initial commit

LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2021 Tyler Stuyfzand
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

Makefile

@@ -0,0 +1,39 @@
+BUILDDIR=./build
+GOTIFY_VERSION=master
+PLUGIN_NAME=smtp
+PLUGIN_ENTRY=plugin.go
+GO_VERSION=`cat $(BUILDDIR)/gotify-server-go-version`
+DOCKER_BUILD_IMAGE=gotify/build
+DOCKER_WORKDIR=/proj
+DOCKER_RUN=docker run --rm -v "$$PWD/.:${DOCKER_WORKDIR}" -v "`go env GOPATH`/pkg/mod/.:/go/pkg/mod:ro" -w ${DOCKER_WORKDIR}
+DOCKER_GO_BUILD=go build -mod=readonly -a -installsuffix cgo -ldflags "$$LD_FLAGS" -buildmode=plugin
+
+download-tools:
+	GO111MODULE=off go get -u github.com/gotify/plugin-api/cmd/gomod-cap
+
+create-build-dir:
+	mkdir -p ${BUILDDIR} || true
+
+update-go-mod: create-build-dir download-tools
+	wget -LO ${BUILDDIR}/gotify-server.mod https://raw.githubusercontent.com/gotify/server/${GOTIFY_VERSION}/go.mod
+	gomod-cap -from ${BUILDDIR}/gotify-server.mod -to go.mod
+	rm ${BUILDDIR}/gotify-server.mod || true
+	go mod edit -require=github.com/gotify/server$(shell echo "/${GOTIFY_VERSION}" | egrep -o "^/v[2-9][0-9]*")@${GOTIFY_VERSION}
+	go mod tidy
+
+get-gotify-server-go-version: create-build-dir
+	rm ${BUILDDIR}/gotify-server-go-version || true
+	wget -LO ${BUILDDIR}/gotify-server-go-version https://raw.githubusercontent.com/gotify/server/${GOTIFY_VERSION}/GO_VERSION
+
+build-linux-amd64: get-gotify-server-go-version update-go-mod
+	${DOCKER_RUN} ${DOCKER_BUILD_IMAGE}:$(GO_VERSION)-linux-amd64 ${DOCKER_GO_BUILD} -o ${BUILDDIR}/${PLUGIN_NAME}-linux-amd64${FILE_SUFFIX}.so ${DOCKER_WORKDIR}
+
+build-linux-arm-7: get-gotify-server-go-version update-go-mod
+	${DOCKER_RUN} ${DOCKER_BUILD_IMAGE}:$(GO_VERSION)-linux-arm-7 ${DOCKER_GO_BUILD} -o ${BUILDDIR}/${PLUGIN_NAME}-linux-arm-7${FILE_SUFFIX}.so ${DOCKER_WORKDIR}
+
+build-linux-arm64: get-gotify-server-go-version update-go-mod
+	${DOCKER_RUN} ${DOCKER_BUILD_IMAGE}:$(GO_VERSION)-linux-arm64 ${DOCKER_GO_BUILD} -o ${BUILDDIR}/${PLUGIN_NAME}-linux-arm64${FILE_SUFFIX}.so ${DOCKER_WORKDIR}
+
+build: build-linux-arm-7 build-linux-amd64 build-linux-arm64
+
+.PHONY: build

README.md

@@ -0,0 +1,18 @@
+Gotify-SMTP
+===========
+
+A plugin for piping email messages into [Gotify](https://gotify.net/) without ever hitting an email service. Inspiration for this comes from MailHog and similar implementations where there is no backing email service, it simply forwards/receives messages as needed.
+
+There are other versions of this (specifically using the API), however this is a standalone plugin that can be loaded by Gotify.
+
+Usage
+-----
+
+Download the plugin from the releases page, or build it from source (using the Makefile).
+
+Point your application settings at GOTIFY_IP port 1025, with the username being the name of the account you'd like to send messages to.
+
+Limitations
+-----------
+
+Currently, HTML messages aren't supported. Markdown might be possible, but currently not planned as most if not all messages include a text/plain variation.

go.mod

@@ -0,0 +1,9 @@
+module github.com/tystuyfzand/gotify-smtp
+
+go 1.16
+
+require (
+	github.com/emersion/go-sasl v0.0.0-20200509203442-7bfe0ed36a21
+	github.com/emersion/go-smtp v0.15.0
+	github.com/gotify/plugin-api v1.0.0
+)

go.sum

@@ -0,0 +1,36 @@
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+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-smtp v0.15.0 h1:3+hMGMGrqP/lqd7qoxZc1hTU8LY8gHV9RFGWlqSDmP8=
+github.com/emersion/go-smtp v0.15.0/go.mod h1:qm27SGYgoIPRot6ubfQ/GpiPy/g3PaZAVRxiO/sDUgQ=
+github.com/gin-contrib/sse v0.0.0-20170109093832-22d885f9ecc7 h1:AzN37oI0cOS+cougNAV9szl6CVoj2RYwzS3DpUQNtlY=
+github.com/gin-contrib/sse v0.0.0-20170109093832-22d885f9ecc7/go.mod h1:VJ0WA2NBN22VlZ2dKZQPAPnyWw5XTlK1KymzLKsr59s=
+github.com/gin-gonic/gin v1.3.0 h1:kCmZyPklC0gVdL728E6Aj20uYBJV93nj/TkwBTKhFbs=
+github.com/gin-gonic/gin v1.3.0/go.mod h1:7cKuhb5qV2ggCFctp2fJQ+ErvciLZrIeoOSOm6mUr7Y=
+github.com/golang/protobuf v1.2.0 h1:P3YflyNX/ehuJFLhxviNdFxQPkGK5cDcApsge1SqnvM=
+github.com/golang/protobuf v1.2.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
+github.com/gotify/plugin-api v1.0.0 h1:kab40p2TEPLzjmcafOc7JOz75aTsYQyS2PXtElH8xmI=
+github.com/gotify/plugin-api v1.0.0/go.mod h1:xZfEyqVK/Zvu3RwA/CtpuiwFmzFDxifrrqMaH9BHnyU=
+github.com/json-iterator/go v1.1.5 h1:gL2yXlmiIo4+t+y32d4WGwOjKGYcGOuyrg46vadswDE=
+github.com/json-iterator/go v1.1.5/go.mod h1:+SdeFBvtyEkXs7REEP0seUULqWtbJapLOCVDaaPEHmU=
+github.com/mattn/go-isatty v0.0.4 h1:bnP0vzxcAdeI1zdubAl5PjU6zsERjGZb7raWodagDYs=
+github.com/mattn/go-isatty v0.0.4/go.mod h1:M+lRXTBqGeGNdLjl/ufCoiOlB5xdOkqRJdNxMWT7Zi4=
+github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd h1:TRLaZ9cD/w8PVh93nsPXa1VrQ6jlwL5oN8l14QlcNfg=
+github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd/go.mod h1:6dJC0mAP4ikYIbvyc7fijjWJddQyLn8Ig3JB5CqoB9Q=
+github.com/modern-go/reflect2 v1.0.1 h1:9f412s+6RmYXLWZSEzVVgPGK7C2PphHj5RJrvfx9AWI=
+github.com/modern-go/reflect2 v1.0.1/go.mod h1:bx2lNnkwVCuqBIxFjflWJWanXIb3RllmbCylyMrvgv0=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
+github.com/ugorji/go/codec v0.0.0-20181209151446-772ced7fd4c2 h1:EICbibRW4JNKMcY+LsWmuwob+CRS1BmdRdjphAm9mH4=
+github.com/ugorji/go/codec v0.0.0-20181209151446-772ced7fd4c2/go.mod h1:VFNgLljTbGfSG7qAOspJ7OScBnGdDN/yBr0sguwnwf0=
+golang.org/x/net v0.0.0-20190110200230-915654e7eabc/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
+golang.org/x/sync v0.0.0-20181221193216-37e7f081c4d4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sys v0.0.0-20190109145017-48ac38b7c8cb h1:1w588/yEchbPNpa9sEvOcMZYbWHedwJjg4VOAdDHWHk=
+golang.org/x/sys v0.0.0-20190109145017-48ac38b7c8cb/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/go-playground/assert.v1 v1.2.1/go.mod h1:9RXL0bg/zibRAgZUYszZSwO/z8Y/a8bDuhia5mkpMnE=
+gopkg.in/go-playground/validator.v8 v8.18.2 h1:lFB4DoMU6B626w8ny76MV7VX6W2VHct2GVOI3xgiMrQ=
+gopkg.in/go-playground/validator.v8 v8.18.2/go.mod h1:RX2a/7Ha8BgOhfk7j780h4/u/RRjR0eouCJSH80/M2Y=
+gopkg.in/yaml.v2 v2.2.2 h1:ZCJp+EgiOT7lHqUV2J862kp8Qj64Jo6az82+3Td9dZw=
+gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=

plugin.go

@@ -0,0 +1,234 @@
+package main
+
+import (
+	"bytes"
+	"encoding/base64"
+	"errors"
+	"fmt"
+	"github.com/emersion/go-smtp"
+	"github.com/gotify/plugin-api"
+	"io"
+	"io/ioutil"
+	"mime"
+	"mime/multipart"
+	"mime/quotedprintable"
+	"net/mail"
+	"strings"
+	"sync"
+	"time"
+)
+
+var (
+	s        *smtp.Server
+	users    = make(map[string]*Plugin)
+	userLock = &sync.RWMutex{}
+)
+
+// GetGotifyPluginInfo returns gotify plugin info
+func GetGotifyPluginInfo() plugin.Info {
+	return plugin.Info{
+		Name:       "SMTP",
+		ModulePath: "github.com/tystuyfzand/gotify-smtp",
+		Author:     "Tyler Stuyfzand",
+		Website:    "https://meow.tf",
+	}
+}
+
+// startServer sets up the SMTP server.
+// This is only called once, and uses usernames to authenticate to different users.
+func startServer() {
+	s = smtp.NewServer(&Backend{})
+
+	s.Addr = ":1025"
+	s.Domain = "0.0.0.0"
+	s.ReadTimeout = 10 * time.Second
+	s.WriteTimeout = 10 * time.Second
+	s.MaxMessageBytes = 1024 * 1024
+	s.MaxRecipients = 50
+	s.AllowInsecureAuth = true
+
+	go s.ListenAndServe()
+}
+
+// Plugin is plugin instance
+type Plugin struct {
+	userCtx    plugin.UserContext
+	msgHandler plugin.MessageHandler
+}
+
+// SetMessageHandler implements plugin.Messenger
+// Invoked during initialization
+func (c *Plugin) SetMessageHandler(h plugin.MessageHandler) {
+	c.msgHandler = h
+}
+
+// Enable adds users to the context map which maps to a Plugin.
+func (c *Plugin) Enable() error {
+	userLock.Lock()
+	users[c.userCtx.Name] = c
+	userLock.Unlock()
+	return nil
+}
+
+// Disable removes users from the context map.
+func (c *Plugin) Disable() error {
+	userLock.Lock()
+	delete(users, c.userCtx.Name)
+	userLock.Unlock()
+	return nil
+}
+
+// NewGotifyPluginInstance creates a plugin instance for a user context.
+func NewGotifyPluginInstance(ctx plugin.UserContext) plugin.Plugin {
+	if s == nil {
+		startServer()
+	}
+
+	return &Plugin{userCtx: ctx}
+}
+
+// The Backend implements SMTP server methods.
+type Backend struct {
+}
+
+// Login handles a login command with username and password.
+func (bkd *Backend) Login(state *smtp.ConnectionState, username, password string) (smtp.Session, error) {
+	userLock.RLock()
+	defer userLock.RUnlock()
+
+	if instance, ok := users[username]; ok {
+		return &Session{instance}, nil
+	}
+
+	return nil, errors.New("user not found")
+}
+
+// AnonymousLogin requires clients to authenticate using SMTP AUTH before sending emails
+func (bkd *Backend) AnonymousLogin(state *smtp.ConnectionState) (smtp.Session, error) {
+	return nil, smtp.ErrAuthRequired
+}
+
+type Session struct {
+	c *Plugin
+}
+
+func (s *Session) Mail(from string, opts smtp.MailOptions) error {
+	return nil
+}
+
+func (s *Session) Rcpt(to string) error {
+	return nil
+}
+
+func (s *Session) Data(r io.Reader) error {
+	if m, err := mail.ReadMessage(r); err != nil {
+		return err
+	} else {
+		var subject string
+
+		if subjectHeader, ok := m.Header["Subject"]; ok && len(subjectHeader) > 0 {
+			subject = subjectHeader[0]
+		}
+
+		mediaType, params, err := mime.ParseMediaType(m.Header.Get("Content-Type"))
+
+		var message string
+
+		if err == nil && strings.HasPrefix(mediaType, "multipart/") {
+			message = ParsePart(m.Body, params["boundary"])
+		} else {
+			b, err := ioutil.ReadAll(m.Body)
+
+			if err != nil {
+				return err
+			}
+
+			message = string(b)
+		}
+
+		if s.c != nil && s.c.msgHandler != nil {
+			s.c.msgHandler.SendMessage(plugin.Message{
+				Title:   subject,
+				Message: message,
+			})
+		}
+	}
+
+	return nil
+}
+
+func (s *Session) Reset() {
+
+}
+
+func (s *Session) Logout() error {
+	return nil
+}
+
+
+// ParsePart will find the first text/plain part from a multipart body.
+// Adapted from https://github.com/kirabou/parseMIMEemail.go
+func ParsePart(body io.Reader, boundary string) string {
+	reader := multipart.NewReader(body, boundary)
+
+	if reader == nil {
+		return ""
+	}
+
+	// Go through each of the MIME part of the message Body with NextPart(),
+	for {
+		part, err := reader.NextPart()
+
+		if err == io.EOF {
+			break
+		}
+
+		if err != nil {
+			fmt.Println("Error going through the MIME parts -", err)
+			break
+		}
+
+		mediaType, params, err := mime.ParseMediaType(part.Header.Get("Content-Type"))
+
+		if err == nil && strings.HasPrefix(mediaType, "multipart/") {
+			// This is a new multipart to be handled recursively
+			str := ParsePart(part, params["boundary"])
+
+			if str != "" {
+				return str
+			}
+		} else {
+			if strings.HasPrefix(mediaType, "text/plain") {
+				b, err := ioutil.ReadAll(part)
+
+				if err != nil {
+					continue
+				}
+
+				encoding := strings.ToLower(part.Header.Get("Content-Transfer-Encoding"))
+
+				switch {
+				case strings.Compare(encoding, "base64") == 0:
+					b, err = base64.StdEncoding.DecodeString(string(b))
+					if err != nil {
+						continue
+					}
+
+				case strings.Compare(encoding, "quoted-printable") == 0:
+					b, err = ioutil.ReadAll(quotedprintable.NewReader(bytes.NewReader(b)))
+					if err != nil {
+						continue
+					}
+				}
+
+				return string(b)
+			}
+		}
+	}
+
+	return ""
+}
+
+func main() {
+	panic("Program must be compiled as a Go plugin")
+}