SMTPBridge

Bridge email to other messaging services.

Do not expose this to the Internet as this is only intended to be used on a local network.

Features

• Receive email from SMTP or HTTP as envelopes
• Send envelopes to endpoints with templates
• Create rules for matching envelopes with endpoints
• View and manage application through the Web UI
• Delete stale envelopes with a retention policy
• Monitor application with healthcheck

Use Cases

• Pictures from IP cameras (e.g. AI Tripwire, ...)
• System messages from servers and applications (e.g. Debian, Nextcloud, UniFi Network Application, ...)

Usage

smtpbridge

Supported Endpoints

• Console
• Telegram
• Shoutrrr
• Apprise
• Script

Apprise

Apprise requires Python to be installed along with the apprise package.

Install Apprise with the following command.

pip install apprise

If you are using a Python virtual environment, then set the python_executable config variable.

python_executable: .venv/bin/python3

Make sure you install Apprise in that virtual environment.

Script

This allows you to run an arbitrary script as an endpoint. stdin is a JSON encoded envelope such as the following.

{
"title": "Test Subject",
"body": "Test Body",
"attachments": [
{
"path": "http://127.0.0.1:8080/apple-touch-icon.png",
"name": "Test Attachment"
}
]
}

The path of an attachment can be a URL or a file path.

Please note that scripts runs concurrently.

Config

Config file is loaded from one of the following locations in order.

• config.yaml
• config.yml
• .smtpbridge.yaml
• .smtpbridge.yml
• ~/.smtpbridge.yaml
• ~/.smtpbridge.yml
• /etc/smtpbridge.yaml
• /etc/smtpbridge.yml

CLI flags take priority over config files and environment.

Simple Config

This config prints emails received via SMTP to console.

endpoints:
hello_world:
kind: consolerules:
hello_world:

Full Config

# Used for developmentdebug: false# Used by HTTP, ...time_format: 12h# [12h, 24h]# Directory for storing datadata_directory: smtpbridge_data# Python executable used by Apprisepython_executable: python3# Healthcheck enables verification that the application has not crashed or lost network access# You can use a third party service such as healthchecks.iohealthcheck:
# URL to fetch, empty means health checking is disabledurl: ""# [https://hc-ping.com/cb8bcf81-d3c4-4c98-85a6-734c3b7ddb2b, ...]# Interval between each fetchinterval: 5m# [5m, 5h45m, ...]# Run on startupstartup: false# Mailman handles sending envelopes to the configured endpointsmailman:
# Number of concurrent workersworkers: 1# Retention policy will delete resources that pass the configured policyretention:
# Envelopes in databaseenvelope_count: # [0, 100, 250, ...]envelope_age: # [5m, 5h45m, ...]# Attachment files in file storeattachment_size: # [100 MB, 1 GB, ...]# Traces in databasetrace_age: 168h# 7 days [5m, 5h45m, ...]# HTTP serverhttp:
disable: falsehost: ""# [127.0.0.1, ...]port: 8080# Authentication is disabled if both username and password are emptyusername: ""password: ""# Public URL used for creating linksurl: ""# [http://127.0.0.1:8080, ...]# SMTP serversmtp:
disable: falsehost: ""# [127.0.0.1, ...]port: 1025# Authentication is disabled if both username and password are emptyusername: ""password: ""# Maximum payload sizemax_payload_size: 25 MB # [100 MB, 1 GB, ...]# Endpoints for envelopesendpoints:
# Consoleconsole_endpoint:
kind: console# Telegramtelegram_endpoint:
kind: telegramconfig:
# https://core.telegram.org/bots/features#creating-a-new-bottoken: 2222222222222222222222# https://stackoverflow.com/a/32572159chat_id: 111111111111111111111# Shoutrrr (can only send text)shoutrrr_endpoint:
kind: shoutrrrconfig:
# https://containrrr.dev/shoutrrr/v0.8/services/overview/urls: telegram://token@telegram?chats=@channel-1[,chat-id-1,...]# Appriseapprise_endpoint:
kind: appriseconfig:
# https://github.com/caronc/apprise#supported-notificationsurls: tgram://bottoken/ChatID# Scriptscript_endpoint:
kind: scriptconfig:
file: my-script.py# Full exampleexample_endpoint:
kind: consolename: Example Endpoint# Do not send title and bodytext_disable: false# Do not send attachmentsattachment_disable: false# Custom template for titletitle_template: "{{ .Message.Subject }}"# Custom template for bodybody_template: "{{ .Message.Text }}"rules:
example_rule:
name: Example Ruleexpression: or (eq .Message.Subject "cam-1") (eq .Message.Subject "cam-2")endpoints:
- console_endpoint

Templates

See text/template on how to template.

Each *_template has access to the Envelope model via the . operator.

The following custom functions are available in endpoint templates.

Name	Description	Example
PermaLink	Permanent HTTP link for the given model.	{{ PermaLink .Message }} => http://127.0.0.1:8080/envelopes/1

Expressions

Rule expressions are just text/template without {{ }}. The Envelope model can be accessed via the . operator. They should always evaluate to a boolean expression.

Example:

or
(eq .Message.Subject "cam-1")
(.Message.To.EQ "my-name@example.com")
(eq .Message.From "unleashed@example.com")

This expression will pass if one of the following is true.

• The message's subject equals "cam-1"
• The message is to "my-name@example.com"
• The message is from "unleashed@example.com"

Docker

Docker Compose

version: "3"services:
smtpbridge:
image: ghcr.io/itsnotgoodname/smtpbridge:latestcontainer_name: smtpbridgeenvironment:
APPRISE_ENABLE: "true"# OptionalAPPRISE_VERSION: "1.5.0"# OptionalSMTPBRIDGE_CONFIG_YAML: | # Optional endpoints: hello_world: kind: console rules: hello_world:ports:
- 1025:1025
- 8080:8080volumes:
- /path/to/data:/data
- /path/to/config:/config # Optional
- /etc/timezone:/etc/timezone:ro # Optional
- /etc/localtime:/etc/localtime:ro # Optionalrestart: unless-stopped

Docker CLI

docker run -d \
--name=smtpbridge \
-e APPRISE_ENABLE=true `# Optional` \
-e APPRISE_ENABLE=1.5.0 `# Optional` \
-p 1025:1025 \
-p 8080:8080 \
-v /path/to/data:/data \
-v /path/to/config:/config `# Optional` \
-v /etc/timezone:/etc/timezone:ro `# Optional` \
-v /etc/localtime:/etc/localtime:ro `# Optional` \
--restart unless-stopped \
ghcr.io/itsnotgoodname/smtpbridge:latest

Development

The following programs are required.

• Make
• Go
• pnpm

Make

You should look at the Makefile before running any of the following commands.

Install tooling.

make tooling

Start the Go server.

make dev

Start Vite.

make dev-web

To Do

• refactor: WAY TOO MANY TOOLS TO BUILD THE PROGRAM, REMOVE SOME
• feat: read mbox files
• feat: IMAP for viewing mail
• feat: OpenAPI
• feat: Windows installer
• fix: chrome keeps thinking some HTTP pages are French