racket/collects/web-server/util.ss
2005-05-27 18:56:37 +00:00

273 lines
12 KiB
Scheme

(module util mzscheme
(require (lib "contract.ss")
(lib "string.ss")
(lib "list.ss")
(lib "url.ss" "net")
(lib "errortrace-lib.ss" "errortrace"))
(provide provide-define-struct
extract-flag
translate-escapes
hash-table-empty?)
(provide/contract
[path->list (path? . -> . (cons/c (union path? (symbols 'up 'same))
(listof (union path? (symbols 'up 'same)))))]
[url-path->path ((union (symbols 'up 'same) path?) string? . -> . path?)]
[directory-part (path? . -> . path?)]
[lowercase-symbol! ((union string? bytes?) . -> . symbol?)]
[exn->string ((union exn? any/c) . -> . string?)]
[get-mime-type (path? . -> . bytes?)]
[build-path-unless-absolute (path? (union string? path?) . -> . path?)])
;; build-path-unless-absolute : path (union string? path?) -> path?
(define (build-path-unless-absolute base path)
(if (absolute-path? path)
(build-path path)
(build-path base path)))
;; exn->string : (union exn any) -> string
;; builds an error message, including errortrace annotations (if present)
;; TODO: do we really need this? Ask Robby about better ways to print exceptions.
(define (exn->string exn)
(if (exn? exn)
(let ([op (open-output-string)])
(display (exn-message exn) op)
(newline op)
(print-error-trace op exn)
(get-output-string op))
(format "~s\n" exn)))
; lowercase-symbol! : (union string bytes) -> symbol
(define (lowercase-symbol! s)
(let ([s (if (bytes? s)
(bytes->string/utf-8 s)
s)])
(string-lowercase! s)
(string->symbol s)))
; prefix? : str -> str -> bool
; more here - consider moving this to mzlib's string.ss
;; Notes: (GregP)
;; 1. What's the significance of char # 255 ???
;; 2. 255 isn't an ascii character. ascii is 7-bit
;; 3. OK fuck this. It is only used in three places, some of them
;; will involve bytes while the others may involve strings. So
;; I will just use regular expressions and get on with life.
(define (prefix?-old prefix)
(let* ([len (string-length prefix)]
[last (string-ref prefix (sub1 len))]
[ascii (char->integer last)])
(if (= 255 ascii)
; something could be done about this - ab255 -> ac
; and all 255's eliminates upper range check
(error 'prefix? "prefix can't end in the largest character")
(let ([next (string-append (substring prefix 0 (sub1 len))
(string (integer->char (add1 ascii))))])
(lambda (x)
(and (string<=? prefix x) (string<? x next)))))))
;; get-mime-type: path -> bytes
;; determine the mime type based on the filename's suffix
;;
;; Notes (GregP):
;; 1. Can we determine the mime type based on file contents?
;; 2. Assuming that 7-bit ASCII is correct for mime-type
(define get-mime-type
(let ([file-suffix-regexp (byte-regexp #".*\\.([^\\.]*$)")])
(lambda (path)
(let ([sffx (cadr (regexp-match file-suffix-regexp (path->bytes path)))])
(hash-table-get MIME-TYPE-TABLE
(lowercase-symbol! sffx)
;(string->symbol (bytes->string/utf-8 sffx))
(lambda () DEFAULT-MIME-TYPE))))))
(define DEFAULT-MIME-TYPE #"text/plain")
(define MIME-TYPE-TABLE
(let ([table (make-hash-table)])
(for-each (lambda (x) (hash-table-put! table (car x) (cdr x)))
'((htm . #"text/html")
(html . #"text/html")
(css . #"text/css")
(txt . #"text/plain")
(hqx . #"application/mac-binhex40")
(doc . #"application/msword")
(plt . #"application/octet-stream")
(w02 . #"application/octet-stream")
(w03 . #"application/octet-stream")
(exe . #"application/octet-stream")
(bin . #"application/octet-stream")
(pdf . #"application/pdf")
(ps . #"application/postscript")
(rtf . #"application/rtf")
(dvi . #"application/x-dvi")
(tar . #"application/x-tar")
(tex . #"application/x-tex")
(zip . #"application/zip")
(xls . #"application/msexcel")
(ppt . #"application/powerpoint")
(pot . #"application/powerpoint")
(ppf . #"application/persuasion")
(fm . #"application/filemaker")
(pm6 . #"application/pagemaker")
(psd . #"application/x-photoshop")
(pdd . #"application/x-photoshop")
(ram . #"audio/x-pn-realaudio")
(ra . #"audio/x-realaudio")
(swf . #"application/x-shockwave-flash")
(aif . #"audio/aiff")
(au . #"audio/basic")
(voc . #"audio/voice")
(wav . #"audio/wave")
(mov . #"video/quicktime")
(mpg . #"video/mpeg")
(png . #"image/png")
(bmp . #"image/bmp")
(gif . #"image/gif")
(jpg . #"image/jpeg")
(tif . #"image/tiff")
(pic . #"image/x-pict")))
table))
(define (directory-part path)
(let-values ([(base name must-be-dir) (split-path path)])
(cond
[(eq? 'relative base) (current-directory)]
[(not base) (error 'directory-part "~a is a top-level directory" path)]
[(path? base) base])))
; more here - ".." should probably raise an error instead of disappearing.
(define (url-path->path base p)
(let ((path-elems (chop-string #\/ p)))
;;; Hardcoded, bad, and wrong
(if (or (string=? (car path-elems) "servlets")
(and (string=? (car path-elems) "")
(string=? (cadr path-elems) "servlets")))
;; Servlets can have extra stuff after them
(let loop ((p-e (if (string=? (car path-elems) "")
(cddr path-elems)
(cdr path-elems)))
(f (build-path base
(if (string=? (car path-elems) "")
(cadr path-elems)
(car path-elems)))))
(cond
((null? p-e) f)
((directory-exists? f) (loop (cdr p-e) (build-path f (car p-e))))
((file-exists? f) f)
(else f))) ;; Don't worry about e.g. links for now
; spidey can't check build-path's use of only certain symbols
(apply build-path base
(foldr (lambda (x acc)
(cond
[(string=? x "") acc]
[(string=? x ".") acc]
[(string=? x "..") acc] ; ignore ".." (cons 'up acc)]
[else (cons x acc)]))
null
(chop-string #\/ p))))))
; update-params : Url (U #f String) -> String
; to create a new url just like the old one, but with a different parameter part
;; GREGP: this is broken! replace with the version from new-kernel
; (define (update-params uri params)
; (url->string
; (make-url (url-scheme uri)
; (url-user uri)
; (url-host uri)
; (url-port uri)
; (url-path uri)
; params
; (url-query uri)
; (url-fragment uri))))
; to convert a platform dependent path into a listof path parts such that
; (forall x (equal? (path->list x) (path->list (apply build-path (path->list x)))))
(define (path->list p)
(let loop ([p p] [acc null])
(let-values ([(base name must-be-dir?) (split-path p)])
(let ([new-acc (cons name acc)])
(cond
[(string? base) (loop base new-acc)]
[else ; conflate 'relative and #f
new-acc])))))
; chop-string : Char String -> (listof String)
(define (chop-string separator s)
(let ([p (open-input-string s)])
(let extract-parts ()
(cons (list->string
(let part ()
(let ([char (peek-char p)])
(cond
[(eof-object? char) null]
[else (cond
[(eq? separator char) null]
[else (read-char p) (cons char (part))])]))))
(cond
[(eof-object? (read-char p)) null]
[else (extract-parts)])))))
; this should go somewhere that other collections can use it too
(define-syntax provide-define-struct
(lambda (stx)
(syntax-case stx ()
[(_ (struct-name parent-name) (field ...))
(syntax (begin (define-struct (struct-name parent-name) (field ...))
(provide (struct struct-name (field ...)))))]
[(_ struct-name (field ...))
(syntax (begin (define-struct struct-name (field ...))
(provide (struct struct-name (field ...)))))])))
; this is used by launchers
; extract-flag : sym (listof (cons sym alpha)) alpha -> alpha
(define (extract-flag name flags default)
(let ([x (assq name flags)])
(if x
(cdr x)
default)))
; hash-table-empty? : hash-table -> bool
(define (hash-table-empty? table)
(let/ec out
(hash-table-for-each table (lambda (k v) (out #f)))
#t))
; This comes from Shriram's collection, and should be exported form there.
; translate-escapes : String -> String
(define-struct servlet-error ())
(define-struct (invalid-%-suffix servlet-error) (chars))
(define-struct (incomplete-%-suffix invalid-%-suffix) ())
(define (translate-escapes raw)
(list->string
(let loop ((chars (string->list raw)))
(if (null? chars) null
(let ((first (car chars))
(rest (cdr chars)))
(let-values (((this rest)
(cond
((char=? first #\+)
(values #\space rest))
((char=? first #\%)
; MF: I rewrote this code so that Spidey could eliminate all checks.
; I am more confident this way that this hairy expression doesn't barf.
(if (pair? rest)
(let ([rest-rest (cdr rest)])
(if (pair? rest-rest)
(values (integer->char
(or (string->number (string (car rest) (car rest-rest)) 16)
(raise (make-invalid-%-suffix
(if (string->number (string (car rest)) 16)
(car rest-rest)
(car rest))))))
(cdr rest-rest))
(raise (make-incomplete-%-suffix rest))))
(raise (make-incomplete-%-suffix rest))))
(else (values first rest)))))
(cons this (loop rest))))))))
)