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Foundry

Email & Verification Services

Overview: Email notifications and verification codes are vital across enterprise web applications. Foundry’s engine (foundry_engine) provides built-in SMTP email delivery and a production-grade VerificationService, eliminating external boilerplate.

1. Core Architecture

Section titled “1. Core Architecture”
  • Standard SMTP: Built upon lettre, compatible with SendGrid, AWS SES, Aliyun DirectMail, Tencent Mail, Gmail, etc.
  • Dual-Mode Verification Code Storage: Leverages Redis when configured, with seamless, zero-crash fallback to in-memory RwLock storage.
  • 60s Anti-Spam Cooldown: Built-in protection against rapid re-sends.
  • 5-Minute TTL Expiration (300s): Automated token invalidation.
  • Atomic Single-Use Invalidation: Tokens are immediately destroyed upon successful verification to prevent replay attacks.
sequenceDiagram
    autonumber
    actor User as User Client
    participant Server as API Handler
    participant VS as VerificationService
    participant Redis as Redis / Memory
    participant SMTP as SMTP Relay


    User->>Server: Request verification code (POST /send-code)
    Server->>VS: save_code(scope, identifier, code)
    VS->>Redis: Check 60s cooldown key?
    alt Inside Cooldown
        VS-->>Server: Error (Wait 60s)
        Server-->>User: HTTP 422 Too frequent
    else Cooldown Expired
        VS->>Redis: Save code (TTL 300s) & set 60s cooldown
        Server->>SMTP: send_email(to, subject, body)
        SMTP-->>User: Deliver email with 6-digit code
        Server-->>User: HTTP 200 Sent
    end

2. Environment Configuration

Section titled “2. Environment Configuration”

In .env:

Terminal window
SMTP_HOST=smtp.example.com
SMTP_PORT=587
SMTP_USER=no-reply@example.com
SMTP_PASS=your_secret_password
SMTP_FROM="Foundry Platform <no-reply@example.com>"

3. Usage Examples

Section titled “3. Usage Examples”

Sending Emails (send_email)

Section titled “Sending Emails (send_email)”
use foundry::prelude::*;
use foundry_engine::services::email::send_email;


pub async fn notify_user(email: &str) -> AppResult<()> {
    send_email(email, "Welcome", "Welcome to Foundry!").await?;
    Ok(())
}

Verification Codes (VerificationService)

Section titled “Verification Codes (VerificationService)”
use foundry::prelude::*;
use foundry_engine::services::verification::VerificationService;


// Save code with cooldown
let verifier = VerificationService::new(state.redis.clone());
let code = VerificationService::generate_code();
verifier.save_code("register", user_email, &code).await?;


// Verify and atomically invalidate
let ok = verifier.verify_code("register", user_email, input_code).await?;