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216 lines
7.8 KiB
Scheme
216 lines
7.8 KiB
Scheme
; author: Thomas Hintz
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; email: t@thintz.com
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; license: bsd
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(module amazon-s3
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(;; debugging
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*last-sig*
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;; params
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access-key secret-key https
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;; procs
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list-objects list-buckets bucket-exists? create-bucket! delete-bucket! get-object put-object! delete-object!
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put-string! put-sexp! put-file! get-string get-sexp get-file
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;; macros
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with-bucket)
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(import scheme chicken srfi-1 extras srfi-13 data-structures ports posix)
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(use base64 sha1 http-client uri-common intarweb srfi-19 hmac ssax sxpath)
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; needed to make intarweb work with Amazon's screwy authorization header
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(define (aws-param-subunparser params)
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(sprintf "~A:~A" (alist-ref 'access-key params)
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(alist-ref 'signed-secret params)))
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(authorization-param-subunparsers
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`((aws . ,aws-param-subunparser) . ,(authorization-param-subunparsers)))
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;;; params
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(define (intarweb-date date) (string->time (date->string date "~a ~b ~d ~T ~Y GMT")))
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(define (sig-date date) (date->string date "~a, ~d ~b ~Y ~T GMT"))
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(define access-key (make-parameter ""))
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(define secret-key (make-parameter ""))
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(define https (make-parameter #f))
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;;; helper methods
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(define (assert-404 exn)
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(if (string=? ((condition-property-accessor 'exn 'message) exn)
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"Client error: 404 Not Found")
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#f
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(abort exn)))
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(define (make-aws-authorization verb resource #!key (date #f) (amz-headers '()) (content-md5 #f) (content-type #f))
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(let* ((can-amz-headers (sort (map (lambda (header)
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`(,(string-downcase (car header)) . ,(cdr header)))
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amz-headers)
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(lambda (v1 v2)
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(string<? (car v1) (car v2)))))
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(can-string (with-output-to-string
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(lambda ()
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(display (string-upcase verb))
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(newline)
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(if content-md5 (display content-md5) (display ""))
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(newline)
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(if content-type (display content-type) (display ""))
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(newline)
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(if date (display date) (display ""))
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(newline)
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(display (fold (lambda (e o)
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(string-append o (sprintf "~a:~a~%" (car e) (cdr e))))
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""
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can-amz-headers))
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(display resource))))
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(hmac-sha1 (base64-encode ((hmac (secret-key) (sha1-primitive)) can-string))))
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(set! *last-sig* can-string)
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(values hmac-sha1 can-string)))
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(define *last-sig* #f)
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(define amazon-ns (make-parameter '(x . "http://s3.amazonaws.com/doc/2006-03-01/")))
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(define (aws-headers bucket path verb content-type content-length)
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(let ((n (current-date 0)))
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(headers `((date #(,(intarweb-date n) ()))
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(authorization #(aws ((access-key . ,(access-key))
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(signed-secret .
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,(make-aws-authorization
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verb
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(string-append "/"
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(if bucket (string-append bucket "/") "")
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(if path path ""))
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date: (sig-date n)
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content-type: content-type)))))
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(content-type ,(string->symbol content-type))
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(content-length ,content-length)))))
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(define (aws-request bucket path verb #!key no-auth (content-type "") (content-length 0))
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(make-request
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method: (string->symbol verb)
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uri: (uri-reference (string-append "http" (if (https) "s" "") "://" (if bucket (string-append bucket ".") "")
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"s3.amazonaws.com" (if path (string-append "/" path) "")))
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headers: (if no-auth (headers '()) (aws-headers bucket path verb content-type content-length))))
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(define (aws-xml-parser path ns)
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(lambda ()
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((sxpath path)
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(ssax:xml->sxml (current-input-port) ns))))
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(define (perform-aws-request #!key
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(bucket #f)
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(path #f)
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(sxpath '())
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(body "")
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(verb "GET")
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(ns '((x . "http://s3.amazonaws.com/doc/2006-03-01/")))
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(no-xml #f)
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(no-auth #f)
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(reader-thunk read-string)
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(content-type "application/x-www-form-urlencoded")
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(content-length 0))
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;(handle-exceptions
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; exn
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; ((condition-property-accessor 'client-error 'body) exn)
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(with-input-from-request
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(aws-request bucket path verb no-auth: no-auth content-type: content-type content-length: content-length)
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body
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(if no-xml
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reader-thunk
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(aws-xml-parser sxpath ns))))
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(define (read-byte-file path . port)
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(lambda ()
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(let ((file (open-input-file path)))
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(letrec ((read-next
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(lambda ()
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(let ((b (read-byte file)))
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(if (eof-object? b)
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#t
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(begin
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(if (> (length port) 0)
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(write-byte b (car port))
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(write-byte b))
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(read-next)))))))
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(read-next))
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(close-input-port file))))
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(define (write-byte-file path . port)
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(lambda ()
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(let ((file (open-output-file path)))
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(letrec ((read-next
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(lambda ()
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(let ((b (if (> (length port) 0)
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(read-byte (car port))
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(read-byte))))
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(if (eof-object? b)
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#t
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(begin
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(write-byte b file)
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(read-next)))))))
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(read-next))
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(close-output-port file))))
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;;; api
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(define-syntax with-bucket
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(syntax-rules ()
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((with-bucket bucket (func p1 ...))
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(func bucket p1 ...))
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((with-bucket bucket exp body ...)
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(begin (with-bucket bucket exp)
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(with-bucket bucket body ...)))))
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(define (list-buckets)
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(perform-aws-request sxpath: '(x:ListAllMyBucketsResult x:Buckets x:Bucket x:Name *text*)))
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(define (bucket-exists? bucket)
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(handle-exceptions
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exn
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(assert-404 exn)
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(perform-aws-request bucket: bucket verb: "HEAD" no-xml: #t)
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#t))
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(define (create-bucket! bucket)
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(perform-aws-request bucket: bucket verb: "PUT" no-xml: #t))
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(define (delete-bucket! bucket)
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(perform-aws-request bucket: bucket verb: "DELETE" no-xml: #t))
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(define (list-objects bucket)
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(perform-aws-request bucket: bucket sxpath: '(x:ListBucketResult x:Contents x:Key *text*)))
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(define (put-object! bucket key object-thunk object-length object-type)
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(perform-aws-request bucket: bucket path: key verb: "PUT" content-type: object-type body: object-thunk
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content-length: object-length no-xml: #t))
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(define (put-string! bucket key string)
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(put-object! bucket key (lambda () (display string)) (string-length string) "text/plain"))
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(define (put-sexp! bucket key sexp)
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(let-values (((res request-uri response) (put-string! bucket key (->string sexp))))
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(values res request-uri response)))
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(define (put-file! bucket key file-path)
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(put-object! bucket key (read-byte-file file-path) (file-size file-path) "binary/octet-stream"))
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(define (get-object bucket key)
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(perform-aws-request bucket: bucket path: key no-xml: #t))
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(define (get-string bucket key)
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(perform-aws-request bucket: bucket path: key no-xml: #t))
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(define (get-sexp bucket key)
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(let-values (((string request-uri response) (get-string bucket key)))
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(values (call-with-input-string string read) request-uri response)))
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(define (get-file bucket key file-path)
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(perform-aws-request bucket: bucket path: key no-xml: #t reader-thunk: (write-byte-file file-path)))
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(define (delete-object! bucket key)
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(perform-aws-request bucket: bucket path: key no-xml: #t verb: "DELETE"))
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)
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