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Unform printer alias example

Outdated material; included only for historical reference


From: "Brian K. White" <br...@aljex.com>
Subject: Re: Printer Alias?
Date: Fri, 5 Oct 2007 06:01:48 -0400


----- Original Message ----- 
From: "Chris Schmidt" <cschm...@unidos.com>
Newsgroups: comp.unix.sco.misc
Sent: Thursday, October 04, 2007 6:23 PM
Subject: Printer Alias?


>I am trying to get an app (Datamodes) on OSR6 to print output through
> UnForm.  I have come across this about a "printer alias" but not sure
> how it works or where it would become part of the system config.  See
> below:
>
>>From the Unform 7 Manual:
>
> UNIX Aliases
> A printer alias line on UNIX generally pipes to a program, such as the
> uf70c client program. This client
> program in turn can pipe its output to the spooler, or to a file, or
> it can instruct the server to handle the
> output from its end, by specifying the -o option.
> Here is a sample alias line that pipes through UnForm to the local
> spooler:
> alias P1 "|uf70c -f my.rul | lp -dxyz -oraw -s 2>/dev/null" "Printer
> Name" ... various modes ...
> Here is a sample alias line that instructs the server to print the job
> to its spooler. The advantage of this
> type of configuration is that the client doesn't have to wait for the
> job to finish. It submits the job to the
> server and exits quickly.
>
> alias P1 "|uf70c -f my.rul -o \'>lp -dxyz -oraw\'" "Printer Name" ...
> various modes ...
>
> Note the use of the -oraw option in the above examples. It is
> important for UnForm's output to be
> handled as binary data by the spooler. The -oraw option is used by
> some UNIX spoolers, such as the
> SCO LaserJet model script, and the CUPS printing system. Other
> spoolers require different options,
> such as "-o-dp" for AIX, -T pcl for Unixware, -b for some older Linux
> installations. Check your lp
> configuration tools or man pages for the appropriate settings for
> options such as "binary", "raw", or
> "pass-thru" printing.
>
> UnForm can also print directly to a device, as in this example:
>
> alias P1 "|uf70c -f my.rul -o /dev/lp0" "Printer Name" ... various modes
> ...
>
> Note that this line will behave differently with the UnForm pipe than
> without. When opening and
> sending output directly to a device, printing will occur immediately,
> without closing the device.
> However, with the pipe to UnForm, the output will not appear until the
> device is closed. The
> application may need to be modified to account for this if UnForm is
> to be used in this circumstance.
>
>
>
> My Question is, where exactly would this "alias" command take place in
> OSR6 to make it work?  Just at the command line?  /etc/printcap?
> CUPS?  We are using CUPS BTW.
>
> If you know of a link that will help me better understand this please
> post it.
>
>
> Thanks,
>
> Chris
> Unidos Inc.

That is just an example for how to inject unform into one particular common 
language that many legacy apps are written in. In that case the language is 
BBx by Basis Inc. (Later versions are called PRO/5)
The example is specific to bbx, yet still serves as an example for any other 
kind of app.

They are just saying, "Here is a sample unform command, it takes data on 
stdin, and outputs to /dev/lp0 if you use the option -o /dev/lp0. Insert 
this command into the pipeline wherever/however your application defines 
it's printers. Here is how you'd do it in a bbx app."

"alias P1 etc...."
is syntax for the config.bbx file in BBx or PRO/5

"config.bbx" might not be named config.bbx. It might be named anything and 
might live in any directory. The name & location is variable/configurable. 
And generally you don't edit it directly but use some screen in your 
application that knows how to regenerate it. There are lot's of quirks about 
config.bbx that aren't obvious and it's easy to make a perfectly good 
looking utterly broken config file, which would then prevent you from being 
able to start up the application to use it's config file maintenance screen 
to regenerate a valid file.

Most apps have some similar kind of config file where printers that are 
defined.

For example, assume you have a typical old app written in BBx, and assume 
the app does not have a config.bbx maintenance module and that it's ok to 
just edit the file directly.

In this app, the bbx config file might be /usr/bbx3/config.bbx
This file file might have a few printers defined in it.

[...]
#alias LP ">lp -dprnlp -s 2>/dev/null" "132 column parallel" CR
#alias P0 /dev/lp1 "132 column parallel" CR,LOCK=/usr/spool/lpd/p0
alias P1 ">lp -d m1 -s -o nff 2>/dev/null" "OneCall upstairs matrix" CR
alias P2 ">lp -d m2 -s -o nff 2>/dev/null" "OneCall downstairs matrix" CR
alias P3 ">lp -d m3 -s -o nff 2>/dev/null" "Clipper matrix" CR
#alias P2 /dev/ttyi07 "132 column serial" CR,LOCK=/usr/spool/lpd/p2
#alias P3 ">lp -dprnp3 -s 2>/dev/null" "132 column serial" CR
#alias P3 /dev/tty "Printer A" cr,bs,pton=5B3469,ptoff=5B3569
#alias P3 /dev/tty "Printer B" cr,bs,pton=5B3669,ptoff=5B3769
#alias P3 /dev/tty "Printer C" cr,bs,pton=5B3869,ptoff=5B3969
#alias P4 /dev/ttyi01 "132 column serial" CR,LOCK=/usr/spool/lpd/p4
#alias P5 /dev/ttyi00 "132 column serial" CR,LOCK=/usr/spool/lpd/p5
[...]

In this case only P1, P2, P3 are in effect, the rest are commented out, but 
they serve to show some valid examplesthat do work and do things that are 
needed in other situations.
This is just the printers, there is lot's of other stuff in the file, 
including some values that would need to be recalculated if I were to 
add/uncomment a new printer line. And, I had better be sure that I didn't 
exceed my license count for number of terminals/printers or else the app 
won't start.

Each line is space-delimited (so if a field needs to include spaces, it must 
be quoted), and the 3rd field of each line is the print destination. In the 
case of BBx, the default assumption about the contens of that field is that 
it contains a device name, like /dev/lp0 or /dev/tty1a for the first 
parallel or the forst serial port respectively. In order to Make BBx pipe 
data into a command (like a spooler print queue) instead of writing directly 
to a raw device, you have to use a special syntax to tell it so.

It happens that in the old version of bbx that my sample app is using, the 
correct syntax for piping data into the printer command is ">command...", 
not "|command..." which was used in the uform example you posted. Later 
versions of bbx (PRO/5) do use the "|command..." syntax.

Let's say I wanted to add a printer that would show up in the app as P4 and 
use UnForm.
(note there are often naming rules/restrictions in bbx as to what you can 
use for a printer or terminal alias or else bbx (or maybe it's the 
applications not bbx itself) won't recognize the line as a valid alias, so, 
unfortulately, you can't name the printer "unform", besides, this needs to 
be typed-in a lot so it needs to be short, but even UF or U or PU may not 
work, so, P# is a safe example that always works)

I might add this line:
alias P4 "|uf70c -f my.rul -o /dev/lp0" "UnForm to lp0" cr

That's all very bbx-specific stuff.

You are probably meant to read that, and only take away the general usage 
example and translate it to whatever you need for your own app.

For example, I used to use bbx and still help a few people here & there 
(which is why I know any of the above), but I mostly write in filePro not 
bbx. filePro has it's own config file with a similar set of lines for 
defining printers. The fp config file is also variable/configurable and 
might be named anything and live anywhere, and whoever wrote/sold/admins the 
app, or is at least familiar with the language, will know where it is or how 
to find it. A typical example is /u/appl/fp/lib/config

In there might be the following lines (taken from the same real system as 
above, which really has both a bbx and a filepro app on it, using the same 
printers & print queues, so you can see real correlatios and differences):

printer1=hplaser,hp-4+,lp -d hplaser -s -o raw,Main Laser Printer
printer2=m1,ibmpro,lp -d m1 -s -o nff,Matrix Upstairs
printer3=m2,ibmpro,lp -d m2 -s -o nff,Matrix Downtairs
printer4=m3,ibmpro,lp -d m3 -s -o nff,Matrix at Clipper

This defines 4 printers in filePro named hplaser, m1, m2, m3.
which are the same names as the unix print spools they map to.

In the case of filepro, the line is comma-delimited not space delimited, and 
the 3rd field contains the print destination. Just the oppisite of BBx, the 
field is assumed to contain a command of some sort and the print data is 
piped into it, not a raw device, and so there is no > or | at the beginning 
of the field.
If I did want to write directly to a raw device then I'd have to use 
">/dev/foo" instead of "lp -d foo"

If I wanted to add a 5th printer that used UnForm and ultimately went to the 
hplaser printer, I might add this line:
printer5=unform,unform,uf70c -f my.rul |lp -s -d hplaser -o raw,UnForm to 
Main Laser Printer

This defimes a new printer, printer number 5, named unform, using a 
print-code table also named unform (which I'd presumably have written by 
taking a copy of the "hp-4+" print code table that the hplaser printer uses, 
and add special unform codes to that, which unform would then recognize and 
act upon.)

There is now a | in the print destination field because now the field 
contains two commands, one piped into the other. The whole thing can be 
treated as one big command but it's really the original printer1 command 
"lp -d foo" with unform inserted before the spooler to make the new command
"unform ... |lp -d foo"

I had to assume several things there because I really don't know anything 
about unform and am not going to go research it now.
I'm assuming, based on the example given in the unform docs, that unform is 
a filter of some sort and still expects to output to a printer. The example 
you posted from the unform docs points the output right at a raw  device 
/dev/lp0. That almost certainly means UnForm is assuming that nothing else 
on the system ever touches /dev/lp0 so that unform is free to write to it 
whenever it wants. This means "uf70c" is taking the place of "lp" as the 
spooler for that device, and you shouldn't have any printers defined in unix 
that have /dev/lp0 as their target device, if you were going to use that 
example.
I on the other hand am assuming that all printer devices are configured into 
the system and have  spooler queues and that unform also allows you to print 
to a configured print spool instead of to a raw device. I assumed that 
unform maybe prints to stdout by default if you simply omit the -o option. 
It's just as likely that -o is always required and that to print to stdout 
instead of a file or device, you use "-" in place of a file or device name. 
In that case the filepro config line would have been:

printer5=unform,unform,uf70c -f my.rul -o - |lp -s -d hplaser -o raw,UnForm 
to Main Laser Printer

A cobol3 application I happen to encounter a lot defines it's printers by 
setting some environment variables in the users environment in the start 
script that launches the app or in the users .profile etc...
like so:

dd_LPT0="> /usr/bin/lp -s -d LPT0"
dd_LPT1="> /usr/bin/lp -s -d LPT1"
dd_SAVIN="> /usr/bin/lp -s -d main"
dd_OKI="> /usr/bin/lp -s -d OKI"
dd_SCREEN="> /usr/bin/mpg -c"
dd_FAX="> /usr/vsifax/bin/fx -N -s"
dd_FILE="/tmp/FILE"
dd_LOCAL="> /usr/bin/lprint"
dd_EMAIL="EMAIL"

export dd_LPT0 dd_LPT1 dd_SAVIN dd_OKI dd_SCREEN dd_FAX dd_FILE dd_LOCAL 
dd_EMAIL

so to inject unform I'd just edit one of those defines.
dd_UNFORM="> /path/to/uf70c -f my.rul \| /usr/bin/lp -s -d main"
export dd_UNFORM

Note, I don't know if it's cobol itself or the application that reads these 
variables. cobol3 may have some config file roughly similar to bbx and 
filepro and it may be the application that is reading these variables. ... 
in fact now that I look I do see a file /u/cobol3/cobcap which contains:

LPT0:W:/usr/bin/lp:-s:-dLPT0:
LPT1:W:/usr/bin/lp:-s:-dLPT1:
OKI:W:/usr/bin/lp:-s:-dOKI:
SCREEN:W:/usr/bin/mpg:-c:
FAX:W:/usr/vsifax/bin/fx -N:-s:
FILE:W:/bin/cat: > /tmp/FILE:
LOCAL:W:/usr/bin/lprint:

It looks like each command line argument to the spoler command is seperated 
in it's own colon-delimited field, and yet, there are also single fields 
that do contain spaces and multiple command line arguments, including at 
least one redirection (>) that isn't escaped or anything, so, I _guess_ you 
could add a line like this:

UNFORM:W:/path/to/unform -f my.rul |/usr/bin/lp:-s:-d main:

it might also be intended and more correct to just take every "word" of the 
command and treat the line as colon-delimited instead of space-delimited 
like usual, and spaces within a single field would not need to be quoted, 
and you can just have as many fields as you want and only the first two are 
special, so it would look like this

UNFORM:W:/path/to/unform:-f:my.rul:|:/usr/bin/lp:-s:-d:main:

That actually makes sense if you imagined a print command that used a field 
that had spaces in it, like
ACCT:W:/bin/mail:-s:Urgent message for the accounting 
department!:account...@mycompany.com:


There are several other common languages/systems that legacy apps are 
written in which I have no idea how their printers are configured but 
whoever wrote/sells/administers the app does know, and knows how to take the 
PRO/5 example from the unform docs (and these others I just made up) and do 
the equivalent in their system.

It's also possible to configure a unix printer that uses unform all the time 
right in the unix spooler and not do anything in the application config at 
all (other than, presumably, start adding special strings into the print 
data that unform recognizes and acts upon). You do that by editing the 
printer interface script (on OSR5 it's a shell script in 
/usr/spool/lp/admins/lp/interfaces/printername). On other OS's and/or in 
other spooling software, the equivalent of the printer interface script is 
in various places and takes various forms, including actually one of your 
guesses /etc/printcap, although usually you do not actually use printcap for 
this kind of thing even though there IS a "filter" field in printcap that is 
intended for roughly this sort of usage. It's just that most spooler 
software like the stock osr5 lp spooler or cups or lprng or apsfiletrs etc 
all have some much more flexible way of doing this kind of stuff and you do 
it in there instead of in printcap.

We would have to know what your app was, and what system/language it's 
written in, and what you were trying to accomplish, in order to suggest 
where and how (or even IF) to insert unform into the mix.

Brian K. White    br...@aljex.com    http://www.myspace.com/KEYofR
+++++[>+++[>+++++>+++++++<<-]<-]>>+.>.+++++.+++++++.-.[>+<---]>++.
filePro  BBx    Linux  SCO  FreeBSD    #callahans  Satriani  Filk!


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