filter(7) Apple Inc. filter(7)
NAME
filter - cups file conversion filter interface
SYNOPSIS
filter job user title num-copies options [ filename ]
DESCRIPTION
The CUPS filter interface provides a standard method for adding support
for new document types to CUPS. Each filter is capable of converting
from one or more input formats to another format that can either be
printed directly or piped into another filter to get it to a printable
format.
Filters must be capable of reading from a filename on the command-line
or from the standard input, copying the standard input to a temporary
file as required by the file format. All output must be sent to the
standard output.
The command name (argv[0]) is set to the name of the destination
printer but is also available in the PRINTER environment variable.
WARNING
CUPS filters are not meant to be run directly by the user. Aside from
the legacy System V interface issues (argv[0] is the printer name),
CUPS filters also expect specific environment variables and file
descriptors, and typically run in a user session that (on OS X) has
additional restrictions that affect how it runs. Unless you are a
developer and know what you are doing, please do not run filters
directly. Instead, use the cupsfilter(8) program to use the appropriate
filters to do the conversions you need.
OPTIONS
Options passed on the command-line typically do not include the default
choices the printer's PPD file. In addition, some options may be speci-
fied in multiple ways - "landscape" is a synonym for "orientation-
requested=4", "media" is a synonym for "PageSize", "PageRegion",
"InputSlot", and "MediaType", and "sides" is a synonym for the various
"Duplex" options. Non-raster filters must support both explicit and
implicit specification of PPD options - use the ppdMarkDefaults and
cupsMarkOptions functions in the CUPS library to use the correct map-
ping, and ppdFindMarkedChoice to get the user-selected choice.
Raster filters should use option choices set through the raster page
header, as those reflect the options in effect for a given page.
Options specified on the command-line determine the default values for
the entire job, which can be overridden on a per-page basis.
LOG MESSAGES
Messages sent to stderr are generally logged to printer-state-message
attribute and the current ErrorLog. Each line begins with a standard
prefix:
ALERT: message
Sets the printer-state-message attribute and adds the specified
message to the current ErrorLog using the "alert" log level.
ATTR: attribute=value [attribute=value]
Sets the named job or printer attribute(s). The following job
attributes can be set: "job-media-progress". The following printer
attributes can be set: "auth-info-required", "marker-colors",
"marker-high-levels", "marker-levels", "marker-low-levels",
"marker-message", "marker-names", "marker-types", "printer-alert",
and "printer-alert-description".
CRIT: message
Sets the printer-state-message attribute and adds the specified
message to the current ErrorLog using the "critical" log level.
DEBUG: message
Sets the printer-state-message attribute and adds the specified
message to the current ErrorLog using the "debug" log level.
DEBUG2: message
Sets the printer-state-message attribute and adds the specified
message to the current ErrorLog using the "debug2" log level.
EMERG: message
Sets the printer-state-message attribute and adds the specified
message to the current ErrorLog using the "emergency" log level.
ERROR: message
Sets the printer-state-message attribute and adds the specified
message to the current ErrorLog using the "error" log level.
INFO: message
Sets the printer-state-message attribute. If the current LogLevel
is set to "debug2", also adds the specified message to the current
ErrorLog using the "info" log level.
NOTICE: message
Sets the printer-state-message attribute and adds the specified
message to the current ErrorLog using the "notice" log level.
PAGE: page-number #-copies
PAGE: total #-pages
Adds an entry to the current PageLog. The first form adds #-copies
to the job-media-sheets-completed attribute. The second form sets
the job-media-sheets-completed attribute to #-pages.
PPD: Keyword=Value ... KeywordN=Value
Sets the named keywords in the printer's PPD file. This is typi-
cally used to update default option keywords such as DefaultPage-
Size and the various installable options in the PPD file.
STATE: printer-state-reason [printer-state-reason ...]
STATE: + printer-state-reason [printer-state-reason ...]
STATE: - printer-state-reason [printer-state-reason ...]
Sets, adds, or removes printer-state-reason keywords to the cur-
rent queue. Typically this is used to indicate media, ink, and
toner conditions on a printer.
WARNING: message
Sets the printer-state-message attribute and adds the specified
message to the current ErrorLog using the "warning" log level.
ENVIRONMENT VARIABLES
The following environment variables are defined by the CUPS server when
executing the filter:
CHARSET
The default text character set, typically utf-8.
CLASS
When a job is submitted to a printer class, contains the name of
the destination printer class. Otherwise this environment variable
will not be set.
CONTENT_TYPE
The MIME type associated with the file (e.g. application/post-
script).
CUPS_CACHEDIR
The directory for semi-persistent cache files can be found.
CUPS_DATADIR
The directory where data files can be found.
CUPS_FILETYPE
The type of file being printed: "job-sheet" for a banner page and
"document" for a regular print file.
CUPS_MAX_MESSAGE
The maximum size of a message sent to stderr, including any lead-
ing prefix and the trailing newline.
CUPS_SERVERROOT
The root directory of the server.
DEVICE_URI
The device-uri associated with the printer.
FINAL_CONTENT_TYPE
The MIME type associated with the printer (e.g. applica-
tion/vnd.cups-postscript).
LANG
The default language locale (typically C or en).
PATH
The standard execution path for external programs that may be run
by the filter.
PPD
The full pathname of the PostScript Printer Description (PPD) file
for this printer.
PRINTER
The name of the printer.
RIP_CACHE
The recommended amount of memory to use for Raster Image Proces-
sors (RIPs).
SOFTWARE
The name and version number of the server (typically CUPS/1.2).
TZ
The timezone of the server.
USER
The user executing the filter, typically "lp" or "root"; consult
the cupsd.conf(5) file for the current setting.
COMPATIBILITY
While the filter interface is compatible with System V interface
scripts, it will only work with the System V interface script as the
only filter. Typically the interface script will be provided via the
lpadmin(8) command using the -i option.
SEE ALSO
backend(7), cupsd(8), cupsfilter(8),
http://localhost:631/help
COPYRIGHT
Copyright 2007-2013 by Apple Inc.
18 May 2012 CUPS filter(7)
Mac OS X 10.9 - Generated Thu Oct 17 05:45:32 CDT 2013