[cups.development] Is cupsGetPPD supposed to fetch PPDs from remote servers?

[Vadim Troshchinskiy]

Hi! I'm debugging an issue with printing from a Java program. The setup is as 
follows:

The program runs inside a VM. The user connects to the VM with NX. Within the 
VM, there's a CUPS instance running. Also, NX forwards port 2100 on the VM to 
port 631 on the computer running the NX client. For the sake of making testing 
easier in this case I'm using cups-pdf as the printer on the client side. The 
CUPS in the VM is then configured as follows:

# Printer configuration file for CUPS v1.4.3
# Written by cupsd
# DO NOT EDIT THIS FILE WHEN CUPSD IS RUNNING
<Printer Virtual_PDF_Printer>
Info Virtual_PDF_Printer
DeviceURI ipp://127.0.0.1:2100/printers/Virtual_PDF_Printer
State Idle
StateTime 1292260814
Type 6
Accepting Yes
Shared No
JobSheets none none
QuotaPeriod 0
PageLimit 0
KLimit 0
OpPolicy default
ErrorPolicy retry-job
</Printer>


The issue is that Java programs fail to print. Debugging the applications 
shows that first it tries to open the printer's PPD in /etc/cups/ppd/, fails to 
find it there, then tries to request it from localhost:631, that also fails, 
and gives up there. Java fails to obtain useful information about the printer, 
so printing fails to work.

I looked at the code of openjdk, which turned out to contain a simple call to 
cupsGetPPD. The way that code looks like it seems unlikely to be the problem.

Then, I think the question is, is what happens a bug, and what should be 
happening? For instance:

Should cupsGetPPD notice that Virtual_PDF_Printer is at  
ipp://127.0.0.1:2100/printers/Virtual_PDF_Printer and fetch the PPD from 
http://127.0.0.1:2100/printers/Virtual_PDF_Printer? (it tries 
http://127.0.0.1:631/printers/Virtual_PDF_Printer which gets a 404)

Or, perhaps if a PPD is requested from the local CUPS it should fetch it from 
the remote one and then deliver it?

Or, are PPDs always supposed to be available locally?


Thanks!


-- 
Vadim Troshchinskiy
Qindel 

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