@flancer64/smtp-logger

📨 A lightweight Node.js utility for logging received emails to a database.
Designed to be used as a pipe-based handler in Postfix (e.g. via always_bcc),
it parses and stores full email messages in a SQL database using knex.
Dependency injection is powered by @teqfw/di.

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Features

• Works as a stdin-based mail handler (e.g. from Postfix aliases)
• Parses full MIME email (headers + plain text or HTML body)
• Logs to PostgreSQL, SQLite, MySQL, or any other Knex-supported DB
• Modular architecture with dependency injection
• Supports both SQLite file-based and network database connections
• Automatic database schema initialization

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Use Cases

• Audit/logging of all outgoing emails in multi-app environments
• Integrates into Postfix using always_bcc or direct aliases
• Useful in production and staging for tracking system-generated messages

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Requirements

• Node.js 18+
• knex (tested with PostgreSQL, SQLite, and MySQL)
• @teqfw/di
• mailparser
• minimist
• dotenv

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Installation

git clone https://github.com/yourname/smtp-logger.git
cd smtp-logger
npm install

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Configuration

Example: SQLite (better-sqlite3)

DB_CLIENT=better-sqlite3
DB_FILE=./var/data.sqlite3

Example: Network databases (PostgreSQL, MySQL, etc.)

DB_CLIENT=pg            # or mysql, etc.
DB_HOST=localhost
DB_PORT=5432
DB_NAME=mydb
DB_USER=user
DB_PASS=password

Command Line Arguments

node index.js log --dbClient=better-sqlite3 --dbFile=./var/data.sqlite3

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Usage

Initialize Database

node index.js init-db

Log an Email

Pipe an email to the utility:

cat sample.eml | node index.js

Or test manually:

cat sample.eml | node index.js log

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Postfix Integration

Step 1: Add alias

Edit /etc/aliases:

logger: "|/usr/local/bin/smtp-logger/index.js"

Then update aliases:

sudo newaliases

Step 2: Configure always_bcc

In /etc/postfix/main.cf:

always_bcc = logger@localhost

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See the output

Use this script (/tmp/log.sh) to redirect output to a file:

#!/bin/sh
cd /path/to/smtp-logger/
./index.js >> /tmp/smtp-logger.log 2>&1

Edit /etc/aliases:

logger: "|/tmp/log.sh"

Then update aliases:

sudo newaliases

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License

Apache License 2.0

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© Alex Gusev & LLMs, 2025