4 .\" filter man page for CUPS.
6 .\" Copyright 2007-2014 by Apple Inc.
7 .\" Copyright 1997-2007 by Easy Software Products.
9 .\" These coded instructions, statements, and computer programs are the
10 .\" property of Apple Inc. and are protected by Federal copyright
11 .\" law. Distribution and use rights are outlined in the file "LICENSE.txt"
12 .\" which should have been included with this file. If this file is
13 .\" file is missing or damaged, see the license at "http://www.cups.org/".
15 .TH filter 7 "CUPS" "4 April 2014" "Apple Inc."
17 filter \- cups file conversion filter interface
30 \fB#include <cups/cups.h>\fR
32 \fBssize_t cupsBackChannelRead\fR(\fBchar *\fIbuffer\fR, \fBsize_t \fIbytes\fR,
33 \fBdouble \fItimeout\fR);
35 \fBcups_sc_status_t cupsSideChannelDoRequest\fR(\fBcups_sc_command_t \fIcommand\fR,
36 \fBchar *\fIdata\fR, \fBint *\fIdatalen\fR,
37 \fBdouble \fItimeout\fR);
39 \fB#include <cups/ppd.h>\fR
41 \fBconst char *cupsGetOption\fR(\fBconst char *\fIname\fR, \fBint \fInum_options\fR,
42 \fBcups_option_t *\fIoptions\fR);
44 \fBint cupsMarkOptions\fR(\fBppd_file_t *\fIppd\fR, \fBint \fInum_options\fR,
45 \fBcups_option_t *\fIoptions\fR);
47 \fBint cupsParseOptions\fR(\fBconst char *\fIarg\fR, \fBint \fInum_options\fR,
48 \fBcups_option_t **\fIoptions\fR);
50 \fBppd_choice_t *ppdFindMarkedChoice\fR(\fBppd_file_t *\fIppd\fR, \fBconst char *\fIkeyword\fR);
52 \fBvoid ppdMarkDefaults\fR(\fBppd_file_t *\fIppd\fR);
54 \fBppd_file_t *ppdOpenFile\fR(\fBconst char *\fIfilename\fR);
57 The CUPS filter interface provides a standard method for adding support for new document types or printers to CUPS.
58 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.
60 Filters \fBMUST\fR 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.
61 All output \fBMUST\fR be sent to the standard output.
62 Filters \fBMUST NOT\fR attempt to communicate directly with the printer, other processes, or other services.
64 The command name (\fIargv[0]\fR) is set to the name of the destination printer but is also available in the \fBPRINTER\fI environment variable.
66 Options are passed in \fIargv[5]\fR and are encoded from the corresponding IPP attributes used when the job was submitted. Use the
67 .BR cupsParseOptions ()
68 function to load the options into a \fBcups_option_t\fR array and the
70 function to get the value of a specific attribute.
71 Be careful to look for common aliases of IPP attributes such as "lansdscape" for the IPP "orientation-requested" attribute.
73 Options passed on the command-line typically do not include the default choices the printer's PPD file. Use the
74 .BR ppdMarkDefaults ()
76 .BR cupsMarkOptions ()
77 functions in the CUPS library to apply the options to the PPD defaults and map any IPP attributes to the corresponding PPD options.
79 .BR ppdFindMarkedChoice ()
80 to get the user-selected choice for a PPD option. For example, a filter might use the following code to determine the current value of the \fBDuplex\fR PPD option:
83 ppd_file_t *ppd = ppdOpenFile(getenv("PPD"));
84 cups_option_t *options = NULL;
85 int num_options = cupsParseOptions(argv[5], 0, &options);
88 cupsMarkOptions(ppd, num_options, options);
90 ppd_choice_t *choice = ppdFindMarkedChoice(ppd, "Duplex");
93 Raster filters should use option choices set through the raster page header, as those reflect the options in effect for a given page.
94 Options specified on the command-line determine the default values for the entire job, which can be overridden on a per-page basis.
96 Messages sent to the standard error are generally stored in the printer's "printer-state-message" attribute and the current \fBErrorLog\fR file.
97 Each line begins with a standard prefix:
99 \fBALERT: \fImessage\fR
100 Sets the "printer-state-message" attribute and adds the specified message to the current \fBErrorLog\fR using the "alert" log level.
102 \fBATTR: \fIattribute=value \fR[ \fI... attribute=value\fR]
103 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:
104 "auth-info-required", "marker-colors", "marker-high-levels", "marker-levels",
105 "marker-low-levels", "marker-message", "marker-names", "marker-types",
106 "printer-alert", and "printer-alert-description".
108 \fBCRIT: \fImessage\fR
109 Sets the "printer-state-message" attribute and adds the specified message to the current \fBErrorLog\fR using the "critical" log level.
111 \fBDEBUG: \fImessage\fR
112 Adds the specified message to the current \fBErrorLog\fR using the "debug" log level.
113 \fBDEBUG\fR messages are never stored in the "printer-state-message" attribute.
115 \fBDEBUG2: \fImessage\fR
117 Adds the specified message to the current \fBErrorLog\fR using the "debug2" log level.
118 \fBDEBUG2\fR messages are never stored in the "printer-state-message" attribute.
120 \fBEMERG: \fImessage\fR
121 Sets the "printer-state-message" attribute and adds the specified message to the current \fBErrorLog\fR using the "emergency" log level.
123 \fBERROR:\fI message\fR
124 Sets the "printer-state-message" attribute and adds the specified message to the current \fBErrorLog\fR using the "error" log level.
126 \fBINFO:\fI message\fR
127 Sets the "printer-state-message" attribute. If the current \fBLogLevel\fR is set to "debug2", also adds the specified message to the current \fBErrorLog\fR using the "info" log level.
129 \fBNOTICE:\fI message\fR
130 Sets the "printer-state-message" attribute and adds the specified message to the current \fBErrorLog\fR using the "notice" log level.
132 \fBPAGE:\fI page-number #-copies\fR
134 \fBPAGE:\fI total #-pages\fR
135 Adds an entry to the current \fBPageLog\fR. The first form adds \fI#-copies\fR to the "job-media-sheets-completed" attribute. The second form sets the "job-media-sheets-completed" attribute to \fI#-pages\fR.
137 \fBPPD:\fI Keyword=Value\fR [ \fI... KeywordN=Value\fR ]
138 Sets the named keywords in the printer's PPD file. This is typically used to update default option keywords such as \fBDefaultPageSize\fR and the various installable options in the PPD file.
140 \fBSTATE:\fI printer-state-reason \fR[ \fI... printer-state-reason\fR ]
142 \fBSTATE: +\fI printer-state-reason \fR[ \fI... printer-state-reason\fR ]
144 \fBSTATE: -\fI printer-state-reason \fR[ \fI... printer-state-reason\fR ]
145 Sets, adds, or removes "printer-state-reason" keywords for the current queue. Typically this is used to indicate media, ink, and toner conditions on a printer.
147 \fBWARNING:\fI message\fR
148 Sets the "printer-state-message" attribute and adds the specified message to the current \fBErrorLog\fR using the "warning" log level.
149 .SH ENVIRONMENT VARIABLES
150 The following environment variables are defined by the CUPS
151 server when executing the filter:
154 The default text character set, typically "utf-8".
157 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.
160 The MIME media type associated with the submitted job file, for example "application/postscript".
163 The directory where semi-persistent cache files can be found and stored.
166 The directory where data files can be found.
169 The type of file being printed: "job-sheet" for a banner page and "document"
170 for a regular print file.
173 The maximum size of a message sent to \fIstderr\fR, including any leading prefix and the trailing newline.
176 The root directory of the server.
178 .B FINAL_CONTENT_TYPE
179 The MIME media type associated with the output destined for the printer, for example "application/vnd.cups-postscript".
182 The default language locale (typically C or en).
185 The standard execution path for external programs that may be run by the filter.
188 The full pathname of the PostScript Printer Description (PPD) file for this printer.
191 The name of the printer.
194 The recommended amount of memory to use for Raster Image Processors (RIPs).
197 The name and version number of the server (typically CUPS/\fImajor.minor\fR).
200 The timezone of the server.
203 The user executing the filter, typically "lp" or "root"; consult the \fIcups-files.conf\fR file for the current setting.
205 While the filter interface is compatible with System V interface
206 scripts, it will only work with the System V interface script as the
207 only filter. Typically the interface script will be provided via the
208 \fIlpadmin(8)\fR command using the \fI-i\fR option.
210 CUPS filters are not meant to be run directly by the user.
211 Aside from the legacy System V interface issues (\fIargv[0]\fR 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.
212 Unless you are a developer and know what you are doing, please do not run filters directly.
215 program to use the appropriate filters to do the conversions you need.
219 .BR cups-files.conf (5),
223 CUPS Online Help (http://localhost:631/help)
225 Copyright \[co] 2007-2014 by Apple Inc.