racket/collects/web-server/http/request.rkt
2012-12-17 16:28:46 -07:00

376 lines
14 KiB
Racket

#lang racket/base
(require racket/contract
racket/match
racket/list
racket/promise
net/url
net/uri-codec
unstable/contract
web-server/private/util
web-server/private/connection-manager
web-server/http/request-structs)
(define read-request/c
(connection?
tcp-listen-port?
(input-port? . -> . (values string? string?))
. -> .
(values request? boolean?)))
(provide/contract
[parse-bindings (-> bytes? (listof binding?))]
[read-headers (-> input-port? (listof header?))]
[rename make-ext:read-request make-read-request
(->* () (#:connection-close? boolean?) read-request/c)]
[rename ext:read-request read-request
read-request/c])
;; **************************************************
;; read-request: connection number (input-port -> string string) -> request boolean?
;; read the request line, and the headers, determine if the connection should
;; be closed after servicing the request and build a request structure
(define ((make-read-request
#:connection-close? [connection-close? #f])
conn host-port port-addresses)
(define ip
(connection-i-port conn))
(define-values (method uri major minor)
(read-request-line ip))
(define initial-headers
(read-headers ip))
(match (headers-assq* #"Content-Length" initial-headers)
[(struct header (f v))
;; Give it one second per byte (with 5 second minimum... a bit
;; arbitrary)
(adjust-connection-timeout!
conn (max 5 (string->number (bytes->string/utf-8 v))))]
[#f
(void)])
(define-values (data-ip headers)
(complete-request ip initial-headers))
(define-values (host-ip client-ip)
(port-addresses ip))
(define-values (bindings/raw-promise raw-post-data)
(read-bindings&post-data/raw data-ip method uri headers))
(values
(make-request method uri headers bindings/raw-promise raw-post-data
host-ip host-port client-ip)
(or connection-close?
(close-connection? headers major minor
client-ip host-ip))))
;; If the headers says it uses chunked transfer encoding, then decode
;; it
(require racket/stxparam
(for-syntax racket/base))
(define-syntax-parameter break
(λ (stx)
(raise-syntax-error 'break "Used outside forever" stx)))
(define-syntax-rule (forever e ...)
(let/ec this-break
(let loop ()
(syntax-parameterize ([break (make-rename-transformer #'this-break)])
(begin e ...))
(loop))))
(define (hex-string->number s)
(string->number s 16))
(define (complete-request real-ip initial-headers)
(match (headers-assq* #"Transfer-Encoding" initial-headers)
[(struct header (f #"chunked"))
(define-values (decoded-ip decode-op) (make-pipe))
(define total-size 0)
(forever
(define size-line (read-line real-ip 'any))
(match-define (cons size-in-hex _) (regexp-split #rx";" size-line))
(define size-in-bytes (hex-string->number size-in-hex))
(set! total-size (+ total-size size-in-bytes))
(when (zero? size-in-bytes)
(break))
(define data-bytes (read-bytes size-in-bytes real-ip))
(write-bytes data-bytes decode-op)
;; Ignore CRLF
(read-line real-ip 'any))
(define more-headers
(list* (header #"Content-Length"
(string->bytes/utf-8 (number->string total-size)))
(read-headers real-ip)))
(close-output-port decode-op)
(values decoded-ip (append initial-headers more-headers))]
[_
(values real-ip initial-headers)]))
(define (make-ext:read-request
#:connection-close? [connection-close? #f])
(define read-request
(make-read-request #:connection-close? connection-close?))
(define (ext:read-request conn host-port port-addresses)
(with-handlers ([exn:fail?
(lambda (exn)
(kill-connection! conn)
(raise exn))])
(read-request conn host-port port-addresses)))
ext:read-request)
(define ext:read-request (make-ext:read-request #:connection-close? #f))
;; **************************************************
;; close-connection?
; close-connection? : (listof (cons symbol bytes)) number number string string -> boolean
;; determine if this connection should be closed after serving the
;; response
(define close-connection?
(let ([rx (byte-regexp #"[cC][lL][oO][sS][eE]")])
(lambda (headers major minor client-ip host-ip)
(or (< major 1)
(and (= major 1) (= minor 0))
(match (headers-assq* #"Connection" headers)
[(struct header (f v))
(and (regexp-match rx v)
#t)]
[#f
#f])
(msie-from-local-machine? headers client-ip host-ip)))))
;; msie-from-local-machine? : table str str -> bool
;; to work around a bug in MSIE for documents < 265 bytes when
;; connecting from the local machine. The server could pad the
;; response as MSIIS does, but closing the connection works, too. We
;; do not check for version numbers since IE 6 under windows is 5.2
;; under macosX
(define msie-from-local-machine?
(let ([rx (byte-regexp #"MSIE")])
(lambda (headers client-ip host-ip)
(and (string=? host-ip client-ip)
(match
(or (headers-assq* #"HTTP_USER_AGENT" headers)
(headers-assq* #"User-Agent" headers))
[(struct header (f v))
(and (regexp-match rx v)
#t)]
[#f
#f])))))
;; **************************************************
;; read-request-line
(define match-method
(let ([rx (byte-regexp #"^([^ ]+) (.+) HTTP/([0-9]+)\\.([0-9]+)$")])
(lambda (a) (regexp-match rx a))))
; read-request-line : iport -> bytes url number number
; to read in the first line of an http request, AKA the "request line"
; effect: in case of errors, complain [MF: where] and close the ports
(define (read-request-line ip)
(define line (read-bytes-line ip 'any))
(if (eof-object? line)
(network-error 'read-request "http input closed abruptly")
(cond
[(match-method line)
=> (match-lambda
[(list _ method url major minor)
(values method
(string->url (bytes->string/utf-8 url))
(string->number (bytes->string/utf-8 major))
(string->number (bytes->string/utf-8 minor)))])]
[else (network-error 'read-request "malformed request ~a" line)])))
;; **************************************************
;; read-headers
(define match-colon
(let ([rx (byte-regexp (bytes-append #"^([^:]*):[ " (bytes 9) #"]*(.*)"))])
(lambda (a) (regexp-match rx a))))
; read-headers : iport -> (listof header?)
(define (read-headers in)
(let read-header ()
(define l (read-bytes-line in 'any))
(cond
[(eof-object? l) null]
[(zero? (bytes-length l)) null]
[(match-colon l)
=> (match-lambda
[(list _ field value)
(list* (make-header field (read-one-head in value))
(read-header))])]
[else (network-error 'read-headers "malformed header: ~e" l)])))
; read-one-head : iport bytes -> bytes
(define (read-one-head in rhs)
(match (peek-byte in)
[(or 32 9) ;(or (eq? c #\space) (eq? c #\tab))
; (read-bytes-line in 'any) can't return eof
; because we just checked with peek-char
; Spidey: FLOW
(read-one-head in (bytes-append rhs (read-bytes-line in 'any)))]
[_ rhs]))
;; **************************************************
;; read-bindings
(define INPUT-BUFFER-SIZE 4096)
(define (read-to-eof in)
(define b (read-bytes INPUT-BUFFER-SIZE in))
(if (eof-object? b)
empty
(list* b (read-to-eof in))))
(define FILE-FORM-REGEXP (byte-regexp #"multipart/form-data; *boundary=(.*)"))
;; read-bindings&post-data/raw: input-port symbol url (listof header?) -> (values (or/c (listof binding?) string?) (or/c bytes? false/c?))
(define (read-bindings&post-data/raw in meth uri headers)
(define bindings-GET
(delay
(filter-map
(match-lambda
[(list-rest k v)
(if (and (symbol? k) (string? v))
(make-binding:form (string->bytes/utf-8 (symbol->string k))
(string->bytes/utf-8 v))
#f)])
(url-query uri))))
(cond
[(bytes-ci=? #"GET" meth)
(values bindings-GET #f)]
[(bytes-ci=? #"POST" meth)
(define content-type (headers-assq* #"Content-Type" headers))
(cond
[(and content-type
(regexp-match FILE-FORM-REGEXP (header-value content-type)))
=> (match-lambda
[(list _ content-boundary)
;; XXX This can't be delay because it reads from the
;; port, which would otherwise be closed. I think
;; this is reasonable because the Content-Type
;; said it would have this format
(define bs
(map (match-lambda
[(struct mime-part (headers contents))
(define rhs
(header-value
(headers-assq* #"Content-Disposition" headers)))
(match*
((regexp-match #"filename=(\"([^\"]*)\"|([^ ;]*))" rhs)
(regexp-match #"[^e]name=(\"([^\"]*)\"|([^ ;]*))" rhs))
[(#f #f)
(network-error
'reading-bindings
"Couldn't extract form field name for file upload")]
[(#f (list _ _ f0 f1))
(make-binding:form (or f0 f1)
(apply bytes-append contents))]
[((list _ _ f00 f01) (list _ _ f10 f11))
(make-binding:file (or f10 f11)
(or f00 f01)
headers
(apply bytes-append contents))])])
(read-mime-multipart content-boundary in)))
(values
(delay (append (force bindings-GET) bs))
#f)])]
[else
(match (headers-assq* #"Content-Length" headers)
[(struct header (_ value))
(cond
[(string->number (bytes->string/utf-8 value))
=> (lambda (len)
(let ([raw-bytes (read-bytes len in)])
(values (delay (append (parse-bindings raw-bytes) (force bindings-GET))) raw-bytes)))]
[else
(network-error
'read-bindings
"Post request contained a non-numeric content-length")])]
[#f
(values (delay empty) #f)])])]
[meth
(define content-type (headers-assq* #"Content-Type" headers))
(match (headers-assq* #"Content-Length" headers)
[(struct header (_ value))
(cond [(string->number (bytes->string/utf-8 value))
=> (lambda (len)
(let ([raw-bytes (read-bytes len in)])
(values (delay empty) raw-bytes)))]
[else
(network-error
'read-bindings
"Non-GET/POST request contained a non-numeric content-length")])]
[#f
(values (delay empty) #f)])]))
;; parse-bindings : bytes? -> (listof binding?)
(define (parse-bindings raw)
(define len (bytes-length raw))
(let loop ([start 0])
(let find= ([key-end start])
(if (>= key-end len)
empty
(if (eq? (bytes-ref raw key-end) (char->integer #\=))
(let find-amp ([amp-end (add1 key-end)])
(if (or (= amp-end len) (eq? (bytes-ref raw amp-end) (char->integer #\&)))
(list* (make-binding:form
(string->bytes/utf-8
(form-urlencoded-decode
(bytes->string/utf-8
(subbytes raw start key-end))))
(string->bytes/utf-8
(form-urlencoded-decode
(bytes->string/utf-8
(subbytes raw (add1 key-end) amp-end)))))
(loop (add1 amp-end)))
(find-amp (add1 amp-end))))
(find= (add1 key-end)))))))
;; **************************************************
;; read-mime-multipart
; mime-part : (listof header?) * (listof bytes?)
(define-struct mime-part (headers contents))
(define CR-NL #"\r\n")
(define (construct-mime-part headers body)
(make-mime-part
headers
(match body
[(list)
(list)]
[(list-rest fst rst)
(list* fst
(foldr (lambda (byt acc)
(list* CR-NL byt acc))
empty
rst))])))
; read-mime-multipart : bytes iport -> (listof part)
(define (read-mime-multipart boundary in)
(define boundary-len (bytes-length boundary))
(define start-boundary (bytes-append #"--" boundary))
(define end-boundary (bytes-append start-boundary #"--"))
(let skip-preamble ()
(define line (read-bytes-line in 'return-linefeed))
(cond
[(eof-object? line)
(network-error 'read-mime-multipart "Port prematurely closed.")]
[(bytes=? line start-boundary)
(let read-parts ()
(define headers (read-headers in))
(let read-mime-part-body
([more-k (lambda (contents)
(list* (construct-mime-part
headers contents)
(read-parts)))]
[end-k (lambda (contents)
(list (construct-mime-part
headers contents)))])
(define line (read-bytes-line in 'return-linefeed))
(cond
[(eof-object? line)
(network-error 'read-mime-multipart "Port prematurely closed.")]
[(bytes=? line start-boundary)
(more-k empty)]
[(bytes=? line end-boundary)
(end-k empty)]
[else
(read-mime-part-body
(lambda (x) (more-k (list* line x)))
(lambda (x) (end-k (list* line x))))])))]
[(bytes=? line end-boundary) null]
[else (skip-preamble)])))