feat: add email adapter DSN parsing

README.md

@@ -83,6 +83,48 @@ $messaging = new FCM('YOUR_SERVICE_ACCOUNT_JSON');
 $messaging->send($message);
 ```
 
+You can also create email adapters from a DSN:
+
+```php
+<?php
+
+use Utopia\Messaging\Adapter\Email;
+
+$smtp = Email::fromDsn('smtp://user:pass@smtp.example.com:587?secure=tls&autotls=1');
+$resend = Email::fromDsn('resend://YOUR_API_KEY@default');
+$sendgrid = Email::fromDsn('sendgrid://YOUR_API_KEY@default');
+$mailgun = Email::fromDsn('mailgun://YOUR_API_KEY@example.com?eu=0');
+```
+
+Supported email DSN schemes are `smtp`, `smtps`, `resend`, `sendgrid`, and `mailgun`.
+
+## Multiple Adapters (Failover)
+
+You can use multiple adapters with automatic failover. If one adapter throws an exception, the next one will be tried.
+
+```php
+<?php
+
+use \Utopia\Messaging\Messenger;
+use \Utopia\Messaging\Messages\SMS;
+use \Utopia\Messaging\Adapter\SMS\Twilio;
+use \Utopia\Messaging\Adapter\SMS\Vonage;
+
+$message = new SMS(
+    to: ['+12025550139'],
+    content: 'Hello World'
+);
+
+$messenger = new Messenger([
+    new Twilio('YOUR_ACCOUNT_SID', 'YOUR_AUTH_TOKEN'),
+    new Vonage('YOUR_API_KEY', 'YOUR_API_SECRET'),
+]);
+
+$messenger->send($message);
+```
+
+The `Messenger` class accepts multiple adapters and tries them in order. It stops at the first successful response and only throws an exception if all adapters fail.
+
 ## Adapters
 
 > Want to implement any of the missing adapters or have an idea for another? We would love to hear from you! Please check out our [contribution guide](./CONTRIBUTING.md) and [new adapter guide](./docs/add-new-adapter.md) for more information.

src/Utopia/Messaging/Adapter/Email.php

@@ -8,6 +8,7 @@
 abstract class Email extends Adapter
 {
     protected const TYPE = 'email';
+
     protected const MESSAGE_TYPE = EmailMessage::class;
 
     protected const MAX_ATTACHMENT_BYTES = 25 * 1024 * 1024; // 25MB
@@ -22,6 +23,37 @@ public function getMessageType(): string
         return static::MESSAGE_TYPE;
     }
 
+    /**
+     * Create an email adapter from a DSN string.
+     *
+     * Supported schemes: smtp, smtps, resend, sendgrid, mailgun.
+     *
+     * @throws \InvalidArgumentException
+     */
+    public static function fromDsn(string $dsn): self
+    {
+        $parts = \parse_url($dsn);
+
+        if ($parts === false || empty($parts['scheme'])) {
+            throw new \InvalidArgumentException('Invalid email DSN.');
+        }
+
+        $scheme = \strtolower($parts['scheme']);
+        $query = [];
+
+        if (isset($parts['query'])) {
+            \parse_str($parts['query'], $query);
+        }
+
+        return match ($scheme) {
+            'smtp', 'smtps' => self::createSmtpAdapter($parts, $query, $scheme),
+            'resend' => self::createApiKeyAdapter($parts, Email\Resend::class, 'Resend'),
+            'sendgrid' => self::createApiKeyAdapter($parts, Email\Sendgrid::class, 'Sendgrid'),
+            'mailgun' => self::createMailgunAdapter($parts, $query),
+            default => throw new \InvalidArgumentException('Unsupported email DSN scheme "'.$scheme.'".'),
+        };
+    }
+
     /**
      * Process an email message.
      *
@@ -30,4 +62,149 @@ public function getMessageType(): string
      * @throws \Exception
      */
     abstract protected function process(EmailMessage $message): array;
+
+    /**
+     * @param  array<string, int|string>  $parts
+     * @param  array<string, mixed>  $query
+     */
+    private static function createSmtpAdapter(array $parts, array $query, string $scheme): self
+    {
+        $host = self::decodeUrlComponent($parts['host'] ?? null);
+
+        if ($host === null || $host === '') {
+            throw new \InvalidArgumentException('SMTP DSN must include a host.');
+        }
+
+        $port = self::parseIntOption(
+            value: $query['port'] ?? ($parts['port'] ?? ($scheme === 'smtps' ? 465 : 25)),
+            option: 'port'
+        );
+
+        $smtpSecure = self::parseSmtpSecureOption($query['secure'] ?? ($scheme === 'smtps' ? 'ssl' : ''));
+        $smtpAutoTLS = self::parseBoolOption($query['autotls'] ?? false, 'autotls');
+        $timeout = self::parseIntOption($query['timeout'] ?? 30, 'timeout');
+        $keepAlive = self::parseBoolOption($query['keepalive'] ?? false, 'keepalive');
+        $timelimit = self::parseIntOption($query['timelimit'] ?? 30, 'timelimit');
+        $xMailer = self::parseStringOption($query['xmailer'] ?? '');
+
+        return new Email\SMTP(
+            host: $host,
+            port: $port,
+            username: self::decodeUrlComponent($parts['user'] ?? null) ?? '',
+            password: self::decodeUrlComponent($parts['pass'] ?? null) ?? '',
+            smtpSecure: $smtpSecure,
+            smtpAutoTLS: $smtpAutoTLS,
+            xMailer: $xMailer,
+            timeout: $timeout,
+            keepAlive: $keepAlive,
+            timelimit: $timelimit,
+        );
+    }
+
+    /**
+     * @param  array<string, int|string>  $parts
+     * @param  class-string<self>  $adapterClass
+     */
+    private static function createApiKeyAdapter(array $parts, string $adapterClass, string $adapterName): self
+    {
+        $apiKey = self::decodeUrlComponent($parts['user'] ?? null)
+            ?? self::decodeUrlComponent($parts['pass'] ?? null);
+
+        if ($apiKey === null || $apiKey === '') {
+            throw new \InvalidArgumentException($adapterName.' DSN must include an API key.');
+        }
+
+        return new $adapterClass($apiKey);
+    }
+
+    /**
+     * @param  array<string, int|string>  $parts
+     * @param  array<string, mixed>  $query
+     */
+    private static function createMailgunAdapter(array $parts, array $query): self
+    {
+        $apiKey = self::decodeUrlComponent($parts['user'] ?? null)
+            ?? self::decodeUrlComponent($parts['pass'] ?? null);
+
+        if ($apiKey === null || $apiKey === '') {
+            throw new \InvalidArgumentException('Mailgun DSN must include an API key.');
+        }
+
+        $domain = self::decodeUrlComponent($parts['host'] ?? null);
+
+        if ($domain === null || $domain === '') {
+            throw new \InvalidArgumentException('Mailgun DSN must include a domain.');
+        }
+
+        return new Email\Mailgun(
+            apiKey: $apiKey,
+            domain: $domain,
+            isEU: self::parseBoolOption($query['eu'] ?? false, 'eu'),
+        );
+    }
+
+    private static function decodeUrlComponent(mixed $value): ?string
+    {
+        if (! \is_string($value) || $value === '') {
+            return null;
+        }
+
+        return \rawurldecode($value);
+    }
+
+    private static function parseStringOption(mixed $value): string
+    {
+        if (! \is_string($value)) {
+            throw new \InvalidArgumentException('Expected string query parameter value.');
+        }
+
+        return $value;
+    }
+
+    private static function parseSmtpSecureOption(mixed $value): string
+    {
+        if (! \is_string($value)) {
+            throw new \InvalidArgumentException('Invalid SMTP "secure" option. Expected "", "ssl", or "tls".');
+        }
+
+        $value = \strtolower($value);
+
+        if (! \in_array($value, ['', 'ssl', 'tls'], true)) {
+            throw new \InvalidArgumentException('Invalid SMTP "secure" option. Expected "", "ssl", or "tls".');
+        }
+
+        return $value;
+    }
+
+    private static function parseBoolOption(mixed $value, string $option): bool
+    {
+        if (\is_bool($value)) {
+            return $value;
+        }
+
+        if (! \is_string($value) && ! \is_int($value)) {
+            throw new \InvalidArgumentException('Invalid "'.$option.'" option. Expected boolean-like value.');
+        }
+
+        $normalized = \filter_var($value, FILTER_VALIDATE_BOOLEAN, FILTER_NULL_ON_FAILURE);
+
+        if ($normalized === null) {
+            throw new \InvalidArgumentException('Invalid "'.$option.'" option. Expected boolean-like value.');
+        }
+
+        return $normalized;
+    }
+
+    private static function parseIntOption(mixed $value, string $option): int
+    {
+        if (\is_int($value)) {
+            return $value;
+        }
+
+        if (! \is_string($value) || $value === '' || ! \ctype_digit($value)) {
+            throw new \InvalidArgumentException('Invalid "'.$option.'" option. Expected integer value.');
+        }
+
+        return (int) $value;
+    }
 }

src/Utopia/Messaging/Messenger.php

@@ -0,0 +1,131 @@
+<?php
+
+namespace Utopia\Messaging;
+
+class Messenger
+{
+    private array $adapters;
+
+    public function __construct(Adapter|array $adapters)
+    {
+        if ($adapters instanceof Adapter) {
+            $adapters = [$adapters];
+        }
+
+        if (empty($adapters)) {
+            throw new \InvalidArgumentException('At least one adapter must be provided.');
+        }
+
+        foreach ($adapters as $index => $adapter) {
+            if (! $adapter instanceof Adapter) {
+                throw new \InvalidArgumentException(
+                    'All elements must be instances of Adapter, but element '
+                    .$index
+                    .' is '
+                    .\get_debug_type($adapter)
+                    .'.'
+                );
+            }
+        }
+
+        $this->validateAdapters($adapters);
+
+        $this->adapters = $adapters;
+    }
+
+    public function send(Message $message): array
+    {
+        $errors = [];
+        $messageType = $this->adapters[0]->getMessageType();
+
+        if (! \is_a($message, $messageType)) {
+            throw new \Exception(
+                'Invalid message type. Expected "'
+                .$messageType
+                .'", got "'
+                .\get_class($message)
+                .'".'
+            );
+        }
+
+        foreach ($this->adapters as $index => $adapter) {
+            try {
+                return $adapter->send($message);
+            } catch (\Exception $e) {
+                $errors[] = $adapter->getName()
+                    .' (adapter '
+                    .($index + 1)
+                    .'): '
+                    .$e->getMessage();
+            }
+        }
+
+        $adapterCount = \count($this->adapters);
+        $adapterLabel = $adapterCount === 1 ? 'adapter' : 'adapters';
+
+        throw new \Exception(
+            'All '
+            .$adapterCount
+            .' '
+            .$adapterLabel
+            ." failed:\n"
+            .\implode("\n", $errors)
+        );
+    }
+
+    public function getMessageType(): string
+    {
+        return $this->adapters[0]->getMessageType();
+    }
+
+    public function getType(): string
+    {
+        return $this->adapters[0]->getType();
+    }
+
+    public function getMaxMessagesPerRequest(): int
+    {
+        return array_reduce(
+            $this->adapters,
+            fn ($min, $adapter) => min($min, $adapter->getMaxMessagesPerRequest()),
+            PHP_INT_MAX
+        );
+    }
+
+    private function validateAdapters(array $adapters): void
+    {
+        $firstAdapter = $adapters[0];
+        $expectedType = $firstAdapter->getType();
+        $expectedMessageType = $firstAdapter->getMessageType();
+
+        foreach (\array_slice($adapters, 1, preserve_keys: true) as $index => $adapter) {
+            if ($adapter->getType() !== $expectedType) {
+                throw new \InvalidArgumentException(
+                    'All adapters must be of the same type. Expected "'
+                    .$expectedType
+                    .'", but adapter '
+                    .($index + 1)
+                    .' ('
+                    .$adapter->getName()
+                    .') has type "'
+                    .$adapter->getType()
+                    .'".'
+                );
+            }
+
+            if ($adapter->getMessageType() !== $expectedMessageType) {
+                throw new \InvalidArgumentException(
+                    'All adapters must support the same message type. Expected "'
+                    .$expectedMessageType
+                    .'", but adapter '
+                    .($index + 1)
+                    .' ('
+                    .$adapter->getName()
+                    .') supports "'
+                    .$adapter->getMessageType()
+                    .'".'
+                );
+            }
+        }
+    }
+}