358 lines
15 KiB
Scheme
358 lines
15 KiB
Scheme
(module response mzscheme
|
|
(require (lib "list.ss")
|
|
(lib "contract.ss")
|
|
(lib "port.ss")
|
|
(lib "pretty.ss")
|
|
(lib "xml.ss" "xml")
|
|
(lib "13.ss" "srfi")
|
|
"connection-manager.ss")
|
|
|
|
;; **************************************************
|
|
;; DATA DEF for response
|
|
;; (make-response/basic number string number string (listof (cons symbol string)))
|
|
(define-struct response/basic (code message seconds mime extras))
|
|
;; (make-response/full ... (listof string))
|
|
(define-struct (response/full response/basic) (body))
|
|
;; (make-response/incremental ... ((string* -> void) -> void))
|
|
(define-struct (response/incremental response/basic) (generator))
|
|
|
|
; response = (cons string (listof string)), where the first string is a mime-type
|
|
; | x-expression
|
|
; | (make-response/full ... (listof string))
|
|
; | (make-response/incremental ... ((string* -> void) -> void))
|
|
|
|
;; **************************************************
|
|
;; response?: any -> boolean
|
|
;; Determine if an object is a response
|
|
(define (response? x)
|
|
(or (and (response/basic? x)
|
|
(number? (response/basic-code x))
|
|
(string? (response/basic-message x))
|
|
(number? (response/basic-seconds x))
|
|
(bytes? (response/basic-mime x))
|
|
(and (list? (response/basic-extras x))
|
|
(andmap
|
|
(lambda (p)
|
|
(and (pair? p)
|
|
(symbol? (car p))
|
|
(string? (cdr p))))
|
|
(response/basic-extras x))))
|
|
; this could fail for dotted lists - rewrite andmap
|
|
(and (pair? x) (pair? (cdr x)) (andmap
|
|
(lambda (x)
|
|
(or (string? x)
|
|
(bytes? x)))
|
|
x))
|
|
; insist that the xexpr has a root element
|
|
(and (pair? x) (xexpr? x))))
|
|
|
|
|
|
;; Weak contracts for output-response because the response? is checked inside
|
|
;; output-response, handled, etc.
|
|
(provide/contract
|
|
[struct (response/full response/basic)
|
|
([code number?]
|
|
[message string?]
|
|
[seconds number?]
|
|
[mime bytes?]
|
|
[extras (listof (cons/c symbol? string?))]
|
|
[body (listof (union string?
|
|
bytes?))])]
|
|
[struct (response/incremental response/basic)
|
|
([code number?]
|
|
[message string?]
|
|
[seconds number?]
|
|
[mime bytes?]
|
|
[extras (listof (cons/c symbol? string?))]
|
|
[generator ((() (listof (union bytes? string?)) . ->* . any) . ->
|
|
. any)]
|
|
)]
|
|
[response? (any/c . -> . boolean?)]
|
|
[output-response (connection? any/c . -> . any)]
|
|
[output-response/method (connection? response? symbol? . -> . any)]
|
|
[output-file (connection? path? symbol? bytes? . -> . any)]
|
|
[TEXT/HTML-MIME-TYPE bytes?]
|
|
)
|
|
|
|
|
|
|
|
|
|
;; Table 1. head responses:
|
|
; ------------------------------------------------------------------------------
|
|
; |method | close? | x-fer coding || response actions
|
|
; |-----------------------------------------------------------------------------
|
|
; |-----------------------------------------------------------------------------
|
|
; |head | #t | chunked || 1. Output the headers only.
|
|
; |-------------------------------|| 2. Add the special connection-close header.
|
|
; |head | #t | not-chunked ||
|
|
; |-----------------------------------------------------------------------------
|
|
; |head | #f | chunked || 1. Output the headers only.
|
|
; |-------------------------------|| 2. Don't add the connection-close header.
|
|
; |head | #f | not-chunked ||
|
|
; |-----------------------------------------------------------------------------
|
|
|
|
;; Table 2. get responses:
|
|
; ------------------------------------------------------------------------------
|
|
; |method | x-fer-coding | close? || response actions
|
|
; |-----------------------------------------------------------------------------
|
|
; |-----------------------------------------------------------------------------
|
|
; | get | chunked | #t || 1. Output headers as above.
|
|
; | | | || 2. Generate trivial chunked response.
|
|
; |-----------------------------------------------------------------------------
|
|
; | get | chunked | #f || 1. Output headers as above.
|
|
; | | | || 2. Generate chunks as per RFC 2616 sec. 3.6
|
|
; |-----------------------------------------------------------------------------
|
|
; | get | not chunked | #t || 1. Output headers as above.
|
|
; |-------------------------------|| 2. Generate usual non-chunked response.
|
|
; | get | not chunked | #f ||
|
|
; |-----------------------------------------------------------------------------
|
|
|
|
;; Notes:
|
|
;; 1. close? is a boolean which corresponds roughly to the protocol version.
|
|
;; #t |-> 1.0 and #f |-> 1.1. See function close-connection? in
|
|
;; #request-parsing.ss
|
|
;;
|
|
;; 2. In the case of a chunked response when close? = #f, then the response
|
|
;; must be compliant with http 1.0. In this case the chunked response is
|
|
;; simply turned into a non-chunked one.
|
|
|
|
(define TEXT/HTML-MIME-TYPE #"text/html")
|
|
|
|
|
|
;;**************************************************
|
|
;; output-headers: connection number string (listof (listof String))
|
|
;; number string -> void
|
|
;; Write the headers portion of a response to an output port.
|
|
;; NOTE: According to RFC 2145 the server should write HTTP/1.1
|
|
;; header for *all* clients.
|
|
(define (output-headers conn code message extras seconds mime)
|
|
(let ([o-port (connection-o-port conn)])
|
|
(for-each
|
|
(lambda (line)
|
|
(for-each
|
|
(lambda (word) (display word o-port))
|
|
line)
|
|
(fprintf o-port "\r\n"))
|
|
(list* `("HTTP/1.1 " ,code " " ,message)
|
|
`("Date: " ,(seconds->gmt-string (current-seconds)))
|
|
`("Last-Modified: " ,(seconds->gmt-string seconds))
|
|
`("Server: PLT Scheme")
|
|
`("Content-type: " ,mime)
|
|
(if (connection-close? conn)
|
|
(cons `("Connection: close") extras)
|
|
extras)))
|
|
(fprintf o-port "\r\n")))
|
|
|
|
; seconds->gmt-string : Nat -> String
|
|
; format is rfc1123 compliant according to rfc2068 (http/1.1)
|
|
(define (seconds->gmt-string s)
|
|
(let* ([local-date (seconds->date s)]
|
|
[date (seconds->date (- s
|
|
(date-time-zone-offset local-date)
|
|
(if (date-dst? local-date) 3600 0)))])
|
|
(format "~a, ~a ~a ~a ~a:~a:~a GMT"
|
|
(vector-ref DAYS (date-week-day date))
|
|
(two-digits (date-day date))
|
|
(vector-ref MONTHS (sub1 (date-month date)))
|
|
(date-year date)
|
|
(two-digits (date-hour date))
|
|
(two-digits (date-minute date))
|
|
(two-digits (date-second date)))))
|
|
|
|
; two-digits : num -> str
|
|
(define (two-digits n)
|
|
(let ([str (number->string n)])
|
|
(if (< n 10) (string-append "0" str) str)))
|
|
|
|
(define MONTHS
|
|
#("Jan" "Feb" "Mar" "Apr" "May" "Jun" "Jul" "Aug" "Sep" "Oct" "Nov" "Dec"))
|
|
|
|
(define DAYS
|
|
#("Sun" "Mon" "Tue" "Wed" "Thu" "Fri" "Sat"))
|
|
|
|
|
|
|
|
;; **************************************************
|
|
;; output-response: connection response -> void
|
|
(define (output-response conn resp)
|
|
(cond
|
|
[(response/full? resp)
|
|
(output-response/basic
|
|
conn resp (response/full->size resp)
|
|
(lambda (o-port)
|
|
(for-each
|
|
(lambda (str) (display str o-port))
|
|
(response/full-body resp))))]
|
|
[(response/incremental? resp)
|
|
(output-response/incremental conn resp)]
|
|
[(and (pair? resp) (string? (car resp)))
|
|
(output-response/basic
|
|
conn
|
|
(make-response/basic 200 "Okay" (current-seconds) (car resp) '())
|
|
(apply + (map
|
|
(lambda (c)
|
|
(if (string? c)
|
|
(string-length c)
|
|
(bytes-length c)))
|
|
(cdr resp)))
|
|
(lambda (o-port)
|
|
(for-each
|
|
(lambda (str) (display str o-port))
|
|
(cdr resp))))]
|
|
[else
|
|
;; TODO: make a real exception for this.
|
|
(with-handlers
|
|
([exn:invalid-xexpr?
|
|
(lambda (exn)
|
|
(output-response/method
|
|
conn
|
|
(xexpr-exn->response exn resp)
|
|
'ignored))]
|
|
[exn? (lambda (exn)
|
|
(raise exn))])
|
|
(let ([str (and (validate-xexpr resp) (xexpr->string resp))])
|
|
(output-response/basic
|
|
conn
|
|
(make-response/basic 200
|
|
"Okay"
|
|
(current-seconds)
|
|
TEXT/HTML-MIME-TYPE
|
|
'())
|
|
(add1 (string-length str))
|
|
(lambda (o-port)
|
|
(display str o-port)
|
|
(newline o-port)))))]))
|
|
|
|
;; response/full->size: response/full -> number
|
|
;; compute the size for a response/full
|
|
(define (response/full->size resp/f)
|
|
(apply + (map
|
|
(lambda (c)
|
|
(if (string? c)
|
|
(string-length c)
|
|
(bytes-length c)))
|
|
(response/full-body resp/f))))
|
|
|
|
;; **************************************************
|
|
;; output-file: connection path symbol bytes -> void
|
|
(define (output-file conn file-path method mime-type)
|
|
(output-headers conn 200 "Okay"
|
|
`(("Content-length: " ,(file-size file-path)))
|
|
(file-or-directory-modify-seconds file-path)
|
|
mime-type)
|
|
(when (eq? method 'get)
|
|
(call-with-input-file file-path
|
|
(lambda (i-port) (copy-port i-port (connection-o-port conn))))))
|
|
|
|
;; **************************************************
|
|
;; output-response/method: connection response/full symbol -> void
|
|
;; If it is a head request output headers only, otherwise output as usual
|
|
(define (output-response/method conn resp meth)
|
|
(cond
|
|
[(eqv? meth 'head)
|
|
(output-headers/response conn resp `(("Content-length: "
|
|
,(response/full->size resp))))]
|
|
[else
|
|
(output-response conn resp)]))
|
|
|
|
;; **************************************************
|
|
;; output-headers/response: connection response (listof (listof string)) -> void
|
|
;; Write the headers for a response to an output port
|
|
(define (output-headers/response conn resp extras)
|
|
(output-headers conn
|
|
(response/basic-code resp)
|
|
(response/basic-message resp)
|
|
extras
|
|
(response/basic-seconds resp)
|
|
(response/basic-mime resp)))
|
|
|
|
;; **************************************************
|
|
;; output-response/basic: connection response number (o-port -> void) -> void
|
|
;; Write a normal response to an output port
|
|
(define (output-response/basic conn resp size responder)
|
|
(output-headers/response conn resp
|
|
`(("Content-length: " ,size)
|
|
. ,(extras->strings resp)))
|
|
(responder (connection-o-port conn)))
|
|
|
|
;; **************************************************
|
|
;; output-response/incremental: connection response/incremental -> void
|
|
;; Write a chunked response to an output port.
|
|
(define (output-response/incremental conn resp/inc)
|
|
(let ([o-port (connection-o-port conn)])
|
|
(cond
|
|
[(connection-close? conn)
|
|
(output-headers/response conn resp/inc '())
|
|
((response/incremental-generator resp/inc)
|
|
(lambda chunks
|
|
(for-each (lambda (chunk) (display chunk o-port)) chunks)))]
|
|
[else
|
|
(output-headers/response conn resp/inc
|
|
`(("Transfer-Encoding: chunked")
|
|
. ,(extras->strings resp/inc)))
|
|
((response/incremental-generator resp/inc)
|
|
(lambda chunks
|
|
(fprintf o-port "~x\r\n"
|
|
(foldl
|
|
(lambda (c acc)
|
|
(if (string? c)
|
|
(+ (string-length c) acc)
|
|
(+ (bytes-length c) acc)))
|
|
0 chunks))
|
|
(for-each (lambda (chunk) (display chunk o-port)) chunks)
|
|
(fprintf o-port "\r\n")))
|
|
; one \r\n ends the last (empty) chunk and the second \r\n ends the (non-existant) trailers
|
|
(fprintf o-port "0\r\n\r\n")])))
|
|
|
|
;; extras->strings: response/basic -> (listof (listof string))
|
|
;; convert the response/basic-extras to the form used by output-headers
|
|
(define (extras->strings r/bas)
|
|
(map
|
|
(lambda (xtra)
|
|
(list (symbol->string (car xtra)) ": " (cdr xtra)))
|
|
(response/basic-extras r/bas)))
|
|
|
|
;; Turn an exn:invalid-xexpr into a response.
|
|
(define (xexpr-exn->response exn x)
|
|
;;; Does it matter what number I use for pretty-print-size-hook?
|
|
(pretty-print-size-hook (lambda (v display? op) 20))
|
|
(pretty-print-print-hook (pretty-print-hook/web-errors
|
|
(exn:invalid-xexpr-code exn)))
|
|
(make-response/full
|
|
500 "Servlet Error"
|
|
(current-seconds)
|
|
#"text/html"
|
|
'()
|
|
(list
|
|
(string-append
|
|
"<html><head><title>Erroneous Xexpr</title></head>"
|
|
"<body><h1>Erroneous Xexpr</h1>"
|
|
"<p>An Xexpr in the servlet is malformed. The exact error is</p>"
|
|
"<pre>" (exn-message exn) "</pre>"
|
|
"<h2>The Full Xexpr Is</h2>"
|
|
"<pre>"
|
|
(let ((o (open-output-string)))
|
|
(pretty-print x o)
|
|
(get-output-string o))
|
|
"</pre>"))))
|
|
|
|
;; Format everything normally, except for the erroneous data.
|
|
(define (pretty-print-hook/web-errors err)
|
|
(letrec ((f-aux (lambda (v)
|
|
(cond
|
|
((equal? v err)
|
|
(format
|
|
(string-append
|
|
"<span style='font-weight: bold; "
|
|
"color: red; background-color: white;'>"
|
|
"~a</span>") v))
|
|
((list? v) (string-append "("
|
|
(string-join (map f-aux v)
|
|
" ")
|
|
")"))
|
|
(else (format "~a" v))))))
|
|
(lambda (v display? op)
|
|
((if display? display write) (f-aux v) op))))
|
|
|
|
)
|