"
 	"code.gitea.io/gitea/services/cron"
 	"code.gitea.io/gitea/services/mailer"
+	mailer_incoming "code.gitea.io/gitea/services/mailer/incoming"
 	markup_service "code.gitea.io/gitea/services/markup"
 	repo_migrations "code.gitea.io/gitea/services/migrations"
 	mirror_service "code.gitea.io/gitea/services/mirror"
@@ -161,6 +162,7 @@ func GlobalInitInstalled(ctx context.Context) {
 	mustInit(task.Init)
 	mustInit(repo_migrations.Init)
 	eventsource.GetManager().Init()
+	mustInitCtx(ctx, mailer_incoming.Init)
 
 	mustInitCtx(ctx, syncAppConfForGit)