From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Sebastian Tennant Newsgroups: gmane.lisp.guile.user Subject: Re: Uploading Word documents, PDFs, PNG files etc Date: Thu, 14 May 2009 12:49:14 +0000 Message-ID: References: <87vdo7au56.fsf@ambire.localdomain> <87vdo5qc52.fsf@gnu.org> <7i0kzuog.fsf@vps203.linuxvps.org> <3ae3aa420905131223i3c7b83b0tf5a6ec9b200a8704@mail.gmail.com> <200905140347.n4E3l6LB003384@fcs13.keithdiane.us> NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: ger.gmane.org 1242306098 19041 80.91.229.12 (14 May 2009 13:01:38 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Thu, 14 May 2009 13:01:38 +0000 (UTC) To: guile-user@gnu.org Original-X-From: guile-user-bounces+guile-user=m.gmane.org@gnu.org Thu May 14 15:01:30 2009 Return-path: Envelope-to: guile-user@m.gmane.org Original-Received: from lists.gnu.org ([199.232.76.165]) by lo.gmane.org with esmtp (Exim 4.50) id 1M4aYz-0000Sr-HJ for guile-user@m.gmane.org; Thu, 14 May 2009 15:01:29 +0200 Original-Received: from localhost ([127.0.0.1]:42923 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1M4aYt-0005FH-9k for guile-user@m.gmane.org; Thu, 14 May 2009 09:01:23 -0400 Original-Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1M4aNN-0000No-4m for guile-user@gnu.org; Thu, 14 May 2009 08:49:29 -0400 Original-Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1M4aNG-0000NE-Pv for guile-user@gnu.org; Thu, 14 May 2009 08:49:27 -0400 Original-Received: from [199.232.76.173] (port=37406 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1M4aNG-0000N8-DK for guile-user@gnu.org; Thu, 14 May 2009 08:49:22 -0400 Original-Received: from main.gmane.org ([80.91.229.2]:47479 helo=ciao.gmane.org) by monty-python.gnu.org with esmtps (TLS-1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1M4aNG-0001HU-2R for guile-user@gnu.org; Thu, 14 May 2009 08:49:22 -0400 Original-Received: from list by ciao.gmane.org with local (Exim 4.43) id 1M4aNB-00011X-H4 for guile-user@gnu.org; Thu, 14 May 2009 12:49:17 +0000 Original-Received: from vps203.linuxvps.org ([91.186.7.203]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Thu, 14 May 2009 12:49:17 +0000 Original-Received: from sebyte by vps203.linuxvps.org with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Thu, 14 May 2009 12:49:17 +0000 X-Injected-Via-Gmane: http://gmane.org/ Original-Lines: 69 Original-X-Complaints-To: usenet@ger.gmane.org X-Gmane-NNTP-Posting-Host: vps203.linuxvps.org X-Composed-In: Gnus User-Agent: Gnus/5.110011 (No Gnus v0.11) Emacs/22.2 (gnu/linux) Cancel-Lock: sha1:+mWXkC68QAW/3wMwjCpC6SzlHKE= X-detected-operating-system: by monty-python.gnu.org: GNU/Linux 2.6, seldom 2.4 (older, 4) X-BeenThere: guile-user@gnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: General Guile related discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Original-Sender: guile-user-bounces+guile-user=m.gmane.org@gnu.org Errors-To: guile-user-bounces+guile-user=m.gmane.org@gnu.org Xref: news.gmane.org gmane.lisp.guile.user:7299 Archived-At: Quoth Keith Wright : >> > Restricting regexps to actual text is fine... until >> > you need to grep binary data, or, as in this case, >> > a combination of text and binary data. >> >> > in cgi.scm that extracted the uploaded (possibly >> > binary) file, because the pattern identifying the >> > beginning of the file in the raw data string is >> > simple ("\n\r\n\r") - >> >> No, this sounds somehow broken. If I remember correctly, >> binary mime-parts should have a ConentLength header >> so you can skip over them. If ContentLength is absent, >> then the part should bee ascii-encoded (e.g. base64) >> yeah, grapping large blocks of ascii sucks, which is >> why the ContetnLength should be used. >> >> -- linas > > If the spec says a length indication followed by > a fixed length of arbitrary binary data, then it > is not just sucky, but incorrect to apply either > grep or regexp to the binary. It will seem to > work until it hits a binary data that "by > accident" contains the string you are looking > for. > > The only correct algorithm is to make a preliminary > pass to somehow remove the binary data and > pseudo-concatenate the remaining strings. Multipart/form-data comes with a Content-Length header that describes the length of any and all parts combined, making it possible to extract a string that looks like this: -----------------------------1307099961880952181245320094\x0d Content-Disposition: form-data; name=\"TABLE\"\x0d \x0d \x0d -----------------------------1307099961880952181245320094\x0d Content-Disposition: form-data; name=\"File-Upload\"; filename=\"null-char.txt\"\x0d Content-Type: text/plain\x0d \x0d foo^@bar \x0d -----------------------------1307099961880952181245320094\x0d Content-Disposition: form-data; name=\"Button\"\x0d \x0d Upload\x0d -----------------------------1307099961880952181245320094--\x0d The boundary can be obtained from the Content-Type header and the above string can then be broken into parts but how can one extract the name, filename, type and value of each part without using regexps? cgi.scm currently uses the following patterns and I can't think of an alternative way of doing it: (let ((name-rx (make-regexp "name=\"([^\"]*)\"")) (filename-rx (make-regexp "filename=\"*([^\"\r]*)\"*")) (type-rx (make-regexp "Content-Type: ([^\r]*)\r\n" regexp/icase)) (value-rx (make-regexp "\r\n\r\n"))) ...) Seb -- Emacs' AlsaPlayer - Music Without Jolts Lightweight, full-featured and mindful of your idyllic happiness. http://home.gna.org/eap