IPP> MOD & PRO - Questions about "printer-uri" or "job-uri"

IPP> MOD & PRO - Questions about "printer-uri" or "job-uri"

Carl Kugler kugler at us.ibm.com
Tue May 12 15:39:22 EDT 1998


The following statement from the PRO doc. seems to imply that the same =
target
printer-uri is placed in the "printer-uri" operation attribute and the =
HTTP
request-URI:


* "printer-uri": When the target is a printer and the transport is HTTP=
 or
HTTP (for TLS), the target printer-uri defined in  each operation in th=
e IPP
model document SHALL be an operation attribute called "printer-uri" and=
 it
SHALL also be specified outside of  the operation layer as the request-=
URI on
the Request-Line at the HTTP level.  This


Must these URIs be identical?


HTTP/1.1 clients generate an abs_path (a relativeURI) as the Request-UR=
I, which
identifies a resource on a server, but does not include scheme, host or=
 port.
Are "printer-uri", "printer-uri-supported", and "job-uri" supposed to b=
e
absoluteURIs or abs_paths (see
ftp://ietf.org/internet-drafts/draft-fielding-uri-syntax-02.txt for def=
initions)
? If "printer-uri-supported" is to specify host, scheme, or port, absol=
uteURIs
are required.  If "printer-uri" or "job-uri" are absoluteURIs, then the=
 HTTP
request-URI and the target Operation Attribute can't be identical.  Whi=
ch
raises some questions:


- Suppose the "printer-uri" (or "job-uri") and request-URI are not iden=
tical?
Should the Printer
 a) Return an error status?  Warning?
 b) Allow one to take precedence over the other?


- Suppose even the "abs_path" part of the URIs differs?


- Suppose they're not identical, but effectively point to the same reso=
urce
because of:
* An empty abs_path is equivalent to an abs_path of "/".
   * Characters other than those in the "reserved" and "unsafe" sets ar=
e
equivalent to their ""%" HEX HEX" encoding.
   * As a result of an HTTP redirect?
- Suppose one copy of the URI has been supplied, but not the other.  Sh=
ould the
Printer
 a) Reject the request?
 b) Return an error status?  Warning?
 c) Perform the operation?


My preferences would be:
  - Make target URI Operation Attribute OPTIONAL when the transport is =
HTTP or
HTTPS.
  - request-URI takes precedence over target Operational Attribute when=
 the
transport is HTTP or HTTPS.
  - "printer-uri" and "job-uri" have abs_path form.
  - "printer-uri-supported", "job-printer-uri", etc. have absoluteURI f=
orm




  Confused implementor in Boulder,


    Carl Kugler
=



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