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webhook-receiver-hardener

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Chinese

Webhook Receiver Hardener

Webhook 接收器加固方案

Build secure, reliable webhook endpoints that handle failures gracefully.
构建可优雅处理故障的安全、可靠Webhook端点。

Core Security

核心安全特性

Signature Verification: HMAC validation before processing Deduplication: Track processed webhook IDs Idempotency: Safe to process same webhook multiple times Retries: Handle provider retry attempts Rate Limiting: Prevent abuse
签名验证：处理前进行HMAC校验 去重机制：记录已处理的Webhook ID 幂等性：重复处理同一Webhook不会产生副作用 重试处理：应对服务提供商的重试请求 速率限制：防止恶意滥用

Signature Verification

签名验证

typescript
import crypto from "crypto";

export const verifyWebhookSignature = (
  payload: string,
  signature: string,
  secret: string
): boolean => {
  const hmac = crypto
    .createHmac("sha256", secret)
    .update(payload)
    .digest("hex");

  return crypto.timingSafeEqual(Buffer.from(signature), Buffer.from(hmac));
};

// Stripe example
router.post(
  "/webhooks/stripe",
  express.raw({ type: "application/json" }),
  async (req, res) => {
    const sig = req.headers["stripe-signature"];

    try {
      const event = stripe.webhooks.constructEvent(
        req.body,
        sig,
        process.env.STRIPE_WEBHOOK_SECRET
      );
      await processStripeEvent(event);
      res.json({ received: true });
    } catch (err) {
      return res.status(400).send(`Webhook Error: ${err.message}`);
    }
  }
);
typescript
import crypto from "crypto";

export const verifyWebhookSignature = (
  payload: string,
  signature: string,
  secret: string
): boolean => {
  const hmac = crypto
    .createHmac("sha256", secret)
    .update(payload)
    .digest("hex");

  return crypto.timingSafeEqual(Buffer.from(signature), Buffer.from(hmac));
};

// Stripe example
router.post(
  "/webhooks/stripe",
  express.raw({ type: "application/json" }),
  async (req, res) => {
    const sig = req.headers["stripe-signature"];

    try {
      const event = stripe.webhooks.constructEvent(
        req.body,
        sig,
        process.env.STRIPE_WEBHOOK_SECRET
      );
      await processStripeEvent(event);
      res.json({ received: true });
    } catch (err) {
      return res.status(400).send(`Webhook Error: ${err.message}`);
    }
  }
);

Deduplication

去重机制

typescript
// Redis-based dedupe
const WEBHOOK_TTL = 60 * 60 * 24; // 24 hours

export const isDuplicate = async (webhookId: string): Promise<boolean> => {
  const key = `webhook:${webhookId}`;
  const exists = await redis.exists(key);

  if (exists) return true;

  await redis.setex(key, WEBHOOK_TTL, "1");
  return false;
};

// Usage
if (await isDuplicate(webhook.id)) {
  return res.status(200).json({ received: true }); // Already processed
}
typescript
// Redis-based dedupe
const WEBHOOK_TTL = 60 * 60 * 24; // 24 hours

export const isDuplicate = async (webhookId: string): Promise<boolean> => {
  const key = `webhook:${webhookId}`;
  const exists = await redis.exists(key);

  if (exists) return true;

  await redis.setex(key, WEBHOOK_TTL, "1");
  return false;
};

// Usage
if (await isDuplicate(webhook.id)) {
  return res.status(200).json({ received: true }); // Already processed
}

Idempotent Processing

幂等性处理

typescript
export const processWebhook = async (webhook: Webhook) => {
  // Use database transaction with unique constraint
  try {
    await db.transaction(async (trx) => {
      // Insert webhook record (unique constraint on webhook_id)
      await trx("processed_webhooks").insert({
        webhook_id: webhook.id,
        processed_at: new Date(),
      });

      // Do actual processing
      await performWebhookAction(webhook, trx);
    });
  } catch (err) {
    if (err.code === "23505") {
      // Unique violation
      console.log("Webhook already processed");
      return; // Idempotent - already processed
    }
    throw err;
  }
};
typescript
export const processWebhook = async (webhook: Webhook) => {
  // Use database transaction with unique constraint
  try {
    await db.transaction(async (trx) => {
      // Insert webhook record (unique constraint on webhook_id)
      await trx("processed_webhooks").insert({
        webhook_id: webhook.id,
        processed_at: new Date(),
      });

      // Do actual processing
      await performWebhookAction(webhook, trx);
    });
  } catch (err) {
    if (err.code === "23505") {
      // Unique violation
      console.log("Webhook already processed");
      return; // Idempotent - already processed
    }
    throw err;
  }
};

Retry Handling

重试处理

typescript
// Acknowledge immediately, process async
router.post("/webhooks/provider", async (req, res) => {
  // Verify signature
  if (!verifySignature(req.body, req.headers["signature"])) {
    return res.status(401).send("Invalid signature");
  }

  // Return 200 immediately
  res.status(200).json({ received: true });

  // Process async
  processWebhookAsync(req.body).catch((err) => {
    console.error("Webhook processing failed:", err);
    // Will be retried by provider
  });
});

// Exponential backoff for provider retries
// Attempt 1: immediate
// Attempt 2: +5 minutes
// Attempt 3: +15 minutes
// Attempt 4: +1 hour
// Attempt 5: +6 hours
typescript
// Acknowledge immediately, process async
router.post("/webhooks/provider", async (req, res) => {
  // Verify signature
  if (!verifySignature(req.body, req.headers["signature"])) {
    return res.status(401).send("Invalid signature");
  }

  // Return 200 immediately
  res.status(200).json({ received: true });

  // Process async
  processWebhookAsync(req.body).catch((err) => {
    console.error("Webhook processing failed:", err);
    // Will be retried by provider
  });
});

// Exponential backoff for provider retries
// Attempt 1: immediate
// Attempt 2: +5 minutes
// Attempt 3: +15 minutes
// Attempt 4: +1 hour
// Attempt 5: +6 hours

Error Responses

错误响应

typescript
// Return appropriate status codes
const webhookHandler = async (req, res) => {
  // 400: Malformed payload (won't retry)
  if (!isValidPayload(req.body)) {
    return res.status(400).json({ error: "Invalid payload" });
  }

  // 401: Invalid signature (won't retry)
  if (!verifySignature(req.body, req.headers["signature"])) {
    return res.status(401).json({ error: "Invalid signature" });
  }

  // 200: Already processed (idempotent)
  if (await isDuplicate(req.body.id)) {
    return res.status(200).json({ received: true });
  }

  // 500: Processing error (will retry)
  try {
    await processWebhook(req.body);
    return res.status(200).json({ received: true });
  } catch (err) {
    console.error("Processing error:", err);
    return res.status(500).json({ error: "Processing failed" });
  }
};
typescript
// Return appropriate status codes
const webhookHandler = async (req, res) => {
  // 400: Malformed payload (won't retry)
  if (!isValidPayload(req.body)) {
    return res.status(400).json({ error: "Invalid payload" });
  }

  // 401: Invalid signature (won't retry)
  if (!verifySignature(req.body, req.headers["signature"])) {
    return res.status(401).json({ error: "Invalid signature" });
  }

  // 200: Already processed (idempotent)
  if (await isDuplicate(req.body.id)) {
    return res.status(200).json({ received: true });
  }

  // 500: Processing error (will retry)
  try {
    await processWebhook(req.body);
    return res.status(200).json({ received: true });
  } catch (err) {
    console.error("Processing error:", err);
    return res.status(500).json({ error: "Processing failed" });
  }
};

Monitoring & Runbook

监控与事件处理手册

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Webhook Incidents

Webhook 事件处理

High Error Rate

高错误率

  1. Check provider status page
  2. Review recent code deploys
  3. Check signature secret rotation
  4. Verify database connectivity
  1. 查看服务提供商状态页面
  2. 检查近期代码部署记录
  3. 确认签名密钥是否已轮换
  4. 验证数据库连接状态

Missing Webhooks

缺失Webhook

  1. Check provider sending (their dashboard)
  2. Verify endpoint is accessible
  3. Check rate limiting rules
  4. Review dedupe cache TTL
  1. 检查服务提供商的发送记录（其控制台）
  2. 验证端点是否可访问
  3. 检查速率限制规则
  4. 查看去重缓存的TTL设置

Duplicate Processing

重复处理

  1. Check dedupe cache connectivity
  2. Verify unique constraints
  3. Review idempotency logic
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  1. 检查去重缓存的连接状态
  2. 验证数据库唯一约束
  3. 复查幂等性逻辑
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Best Practices

最佳实践

  • Verify signature BEFORE any processing
  • Return 200 quickly, process async
  • Dedupe with Redis + database constraints
  • Log all webhook attempts
  • Monitor processing latency
  • Set up alerts for failures
  • Document expected payload schemas
  • 先验证签名，再进行任何处理
  • 快速返回200响应，异步处理业务逻辑
  • 结合Redis与数据库约束实现去重
  • 记录所有Webhook请求尝试
  • 监控处理延迟
  • 为失败请求设置告警
  • 记录预期的负载 schema

Output Checklist

输出检查清单

  • Signature verification
  • Deduplication mechanism
  • Idempotent processing
  • Async processing pattern
  • Proper status codes
  • Error logging
  • Monitoring/alerts
  • Incident runbook
  • 签名验证
  • 去重机制
  • 幂等性处理
  • 异步处理模式
  • 正确的状态码
  • 错误日志
  • 监控/告警
  • 事件处理手册