CPAN
CPAN(3) User Contributed Perl Documentation CPAN(3)
NAME
CPAN - query, download and build perl modules from CPAN sites
SYNOPSIS
Interactive mode:
perl -MCPAN -e shell
--or--
cpan
Basic commands:
# Modules:
cpan> install Acme::Meta # in the shell
CPAN::Shell->install("Acme::Meta"); # in perl
# Distributions:
cpan> install NWCLARK/Acme-Meta-0.02.tar.gz # in the shell
CPAN::Shell->
install("NWCLARK/Acme-Meta-0.02.tar.gz"); # in perl
# module objects:
$mo = CPAN::Shell->expandany($mod);
$mo = CPAN::Shell->expand("Module",$mod); # same thing
# distribution objects:
$do = CPAN::Shell->expand("Module",$mod)->distribution;
$do = CPAN::Shell->expandany($distro); # same thing
$do = CPAN::Shell->expand("Distribution",
$distro); # same thing
DESCRIPTION
The CPAN module automates or at least simplifies the make and install
of perl modules and extensions. It includes some primitive searching
capabilities and knows how to use Net::FTP or LWP or some external
download clients to fetch the distributions from the net.
These are fetched from one or more of the mirrored CPAN (Comprehensive
Perl Archive Network) sites and unpacked in a dedicated directory.
The CPAN module also supports the concept of named and versioned bun-
dles of modules. Bundles simplify the handling of sets of related mod-
ules. See Bundles below.
The package contains a session manager and a cache manager. The session
manager keeps track of what has been fetched, built and installed in
the current session. The cache manager keeps track of the disk space
occupied by the make processes and deletes excess space according to a
simple FIFO mechanism.
All methods provided are accessible in a programmer style and in an
interactive shell style.
CPAN::shell([$prompt, $command]) Starting Interactive Mode
The interactive mode is entered by running
perl -MCPAN -e shell
or
cpan
which puts you into a readline interface. If "Term::ReadKey" and either
"Term::ReadLine::Perl" or "Term::ReadLine::Gnu" are installed it sup-
ports both history and command completion.
Once you are on the command line, type "h" to get a one page help
screen and the rest should be self-explanatory.
The function call "shell" takes two optional arguments, one is the
prompt, the second is the default initial command line (the latter only
works if a real ReadLine interface module is installed).
The most common uses of the interactive modes are
Searching for authors, bundles, distribution files and modules
There are corresponding one-letter commands "a", "b", "d", and "m"
for each of the four categories and another, "i" for any of the men-
tioned four. Each of the four entities is implemented as a class with
slightly differing methods for displaying an object.
Arguments you pass to these commands are either strings exactly
matching the identification string of an object or regular expres-
sions that are then matched case-insensitively against various
attributes of the objects. The parser recognizes a regular expression
only if you enclose it between two slashes.
The principle is that the number of found objects influences how an
item is displayed. If the search finds one item, the result is dis-
played with the rather verbose method "as_string", but if we find
more than one, we display each object with the terse method
"as_glimpse".
"get", "make", "test", "install", "clean" modules or distributions
These commands take any number of arguments and investigate what is
necessary to perform the action. If the argument is a distribution
file name (recognized by embedded slashes), it is processed. If it is
a module, CPAN determines the distribution file in which this module
is included and processes that, following any dependencies named in
the module's META.yml or Makefile.PL (this behavior is controlled by
the configuration parameter "prerequisites_policy".)
"get" downloads a distribution file and untars or unzips it, "make"
builds it, "test" runs the test suite, and "install" installs it.
Any "make" or "test" are run unconditionally. An
install <distribution_file>
also is run unconditionally. But for
install <module>
CPAN checks if an install is actually needed for it and prints module
up to date in the case that the distribution file containing the mod-
ule doesn't need to be updated.
CPAN also keeps track of what it has done within the current session
and doesn't try to build a package a second time regardless if it
succeeded or not. It does not repeat a test run if the test has been
run successfully before. Same for install runs.
The "force" pragma may precede another command (currently: "get",
"make", "test", or "install") and executes the command from scratch
and tries to continue in case of some errors. See the section below
on the "force" and the "fforce" pragma.
The "notest" pragma may be used to skip the test part in the build
process.
Example:
cpan> notest install Tk
A "clean" command results in a
make clean
being executed within the distribution file's working directory.
"readme", "perldoc", "look" module or distribution
"readme" displays the README file of the associated distribution.
"Look" gets and untars (if not yet done) the distribution file,
changes to the appropriate directory and opens a subshell process in
that directory. "perldoc" displays the pod documentation of the mod-
ule in html or plain text format.
"ls" author
"ls" globbing_expression
The first form lists all distribution files in and below an author's
CPAN directory as they are stored in the CHECKUMS files distributed
on CPAN. The listing goes recursive into all subdirectories.
The second form allows to limit or expand the output with shell glob-
bing as in the following examples:
ls JV/make*
ls GSAR/*make*
ls */*make*
The last example is very slow and outputs extra progress indicators
that break the alignment of the result.
Note that globbing only lists directories explicitly asked for, for
example FOO/* will not list FOO/bar/Acme-Sthg-n.nn.tar.gz. This may
be regarded as a bug and may be changed in future versions.
"failed"
The "failed" command reports all distributions that failed on one of
"make", "test" or "install" for some reason in the currently running
shell session.
Persistence between sessions
If the "YAML" or the c<YAML::Syck> module is installed a record of
the internal state of all modules is written to disk after each step.
The files contain a signature of the currently running perl version
for later perusal.
If the configurations variable "build_dir_reuse" is set to a true
value, then CPAN.pm reads the collected YAML files. If the stored
signature matches the currently running perl the stored state is
loaded into memory such that effectively persistence between sessions
is established.
The "force" and the "fforce" pragma
To speed things up in complex installation scenarios, CPAN.pm keeps
track of what it has already done and refuses to do some things a
second time. A "get", a "make", and an "install" are not repeated. A
"test" is only repeated if the previous test was unsuccessful. The
diagnostic message when CPAN.pm refuses to do something a second time
is one of Has already been "unwrapped|made|tested successfully" or
something similar. Another situation where CPAN refuses to act is an
"install" if the according "test" was not successful.
In all these cases, the user can override the goatish behaviour by
prepending the command with the word force, for example:
cpan> force get Foo
cpan> force make AUTHOR/Bar-3.14.tar.gz
cpan> force test Baz
cpan> force install Acme::Meta
Each forced command is executed with the according part of its memory
erased.
The "fforce" pragma is a variant that emulates a "force get" which
erases the entire memory followed by the action specified, effec-
tively restarting the whole get/make/test/install procedure from
scratch.
Lockfile
Interactive sessions maintain a lockfile, per default
"~/.cpan/.lock". Batch jobs can run without a lockfile and do not
disturb each other.
The shell offers to run in degraded mode when another process is
holding the lockfile. This is an experimental feature that is not yet
tested very well. This second shell then does not write the history
file, does not use the metadata file and has a different prompt.
Signals
CPAN.pm installs signal handlers for SIGINT and SIGTERM. While you
are in the cpan-shell it is intended that you can press "^C" anytime
and return to the cpan-shell prompt. A SIGTERM will cause the cpan-
shell to clean up and leave the shell loop. You can emulate the
effect of a SIGTERM by sending two consecutive SIGINTs, which usually
means by pressing "^C" twice.
CPAN.pm ignores a SIGPIPE. If the user sets inactivity_timeout, a
SIGALRM is used during the run of the "perl Makefile.PL" or "perl
Build.PL" subprocess.
CPAN::Shell
The commands that are available in the shell interface are methods in
the package CPAN::Shell. If you enter the shell command, all your input
is split by the Text::ParseWords::shellwords() routine which acts like
most shells do. The first word is being interpreted as the method to be
called and the rest of the words are treated as arguments to this
method. Continuation lines are supported if a line ends with a literal
backslash.
autobundle
"autobundle" writes a bundle file into the "$CPAN::Con-
fig->{cpan_home}/Bundle" directory. The file contains a list of all
modules that are both available from CPAN and currently installed
within @INC. The name of the bundle file is based on the current date
and a counter.
hosts
Note: this feature is still in alpha state and may change in future
versions of CPAN.pm
This commands provides a statistical overview over recent download
activities. The data for this is collected in the YAML file "FTP-
stats.yml" in your "cpan_home" directory. If no YAML module is config-
ured or YAML not installed, then no stats are provided.
mkmyconfig
mkmyconfig() writes your own CPAN::MyConfig file into your ~/.cpan/
directory so that you can save your own preferences instead of the sys-
tem wide ones.
recompile
recompile() is a very special command in that it takes no argument and
runs the make/test/install cycle with brute force over all installed
dynamically loadable extensions (aka XS modules) with 'force' in
effect. The primary purpose of this command is to finish a network
installation. Imagine, you have a common source tree for two different
architectures. You decide to do a completely independent fresh instal-
lation. You start on one architecture with the help of a Bundle file
produced earlier. CPAN installs the whole Bundle for you, but when you
try to repeat the job on the second architecture, CPAN responds with a
"Foo up to date" message for all modules. So you invoke CPAN's recom-
pile on the second architecture and you're done.
Another popular use for "recompile" is to act as a rescue in case your
perl breaks binary compatibility. If one of the modules that CPAN uses
is in turn depending on binary compatibility (so you cannot run CPAN
commands), then you should try the CPAN::Nox module for recovery.
report Bundle|Distribution|Module
The "report" command temporarily turns on the "test_report" config
variable, then runs the "force test" command with the given arguments.
The "force" pragma is used to re-run the tests and repeat every step
that might have failed before.
upgrade [Module|/Regex/]...
The "upgrade" command first runs an "r" command with the given argu-
ments and then installs the newest versions of all modules that were
listed by that.
The four "CPAN::*" Classes: Author, Bundle, Module, Distribution
Although it may be considered internal, the class hierarchy does matter
for both users and programmer. CPAN.pm deals with above mentioned four
classes, and all those classes share a set of methods. A classical sin-
gle polymorphism is in effect. A metaclass object registers all objects
of all kinds and indexes them with a string. The strings referencing
objects have a separated namespace (well, not completely separated):
Namespace Class
words containing a "/" (slash) Distribution
words starting with Bundle:: Bundle
everything else Module or Author
Modules know their associated Distribution objects. They always refer
to the most recent official release. Developers may mark their releases
as unstable development versions (by inserting an underbar into the
module version number which will also be reflected in the distribution
name when you run 'make dist'), so the really hottest and newest dis-
tribution is not always the default. If a module Foo circulates on
CPAN in both version 1.23 and 1.23_90, CPAN.pm offers a convenient way
to install version 1.23 by saying
install Foo
This would install the complete distribution file (say
BAR/Foo-1.23.tar.gz) with all accompanying material. But if you would
like to install version 1.23_90, you need to know where the distribu-
tion file resides on CPAN relative to the authors/id/ directory. If the
author is BAR, this might be BAR/Foo-1.23_90.tar.gz; so you would have
to say
install BAR/Foo-1.23_90.tar.gz
The first example will be driven by an object of the class CPAN::Mod-
ule, the second by an object of class CPAN::Distribution.
Integrating local directories
Note: this feature is still in alpha state and may change in future
versions of CPAN.pm
Distribution objects are normally distributions from the CPAN, but
there is a slightly degenerate case for Distribution objects, too, of
projects held on the local disk. These distribution objects have the
same name as the local directory and end with a dot. A dot by itself is
also allowed for the current directory at the time CPAN.pm was used.
All actions such as "make", "test", and "install" are applied directly
to that directory. This gives the command "cpan ." an interesting
touch: while the normal mantra of installing a CPAN module without
CPAN.pm is one of
perl Makefile.PL perl Build.PL
( go and get prerequisites )
make ./Build
make test ./Build test
make install ./Build install
the command "cpan ." does all of this at once. It figures out which of
the two mantras is appropriate, fetches and installs all prerequisites,
cares for them recursively and finally finishes the installation of the
module in the current directory, be it a CPAN module or not.
The typical usage case is for private modules or working copies of
projects from remote repositories on the local disk.
CONFIGURATION
When the CPAN module is used for the first time, a configuration dialog
tries to determine a couple of site specific options. The result of the
dialog is stored in a hash reference $CPAN::Config in a file CPAN/Con-
fig.pm.
The default values defined in the CPAN/Config.pm file can be overridden
in a user specific file: CPAN/MyConfig.pm. Such a file is best placed
in $HOME/.cpan/CPAN/MyConfig.pm, because $HOME/.cpan is added to the
search path of the CPAN module before the use() or require() state-
ments. The mkmyconfig command writes this file for you.
The "o conf" command has various bells and whistles:
completion support
If you have a ReadLine module installed, you can hit TAB at any
point of the commandline and "o conf" will offer you completion for
the built-in subcommands and/or config variable names.
displaying some help: o conf help
Displays a short help
displaying current values: o conf [KEY]
Displays the current value(s) for this config variable. Without KEY
displays all subcommands and config variables.
Example:
o conf shell
changing of scalar values: o conf KEY VALUE
Sets the config variable KEY to VALUE. The empty string can be
specified as usual in shells, with '' or ""
Example:
o conf wget /usr/bin/wget
changing of list values: o conf KEY SHIFT|UNSHIFT|PUSH|POP|SPLICE|LIST
If a config variable name ends with "list", it is a list. "o conf
KEY shift" removes the first element of the list, "o conf KEY pop"
removes the last element of the list. "o conf KEYS unshift LIST"
prepends a list of values to the list, "o conf KEYS push LIST"
appends a list of valued to the list.
Likewise, "o conf KEY splice LIST" passes the LIST to the according
splice command.
Finally, any other list of arguments is taken as a new list value
for the KEY variable discarding the previous value.
Examples:
o conf urllist unshift http://cpan.dev.local/CPAN
o conf urllist splice 3 1
o conf urllist http://cpan1.local http://cpan2.local ftp://ftp.perl.org
reverting to saved: o conf defaults
Reverts all config variables to the state in the saved config file.
saving the config: o conf commit
Saves all config variables to the current config file (CPAN/Con-
fig.pm or CPAN/MyConfig.pm that was loaded at start).
The configuration dialog can be started any time later again by issuing
the command " o conf init " in the CPAN shell. A subset of the configu-
ration dialog can be run by issuing "o conf init WORD" where WORD is
any valid config variable or a regular expression.
Config Variables
Currently the following keys in the hash reference $CPAN::Config are
defined:
applypatch path to external prg
auto_commit commit all changes to config variables to disk
build_cache size of cache for directories to build modules
build_dir locally accessible directory to build modules
build_dir_reuse boolean if distros in build_dir are persistent
build_requires_install_policy
to install or not to install when a module is
only needed for building. yes|no|ask/yes|ask/no
bzip2 path to external prg
cache_metadata use serializer to cache metadata
commands_quote prefered character to use for quoting external
commands when running them. Defaults to double
quote on Windows, single tick everywhere else;
can be set to space to disable quoting
check_sigs if signatures should be verified
colorize_debug Term::ANSIColor attributes for debugging output
colorize_output boolean if Term::ANSIColor should colorize output
colorize_print Term::ANSIColor attributes for normal output
colorize_warn Term::ANSIColor attributes for warnings
commandnumber_in_prompt
boolean if you want to see current command number
cpan_home local directory reserved for this package
curl path to external prg
dontload_hash DEPRECATED
dontload_list arrayref: modules in the list will not be
loaded by the CPAN::has_inst() routine
ftp path to external prg
ftp_passive if set, the envariable FTP_PASSIVE is set for downloads
ftp_proxy proxy host for ftp requests
getcwd see below
gpg path to external prg
gzip location of external program gzip
histfile file to maintain history between sessions
histsize maximum number of lines to keep in histfile
http_proxy proxy host for http requests
inactivity_timeout breaks interactive Makefile.PLs or Build.PLs
after this many seconds inactivity. Set to 0 to
never break.
index_expire after this many days refetch index files
inhibit_startup_message
if true, does not print the startup message
keep_source_where directory in which to keep the source (if we do)
lynx path to external prg
make location of external make program
make_arg arguments that should always be passed to 'make'
make_install_make_command
the make command for running 'make install', for
example 'sudo make'
make_install_arg same as make_arg for 'make install'
makepl_arg arguments passed to 'perl Makefile.PL'
mbuild_arg arguments passed to './Build'
mbuild_install_arg arguments passed to './Build install'
mbuild_install_build_command
command to use instead of './Build' when we are
in the install stage, for example 'sudo ./Build'
mbuildpl_arg arguments passed to 'perl Build.PL'
ncftp path to external prg
ncftpget path to external prg
no_proxy don't proxy to these hosts/domains (comma separated list)
pager location of external program more (or any pager)
password your password if you CPAN server wants one
patch path to external prg
prefer_installer legal values are MB and EUMM: if a module comes
with both a Makefile.PL and a Build.PL, use the
former (EUMM) or the latter (MB); if the module
comes with only one of the two, that one will be
used in any case
prerequisites_policy
what to do if you are missing module prerequisites
('follow' automatically, 'ask' me, or 'ignore')
prefs_dir local directory to store per-distro build options
proxy_user username for accessing an authenticating proxy
proxy_pass password for accessing an authenticating proxy
randomize_urllist add some randomness to the sequence of the urllist
scan_cache controls scanning of cache ('atstart' or 'never')
shell your favorite shell
show_upload_date boolean if commands should try to determine upload date
tar location of external program tar
term_is_latin if true internal UTF-8 is translated to ISO-8859-1
(and nonsense for characters outside latin range)
term_ornaments boolean to turn ReadLine ornamenting on/off
test_report email test reports (if CPAN::Reporter is installed)
unzip location of external program unzip
urllist arrayref to nearby CPAN sites (or equivalent locations)
use_sqlite use CPAN::SQLite for metadata storage (fast and lean)
username your username if you CPAN server wants one
wait_list arrayref to a wait server to try (See CPAN::WAIT)
wget path to external prg
yaml_module which module to use to read/write YAML files
You can set and query each of these options interactively in the cpan
shell with the "o conf" or the "o conf init" command as specified
below.
"o conf <scalar option>"
prints the current value of the scalar option
"o conf <scalar option> <value>"
Sets the value of the scalar option to value
"o conf <list option>"
prints the current value of the list option in MakeMaker's neatvalue
format.
"o conf <list option> [shift|pop]"
shifts or pops the array in the list option variable
"o conf <list option> [unshift|push|splice] <list>"
works like the corresponding perl commands.
interactive editing: o conf init [MATCH|LIST]
Runs an interactive configuration dialog for matching variables.
Without argument runs the dialog over all supported config variables.
To specify a MATCH the argument must be enclosed by slashes.
Examples:
o conf init ftp_passive ftp_proxy
o conf init /color/
Note: this method of setting config variables often provides more
explanation about the functioning of a variable than the manpage.
CPAN::anycwd($path): Note on config variable getcwd
CPAN.pm changes the current working directory often and needs to deter-
mine its own current working directory. Per default it uses Cwd::cwd
but if this doesn't work on your system for some reason, alternatives
can be configured according to the following table:
cwd Calls Cwd::cwd
getcwd
Calls Cwd::getcwd
fastcwd
Calls Cwd::fastcwd
backtickcwd
Calls the external command cwd.
Note on the format of the urllist parameter
urllist parameters are URLs according to RFC 1738. We do a little
guessing if your URL is not compliant, but if you have problems with
"file" URLs, please try the correct format. Either:
file://localhost/whatever/ftp/pub/CPAN/
or
file:///home/ftp/pub/CPAN/
The urllist parameter has CD-ROM support
The "urllist" parameter of the configuration table contains a list of
URLs that are to be used for downloading. If the list contains any
"file" URLs, CPAN always tries to get files from there first. This fea-
ture is disabled for index files. So the recommendation for the owner
of a CD-ROM with CPAN contents is: include your local, possibly out-
dated CD-ROM as a "file" URL at the end of urllist, e.g.
o conf urllist push file://localhost/CDROM/CPAN
CPAN.pm will then fetch the index files from one of the CPAN sites that
come at the beginning of urllist. It will later check for each module
if there is a local copy of the most recent version.
Another peculiarity of urllist is that the site that we could success-
fully fetch the last file from automatically gets a preference token
and is tried as the first site for the next request. So if you add a
new site at runtime it may happen that the previously preferred site
will be tried another time. This means that if you want to disallow a
site for the next transfer, it must be explicitly removed from urllist.
Maintaining the urllist parameter
If you have YAML.pm (or some other YAML module configured in "yaml_mod-
ule") installed, CPAN.pm collects a few statistical data about recent
downloads. You can view the statistics with the "hosts" command or
inspect them directly by looking into the "FTPstats.yml" file in your
"cpan_home" directory.
To get some interesting statistics it is recommended to set the "ran-
domize_urllist" parameter that introduces some amount of randomness
into the URL selection.
The "requires" and "build_requires" dependency declarations
Since CPAN.pm version 1.88_51 modules declared as "build_requires" by a
distribution are treated differently depending on the config variable
"build_requires_install_policy". By setting
"build_requires_install_policy" to "no" such a module is not being
installed. It is only built and tested and then kept in the list of
tested but uninstalled modules. As such it is available during the
build of the dependent module by integrating the path to the
"blib/arch" and "blib/lib" directories in the environment variable
PERL5LIB. If "build_requires_install_policy" is set ti "yes", then both
modules declared as "requires" and those declared as "build_requires"
are treated alike. By setting to "ask/yes" or "ask/no", CPAN.pm asks
the user and sets the default accordingly.
Configuration for individual distributions (Distroprefs)
(Note: This feature has been introduced in CPAN.pm 1.8854 and is still
considered beta quality)
Distributions on the CPAN usually behave according to what we call the
CPAN mantra. Or since the event of Module::Build we should talk about
two mantras:
perl Makefile.PL perl Build.PL
make ./Build
make test ./Build test
make install ./Build install
But some modules cannot be built with this mantra. They try to get some
extra data from the user via the environment, extra arguments or inter-
actively thus disturbing the installation of large bundles like Pha-
lanx100 or modules with many dependencies like Plagger.
The distroprefs system of "CPAN.pm" addresses this problem by allowing
the user to specify extra informations and recipes in YAML files to
either
o pass additional arguments to one of the four commands,
o set environment variables
o instantiate an Expect object that reads from the console, waits for
some regular expressions and enters some answers
o temporarily override assorted "CPAN.pm" configuration variables
o disable the installation of an object altogether
See the YAML and Data::Dumper files that come with the "CPAN.pm" dis-
tribution in the "distroprefs/" directory for examples.
Filenames
The YAML files themselves must have the ".yml" extension, all other
files are ignored (for two exceptions see Fallback Data::Dumper and
Storable below). The containing directory can be specified in "CPAN.pm"
in the "prefs_dir" config variable. Try "o conf init prefs_dir" in the
CPAN shell to set and activate the distroprefs system.
Every YAML file may contain arbitrary documents according to the YAML
specification and every single document is treated as an entity that
can specify the treatment of a single distribution.
The names of the files can be picked freely, "CPAN.pm" always reads all
files (in alphabetical order) and takes the key "match" (see below in
Language Specs) as a hashref containing match criteria that determine
if the current distribution matches the YAML document or not.
Fallback Data::Dumper and Storable
If neither your configured "yaml_module" nor YAML.pm is installed
CPAN.pm falls back to using Data::Dumper and Storable and looks for
files with the extensions ".dd" or ".st" in the "prefs_dir" directory.
These files are expected to contain one or more hashrefs. For
Data::Dumper generated files, this is expected to be done with by
defining $VAR1, $VAR2, etc. The YAML shell would produce these with the
command
ysh < somefile.yml > somefile.dd
For Storable files the rule is that they must be constructed such that
"Storable::retrieve(file)" returns an array reference and the array
elements represent one distropref object each. The conversion from YAML
would look like so:
perl -MYAML=LoadFile -MStorable=nstore -e '
@y=LoadFile(shift);
nstore(\@y, shift)' somefile.yml somefile.st
In bootstrapping situations it is usually sufficient to translate only
a few YAML files to Data::Dumper for the crucial modules like
"YAML::Syck", "YAML.pm" and "Expect.pm". If you prefer Storable over
Data::Dumper, remember to pull out a Storable version that writes an
older format than all the other Storable versions that will need to
read them.
Blueprint
The following example contains all supported keywords and structures
with the exception of "eexpect" which can be used instead of "expect".
---
comment: "Demo"
match:
module: "Dancing::Queen"
distribution: "^CHACHACHA/Dancing-"
perl: "/usr/local/cariba-perl/bin/perl"
perlconfig:
archname: "freebsd"
disabled: 1
cpanconfig:
make: gmake
pl:
args:
- "--somearg=specialcase"
env: {}
expect:
- "Which is your favorite fruit"
- "apple\n"
make:
args:
- all
- extra-all
env: {}
expect: []
commendline: "echo SKIPPING make"
test:
args: []
env: {}
expect: []
install:
args: []
env:
WANT_TO_INSTALL: YES
expect:
- "Do you really want to install"
- "y\n"
patches:
- "ABCDE/Fedcba-3.14-ABCDE-01.patch"
Language Specs
Every YAML document represents a single hash reference. The valid keys
in this hash are as follows:
comment [scalar]
A comment
cpanconfig [hash]
Temporarily override assorted "CPAN.pm" configuration variables.
Supported are: "build_requires_install_policy", "check_sigs",
"make", "make_install_make_command", "prefer_installer",
"test_report". Please report as a bug when you need another one
supported.
disabled [boolean]
Specifies that this distribution shall not be processed at all.
goto [string]
The canonical name of a delegate distribution that shall be
installed instead. Useful when a new version, although it tests OK
itself, breaks something else or a developer release or a fork is
already uploaded that is better than the last released version.
install [hash]
Processing instructions for the "make install" or "./Build install"
phase of the CPAN mantra. See below under Processiong Instructions.
make [hash]
Processing instructions for the "make" or "./Build" phase of the
CPAN mantra. See below under Processiong Instructions.
match [hash]
A hashref with one or more of the keys "distribution", "modules",
"perl", and "perlconfig" that specify if a document is targeted at
a specific CPAN distribution or installation.
The corresponding values are interpreted as regular expressions.
The "distribution" related one will be matched against the canoni-
cal distribution name, e.g. "AUTHOR/Foo-Bar-3.14.tar.gz".
The "module" related one will be matched against all modules con-
tained in the distribution until one module matches.
The "perl" related one will be matched against $^X.
The value associated with "perlconfig" is itself a hashref that is
matched against corresponding values in the %Config::Config hash
living in the " Config.pm " module.
If more than one restriction of "module", "distribution", and
"perl" is specified, the results of the separately computed match
values must all match. If this is the case then the hashref repre-
sented by the YAML document is returned as the preference structure
for the current distribution.
patches [array]
An array of patches on CPAN or on the local disk to be applied in
order via the external patch program. If the value for the "-p"
parameter is 0 or 1 is determined by reading the patch beforehand.
Note: if the "applypatch" program is installed and "CPAN::Config"
knows about it and a patch is written by the "makepatch" program,
then "CPAN.pm" lets "applypatch" apply the patch. Both "makepatch"
and "applypatch" are available from CPAN in the "JV/makepatch-*"
distribution.
pl [hash]
Processing instructions for the "perl Makefile.PL" or "perl
Build.PL" phase of the CPAN mantra. See below under Processiong
Instructions.
test [hash]
Processing instructions for the "make test" or "./Build test" phase
of the CPAN mantra. See below under Processiong Instructions.
Processing Instructions
args [array]
Arguments to be added to the command line
commandline
A full commandline that will be executed as it stands by a system
call. During the execution the environment variable PERL will is
set to $^X. If "commandline" is specified, the content of "args" is
not used.
eexpect [hash]
Extended "expect". This is a hash reference with three allowed
keys, "mode", "timeout", and "talk".
"mode" may have the values "deterministic" for the case where all
questions come in the order written down and "anyorder" for the
case where the questions may come in any order. The default mode is
"deterministic".
"timeout" denotes a timeout in seconds. Floating point timeouts are
OK. In the case of a "mode=deterministic" the timeout denotes the
timeout per question, in the case of "mode=anyorder" it denotes the
timeout per byte received from the stream or questions.
"talk" is a reference to an array that contains alternating ques-
tions and answers. Questions are regular expressions and answers
are literal strings. The Expect module will then watch the stream
coming from the execution of the external program ("perl Make-
file.PL", "perl Build.PL", "make", etc.).
In the case of "mode=deterministic" the CPAN.pm will inject the
according answer as soon as the stream matches the regular expres-
sion. In the case of "mode=anyorder" the CPAN.pm will answer a
question as soon as the timeout is reached for the next byte in the
input stream. In the latter case it removes the according ques-
tion/answer pair from the array, so if you want to answer the ques-
tion "Do you really want to do that" several times, then it must be
included in the array at least as often as you want this answer to
be given.
env [hash]
Environment variables to be set during the command
expect [array]
"expect: <array>" is a short notation for
eexpect:
mode: deterministic
timeout: 15
talk: <array>
Schema verification with "Kwalify"
If you have the "Kwalify" module installed (which is part of the Bun-
dle::CPANxxl), then all your distroprefs files are checked for syntac-
tical correctness.
Example Distroprefs Files
"CPAN.pm" comes with a collection of example YAML files. Note that
these are really just examples and should not be used without care
because they cannot fit everybody's purpose. After all the authors of
the packages that ask questions had a need to ask, so you should watch
their questions and adjust the examples to your environment and your
needs. You have beend warned:-)
PROGRAMMER'S INTERFACE
If you do not enter the shell, the available shell commands are both
available as methods ("CPAN::Shell->install(...)") and as functions in
the calling package ("install(...)"). Before calling low-level com-
mands it makes sense to initialize components of CPAN you need, e.g.:
CPAN::HandleConfig->load;
CPAN::Shell::setup_output;
CPAN::Index->reload;
High-level commands do such initializations automatically.
There's currently only one class that has a stable interface -
CPAN::Shell. All commands that are available in the CPAN shell are
methods of the class CPAN::Shell. Each of the commands that produce
listings of modules ("r", "autobundle", "u") also return a list of the
IDs of all modules within the list.
expand($type,@things)
The IDs of all objects available within a program are strings that
can be expanded to the corresponding real objects with the
"CPAN::Shell->expand("Module",@things)" method. Expand returns a list
of CPAN::Module objects according to the @things arguments given. In
scalar context it only returns the first element of the list.
expandany(@things)
Like expand, but returns objects of the appropriate type, i.e.
CPAN::Bundle objects for bundles, CPAN::Module objects for modules
and CPAN::Distribution objects for distributions. Note: it does not
expand to CPAN::Author objects.
Programming Examples
This enables the programmer to do operations that combine functional-
ities that are available in the shell.
# install everything that is outdated on my disk:
perl -MCPAN -e 'CPAN::Shell->install(CPAN::Shell->r)'
# install my favorite programs if necessary:
for $mod (qw(Net::FTP Digest::SHA Data::Dumper)){
CPAN::Shell->install($mod);
}
# list all modules on my disk that have no VERSION number
for $mod (CPAN::Shell->expand("Module","/./")){
next unless $mod->inst_file;
# MakeMaker convention for undefined $VERSION:
next unless $mod->inst_version eq "undef";
print "No VERSION in ", $mod->id, "\n";
}
# find out which distribution on CPAN contains a module:
print CPAN::Shell->expand("Module","Apache::Constants")->cpan_file
Or if you want to write a cronjob to watch The CPAN, you could list
all modules that need updating. First a quick and dirty way:
perl -e 'use CPAN; CPAN::Shell->r;'
If you don't want to get any output in the case that all modules are
up to date, you can parse the output of above command for the regular
expression //modules are up to date// and decide to mail the output
only if it doesn't match. Ick?
If you prefer to do it more in a programmer style in one single pro-
cess, maybe something like this suits you better:
# list all modules on my disk that have newer versions on CPAN
for $mod (CPAN::Shell->expand("Module","/./")){
next unless $mod->inst_file;
next if $mod->uptodate;
printf "Module %s is installed as %s, could be updated to %s from CPAN\n",
$mod->id, $mod->inst_version, $mod->cpan_version;
}
If that gives you too much output every day, you maybe only want to
watch for three modules. You can write
for $mod (CPAN::Shell->expand("Module","/Apache|LWP|CGI/")){
as the first line instead. Or you can combine some of the above
tricks:
# watch only for a new mod_perl module
$mod = CPAN::Shell->expand("Module","mod_perl");
exit if $mod->uptodate;
# new mod_perl arrived, let me know all update recommendations
CPAN::Shell->r;
Methods in the other Classes
CPAN::Author::as_glimpse()
Returns a one-line description of the author
CPAN::Author::as_string()
Returns a multi-line description of the author
CPAN::Author::email()
Returns the author's email address
CPAN::Author::fullname()
Returns the author's name
CPAN::Author::name()
An alias for fullname
CPAN::Bundle::as_glimpse()
Returns a one-line description of the bundle
CPAN::Bundle::as_string()
Returns a multi-line description of the bundle
CPAN::Bundle::clean()
Recursively runs the "clean" method on all items contained in the
bundle.
CPAN::Bundle::contains()
Returns a list of objects' IDs contained in a bundle. The associ-
ated objects may be bundles, modules or distributions.
CPAN::Bundle::force($method,@args)
Forces CPAN to perform a task that it normally would have refused
to do. Force takes as arguments a method name to be called and any
number of additional arguments that should be passed to the called
method. The internals of the object get the needed changes so that
CPAN.pm does not refuse to take the action. The "force" is passed
recursively to all contained objects. See also the section above on
the "force" and the "fforce" pragma.
CPAN::Bundle::get()
Recursively runs the "get" method on all items contained in the
bundle
CPAN::Bundle::inst_file()
Returns the highest installed version of the bundle in either @INC
or "$CPAN::Config-"{cpan_home}>. Note that this is different from
CPAN::Module::inst_file.
CPAN::Bundle::inst_version()
Like CPAN::Bundle::inst_file, but returns the $VERSION
CPAN::Bundle::uptodate()
Returns 1 if the bundle itself and all its members are uptodate.
CPAN::Bundle::install()
Recursively runs the "install" method on all items contained in the
bundle
CPAN::Bundle::make()
Recursively runs the "make" method on all items contained in the
bundle
CPAN::Bundle::readme()
Recursively runs the "readme" method on all items contained in the
bundle
CPAN::Bundle::test()
Recursively runs the "test" method on all items contained in the
bundle
CPAN::Distribution::as_glimpse()
Returns a one-line description of the distribution
CPAN::Distribution::as_string()
Returns a multi-line description of the distribution
CPAN::Distribution::author
Returns the CPAN::Author object of the maintainer who uploaded this
distribution
CPAN::Distribution::clean()
Changes to the directory where the distribution has been unpacked
and runs "make clean" there.
CPAN::Distribution::containsmods()
Returns a list of IDs of modules contained in a distribution file.
Only works for distributions listed in the 02pack-
ages.details.txt.gz file. This typically means that only the most
recent version of a distribution is covered.
CPAN::Distribution::cvs_import()
Changes to the directory where the distribution has been unpacked
and runs something like
cvs -d $cvs_root import -m $cvs_log $cvs_dir $userid v$version
there.
CPAN::Distribution::dir()
Returns the directory into which this distribution has been
unpacked.
CPAN::Distribution::force($method,@args)
Forces CPAN to perform a task that it normally would have refused
to do. Force takes as arguments a method name to be called and any
number of additional arguments that should be passed to the called
method. The internals of the object get the needed changes so that
CPAN.pm does not refuse to take the action. See also the section
above on the "force" and the "fforce" pragma.
CPAN::Distribution::get()
Downloads the distribution from CPAN and unpacks it. Does nothing
if the distribution has already been downloaded and unpacked within
the current session.
CPAN::Distribution::install()
Changes to the directory where the distribution has been unpacked
and runs the external command "make install" there. If "make" has
not yet been run, it will be run first. A "make test" will be
issued in any case and if this fails, the install will be canceled.
The cancellation can be avoided by letting "force" run the
"install" for you.
This install method has only the power to install the distribution
if there are no dependencies in the way. To install an object and
all of its dependencies, use CPAN::Shell->install.
Note that install() gives no meaningful return value. See upto-
date().
CPAN::Distribution::install_tested()
Install all the distributions that have been tested sucessfully but
not yet installed. See also "is_tested".
CPAN::Distribution::isa_perl()
Returns 1 if this distribution file seems to be a perl distribu-
tion. Normally this is derived from the file name only, but the
index from CPAN can contain a hint to achieve a return value of
true for other filenames too.
CPAN::Distribution::is_tested()
List all the distributions that have been tested sucessfully but
not yet installed. See also "install_tested".
CPAN::Distribution::look()
Changes to the directory where the distribution has been unpacked
and opens a subshell there. Exiting the subshell returns.
CPAN::Distribution::make()
First runs the "get" method to make sure the distribution is down-
loaded and unpacked. Changes to the directory where the distribu-
tion has been unpacked and runs the external commands "perl Make-
file.PL" or "perl Build.PL" and "make" there.
CPAN::Distribution::perldoc()
Downloads the pod documentation of the file associated with a dis-
tribution (in html format) and runs it through the external command
lynx specified in "$CPAN::Config-"{lynx}>. If lynx isn't available,
it converts it to plain text with external command html2text and
runs it through the pager specified in "$CPAN::Config-"{pager}>
CPAN::Distribution::prefs()
Returns the hash reference from the first matching YAML file that
the user has deposited in the "prefs_dir/" directory. The first
succeeding match wins. The files in the "prefs_dir/" are processed
alphabetically and the canonical distroname (e.g.
AUTHOR/Foo-Bar-3.14.tar.gz) is matched against the regular expres-
sions stored in the $root->{match}{distribution} attribute value.
Additionally all module names contained in a distribution are
matched agains the regular expressions in the $root->{match}{mod-
ule} attribute value. The two match values are ANDed together. Each
of the two attributes are optional.
CPAN::Distribution::prereq_pm()
Returns the hash reference that has been announced by a distribu-
tion as the the "requires" and "build_requires" elements. These can
be declared either by the "META.yml" (if authoritative) or can be
deposited after the run of "Build.PL" in the file "./_build/pre-
reqs" or after the run of "Makfile.PL" written as the "PREREQ_PM"
hash in a comment in the produced "Makefile". Note: this method
only works after an attempt has been made to "make" the distribu-
tion. Returns undef otherwise.
CPAN::Distribution::readme()
Downloads the README file associated with a distribution and runs
it through the pager specified in "$CPAN::Config-"{pager}>.
CPAN::Distribution::reports()
Downloads report data for this distribution from cpan-
testers.perl.org and displays a subset of them.
CPAN::Distribution::read_yaml()
Returns the content of the META.yml of this distro as a hashref.
Note: works only after an attempt has been made to "make" the dis-
tribution. Returns undef otherwise. Also returns undef if the con-
tent of META.yml is not authoritative. (The rules about what
exactly makes the content authoritative are still in flux.)
CPAN::Distribution::test()
Changes to the directory where the distribution has been unpacked
and runs "make test" there.
CPAN::Distribution::uptodate()
Returns 1 if all the modules contained in the distribution are
uptodate. Relies on containsmods.
CPAN::Index::force_reload()
Forces a reload of all indices.
CPAN::Index::reload()
Reloads all indices if they have not been read for more than
"$CPAN::Config-"{index_expire}> days.
CPAN::InfoObj::dump()
CPAN::Author, CPAN::Bundle, CPAN::Module, and CPAN::Distribution
inherit this method. It prints the data structure associated with
an object. Useful for debugging. Note: the data structure is con-
sidered internal and thus subject to change without notice.
CPAN::Module::as_glimpse()
Returns a one-line description of the module in four columns: The
first column contains the word "Module", the second column consists
of one character: an equals sign if this module is already
installed and uptodate, a less-than sign if this module is
installed but can be upgraded, and a space if the module is not
installed. The third column is the name of the module and the
fourth column gives maintainer or distribution information.
CPAN::Module::as_string()
Returns a multi-line description of the module
CPAN::Module::clean()
Runs a clean on the distribution associated with this module.
CPAN::Module::cpan_file()
Returns the filename on CPAN that is associated with the module.
CPAN::Module::cpan_version()
Returns the latest version of this module available on CPAN.
CPAN::Module::cvs_import()
Runs a cvs_import on the distribution associated with this module.
CPAN::Module::description()
Returns a 44 character description of this module. Only available
for modules listed in The Module List (CPAN/modules/00mod-
list.long.html or 00modlist.long.txt.gz)
CPAN::Module::distribution()
Returns the CPAN::Distribution object that contains the current
version of this module.
CPAN::Module::dslip_status()
Returns a hash reference. The keys of the hash are the letters "D",
"S", "L", "I", and <P>, for development status, support level, lan-
guage, interface and public licence respectively. The data for the
DSLIP status are collected by pause.perl.org when authors register
their namespaces. The values of the 5 hash elements are one-charac-
ter words whose meaning is described in the table below. There are
also 5 hash elements "DV", "SV", "LV", "IV", and <PV> that carry a
more verbose value of the 5 status variables.
Where the 'DSLIP' characters have the following meanings:
D - Development Stage (Note: *NO IMPLIED TIMESCALES*):
i - Idea, listed to gain consensus or as a placeholder
c - under construction but pre-alpha (not yet released)
a/b - Alpha/Beta testing
R - Released
M - Mature (no rigorous definition)
S - Standard, supplied with Perl 5
S - Support Level:
m - Mailing-list
d - Developer
u - Usenet newsgroup comp.lang.perl.modules
n - None known, try comp.lang.perl.modules
a - abandoned; volunteers welcome to take over maintainance
L - Language Used:
p - Perl-only, no compiler needed, should be platform independent
c - C and perl, a C compiler will be needed
h - Hybrid, written in perl with optional C code, no compiler needed
+ - C++ and perl, a C++ compiler will be needed
o - perl and another language other than C or C++
I - Interface Style
f - plain Functions, no references used
h - hybrid, object and function interfaces available
n - no interface at all (huh?)
r - some use of unblessed References or ties
O - Object oriented using blessed references and/or inheritance
P - Public License
p - Standard-Perl: user may choose between GPL and Artistic
g - GPL: GNU General Public License
l - LGPL: "GNU Lesser General Public License" (previously known as
"GNU Library General Public License")
b - BSD: The BSD License
a - Artistic license alone
o - open source: appoved by www.opensource.org
d - allows distribution without restrictions
r - restricted distribtion
n - no license at all
CPAN::Module::force($method,@args)
Forces CPAN to perform a task that it normally would have refused
to do. Force takes as arguments a method name to be called and any
number of additional arguments that should be passed to the called
method. The internals of the object get the needed changes so that
CPAN.pm does not refuse to take the action. See also the section
above on the "force" and the "fforce" pragma.
CPAN::Module::get()
Runs a get on the distribution associated with this module.
CPAN::Module::inst_file()
Returns the filename of the module found in @INC. The first file
found is reported just like perl itself stops searching @INC when
it finds a module.
CPAN::Module::available_file()
Returns the filename of the module found in PERL5LIB or @INC. The
first file found is reported. The advantage of this method over
"inst_file" is that modules that have been tested but not yet
installed are included because PERL5LIB keeps track of tested mod-
ules.
CPAN::Module::inst_version()
Returns the version number of the installed module in readable for-
mat.
CPAN::Module::available_version()
Returns the version number of the available module in readable for-
mat.
CPAN::Module::install()
Runs an "install" on the distribution associated with this module.
CPAN::Module::look()
Changes to the directory where the distribution associated with
this module has been unpacked and opens a subshell there. Exiting
the subshell returns.
CPAN::Module::make()
Runs a "make" on the distribution associated with this module.
CPAN::Module::manpage_headline()
If module is installed, peeks into the module's manpage, reads the
headline and returns it. Moreover, if the module has been down-
loaded within this session, does the equivalent on the downloaded
module even if it is not installed.
CPAN::Module::perldoc()
Runs a "perldoc" on this module.
CPAN::Module::readme()
Runs a "readme" on the distribution associated with this module.
CPAN::Module::reports()
Calls the reports() method on the associated distribution object.
CPAN::Module::test()
Runs a "test" on the distribution associated with this module.
CPAN::Module::uptodate()
Returns 1 if the module is installed and up-to-date.
CPAN::Module::userid()
Returns the author's ID of the module.
Cache Manager
Currently the cache manager only keeps track of the build directory
($CPAN::Config->{build_dir}). It is a simple FIFO mechanism that
deletes complete directories below "build_dir" as soon as the size of
all directories there gets bigger than $CPAN::Config->{build_cache} (in
MB). The contents of this cache may be used for later re-installations
that you intend to do manually, but will never be trusted by CPAN
itself. This is due to the fact that the user might use these directo-
ries for building modules on different architectures.
There is another directory ($CPAN::Config->{keep_source_where}) where
the original distribution files are kept. This directory is not covered
by the cache manager and must be controlled by the user. If you choose
to have the same directory as build_dir and as keep_source_where direc-
tory, then your sources will be deleted with the same fifo mechanism.
Bundles
A bundle is just a perl module in the namespace Bundle:: that does not
define any functions or methods. It usually only contains documenta-
tion.
It starts like a perl module with a package declaration and a $VERSION
variable. After that the pod section looks like any other pod with the
only difference being that one special pod section exists starting with
(verbatim):
=head1 CONTENTS
In this pod section each line obeys the format
Module_Name [Version_String] [- optional text]
The only required part is the first field, the name of a module (e.g.
Foo::Bar, ie. not the name of the distribution file). The rest of the
line is optional. The comment part is delimited by a dash just as in
the man page header.
The distribution of a bundle should follow the same convention as other
distributions.
Bundles are treated specially in the CPAN package. If you say 'install
Bundle::Tkkit' (assuming such a bundle exists), CPAN will install all
the modules in the CONTENTS section of the pod. You can install your
own Bundles locally by placing a conformant Bundle file somewhere into
your @INC path. The autobundle() command which is available in the
shell interface does that for you by including all currently installed
modules in a snapshot bundle file.
PREREQUISITES
If you have a local mirror of CPAN and can access all files with
"file:" URLs, then you only need a perl better than perl5.003 to run
this module. Otherwise Net::FTP is strongly recommended. LWP may be
required for non-UNIX systems or if your nearest CPAN site is associ-
ated with a URL that is not "ftp:".
If you have neither Net::FTP nor LWP, there is a fallback mechanism
implemented for an external ftp command or for an external lynx com-
mand.
UTILITIES
Finding packages and VERSION
This module presumes that all packages on CPAN
o declare their $VERSION variable in an easy to parse manner. This pre-
requisite can hardly be relaxed because it consumes far too much mem-
ory to load all packages into the running program just to determine
the $VERSION variable. Currently all programs that are dealing with
version use something like this
perl -MExtUtils::MakeMaker -le \
'print MM->parse_version(shift)' filename
If you are author of a package and wonder if your $VERSION can be
parsed, please try the above method.
o come as compressed or gzipped tarfiles or as zip files and contain a
"Makefile.PL" or "Build.PL" (well, we try to handle a bit more, but
without much enthusiasm).
Debugging
The debugging of this module is a bit complex, because we have inter-
ferences of the software producing the indices on CPAN, of the mirror-
ing process on CPAN, of packaging, of configuration, of synchronicity,
and of bugs within CPAN.pm.
For debugging the code of CPAN.pm itself in interactive mode some more
or less useful debugging aid can be turned on for most packages within
CPAN.pm with one of
o debug package...
sets debug mode for packages.
o debug -package...
unsets debug mode for packages.
o debug all
turns debugging on for all packages.
o debug number
which sets the debugging packages directly. Note that "o debug 0" turns
debugging off.
What seems quite a successful strategy is the combination of "reload
cpan" and the debugging switches. Add a new debug statement while run-
ning in the shell and then issue a "reload cpan" and see the new debug-
ging messages immediately without losing the current context.
"o debug" without an argument lists the valid package names and the
current set of packages in debugging mode. "o debug" has built-in com-
pletion support.
For debugging of CPAN data there is the "dump" command which takes the
same arguments as make/test/install and outputs each object's
Data::Dumper dump. If an argument looks like a perl variable and con-
tains one of "$", "@" or "%", it is eval()ed and fed to Data::Dumper
directly.
Floppy, Zip, Offline Mode
CPAN.pm works nicely without network too. If you maintain machines that
are not networked at all, you should consider working with file: URLs.
Of course, you have to collect your modules somewhere first. So you
might use CPAN.pm to put together all you need on a networked machine.
Then copy the $CPAN::Config->{keep_source_where} (but not $CPAN::Con-
fig->{build_dir}) directory on a floppy. This floppy is kind of a per-
sonal CPAN. CPAN.pm on the non-networked machines works nicely with
this floppy. See also below the paragraph about CD-ROM support.
Basic Utilities for Programmers
has_inst($module)
Returns true if the module is installed. Used to load all modules
into the running CPAN.pm which are considered optional. The config
variable "dontload_list" can be used to intercept the "has_inst()"
call such that an optional module is not loaded despite being avail-
able. For example the following command will prevent that "YAML.pm"
is being loaded:
cpan> o conf dontload_list push YAML
See the source for details.
has_usable($module)
Returns true if the module is installed and is in a usable state.
Only useful for a handful of modules that are used internally. See
the source for details.
instance($module)
The constructor for all the singletons used to represent modules,
distributions, authors and bundles. If the object already exists,
this method returns the object, otherwise it calls the constructor.
SECURITY
There's no strong security layer in CPAN.pm. CPAN.pm helps you to
install foreign, unmasked, unsigned code on your machine. We compare to
a checksum that comes from the net just as the distribution file
itself. But we try to make it easy to add security on demand:
Cryptographically signed modules
Since release 1.77 CPAN.pm has been able to verify cryptographically
signed module distributions using Module::Signature. The CPAN modules
can be signed by their authors, thus giving more security. The simple
unsigned MD5 checksums that were used before by CPAN protect mainly
against accidental file corruption.
You will need to have Module::Signature installed, which in turn
requires that you have at least one of Crypt::OpenPGP module or the
command-line gpg tool installed.
You will also need to be able to connect over the Internet to the pub-
lic keyservers, like pgp.mit.edu, and their port 11731 (the HKP proto-
col).
The configuration parameter check_sigs is there to turn signature
checking on or off.
EXPORT
Most functions in package CPAN are exported per default. The reason for
this is that the primary use is intended for the cpan shell or for
one-liners.
ENVIRONMENT
When the CPAN shell enters a subshell via the look command, it sets the
environment CPAN_SHELL_LEVEL to 1 or increments it if it is already
set.
When CPAN runs, it sets the environment variable PERL5_CPAN_IS_RUNNING.
When the config variable ftp_passive is set, all downloads will be run
with the environment variable FTP_PASSIVE set to this value. This is in
general a good idea as it influences both Net::FTP and LWP based con-
nections. The same effect can be achieved by starting the cpan shell
with this environment variable set. For Net::FTP alone, one can also
always set passive mode by running libnetcfg.
POPULATE AN INSTALLATION WITH LOTS OF MODULES
Populating a freshly installed perl with my favorite modules is pretty
easy if you maintain a private bundle definition file. To get a useful
blueprint of a bundle definition file, the command autobundle can be
used on the CPAN shell command line. This command writes a bundle defi-
nition file for all modules that are installed for the currently run-
ning perl interpreter. It's recommended to run this command only once
and from then on maintain the file manually under a private name, say
Bundle/my_bundle.pm. With a clever bundle file you can then simply say
cpan> install Bundle::my_bundle
then answer a few questions and then go out for a coffee.
Maintaining a bundle definition file means keeping track of two things:
dependencies and interactivity. CPAN.pm sometimes fails on calculating
dependencies because not all modules define all MakeMaker attributes
correctly, so a bundle definition file should specify prerequisites as
early as possible. On the other hand, it's a bit annoying that many
distributions need some interactive configuring. So what I try to
accomplish in my private bundle file is to have the packages that need
to be configured early in the file and the gentle ones later, so I can
go out after a few minutes and leave CPAN.pm untended.
WORKING WITH CPAN.pm BEHIND FIREWALLS
Thanks to Graham Barr for contributing the following paragraphs about
the interaction between perl, and various firewall configurations. For
further information on firewalls, it is recommended to consult the doc-
umentation that comes with the ncftp program. If you are unable to go
through the firewall with a simple Perl setup, it is very likely that
you can configure ncftp so that it works for your firewall.
Three basic types of firewalls
Firewalls can be categorized into three basic types.
http firewall
This is where the firewall machine runs a web server and to access
the outside world you must do it via the web server. If you set
environment variables like http_proxy or ftp_proxy to a values
beginning with http:// or in your web browser you have to set proxy
information then you know you are running an http firewall.
To access servers outside these types of firewalls with perl (even
for ftp) you will need to use LWP.
ftp firewall
This where the firewall machine runs an ftp server. This kind of
firewall will only let you access ftp servers outside the firewall.
This is usually done by connecting to the firewall with ftp, then
entering a username like "user@outside.host.com"
To access servers outside these type of firewalls with perl you
will need to use Net::FTP.
One way visibility
I say one way visibility as these firewalls try to make themselves
look invisible to the users inside the firewall. An FTP data
connection is normally created by sending the remote server your IP
address and then listening for the connection. But the remote
server will not be able to connect to you because of the firewall.
So for these types of firewall FTP connections need to be done in a
passive mode.
There are two that I can think off.
SOCKS
If you are using a SOCKS firewall you will need to compile perl
and link it with the SOCKS library, this is what is normally
called a 'socksified' perl. With this executable you will be
able to connect to servers outside the firewall as if it is not
there.
IP Masquerade
This is the firewall implemented in the Linux kernel, it allows
you to hide a complete network behind one IP address. With this
firewall no special compiling is needed as you can access hosts
directly.
For accessing ftp servers behind such firewalls you usually
need to set the environment variable "FTP_PASSIVE" or the con-
fig variable ftp_passive to a true value.
Configuring lynx or ncftp for going through a firewall
If you can go through your firewall with e.g. lynx, presumably with a
command such as
/usr/local/bin/lynx -pscott:tiger
then you would configure CPAN.pm with the command
o conf lynx "/usr/local/bin/lynx -pscott:tiger"
That's all. Similarly for ncftp or ftp, you would configure something
like
o conf ncftp "/usr/bin/ncftp -f /home/scott/ncftplogin.cfg"
Your mileage may vary...
FAQ
1) I installed a new version of module X but CPAN keeps saying, I have
the old version installed
Most probably you do have the old version installed. This can hap-
pen if a module installs itself into a different directory in the
@INC path than it was previously installed. This is not really a
CPAN.pm problem, you would have the same problem when installing
the module manually. The easiest way to prevent this behaviour is
to add the argument "UNINST=1" to the "make install" call, and that
is why many people add this argument permanently by configuring
o conf make_install_arg UNINST=1
2) So why is UNINST=1 not the default?
Because there are people who have their precise expectations about
who may install where in the @INC path and who uses which @INC
array. In fine tuned environments "UNINST=1" can cause damage.
3) I want to clean up my mess, and install a new perl along with all
modules I have. How do I go about it?
Run the autobundle command for your old perl and optionally rename
the resulting bundle file (e.g. Bundle/mybundle.pm), install the
new perl with the Configure option prefix, e.g.
./Configure -Dprefix=/usr/local/perl-5.6.78.9
Install the bundle file you produced in the first step with some-
thing like
cpan> install Bundle::mybundle
and you're done.
4) When I install bundles or multiple modules with one command there
is too much output to keep track of.
You may want to configure something like
o conf make_arg "| tee -ai /root/.cpan/logs/make.out"
o conf make_install_arg "| tee -ai /root/.cpan/logs/make_install.out"
so that STDOUT is captured in a file for later inspection.
5) I am not root, how can I install a module in a personal directory?
First of all, you will want to use your own configuration, not the
one that your root user installed. If you do not have permission to
write in the cpan directory that root has configured, you will be
asked if you want to create your own config. Answering "yes" will
bring you into CPAN's configuration stage, using the system config
for all defaults except things that have to do with CPAN's work
directory, saving your choices to your MyConfig.pm file.
You can also manually initiate this process with the following com-
mand:
% perl -MCPAN -e 'mkmyconfig'
or by running
mkmyconfig
from the CPAN shell.
You will most probably also want to configure something like this:
o conf makepl_arg "LIB=~/myperl/lib \
INSTALLMAN1DIR=~/myperl/man/man1 \
INSTALLMAN3DIR=~/myperl/man/man3 \
INSTALLSCRIPT=~/myperl/bin \
INSTALLBIN=~/myperl/bin"
and then (oh joy) the equivalent command for Module::Build.
You can make this setting permanent like all "o conf" settings with
"o conf commit" or by setting "auto_commit" beforehand.
You will have to add ~/myperl/man to the MANPATH environment vari-
able and also tell your perl programs to look into ~/myperl/lib,
e.g. by including
use lib "$ENV{HOME}/myperl/lib";
or setting the PERL5LIB environment variable.
While we're speaking about $ENV{HOME}, it might be worth mention-
ing, that for Windows we use the File::HomeDir module that provides
an equivalent to the concept of the home directory on Unix.
Another thing you should bear in mind is that the UNINST parameter
can be dnagerous when you are installing into a private area
because you might accidentally remove modules that other people
depend on that are not using the private area.
6) How to get a package, unwrap it, and make a change before building
it?
Have a look at the "look" (!) command.
7) I installed a Bundle and had a couple of fails. When I retried,
everything resolved nicely. Can this be fixed to work on first try?
The reason for this is that CPAN does not know the dependencies of
all modules when it starts out. To decide about the additional
items to install, it just uses data found in the META.yml file or
the generated Makefile. An undetected missing piece breaks the pro-
cess. But it may well be that your Bundle installs some prerequi-
site later than some depending item and thus your second try is
able to resolve everything. Please note, CPAN.pm does not know the
dependency tree in advance and cannot sort the queue of things to
install in a topologically correct order. It resolves perfectly
well IF all modules declare the prerequisites correctly with the
PREREQ_PM attribute to MakeMaker or the "requires" stanza of Mod-
ule::Build. For bundles which fail and you need to install often,
it is recommended to sort the Bundle definition file manually.
8) In our intranet we have many modules for internal use. How can I
integrate these modules with CPAN.pm but without uploading the mod-
ules to CPAN?
Have a look at the CPAN::Site module.
9) When I run CPAN's shell, I get an error message about things in my
/etc/inputrc (or ~/.inputrc) file.
These are readline issues and can only be fixed by studying read-
line configuration on your architecture and adjusting the refer-
enced file accordingly. Please make a backup of the /etc/inputrc or
~/.inputrc and edit them. Quite often harmless changes like upper-
casing or lowercasing some arguments solves the problem.
10) Some authors have strange characters in their names.
Internally CPAN.pm uses the UTF-8 charset. If your terminal is
expecting ISO-8859-1 charset, a converter can be activated by set-
ting term_is_latin to a true value in your config file. One way of
doing so would be
cpan> o conf term_is_latin 1
If other charset support is needed, please file a bugreport against
CPAN.pm at rt.cpan.org and describe your needs. Maybe we can extend
the support or maybe UTF-8 terminals become widely available.
11) When an install fails for some reason and then I correct the error
condition and retry, CPAN.pm refuses to install the module, saying
"Already tried without success".
Use the force pragma like so
force install Foo::Bar
Or you can use
look Foo::Bar
and then 'make install' directly in the subshell.
12) How do I install a "DEVELOPER RELEASE" of a module?
By default, CPAN will install the latest non-developer release of a
module. If you want to install a dev release, you have to specify
the partial path starting with the author id to the tarball you
wish to install, like so:
cpan> install KWILLIAMS/Module-Build-0.27_07.tar.gz
Note that you can use the "ls" command to get this path listed.
13) How do I install a module and all its dependencies from the comman-
dline, without being prompted for anything, despite my CPAN config-
uration (or lack thereof)?
CPAN uses ExtUtils::MakeMaker's prompt() function to ask its ques-
tions, so if you set the PERL_MM_USE_DEFAULT environment variable,
you shouldn't be asked any questions at all (assuming the modules
you are installing are nice about obeying that variable as well):
% PERL_MM_USE_DEFAULT=1 perl -MCPAN -e 'install My::Module'
14) How do I create a Module::Build based Build.PL derived from an
ExtUtils::MakeMaker focused Makefile.PL?
http://search.cpan.org/search?query=Module::Build::Convert
http://www.refcnt.org/papers/module-build-convert
15) What's the best CPAN site for me?
The urllist config parameter is yours. You can add and remove sites
at will. You should find out which sites have the best uptodate-
ness, bandwidth, reliability, etc. and are topologically close to
you. Some people prefer fast downloads, others uptodateness, others
reliability. You decide which to try in which order.
Henk P. Penning maintains a site that collects data about CPAN
sites:
http://www.cs.uu.nl/people/henkp/mirmon/cpan.html
COMPATIBILITY
OLD PERL VERSIONS
CPAN.pm is regularly tested to run under 5.004, 5.005, and assorted
newer versions. It is getting more and more difficult to get the mini-
mal prerequisites working on older perls. It is close to impossible to
get the whole Bundle::CPAN working there. If you're in the position to
have only these old versions, be advised that CPAN is designed to work
fine without the Bundle::CPAN installed.
To get things going, note that GBARR/Scalar-List-Utils-1.18.tar.gz is
compatible with ancient perls and that File::Temp is listed as a pre-
requisite but CPAN has reasonable workarounds if it is missing.
CPANPLUS
This module and its competitor, the CPANPLUS module, are both much
cooler than the other. CPAN.pm is older. CPANPLUS was designed to be
more modular but it was never tried to make it compatible with CPAN.pm.
SECURITY ADVICE
This software enables you to upgrade software on your computer and so
is inherently dangerous because the newly installed software may con-
tain bugs and may alter the way your computer works or even make it
unusable. Please consider backing up your data before every upgrade.
BUGS
Please report bugs via http://rt.cpan.org/
Before submitting a bug, please make sure that the traditional method
of building a Perl module package from a shell by following the instal-
lation instructions of that package still works in your environment.
AUTHOR
Andreas Koenig "<andk@cpan.org>"
LICENSE
This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
See <http://www.perl.com/perl/misc/Artistic.html>
TRANSLATIONS
Kawai,Takanori provides a Japanese translation of this manpage at
http://homepage3.nifty.com/hippo2000/perltips/CPAN.htm
SEE ALSO
cpan(1), CPAN::Nox(3pm), CPAN::Version(3pm)
perl v5.8.6 2007-05-08 CPAN(3)
