See my comments preceded by TH>
From: email@example.com [mailto:firstname.lastname@example.org]
Sent: Tuesday, March 28, 2000 09:35
To: Hastings, Tom N
Cc: email@example.com; firstname.lastname@example.org; email@example.com
Subject: RE: IPP> Document-format attribute.. [ipp-mod] clarification
I'm OK with the clarification. You are basically just adding the fact that
the sniffing method is implementation dependent... right?
More important, to me, is to encourage that no client ever use
application/octet-string when they are aware of and capable of indicating
the correct document format in mimeMediaType!
TH> I agree. I scanned the model document and found the following:
18.104.22.168 Print-Job Response says:
If the client omits this "document-format" operation attribute, the Printer
object MUST respond as if the attribute had been supplied with the value of
the Printer object's "document-format-default" attribute. It is RECOMMENDED
that the client always supply a value for "document-format", since the
Printer object's "document-format-default" may be
'application/octet-stream', in which case the returned attributes and values
are for the union of the document formats that the Printer can automatically
sense. For more details, see the description of the 'mimeMediaType'
attribute syntax in section 4.1.9.
I think this is good enough. However, the word "recommended" wasn't in
caps, so I'll change that with the RFC editor, ok?
IBM Printing Systems
I searched both the Model and the Implementer's Guide and there isn't
anything that explains what "auto-sensing" is.
So, ok to add the following clarification to the [ipp-mod] document in
using an implementation-dependent method that examines some number of
octets of the document data
so that it reads:
22.214.171.124 Application/octet-stream -- Auto-Sensing the document format
One special type is 'application/octet-stream'. If the Printer object
supports this value, the Printer object MUST be capable of auto-sensing
format of the document data using an implementation-dependent method that
examines some number of octets of the document data, either as part of the
create operation and/or at document processing time.
Or should we put something similar in the Implementer's Guide, instead?
It can usually tell from the first few bytes of the file. For example,
PostScript files start with %!PS and PDF files start with %PDF. Gif files
start with GIF89 and so on.
I have a doubt in the "document-format" attribute that the client
optionally specifies in the request..(according to IPP/1.1 draft)
The draft says that if theclient supplies this attribute and its value
'application/octet-stream' then the server needs to aut-sense the
Can anyone explain me how does this autosensing happens.......
How actually will the Printer Object perform this task...
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