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(define-module (web http make-routes)
:use-module (hnh util)
:use-module (ice-9 regex)
:use-module (ice-9 match)
:use-module (ice-9 curried-definitions)
:use-module (ice-9 control)
:use-module (srfi srfi-1)
:use-module (srfi srfi-71)
:use-module (srfi srfi-88)
:use-module ((web query) :select (parse-query))
:use-module ((web response) :select (build-response))
:use-module ((ice-9 iconv) :select (bytevector->string))
:export (parse-endpoint-string
make-routes)
)
;; Parses an endpoint description, and returns two values:
;; - a regex string which matches the rule
;; - the list of symbols embedded int the string
;; An endpoint string looks like
;; /calendar/:uid{.*}.ics
;; Where "/calendar/" matches literally
;; followed by something matching ".*"
;; followed by something literally matching ".ics"
;; and '(uid) would be the second return
(define (parse-endpoint-string str)
(let ((rx (make-regexp ":([^/.]+)(\\{([^}]+)\\})?([.])?")))
(let loop ((str str)
(string "")
(tokens '()))
(let ((m (regexp-exec rx str 0)))
(if (not m)
;; done
(values (string-append string str) (reverse tokens))
(loop (match:suffix m)
(string-append string (match:prefix m)
(aif (match:substring m 3)
(string-append "(" it ")")
"([^/.]+)")
;; period directly following matched variable.
;; since many variables break on period, we often
;; want to match a literal period directly after them.
;; Ideally all periods outside of pattern should be
;; matched literally, but that's harder to implement.
(regexp-quote
(aif (match:substring m 4)
"." "")))
(cons (string->symbol (match:substring m 1))
tokens)))))))
(define ((generate-case regexes r:method r:path) stx)
(syntax-case stx ()
((method uri param-list body ...)
(let* ((regex tokens (parse-endpoint-string (syntax->datum #'uri)))
(diff intersect (lset-diff+intersection eq? (syntax->datum #'param-list)
tokens))
(argument-list (if (null? diff)
#'() #`(key: #,@(map (lambda (x) (datum->syntax stx x)) diff)
allow-other-keys: rest: rest)))
(intersect-list (map (lambda (x) (datum->syntax stx x)) intersect))
(rx-var (list-ref (assoc regex regexes) 1)))
#`((and (eq? #,r:method (quote method))
(regexp-exec #,rx-var #,r:path))
=> (lambda (match-object)
;; Those parameters which were present in the template uri
((lambda #,intersect-list
;; Those that only are in the query string
(lambda* #,argument-list body ...))
#,@(unless (null? intersect)
(map (lambda (i) #`(match:substring match-object #,i))
(cdr (iota (1+ (length intersect)))))))))))))
(define-syntax (make-routes stx)
(syntax-case stx ()
((_ options-and-routes ...)
(with-syntax ((r:method (datum->syntax stx 'r:method))
(r:uri (datum->syntax stx 'r:uri))
(r:version (datum->syntax stx 'r:version))
(r:headers (datum->syntax stx 'r:headers))
(r:meta (datum->syntax stx 'r:meta))
(r:scheme (datum->syntax stx 'r:scheme))
(r:userinfo (datum->syntax stx 'r:userinfo))
(r:host (datum->syntax stx 'r:host))
(r:port (datum->syntax stx 'r:port))
(r:path (datum->syntax stx 'r:path))
(r:query (datum->syntax stx 'r:query))
(r:fragment (datum->syntax stx 'r:fragment))
(return (datum->syntax stx 'return))
(request (datum->syntax stx 'request))
(body (datum->syntax stx 'body))
(state (datum->syntax stx 'state))
)
(define-values (options routes)
(let loop ((options '()) (items #'(options-and-routes ...)))
(when (null? items)
(scm-error 'misc-error "make-routes"
"Needs at least one route" '() #f))
;; (format #t "options: ~s, items: ~s~%" options items)
(let ((kv (syntax->datum (car items))))
(if (keyword? kv)
(loop (cons (cons kv (cadr items))
options)
(cddr items))
(values (reverse options) items)))))
;; Ensures that all regexes are only compiled once.
;; Given (GET "/today/" (view date) body ...)
;; returns ("/today/" #'*random-symbol* #'(make-regexp "^/today//?$" regexp/icase))
(define routes-regexes
(map (lambda (stx-1)
(syntax-case stx-1 ()
((%fst uri %rest ...)
(let ((regex _ (parse-endpoint-string (syntax->datum #'uri))))
(list regex (datum->syntax stx (gensym "rx-"))
#`(make-regexp #,(string-append "^" regex "/?$") regexp/icase))))))
routes))
#`(let #,(map cdr routes-regexes)
(lambda* (request body optional: state)
;; All these bindings generate compile time warnings since the expansion
;; of the macro might not use them. This isn't really a problem.
(let ((r:method ((@ (web request) request-method) request))
(r:uri ((@ (web request) request-uri) request))
(r:version ((@ (web request) request-version) request))
(r:headers ((@ (web request) request-headers) request))
(r:meta ((@ (web request) request-meta) request)))
(let ((r:scheme ((@ (web uri) uri-scheme) r:uri))
(r:userinfo ((@ (web uri) uri-userinfo) r:uri))
;; uri-{host,port} is (probably) not set when we are a server,
;; fetch them from the request instead
(r:host (or ((@ (web uri) uri-host) r:uri)
(and=> ((@ (web request) request-host) request) car)))
(r:port (or ((@ (web uri) uri-port) r:uri)
(and=> ((@ (web request) request-host) request) cdr)))
(r:path ((@ (web uri) uri-path) r:uri))
(r:query ((@ (web uri) uri-query) r:uri))
(r:fragment ((@ (web uri) uri-fragment) r:uri)))
;; TODO propper logging
(display (format #f "[~a] ~a ~a:~a~a?~a~%"
(datetime->string (current-datetime))
r:method r:host r:port r:path (or r:query ""))
(current-error-port))
(call-with-values
(call/ec (lambda (return)
(apply
(with-throw-handler #t
(lambda ()
(cond #,@(map (generate-case routes-regexes #'r:method #'r:path) routes)
(else (lambda* _ (return (build-response code: 404)
"404 Not Fonud")))))
#,(assoc-ref options with-throw-handler:))
(append
(parse-query r:query)
;; When content-type is application/x-www-form-urlencoded,
;; decode them, and add it to the argument list
(let ((content-type (assoc-ref r:headers 'content-type)))
(when content-type
(let ((type args (car+cdr content-type)))
(when (eq? type 'application/x-www-form-urlencoded)
(let ((encoding (or (assoc-ref args 'encoding) "UTF-8")))
(parse-query (bytevector->string body encoding)
encoding))))))))))
(case-lambda ((headers body new-state) (values headers body new-state))
((headers body) (values headers body state))
((headers) (values headers "" state))))))))))))
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