Schematra로 Chicken Scheme 웹 앱을 만들 수 있다

;; Webhook handler with HMAC-SHA256 signature verification ;; body-parser-middleware captures a replayable request body so you can verify it (import schematra schematra.body-parser hmac sha2 message-digest) (use-middleware! (body-parser-middleware)) (define (hmac-sha256-hex key data)   (message-digest->string    (hmac-message-digest (open-input-string key)                         sha256-primitive                         (open-input-string data) byte))) (define (signature-valid? secret raw sig)   (and sig        (string=? sig (string-append "sha256="                                     (hmac-sha256-hex secret raw))))) (post "/webhook"   (let* ((raw (request-body-string (current-request-body)))          (sig (alist-ref "x-hub-signature-256"                           (request-headers (current-request)) equal?)))     (if (signature-valid? (get-environment-variable "WEBHOOK_SECRET") raw sig)         (begin           (process-event! (read-json raw))           '(ok "Received"))         '(forbidden "Invalid signature")))) ;; Test without a live server — body: is captured by body-parser-middleware (define secret "test-secret") (define payload "{\"action\":\"push\"}") (define valid-sig (string-append "sha256=" (hmac-sha256-hex secret payload))) (test "rejects request with missing signature"   'forbidden   (test-route-status webhook-app 'POST "/webhook"                      body: payload)) (test "accepts request with valid signature"   'ok   (test-route-status webhook-app 'POST "/webhook"                      body: payload                      headers: