In post-message:
(frontpage (lookup-def 'frontpage params))
(message (decode-formdata (lookup-def 'epistula params)))From lookup-def:
((lookup-def key alist)
(let ((nkey key) (nalist alist)) ; evaluate them only once
(let ((res (assq nkey nalist)))
(if res
(let ((res (cdr res)))
(cond
((not (pair? res)) res)
((null? (cdr res)) (car res))
(else res)))
(error "Failed to find " nkey " in " nalist)))))As a result, posting without frontpage or epistula gives:
HTTP/1.1 502 Bad Gateway
Server: nginx/1.18.0
Date: Wed, 01 Jul 2020 10:35:57 GMT
Content-Type: text/html
Content-Length: 496
Connection: keep-alive
ETag: "5ecc391b-1f0"Both lookups need a default followed by validation if 502 Bad Gateway is to be avoided.