Mailhog fails to send messages

Question

My PHP script fails to send messages to Mailhog client. I'm using the Slim PHP framework. Here's what I've tried:-

Container is up and running with sendmail path set:

docker exec -it php cat /usr/local/etc/php/conf.d/local.ini
error_reporting=E_ALL
sendmail_path="mhsendmail --smtp-addr=mailhog:1025"

Sendmail installed locally sudo apt-get install sendmail

docker-compose.yaml

version: '3'
services:

  #PHP Service
  php:
    build:
      context: .
      dockerfile: Dockerfile
    container_name: php
    restart: unless-stopped
    tty: true
    environment:
      SERVICE_NAME: php
      SERVICE_TAGS: dev
    working_dir: /var/www
    volumes:
      - ./:/var/www
      - ./docker/php/local.ini:/usr/local/etc/php/conf.d/local.ini
    networks:
      - app-network

  #Mailhog
  mailhog:
    container_name: mailhog
    image: mailhog/mailhog
    ports:
      - "1025:1025"
      - "8025:8025"
    networks:
      - app-network

Dockerfile

FROM php:8.1-fpm

# Copy composer.lock and composer.json
# COPY composer.lock composer.json /var/www/

# Set working directory
WORKDIR /var/www

# Install dependencies
RUN apt-get update && apt-get install -y \
    build-essential \
    libpng-dev \
    libjpeg62-turbo-dev \
    libfreetype6-dev \
    locales \
    libzip-dev \
    zip \
    jpegoptim optipng pngquant gifsicle \
    vim \
    unzip \
    git \
    curl

# Clear cache
RUN apt-get clean && rm -rf /var/lib/apt/lists/*

# Install extensions
RUN docker-php-ext-install mysqli pdo pdo_mysql && docker-php-ext-enable pdo_mysql
RUN docker-php-ext-configure gd --with-freetype --with-jpeg
RUN docker-php-ext-install gd

# Install composer
RUN curl -sS https://getcomposer.org/installer | php -- --install-dir=/usr/local/bin --filename=composer


RUN groupadd -g 1000 www
RUN useradd -u 1000 -ms /bin/bash -g www www

# Copy existing application directory contents
COPY . /var/www

# Copy existing application directory permissions
COPY --chown=www:www . /var/www

# Change current user to www
USER www

# Expose port 9000 and start php-fpm server
EXPOSE 9000
CMD ["php-fpm"]

In my PHP script:

$to = 'recipients@email-address.com';
    $subject = 'Hello from Ubuntu!';
    $message = 'This is a Mailhog test';
    $headers = "From: your@email-address.com\r\n";

    if (mail($to, $subject, $message, $headers)) {
        echo "SUCCESS";
    } else {
        echo "ERROR";
    }

Upon hitting my endpoint, the script returns ERROR? Any ideas?

Answer 1

Can you try the followings?

1. Add this to your php Dockfile, then rebuild

# Install MailHog
FROM golang:1.15 AS builder
COPY --from=builder /go/src/github.com/mailhog/mhsendmail/mhsendmail /usr/local/bin/
RUN chmod +x /usr/local/bin/mhsendmail

2. Update this to your php ini file

sendmail_path = '/usr/local/bin/mhsendmail --smtp-addr="mailhog:1025"'

Answer 2

Use PHPMailer as this has integrated SMTP support – send without a local mail server. Full code here:-

<?php
require __DIR__ . '/../vendor/autoload.php';

use Psr\Http\Message\RequestInterface;
use Psr\Http\Message\ResponseInterface;
use Slim\Factory\AppFactory;
use PHPMailer\PHPMailer\PHPMailer;

$app = AppFactory::create();


$app->post('/send-email', function (RequestInterface $request, ResponseInterface $response) {

    $data = $request->getParsedBody();

    $recipient = $data['recipient'];
    $subject = $data['subject'];
    $body = $data['body'];
    $recipientName = $data['recipient_name'];

    $mail = new PHPMailer(true);

    try {
        //Server settings
        $mail->isSMTP();
        $mail->Host       = 'mailhog'; // Set the SMTP server to send through
        $mail->SMTPAuth   = true; // Enable SMTP authentication
        $mail->Username   = ''; // SMTP username
        $mail->Password   = ''; // SMTP password
        $mail->Port       = 1025; // TCP port to connect to, use 465 for `PHPMailer::ENCRYPTION_SMTPS` above

        //Recipients
        $mail->setFrom('from@example.com', 'Mailer');
        $mail->addAddress($recipient, $recipientName); // Add a recipient

        // Content
        $mail->isHTML(true); // Set email format to HTML
        $mail->Subject = $subject;
        $mail->Body    = $body;
        $mail->AltBody = 'This is the body in plain text for non-HTML mail clients';

        $mail->send();
        $response->getBody()->write(json_encode(['message' => 'Email sent successfully']));

        return $response->withHeader('Content-Type', 'application/json')->withStatus(200);

    } catch (Exception $e) {
        $response->getBody()->write(json_encode(['error' => $mail->ErrorInfo]));

        return $response->withHeader('Content-Type', 'application/json')->withStatus(500);
    }
});

$app->run();