one thing we do, is we store the MIME type in the database, and we
don't have those problems. I think you need to use the specific mime
type for the type of file you are serving, like application/pdf or
whatever. Also, I don't think you need the NAME in the content-type
header.
One last thing, many browsers will now balk at you if you do not have
a content-length header, you should be specifying content-length
header on every download like this. Not only will this make your code
more compatible, but it will also make downloading a more pleasant
experience for your clients. When you download without content-length,
the client end will show an unknown and some barber pole like
progress, cuz it has no idea when the file ends.
I believe those 2 issues, mime-type and content-length will solve your
problems. There is one more mine field.
Other languages, like php, automatically do content-length for you, so
it is much better and I have found always accurate. Witango is
different story. Witango treats every variable like TEXT, not binary
data, so every so often, when you do
<@length "@VARlocal$fileContents encoding=none>">
The resulting length will be off slightly, usually by one byte. This
is one of those times where I beat my head against walls trying to
figure this one out. It seemed to happen on about 1 out of every few
hundred files, but it would occur on the same file every time, and
will cause the file to be corrupted on download. Unfortunately, there
is no way around this on witango. There is no way to know which binary
files will do this in witango, so you can't do some type of IF, and
add or subtract a byte to length.
So, in order to have a full proof compatible digital delivery system
in witango, we have found the best way is to handle these things on
upload. On upload, or when the files are stored, we would populate the
mime-type in the database, and we would run a witango external command
that would return the length of the file, correctly, to store in the
db to be used on content-length on time of distribution. You can also
add those files to your database, and then use a binary length
function in a select command to get the length if you db supports it
and you are using blobs. I believe mysql does.
This is one of those cases, and their are many, where you really have
to way out certain applications and witango. The ease of use on other
areas, get totally negated when you run into issues like this.
Uploading and distributing binary files in php for example, is
incredibly simple and robust, just a few lines of code. Witango can be
as reliable, but you have to get around the content-length issue.
--
Robert Garcia
President - BigHead Technology
VP Application Development - eventpix.com
13653 West Park Dr
Magalia, Ca 95954
ph: 530.645.4040 x222 fax: 530.645.4040
[EMAIL PROTECTED] - [EMAIL PROTECTED]
http://bighead.net/ - http://eventpix.com/
On Dec 13, 2007, at 3:57 AM, Mike Scally wrote:
Hi All,
Maybe someone can help me out here. We have a document management
system written in Witango, and as part of the system we restrict
access to files based on the users profile. When a user requests a
file, we check their credentials and then send the file back to them
using the following (where fileContents contains the contents of the
file):
<@PURGERESULTS><@ASSIGN request$httpHeader "HTTP/1.1
<@HTTPSTATUSCODE> <@HTTPREASONPHRASE> <@crlf>Server:
Witango<@version><@crlf>Content-Type: application/octet-stream;
name=<@VAR LOCAL$fileName ENCODING=NONE><@CRLF>Content-Disposition:
inline; filename=<@VAR LOCAL$fileName ENCODING=NONE><@CRLF><@IF
EXPR='len(<@USERREFERENCECOOKIE>)'
TRUE='<@USERREFERENCECOOKIE>'><@crlf>"><@VARlocal$fileContents
encoding=none>
This application was untouched for some years, and it always served
the files correctly including PDF files. The user got the Open, Save
and Cancel dialog for known file types. However, after we installed
Adobe Reader 8.0+, we no longer get the option to Open the PDF files
directly, but can only Save them to the file system. I have included
the HTTP response header below. Should Content-Type be set
differently to give the Open option? If I specifically set it to
“application/pdf”, I get the open file option, but I cannot do this
as we server all different file types. Maybe someone is doing
something similar and may have run into the same problem.
-----------------------------------HTTP
Header------------------------------------------
HTTP/1.1 200 OK
Server: Microsoft-IIS/5.1
Date: Thu, 13 Dec 2007 11:39:32 GMT
X-Powered-By: ASP.NET
Connection: close
Server: Witango 5.5.003 Liquorice (Win32)
Content-Type: application/octet-stream; name=Certificate.pdf
Content-Disposition: inline; filename=Certificate.pdf
PDF contents start here……
------------------------------------------------------------------
Any help greatly appreciated.
Thanks
Mike.
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